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Transcript
CH30_Mahan_0705-0737 9/26/03 9:54 AM Page 705
C H A P T E R
30
Medical NutritionTherapy for Lower
GastrointestinalTract Disorders
PETER L. BEYER, MS, RD, LD
CHAPTER OUTLINE
•
•
•
•
•
•
Common Intestinal Problems
Diseases of the Small Intestine
Intestinal Brush-Border Enzyme Deficiencies
Inflammatory Bowel Diseases
Disorders of the Large Intestine
Intestinal Surgery
KEY TERMS
aerophagia–swallowing of air
blind loop syndrome–a disorder of bacterial overgrowth with resultant malabsorption secondary to alterations in the anatomy of the small intestine involving a
loop that is disconnected from the main intestinal tract
borborygmus–intestinal rumbling
celiac disease–common term for gluten-sensitive enteropathy
colostomy–surgical creation of an opening into the
colon through a stoma in the abdominal wall to permit
defecation
constipation–a condition in which the frequency or
quantity of stools is reduced
Crohn’s disease–a chronic, granulomatous inflammatory disease of unknown etiology involving the small or
large intestine that results in diarrhea, strictures, fistulas,
malabsorption, and the need for surgical resection
dermatitis herpetiformis–a skin disorder that is a
variant of celiac disease
diarrhea–abnormal volume and liquidity of stools
diverticulitis–inflammation of diverticula
diverticulosis–presence of herniations of the mucous
membrane through the muscular layers of the colonic
wall
fistula–an abnormal passage between two internal
organs, or from an internal organ to the surface of the
body
flatulence–excessive collection and passage of gas
from the gastrointestinal tract
flatus–gas in the gastrointestinal tract that is expelled
through the anus
glutamine–an amino acid and the preferred fuel of
the enterocyte
gluten-sensitive enteropathy (celiac disease)–a syndrome precipitated by the immunologic interaction of
gluten-containing foods and intestinal cells; characterized by flattening of the villi of the small intestine
high-fiber diet–a diet containing more than 25 g of
dietary fiber
hypolactasia–a decrease in the amount of the intestinal enzyme lactase
ileostomy–surgical creation of an opening into the
ileum through a stoma in the abdominal wall
ileal pouch–surgical creation of a small reservoir, using folds of the distal ileum, which is then attached to the
rectum
inflammatory bowel disease (IBD)–a general term
for inflammatory diseases of the bowel of unknown
etiology, including Crohn’s disease and ulcerative
colitis
irritable bowel syndrome (IBS)–an abnormal stooling pattern associated with symptoms of intestinal dysfunction that persists for more than 3 months of the
year
705
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5 / MEDICAL NUTRITION THERAPY
KEY TERMS—Continued
lactose intolerance–an inability to digest lactose to
galactose and glucose because of a deficiency of the enzyme lactase
medium-chain triglycerides (MCTs)–triacylglycerols
with fatty acids of 8 and 10 carbons in length—short
enough to be absorbed directly into the portal blood
minimal-residue diet–a diet that results in decreased fecal volume
phytobezoars–stomach obstructions composed of partially digested plant foods
prebiotic–dietary substrates used to promote the growth
of beneficial intestinal bacteria
probiotic–orally consumed source of bacteria used to
reestablish the presence of beneficial intestinal flora
refractory sprue–celiac disease that persists even after
adherence to a strict gluten-free diet
residue–the fecal contents, including bacteria and any
remaining gastrointestinal secretions and foods not digested or absorbed
short-bowel syndrome (SBS)–a malabsorption syndrome resulting from major resections of the small bowel;
characterized by diarrhea, steatorrhea, and malnutrition
steatorrhea–excessive amounts of fat in the feces, as
seen in malabsorption syndromes
tropical sprue–a syndrome of unknown etiology that
causes diarrhea and malabsorption but is not responsive to
gluten-free diet therapy
ulcerative colitis–an inflammatory disease of the colonic
mucosa
D
When patients complain about “excessive gas,”
they may be referring to increased volume or frequency of passage of gas (flatulence). They may also
be complaining about abdominal distention or
cramping pain associated with the accumulation of
gases in the upper or lower GI tract. The association
between the amount of gas in the GI tract perceived
by an individual and the amount actually measured
is not always accurate (Levitt et al, 1996). Inactivity,
decreased GI motility, aerophagia, dietary components, and GI disorders can all contribute to the
amount of intestinal gas and an individual’s gasrelated symptoms.
Gas in the upper intestinal tract results primarily
from swallowing air (aerophagia) and, to a lesser extent, from chemical reactions that occur during the
digestion of foods. Normally, only small amounts of
swallowed air or gases dissolved in foods make their
way as far as the colon. High N2 and O2 concentrations in rectal gas, both of which are substances that
are present in the atmosphere in high concentrations,
may indicate aerophagia. Aerophagia can be avoided
to some degree by eating slowly, chewing with the
mouth closed, and refraining from drinking through
straws.
Increased gas production may occur in the stomach and small intestine because of bacterial fermentation, particularly with the consumption of carbohydrate, and can result in abdominal discomfort and
distention. Bacterial overgrowth may occur in the
stomach or small intestine with partial obstruction,
with dysmotility, in immune disorders, or after some
GI surgical procedures.
Increased amounts of H2 and CO2—and sometimes, CH4—in rectal gas with lowered fecal pH indicate excessive colonic bacterial fermentation and suggest malabsorption of a fermentable substrate. The
ietary modifications in disorders of the intestinal tract are designed to alleviate symptoms, correct nutrient deficiencies, and,
when possible, address the primary cause of difficulty. In disease, assessment of the nature and severity of the primary gastrointestinal problem precedes
targeted medical, nutrition, and other forms of therapy. Increased intakes of energy, protein, vitamins,
minerals, and electrolytes are frequently required to
replace nutrients lost as a result of impaired digestive
and absorptive capacity. Consistency, meal frequency,
and other characteristics of the diet may be altered to
fit the patient’s needs. Medical nutrition therapy
(MNT) for all patients with diseases of the intestines
must be individualized. For this reason, the principles
presented in the chapter are general guidelines.
COMMON INTESTINAL PROBLEMS
Intestinal Gas and Flatulence
Pathophysiology
Intestinal gases include nitrogen (N2), oxygen (O2),
carbon dioxide (CO2), hydrogen (H2), and, in some
persons, methane (CH4). About 200 ml of gas is normally present in the gastrointestinal (GI) tract, and
humans excrete an average of 700 ml each day. However, the difference in the amount of intestinal gas
among individuals and from day to day varies
greatly (Strocchi and Levitt, 1998). Considerable
amounts of gas may be swallowed or produced
within the GI tract and may be absorbed across the
alimentary tract into the bloodstream and expired
through the lungs, expelled through eructation
(belching), or passed rectally.
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
amounts and types of gases produced may depend
on the mix of microorganisms in the individual’s
colon. Consumption of large amounts of dietary fiber
(especially soluble fiber), resistant starches, lactose in
persons who are lactase deficient, or modest amounts
of fructose or alcohol sugars (such as sorbitol) may
result in increased gas production in the colon and
increased flatulence.
Consumption of fructose in the United States, especially from fruit juices and fruit drinks and highfructose corn syrup in soft drinks and confections,
has increased significantly in recent years. The average level of fructose in the daily diet is in the range of
35 to 40 g, which is sufficient in many children and
adults to result in malabsorption of fructose and
evoke symptoms. Sucrose is normally well tolerated
but in large quantities may also result in increased
amounts of fecal substrate.
Medical Nutrition Therapy
In the assessment of the patient, one must ask
whether the problem is increased production of gas
or whether the patient has difficulty with cramping
and distention because the gas is not being passed.
Inactivity, dysmotility, or partial obstruction may be
contributing to the inability to move normal amounts
of gas produced. Movement or exercise may help expel gases through eructation or rectal passage.
The primary emphasis in dietary management is
the reduction of carbohydrate foods that are likely to
be malabsorbed and fermented, including legumes,
soluble fiber, resistant starches, and simple sugars
such as fructose and alcohol sugars. When undigested
carbohydrates pass into the colon, they are fermented
to varying degrees to short-chain fatty acids and gases.
The primary gases include H2, CO2, and, in about one
third of individuals, CH4. The widely recognized
propensity of legumes to produce flatus (gas) is related to the presence of not only ample amounts of
fiber but also stachyose and raffinose—carbohydrates
that are only partially digested in the small intestine.
Excess production of gas may also be related to the
dose of carbohydrate consumed. Starches such as
breads, baked goods, and starchy vegetables may be
almost completely digested in normal portions but
when consumed in large quantities may leave a considerable fraction of undigested or unabsorbed
residue for bacterial action in the colon. The properties of some so-called gas-forming foods may be explained simply by the type and amount of sugar,
starch, or fiber they contain.
Constipation
707
itions of constipation tend to be highly subjective but
usually include hard stools, straining with defecation, and infrequent bowel movements. At least in
older patients, hard stools, incomplete evacuation,
and difficulty passing stools may be more troublesome than the infrequency of bowel movements.
Normal stool weight is about 100 to 200 g daily,
and normal frequency may range from one stool
every 3 days to three times per day. Normal transit
time through the GI tract ranges from about 18 to
about 48 hours. Persons who consume a diet that
contains the recommended amounts of dietary fiber
in the form of fruits, vegetables, and whole-grain
breads and cereals tend to have larger, softer stools
that are relatively easy to pass. Some people who believe that it is necessary to have frequent bowel
movements and who ignore dietary and other health
recommendations may become disturbed when this
does not occur and try to compensate with the use of
medications and enemas.
The most common causes of constipation in otherwise healthy persons include repeated lack of response to the urge to defecate, lack of fiber in the diet,
insufficient fluid intake, inactivity, and chronic use of
laxatives. Nervous strain or anxiety may aggravate
the condition. Chronic constipation may also result
from a variety of causes, as outlined in Box 30-1.
Box 30-1. Causes of Constipation
Systemic/Neurogenic/Metabolic
Side effect of medication
Metabolic and endocrine abnormalities, such as
hypothyroidism, uremia, and hypercalcemia
Lack of exercise
Ignoring the urge to defecate
Vascular disease of the large bowel
Systemic neuromuscular disease leading to deficiency of voluntary muscles
Poor diet, low in fiber
Pregnancy
Gastrointestinal
Cancer
Diseases of the upper gastrointestinal tract
Diseases of the large bowel resulting in:
Failure of propulsion along the colon (colonic
inertia)
Failure of passage through anorectal structures (outlet obstruction)
Irritable bowel syndrome
Anal fissure or hemorrhoid
Laxative abuse
Pathophysiology
Constipation is one of the most common intestinal
maladies in Western societies, and it occurs in 5% to
more than 25% of the population, depending on the
definition of the disorder (Candelli et al, 2001). Defin-
Data from Siddiqui MA, Castell DO: Gastrointestinal disorders in the
elderly, Comp Ther 23:349, 1997; DeLillo AR and Rose S: Functional
bowel disorders in the geriatric patient: constipation, fecal impaction
and fecal incontinence, Am J Coll Gastroenterol 95:901, 2000.
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5 / MEDICAL NUTRITION THERAPY
Medical Treatment for Adults
High-Fiber Diet
The first approach to treatment of constipation is to
ensure adequate dietary fiber, fluid, and exercise and
heed the urge to defecate. Patients dependent on laxatives are usually encouraged to use milder products
and reduce the dose until withdrawal is complete.
When constipation is not amenable to conservative
treatment, that is, the patient is unable to consume an
adequate amount of fibrous foods or exercise, substances that promote regular evacuation of soft stools
may be prescribed. Bulking agents, such as cellulose,
hemicellulose derivatives, psyllium seed, flaxseed,
and ispaghula, and osmotic agents, such as lactose,
magnesium hydroxide, and sorbitol, can be used.
Stool softeners such as Colace may also be used.
Impactions of stool may require additional evaluation,
more stringent oral medications, rapid consumption
of large volumes of fluids, enemas, or digital evacuation (Candelli et al, 2001). In more extreme cases, such
as toxic megacolon, surgery may be advised.
Dietary fiber refers primarily to edible plant materials not digested by the enzymes in the upper digestive tract of humans. It generally consists of cellulose,
hemicelluloses, pectins, gums, and lignin. Newer
definitions may include starchy materials and
oligosaccharides that are at least partially resistant to
digestive enzymes. Some forms of fiber and resistant
starches may also be termed prebiotics. The term
roughage tends to refer to vegetable matter, but it is
not a quantitative term. Residue is not the same as
fiber, and this term refers to the end result of digestive, secretory, absorptive, and fermentative processes. Thus, increasing dietary fiber may result in increased fecal output, but increasing dietary lactose (a
fiber-free food) in a person who is a lactose malabsorber would also increase fecal weight (residue).
The high-fiber diet in Box 30-2 provides more than
25 g of dietary fiber, depending on the foods selected.
A high-fiber therapeutic diet may exceed 25 to 38 g,
but amounts greater than 50 g per day are not likely
to be necessary and may increase abdominal distention and excessive flatulence in some persons. Appendix 42 provides a list of the fiber content of
foods.
Ideally, fiber in the diet should be ingested in the
form of foods such as fruits, vegetables, whole-grain
breads and cereals, legumes, nuts, and seeds. These
foods are not only rich in fiber but are excellent
sources of vitamins, minerals, trace elements, antioxidants, and numerous protective phytochemicals. Fibrous powders or bran concentrates may be necessary to obtain the desired fiber level in some persons.
Several of these concentrates available on the market
are palatable and can be added to cereals, yogurts,
fruit sauces, juices, or soups. The use of foods as the
Medical Treatment for Infants and Children
About 3% to 5% of all pediatric outpatient visits are
related to chronic constipation. In the most severe
cases, there is a flaccid colon that is insensitive to distention and encopresis develops. After initial treatment with laxatives and lubricants, fiber intake is the
next focus of care. A careful history and physical examination, followed by parent and child education,
behavioral intervention, and appropriate use of laxatives, often leads to dramatic improvement (LoeningBaucke, 2002) (see Chapter 10).
Medical Nutrition Therapy
Primary nutrition therapy for constipation is adequate consumption of both soluble and insoluble dietary fiber. Fiber increases colonic fecal fluid, microbial mass, stool weight and frequency and the rate of
colonic transit. Fiber also softens stools and makes
them easier to pass. Most adults and children in the
United States chronically consume only about half
the amount of fiber recommended (Institute of Medicine, 2002). These recommendations need to be written out the first time.
The recommended amount of dietary fiber is about
14 g per 1000 kcal. For adult women the diet should
contain 25 g of fiber daily, and for men about 38 g (Institute of Medicine, 2002). Fiber is best provided in the
form of whole grains, fruits, vegetables, legumes,
seeds, and nuts (Marlett et al, 2002). These foods are
high in nutrients and healthful phytochemicals and
may serve as prebiotics to maintain the desired
colonic microflora. Brans and powdered fiber supplements may be helpful in persons who cannot or will
not eat sufficient amounts of fibrous foods. When
changes in diet and activity patterns do not improve
constipation, further evaluation is warranted.
Box 30-2. Guidelines for HighFiber Diets*
1. Increase consumption of whole-grain breads,
cereals, flours, and other whole-grain products (6-11 servings daily).
2. Increase consumption of vegetables, legumes,
and fruits, nuts, and edible seeds (5-8 servings daily).
3. Consume high-fiber cereals, granolas, and
legumes as needed to bring fiber intake to
25 g or more daily.
4. Increase consumption of fluids to at least 2 L
(or about 2 qt) daily.
*May increase stool weight, fecal water, and/or gas. The amount that
causes clinical symptoms varies among individuals. The age of the individual, the presence of gastrointestinal (GI) disease or malnutrition,
any resection of the GI tract, and recent use of the GI tract all impact
tolerance.
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fiber source results in benefits from both the fiber
content and the nutrients and protective phytochemicals included in the foods.
Cooking does not destroy fiber, although the structure may change. Consumption of eight 8-oz glasses
(2 L) of fluids daily is recommended to facilitate the
effectiveness of a high-fiber intake. Gastric obstruction and fecal impaction may occur when boluses of
fibrous gels or bran are not consumed with sufficient
fluid to disperse the fiber. Appropriate cautions are
also warranted for persons with GI strictures or dysmotility syndromes. In these situations, the fiber content of the diet should be increased slowly, taking almost a month to reach intakes of 25 to 38 g of fiber
per day (Institute of Medicine, 2002).
On initiation of a high-fiber diet, unpleasant side
effects may occur, such as increased flatulence, borborygmus, cramps, or diarrhea. A gradual increase in
fiber intake helps alleviate these symptoms. If fiber
supplements are used, doses should be interspersed
with meals, preferably in two or more small doses
per day, and fluid intake may need to be increased at
the same time. GI disturbances associated with initial
fiber ingestion usually decrease within 4 to 5 days,
but some increase in flatulence is normal with a highfiber intake. The high-fiber diet is most effective
when consumed continuously for several months.
Diarrhea
Pathophysiology
Diarrhea is characterized by the frequent evacuation
of liquid stools, usually exceeding 300 ml, accompanied by an excessive loss of fluid and electrolytes, especially sodium and potassium. It occurs when there
is excessively rapid transit of intestinal contents
through the small intestine, decreased enzymatic digestion of foodstuffs, decreased absorption of fluids
and nutrients, or increased secretion of fluids into the
GI tract (Branski et al, 1996; Fine, 1998). Causes may
be related to inflammatory disease; infections with
fungal, bacterial, or viral agents; medications; the
overconsumption of sugars; an insufficient or damaged mucosal absorptive surface; or malnutrition.
Osmotic diarrheas occur when osmotically active
solutes are present in the intestinal tract and are
poorly absorbed. Examples include the diarrhea that
accompanies dumping syndrome and following lactose ingestion in the person with a lactase deficiency.
Secretory diarrheas are the result of active secretion of electrolytes and water by the intestinal epithelium. Bacterial exotoxins, viruses, and increased intestinal hormone secretion cause acute secretory
diarrheas. Unlike osmotic diarrhea, fasting does not
relieve secretory diarrhea.
Exudative diarrheas are always associated with
mucosal damage, which leads to an outpouring of
mucus, fluid, blood, and plasma proteins, with a net
accumulation of electrolytes and water in the gut.
Prostaglandin and cytokine release may be involved.
709
The diarrheas associated with Crohn’s disease, ulcerative colitis, and radiation enteritis are exudative.
Medications, especially antibiotics, can contribute to
diarrhea in several ways. Antibiotics can reduce the
usual “salvage” by colonic bacteria of the small
amounts of foodstuffs that escape digestion and absorption. Broad-spectrum antibiotics can greatly reduce
the numbers of colonic bacteria that normally convert
osmotically active molecules (carbohydrate and amino
acids) to gases and short-chain fatty acids (SCFAs). The
SCFAs are normally absorbed from the lumen of the
colon as long as the amount produced is close to normal. Absorption of the SCFAs also aids absorption of
electrolytes and water from the colon (Cunha, 1998).
Eradication of the bacteria from the colon results in accumulation of osmotically active molecules and reduced absorption of electrolytes and water.
If more substrates than usual are malabsorbed, as
often occurs in acutely ill patients, the resulting rise
in osmolality can cause considerable fluid loss. Antibiotics can also have direct effects on GI function
(Bartlett, 2002; Kyne et al, 2001) (see Chapter 19).
Erythromycin, for example, increases GI motility.
Erythromycin, clarithromycin, and clindamycin may
all increase GI secretions. Finally, some antibiotics allow opportunistic proliferation of pathogenic organisms normally suppressed by competitive organisms
in the GI tract. The organisms or the toxins produced
decrease absorption and increase secretion of fluid
and electrolytes. Clostridium difficile is most commonly associated with antibiotic-related diarrhea
and accounts for 10% to 25% of cases, but Clostridium
perfringens, Salmonella, Shigella, Campylobacter, Yersinia
enterocolitica, and Escherichia coli organisms have also
been implicated in antibiotic-associated diarrhea
(Bartlett, 2002; Job and Jacobs, 1997; Kyne et al, 2001).
Clindamycin, penicillins, and cephalosporins are associated most often with the development of C. difficile infection, and its occurrence depends on the number of antibiotics used, the duration of exposure to
antibiotics, and the patient’s overall health.
With human immunodeficiency virus (HIV) and
other immune deficiency states, several factors may
contribute to the diarrhea, including the toxic effects
of medications, proliferation of opportunistic organisms, and the GI manifestations of the disease itself
(Fine, 1998; Mitra et al, 2001). Increased risk of opportunistic infection is also associated with use of antineoplastic agents (Fine, 1998; Kornblau et al, 2000)
and with severe malnutrition. Antacids (especially
magnesium salts), histamine H2-receptor blockers,
and proton pump inhibitors have also been implicated in cases of diarrhea.
Diarrhea caused by limited functional mucosa results from conditions of inadequate absorptive area
or rapid transit of chyme, such as might occur in
Crohn’s disease or after extensive bowel resection.
This type of diarrhea is often complicated by malabsorption of lipid (steatorrhea) and other macronutrients and micronutrients.
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5 / MEDICAL NUTRITION THERAPY
TABLE 30-1 Foods to Limit in a Lowor Minimal-Residue Diet
FOOD
COMMENTS
Lactose (in lactose
malabsorbers)
Fiber (excess; 20 g)
6-12 g normally tolerated in healthy,
lactase-deficient individuals
Modest amounts (10-15 g) may help
maintain normal consistency of
GI contents and normal colonic
mucosa in healthy states and in
GI disease
Resistant starch (especially raffinose and
stachyose found in
legumes)
Sorbitol, mannitol,
and xylitol (excess;
10 g/day)
Fructose (excess;
20-25 g/meal)
Sucrose (excess;
25-50 g/meal)
Caffeine
Alcoholic beverages
(especially wine
and beer)
Well tolerated in moderate amounts;
large amounts may cause hyperosmolar diarrhea or decreased
fecal pH with fermentation to
short-chain fatty acids
Increases GI secretions, colonic
motility
Increase GI secretions
Data from Rummessen JJ, Gudmand-Hoyer E: Functional bowel disease:
malabsorption and abdominal distress after ingestion of fructose, sorbitol,
and fructose-sorbitol mixtures, Gastroenterology 95:694, 1998; GudmandHoyer E: The clinical significance of disaccharide maldigestion, Am J Clin
Nutr 59:(suppl):735, 1994; Piche T et al: Colonic fermentation influences
lower esophageal sphincter function in gastroesophageal reflux disease,
Gastroenterology 124:894, 2003; and Rao SS et al: Is coffee a colonic stimulant?
Eur J Gastroenterol Hepatol 10:113, 1998.
Medical Treatment
Because diarrhea is a symptom of a disease state, the
first step in medical treatment is to identify and
treat the underlying problem. The next priority is to
manage fluid and electrolyte replacement. Losses of
electrolytes, especially potassium and sodium,
should be corrected early by using oral glucose electrolyte solutions with added potassium. With intractable diarrhea, especially in an infant or young
child, parenteral feeding may be required. Parenteral nutrition may even be necessary if exploratory surgery is anticipated or if the patient is
not expected to resume full oral intake within 5 to 7
days (see Chapter 23).
Medical Nutrition Therapy for Adults
Nutrition therapy for adults with diarrhea includes
replacing lost fluids and electrolytes by adding
broths and electrolyte solutions. In most cases of diarrhea, a minimum-residue diet (Table 30-1) may be
started as the acute episode resolves. Modest
amounts of fat may be used if digestive mechanisms
for lipid are intact. Sugar alcohols, lactose, fructose,
and large amounts of sucrose may worsen osmotic
diarrheas and might need to be limited. Because the
activity of the disaccharidases and transport mechanisms may be decreased during inflammatory and
infectious intestinal disease, sugars may need to be
limited (Rumessen and Gudmand-Hoyer, 1998).
Use of modest amounts of foods or dietary supplements containing prebiotic components, such as
pectin, fructose, oligosaccharides, inulin, oats, banana flakes, and chicory, may help to control or treat
diarrhea. They favor the maintenance of so-called
friendly lactobacillus and bifidus microbes and may
prevent the overgrowth of potentially pathogenic organisms (Gibson, 1999; Van Loo et al, 1999). SCFAs in
physiologic quantities serve as substrate for colonocytes, facilitate the absorption of fluid and salts, and
may help to regulate GI motility. Fibrous material
and several types of prebiotic foods also tend to slow
gastric emptying, moderate overall GI transit, and
hold water.
Ingestion of some types of probiotics (sources of
bacteria used to reestablish beneficial gut flora) in the
form of cultured foods or supplements, with or without prebiotics, has been modestly successful in antibiotic-related diarrhea, traveler’s diarrhea, bacterial
overgrowth, and some pediatric diarrhea. Additional
study is needed, but some products appear to have
promise in specific applications (Madsen, 2001; Szajewska and Mrukowicz, 2001).
Severe and chronic diarrhea is accompanied by dehydration and electrolyte depletion. If also accompanied by prolonged infectious, immunodeficiency, or
inflammatory disease, malabsorption of vitamins,
minerals, and protein or lipid may also occur, and the
nutrients may need to be replaced parenterally or enterally. The loss of potassium alters bowel motility,
encourages anorexia, and can introduce a cycle of
bowel distress. Loss of iron from GI bleeding may be
severe enough to cause anemia. Nutrition deficiencies themselves cause mucosal changes, such as decreased villi height and reduced enzyme secretion,
further contributing to malabsorption. As the diarrhea begins to resolve, the addition of more normal
amounts of fiber to the diet may help to restore normal mucosal function, increase electrolyte and water
absorption, and increase the firmness of the stool.
Food in the lumen is needed to restore the compromised GI tract after disease and periods of fasting.
Early refeeding after rehydration reduces stool output and shortens the duration of illness. Micronutrient replacement or supplementation may also be useful for acute diarrhea, probably because it accelerates
the normal regeneration of damaged mucosal epithelial cells.
Medical Nutrition Therapy for Infants
and Children
Acute diarrhea is most dangerous in infants and
small children, who are easily dehydrated by large
fluid losses. In these cases, replacement of fluid and
electrolytes must be aggressive and immediate. Standard oral rehydration solutions recommended by
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
TABLE 30-2 Oral Rehydration Solution:
Composition and Recipe
ELEMENT
Glucose (g/100 ml)
Sodium (mEq/L)
Potassium (mEq/L)
Chloride (mEq/L)
Bicarbonate (mEq/L)
Osmolarity (mOsm/L)
COMPOSITION
20
90
20
80
30
330
Recipe*
To 1 L of water add the following:
3.5 g sodium chloride
2.5 g sodium bicarbonate
1.5 g potassium chloride
20.0 g glucose
Data from World Health Organization, 1986.
*The solution should be made fresh every 24 hr.
the World Health Organization (WHO) since 1986
and the American Academy of Pediatrics (AAP) contain a 2% concentration of glucose (20 g/L), 45 to 90
mEq/L of sodium, 20 mEq/L of potassium, and a citrate base (Table 30-2). Newer, reduced osmolarity solutions (osm 130 to 200 mOsm/L) have been
shown to be equally or more effective in treating persistent diarrhea in children (Hahn, Kim, and Garner,
2002).
Newer solutions such as Pedialyte, Infalyte,
Lytren, Equalyte, and Rehydralyte typically contain
less glucose and slightly less salt and are available in
pharmacies, some without prescription. Oral rehydration therapy is less invasive and less expensive
than intravenous rehydration and, when used with
children, allows parents to assist with their children’s recovery (Goepp and Katz, 1993).
A substantial proportion of children 9 to 20
months of age can maintain adequate intake when
offered either a liquid or a semisolid diet continuously during bouts of acute diarrhea. Even during
acute diarrhea, the intestine can absorb up to 60% of
the food eaten. Some practitioners have been slow to
adopt the practice of early refeeding after severe diarrhea in infants, despite evidence that “resting the
gut” is actually more damaging (Booth, 1993). A recent report from the working group report of the
First World Congress of Pediatric Gastroenterology,
Hepatology, and Nutrition suggests that strategies
must be cohesive and uniform to address the problems of pediatric diarrhea to reduce deaths worldwide (Davidson et al, 2002). Prescription of a highsugar, clear liquid diet is inappropriate for recovery
from diarrhea.
Steatorrhea
Pathophysiology
Steatorrhea, or excessive fat in the stool, is a consequence of disease, surgical resection of organs involved in digestion, and absorption of lipid. Nor-
711
mally, 90% to 98% of ingested fat is absorbed; but in
steatorrhea, the percent remaining in the stool may
increase to 20% or more. Diagnosis is usually based
on a ratio of fecal fat to ingested fat or a coefficient of
absorption. A diet containing 75 to 100 g of fat is usually fed for 72 hours, the amount of fat actually consumed is recorded, and the fecal fat content is analyzed. The upper limit of normal fecal fat is usually in
the range of 7%. Steatorrhea may result from (1) inadequate bile secretion secondary to liver disease or biliary obstruction; (2) blind loop syndrome; (3) pancreatic insufficiency; (4) inadequate reabsorption of bile
salts due to diseases involving the distal ileum (as in
sprue, Crohn’s disease, or GI irritation); or (5) decreased fat reesterification and decreased formation
and transport of chylomicrons, as may be seen in
abetalipoproteinemia and intestinal lymphangiectasia. Box 30-3 lists disorders associated with malabsorption.
Medical Treatment
Because steatorrhea is a symptom and not a disease,
the underlying cause of malabsorption must be determined and treated. With pancreatic insufficiency,
oral pancreatic enzymes can be used to increase lipid
digestion.
Medical Nutrition Therapy
Steatorrhea can result in chronic weight loss and may
require compensatory increased energy intake, primarily in the form of dietary protein and complex
carbohydrate. Medium-chain triglycerides (MCTs)
can be used in the diet because they have a short
chain length, allowing easier absorption in the absence of bile acids. Medium-and short-chain fatty
acids are able to enter the portal venous blood for direct transport to the liver without being resynthesized into triglycerides in the intestinal cell.
The MCTs are available in some enteral formulas
and also as MCT oil (8.3 kcal/g; 1 T 116 kcal). The
oil is best used when it is incorporated into foods
rather than administered by the spoonful. MCT can
be used to make salad dressings, sandwich spreads,
or confections, and it can be substituted for fats in
most recipes. Normally, divided doses of less than 15 g
of oil per feeding are better tolerated and absorbed
than larger quantities. When steatorrhea is present,
there is increased risk of vitamin deficiencies, especially fat-soluble vitamins and deficiencies of the minerals calcium, zinc, and magnesium.
Gastrointestinal Strictures
and Obstruction
Pathophysiology
Inflammatory bowel disease (IBD), peptic ulcer disease, GI surgeries, tumors, or radiation enteritis may
partially or completely obstruct the GI tract as can
scarring or dysfunctional segments. Obstructions in
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5 / MEDICAL NUTRITION THERAPY
the stomach that result from the ingestion of plant
foods are called phytobezoars and are more common
in patients who are edentulous, have poor dentition,
or use dentures. Foods commonly incriminated in the
formation of phytobezoars include potato skins, or-
anges, and grapefruit, but many foods that are consumed in large segments or that have skins that are
difficult to chew may be problematic. When obstructions occur in the intestine, the patient usually experiences prolonged bloating, abdominal distention
and pain, and sometimes nausea and vomiting.
Medical Nutrition Therapy
Box 30-3. Diseases and
Conditions Associated
With Malabsorption
Inadequate digestion
Pancreatic insufficiency
Gastric acid hypersecretion
Gastric resection
Altered bile salt metabolism with impaired micelle formation
Hepatobiliary disease
Interrupted enterohepatic circulation of bile
salts
Bacterial overgrowth
Drugs that precipitate bile salts
Abnormalities of mucosal cell transport
Biochemical or genetic abnormalities
Disaccharidase deficiency
Monosaccharide malabsorption
Specific disorders of amino acid malabsorption
Abetalipoproteinemia
Vitamin B12 malabsorption
Celiac disease
Inflammatory of infiltrative disorders
Crohn’s disease
Ulcerative colitis
Amyloidosis
Scleroderma
Tropical sprue
Gastrointestinal allergy
Infectious enteritis
Whipple’s disease
Intestinal lymphoma
Radiation enteritis
Drug-induced enteritis
Endocrine and metabolic disorders
Short-bowel syndrome
Abnormalities of intestinal lymphatics and vascular system
Intestinal lymphangiectasia
Mesenteric vascular insufficiency
Chronic congestive heart failure
Data from Beyer PL: Short bowel syndrome. In Coulston AM, Rock CL,
Monson ER, editors: Nutrition in the prevention and treatment of disease,
ed 1, San Diego, 2001, Academic Press; Sundarum A et al: Nutritional
management of short bowel syndrome in adults, J Clin Gastroenterol
34:207, 2002; Podolsky DK: Inflammatory bowel disease, N Engl J Med
347:417, 2002; Mitra AD et al: Management of diarrhea in HIV-infected
patients, Int J STD AIDS 12:630, 2001; Branski D et al: Chronic diarrhea
and malabsorption, Pediatr Clin North Am 43:307, 1996; and Fine KD:
Diarrhea. In Feldman M, Sleisenger MH, Scharschmidt BF, editors: Gastrointestinal and liver disease, ed 6, Philadelphia, 1998, WB Saunders.
Because fiber is not digested to any significant degree (except by fermentation in the colon), and because chewing is not a reliable way of reducing the
size of fibrous foods, both the amount and size of fibrous material usually must be controlled. A restricted-fiber diet typically restricts fruits, vegetables, and coarse grains and usually provides less
than 10 to 15 g of dietary fiber, usually in the form of
particulate matter. Particularly with distal obstructions or strictures, it may be beneficial to keep the
stool soft by including modest amounts of fiber but
of small particle size.
Some intestinal obstruction cases may require
clear liquids or total restriction of food and parenteral nutrition and fluid used as needed. Working
with the physician is necessary to determine the nature, site, and duration of the obstruction so that nutrition therapy can be individualized.
DISEASES OF THE SMALL INTESTINE
Celiac Disease (Gluten-Sensitive
Enteropathy)
Pathophysiology
Celiac disease, or gluten-sensitive enteropathy, results from an inappropriate T-cell–mediated immune
response caused by ingested gluten by people who
are genetically predisposed. The prevalence of the
disease may have been underestimated in the past
and now is considered to be about 1 in 133 persons in
the United States. Prevalence is higher in relatives of
persons with celia disease (Fasano et al, 2003). Onset
is usually from infancy to young adulthood, but
about 20% of cases occur in adults over 60 years of
age (Farrell and Kelley, 2002).
Gluten refers to specific peptide fractions of proteins found in wheat, rye, and barley. These peptide
molecules are modified during absorption to a form
that triggers a local and in many cases systemic immune response. In untreated cases, the overzealous
immune and inflammatory response eventually results in damage to the intestinal mucosa, altered
neuropeptide secretion, and decreased digestive and
absorptive functions. Cells of the villi become deficient in the disaccharidases and peptidases needed
for digestion and also in the carriers needed to transport nutrients into the bloodstream. The extent of
villous changes varies greatly, but sufficient atrophy
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
and flattening of the villi eventually occur to compromise micronutrient and macronutrient absorption (Figure 30-1).
Decreased release of peptide hormones from the
small intestine results in reduced secretions from the
gallbladder and pancreas, further contributing to
maldigestion. The disease primarily affects the proximal and midportions of the small bowel, although
the more distal segments may also be involved. Because the symptoms are nonspecific and vary greatly,
celiac disease may be misdiagnosed for years as irritable bowel or other GI disorders.
The disease may also be associated with other inflammatory states such as dermatitis herpetiformis
(a variant of celiac disease that involves the skin),
muscle and joint pain, and other autoimmune diseases such as thyroiditis and type 1 diabetes. Celiac
disease is normally considered chronic and requires
life-long omission of gluten from the diet. Morbidity
and mortality rates may be increased in persons
who are undiagnosed until late or in persons who
are unable to comply with the diet (Seraphin and
Mobarin, 2002). Increased risk of lymphomas and
other malignancies influences overall morbidity,
and the risk of malignancies appears to be increased
in those who continue to eat gluten-containing
A
713
foods (Troncone et al, 1996). Box 30-4 lists the extraintestinal manifestations.
The diagnosis of celiac disease is made by a combination of clinical, laboratory, and histologic evaluations, but small bowel biopsy is the final diagnostic
end point. The disease may become apparent when
an infant begins eating gluten-containing cereals, or
it may not appear until middle age, when it may be
triggered or unmasked by GI surgery, stress, pregnancy, or viral infection. The presentation in young
children is more likely to include the more “classic”
symptoms of diarrhea and steatorrhea, malodorous
stools, abdominal bloating, apathy, and poor weight
gain. In late onset, the first manifestation is more varied and may include other inflammatory and autoimmune disorders, generalized fatigue, failure to gain
or maintain weight, or the consequences of nutrient
malabsorption, including anemias, osteoporosis, or
vitamin K–related coagulopathy. Fifty percent of
celiac patients, however, have few or no obvious
symptoms, and some may be overweight at presentation (Fasano and Catassi, 2001; Hill et al, 2002).
Persons in whom celiac disease is suspected are further evaluated for the overall pattern of symptoms and
family history and then are typically screened using
serologic tests, which include the presence of antien-
B
FIGURE 30-1 • A, Low-power photomicrograph (100) of a normal human duodenal mucosa. Note the long, thin villi. B, Low-power
photomicrograph (100) of a peroral small-bowel biopsy specimen from a patient with gluten enteropathy. Note the complete loss of villi
and the heavy infiltrate of white blood cells in the lamina propria. (From Floch MH: Nutrition and diet therapy in gastrointestinal disease, New
York, 1981, Plenum Medical.)
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5 / MEDICAL NUTRITION THERAPY
Box 30-4. Extraintestinal
and Associated
Manifestations of Celiac
Disease
(Farrell and Kelley, 2002; Hill et al, 2002). A small percentage of patients may be refractory to dietary therapy because of inadvertent gluten intake, pancreatic
insufficiency, irritable bowel, bacterial overgrowth,
fructose intolerance, or other coexisting GI maladies
(Abdulkarim et al, 2002).
Extraintestinal
Medical Treatment
Anemia (iron or folate, rarely, B12)
Lassitude, malaise (sometimes despite lack of
anemia), arthritis, arthralgia
Dermatitis herpetiformis
Osteomalacia, osteopenia, fractures (vitamin D
deficiency, inadequate calcium absorption)
Dental enamel hypoplasia
Coagulopathies (vitamin K deficiency)
Infertility, increased risk of abortion, delayed
puberty, delayed growth
Hepatic steatosis, hepatitis
Neurologic symptoms (ataxia, poly-neuropathy, seizures)
Psychiatric syndromes
Associated Disorders
Institution of a gluten-free diet greatly diminishes the
autoimmune process, and the intestinal mucosa usually reverts to normal; however, some patients may require months or even years of diet therapy for maximal recovery. The toxic peptide fractions of the
respective cereals must be avoided for life. Refractory
sprue may not respond entirely to the removal of
gluten, or it may respond only temporarily. Many of
these patients, however, do show a response to
steroids, azathioprine, cyclosporine, or other medications classically used in inflammatory or immunologic
reactions. For some, treatment of other underlying disease may further resolve symptoms (Figure 30-2).
A new study has identified the peptide fraction
from gliadin that causes the problem (see New Directions: Bacterial Endopeptidase—A New Treatment
for Celiac Disease?).
Autoimmune diseases—type 1 diabetes, thyroiditis, hepatitis, collagen vascular disease
Malignancies
IgA deficiencies
Medical Nutrition Therapy
Data from Hill ID et al: Celiac disease: working group report of the first
world congress of pediatric gastoenterology, hepatology and nutrition,
J Pediatr Gastroenterol Nutr 35:785, 2002; Fasano A, Catassi C: Current
approaches to diagnosis and treatment of celiac disease: an evolving
spectrum, Gastroenterology 120:636, 2001.
IgA, Immunoglobulin.
domysial antibodies (AEAs), immunoglobulin A (IgA)
or IgG-AGA antibodies (antigliadin antibodies), or the
autoantigen that appears to trigger the immune response (IgA tissue transglutaminase [tTG]) (Hill et al,
2002; Mustalahi et al, 2002; Petaros et al, 2002). Some
persons thought to have celiac disease may be IgA deficient, and so IgA levels are normally done first. The
serologic tests may also be used for monitoring the
progress of persons with confirmed celiac disease.
The serologic tests are highly specific and sensitive
for celiac disease, but the gold standard for final diagnosis is still the intestinal mucosal biopsy (Farrell
and Kelly, 2002). Because intestinal biopsy is relatively expensive and must be performed by upper GI
endoscopy, it is not usually used for initial screening.
Because dietary change would alter the diagnostic results, initial diagnostic evaluation should be done before the patient has withdrawn gluten-containing
foods from the diet.
Major clinical symptoms usually abate in most patients 2 to 8 weeks after consuming a gluten-free diet,
but for some patients it may take longer. With strict
dietary control, levels of the specific antibodies usually become undetectable in 3 to 6 months in most
persons, but in some the recovery may be slower
Complete withdrawal of gluten results in clinical improvement. The diet requires a major life change on
the part of the patient to adhere to it sufficiently to
bring about remission. Insofar as possible, the diet
omits all dietary wheat (gliadin), rye (secalin), and
barley (hordein), sources of the prolamin fractions
(Thompson, 2001) (Table 30-3).
The diet should initially be supplemented with vitamins, minerals, and extra protein to remedy deficiencies and replenish nutrient stores. Anemia
should be treated with iron, folate, or vitamin B12, depending on the nature of the anemia. Calcium and vitamin D administration may be necessary to correct
osteoporosis or osteomalacia. Vitamins A and E may
be necessary to replenish stores depleted by steatorrhea. Vitamin K may be prescribed for purpura,
bleeding, or prolonged prothrombin time. Electrolyte
and fluid replacement is essential for those dehydrated from severe diarrhea.
Those who continue to have malabsorption should
take a multiple vitamin and mineral supplement to at
least meet dietary reference intakes (DRIs). MCT may
help provide calories, especially in persons with steatorrhea. Lactose and fructose intolerance sometimes
occurs secondary to celiac disease. A low-lactose or
low-fructose diet may be useful in controlling symptoms, at least initially. Once the GI tract returns to
more normal function, lactase activity may also return
and a trial of lactose ingestion can be tried.
In the traditional diet, wheat, rye, barley, and oats
are normally excluded. Recently, the need for exclu-
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
715
CELIAC DISEASE
(GLUTEN-SENSITIVE ENTEROPATHY OR NONTROPICAL SPRUE)
Immune
component:
antibodies to
specific dietary
protein
fractions
Genetic
contribution
CAUSE
Gluten
intolerance
Alcohol-soluble
component
of wheat, rye,
barley
protein
DAMAGE TO
SMALL BOWEL
PATHOPHYSIOLOGY
Atrophy and flattening of villi
Reduced area for absorption
Cellular deficiency of
disaccharidases and
peptidases
Reduced nutrient
transport carriers
MEDICAL MANAGEMENT
Electrolyte
and fluid
replacement
Vitamin and
mineral
supplementation
Calcium and
vitamin D
administration
FIGURE 30-2
•
EXTRAINTESTINAL
EFFECTS
Anemia
Bone loss
Muscle weakness
Polyneuropathy
Endocrine disorders
Follicular hyperkeratosis
NUTRITIONAL MANAGEMENT
Delete
gluten sources
(wheat, rye, barley)
from diet
Substitute
with corn, potato,
rice, soybean,
tapioca, and
arrowroot
Read
food labels
carefully for hidden
gluten-containing
ingredients
Pathophysiology algorithm: celiac disease (gluten-sensitive enteropathy or nontropical sprue). (Algorithm content de-
veloped by John Anderson, PhD, and Sanford C. Garner, PhD, 2000. Updated by Peter L. Beyer, MS, RD, LD, 2002.)
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5 / MEDICAL NUTRITION THERAPY
NEW DIRECTIONS
Bacterial Endopeptidase—A New Treatment
for Celiac Disease?
ecently scientists identified a 33-amino acid peptide
fraction from the 266-amino acid gliadin that triggers
the destructive inflammatory response in celiac disease
(Shan et al, 2002). The fragment appears to be the same
one in other grains that contain gluten. It appears that
this peptide fraction is resistant to digestion by normal
human digestive enzymes, but it can be degraded by
bacterial endopeptidases. In preliminary studies, de-
R
sion of oats from the diet of persons with celiac disease and dermatitis herpetiformis has been challenged (Janatuinen et al, 2002). Clinical and GI manifestations of gluten sensitivity do not appear to recur
in evaluations of oat intake lasting from 6 months to 5
years or longer. Until larger numbers of patients have
been evaluated, however, some clinicians and patients may still be reluctant to add oat products to the
diet. Many oat products may be contaminated with
wheat or other grains, and contamination may not be
easily detected. Long-term study in larger populations and strict guidelines regarding contamination
of gluten-containing grains in oat products may help
to resolve the issue in the future.
Products made from corn, potato, rice, soybean,
tapioca, arrowroot, amaranth, quinoa, millet, and
buckwheat can be substituted in food products. When
using the flours, it is important that they also not be
contaminated with gluten-containing flour during
milling. Patients can expect differences in textures and
flavors of common foods using the substitute flours,
but the new recipes can also be quite acceptable once
the adjustment is made. In some countries, specially
processed wheat starch has been considered sufficiently low in gluten to be safe for consumption, but in
other countries the protein fraction remaining after extraction may be expressed only as nitrogen or protein
rather than the more specific gluten or gliadin content
of the final product. When reading a product label listing only nitrogen content, one would not be able to be
certain that the source of the remaining nitrogen or
protein was gliadin or another protein (Thompson,
2001). Celiac organizations in North America do not
yet recommend consumption of these wheat starch
products or oat products. Table 30-4 provides suggestions for incorporating flour substitutions into recipes.
The diet for celiac disease requires a major change in
the types of foods normally consumed in the Western
diet. Foods made from wheat, in particular (breads,
cereals, pastas, and baked goods), are consumed as staples in the U.S. diet. A truly gluten-free diet requires
careful scrutiny of the labels of all bakery products and
packaged foods. Gluten-containing grains are not only
used as a primary ingredient but may also be added
struction of the peptide fragment by the addition of the
endopeptidase enzyme prevented the typical immunologic response seen with celiac disease. The hope is
that oral endopeptidase enzymes can be used as an
oral supplement to digest and destroy the specific fragment of gliadin in the foods that contain gluten, thus allowing their consumption.
during processing or preparation of foods. Hydrolyzed vegetable protein can be made from wheat, soy,
corn, or mixtures of these grains (Table 30-5).
Freedom from symptoms after eating gluten does
not necessarily mean that cells of the GI tract are undamaged. The precipitating condition usually continues to exist, and gluten causes mucosal changes
within hours; however, overt symptoms may take 8
weeks or longer to reappear or may remain latent.
Adults who start and stop a gluten-free diet numerous times eventually may reach a state at which they
do not respond to the diet. Complications of chronic
ulcerative jejunoileitis and extraintestinal manifestations may develop. Risk of malignant disease, especially lymphoma, is increased, and adherence to a
gluten-free diet appears to reduce the risk (Saraphin
and Mobarin, 2002; Troncone, 1996).
Tropical Sprue
Pathophysiology
Tropical sprue is a diarrheal syndrome that occurs in
many tropical areas. The diarrhea appears to be an
infectious type, and the intestinal organism identified
may differ from one region of the tropics to the next
(Farthing, 1998). As in celiac disease, the intestinal
villi are shortened, but the surface cell alterations are
much less severe. The gastric mucosa may be atrophied and inflamed, with diminished secretion of hydrochloric acid and intrinsic factor.
Symptoms include diarrhea, anorexia, and abdominal distention as well as symptoms of nutritional deficiency, such as night blindness, glossitis, stomatitis,
cheilosis, pallor, and edema. Anemia may result from
iron, folic acid, and vitamin B12 deficiencies.
Medical Treatment
Treatment involves restoration of fluids, electrolytes,
and nutrients. Tropical sprue typically responds
promptly to broad-spectrum antibiotics and folate
therapy. Along with other nutrients as needed, folate is
given orally, 5 mg daily, along with intramuscular vitamin B12 (1000 mg/month) until symptoms subside.
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717
TABLE 30-3 Gluten-Free Diet by Food Groups
FOOD
PRODUCTS
Milk
products
Grain
products
FOODS ALLOWED
FOODS TO QUESTION
FOODS NOT ALLOWED
Milk, cream, most ice cream, buttermilk,
plain yogurt, cheese, cream cheese,
processed cheese, processed cheese
foods, cottage cheese
Breads: Bread and baked products containing amaranth, arrowroot, buckwheat, corn bran, corn flour, cornmeal, cornstarch, flax, legume flours
(bean, garbanzo or chickpea, fava,
lentil, pea), millet, potato flour, potato
starch, quinoa, rice bran, rice flours
(white, brown, sweet), sago, sorghum
flour, soy flour, sweet potato flour,
tapioca and teff
Milk drinks, flavored yogurt,
frozen yogurt, sour cream,
cheese sauces, cheese spreads
Malted milk, ice cream made with
ingredients not allowed
Buckwheat flour
Bread and baked products containing wheat, rye, triticale, barley,
oats, wheat germ, wheat bran,
graham flour, gluten flour,
durum flour, wheat starch, oat
bran, bulgur, farina, wheatbased semolina, spelt, kamut,
einkorn, emmer, farro, imported
foods labeled “gluten-free,”
which may contain ingredients
not allowed, e.g., wheat starch
Cereals made from wheat, rye,
triticale, barley and oats; cereals
with added malt extract or malt
flavoring
Cereals:
Hot: Amaranth flakes, cornmeal,
cream of buckwheat, cream of rice
(brown, white), hominy grits, rice
flakes, quinoa flakes, soy flakes
and soy grits
Cold: Puffed amaranth, puffed buckwheat, puffed corn, puffed millet,
puffed rice, rice flakes and soy
cereals
Pastas: Macaroni, spaghetti, and
noodles from beans, corn, pea, potato,
quinoa, rice, soy and wild rice flours
Miscellaneous: Corn tacos, corn torillas
Meats and
alternatives
Fruits and
vegetables
Meat, fish, poultry: Fresh
Eggs: Eggs
Others: Lentils, chickpeas (garbanzo
beans), peas, beans, nuts, seeds, tofu
Fruits: Fresh, frozen, and canned fruits
and juices
Vegetables: Fresh, frozen, dried and
canned
Rice and corn cereals, rice and
soy pablum
Buckwheat pasta
Rice crackers, some rice cakes
and popped corn cakes
Deli or processed meats such as
luncheon meat, ham, bacon,
meat and sandwich spreads,
meat loaf, frozen meat patties, sausages, pâté, wieners,
bologna, salami, imitation
meat or fish products, meat
product extenders
Egg substitutes, dried eggs
Baked beans, dry roasted nuts
Fruit pie fillings, dried fruits,
fruits or vegetables with
sauces
French-fried potatoes (e.g.,
those in restaurants)
Canned soups, dried soup
mixes, soup bases and
bouillon cubes
Soups
Homemade broth, gluten-free bouillon
cubes, cream soups and stocks made
from allowed ingredients
Fats
Butter, margarine, lard, vegetable oil,
cream, shortening, homemade salad
dressing with allowed ingredients
Ice cream, sherbet, whipped toppings,
egg custards, gelatin desserts; cakes,
cookies, pastries made with allowed
ingredients; gluten-free ice cream
cones, wafers, and waffles
Salad dressings, some
mayonnaise
Beverages: Tea, instant or ground coffee
(regular or decaffeinated), cocoa, soft
drinks, cider; distilled alcoholic beverages such as rum, gin, whiskey,
vodka, wines and pure liqueurs;
some soy and rice beverages
Instant tea, flavored and
herbal teas, flavored coffees,
coffee substitutes, fruitflavored drinks, chocolate
drinks, chocolate mixes
Desserts
Miscellaneous
Milk puddings, custard
powder, pudding mixes
Pastas made from wheat, wheat
starch and other ingredients not
allowed
Wheat flour tacos, wheat tortillas
Fish canned in vegetable broth
containing HVP/HPP*
Turkey basted or injected with
HVP/HPP*
Frozen chicken containing chicken
broth (made with ingredients
not allowed)
Scalloped potatoes (containing
wheat flour)
Battered dipped vegetables
Soups made with ingredients not
allowed, bouillon and bouillon
cubes containing HVP or HPP*
or wheat
Packaged suet
Ice cream made with ingredients
not allowed; cakes, cookies,
muffins, pies and pastries made
with ingredients not allowed; ice
cream cones, wafers and waffles
made with ingredients not
allowed
Beer, ale and lager; cereal and
malted beverages; soy or rice
beverages made with barley or
oats
Modified by Case S, Molloy M, and Zarkadas M. From Canadian Celiac Association: Celiac disease needs a diet for life, October 2000. Further revisions by Case S,
April 2002 and June 2003.
*If the plant source in HVP/HPP (hydrolyzed vegetable protein/hydrolyzed plant protein) is not identified or if the source is from wheat protein, HVP/HPP
must be avoided.
Continued
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5 / MEDICAL NUTRITION THERAPY
TABLE 30-3 Gluten-Free Diet by Food Groups—cont’d
FOOD
PRODUCTS
Miscellaneous
—cont’d
FOODS ALLOWED
FOODS TO QUESTION
FOODS NOT ALLOWED
Sweets: Honey, jam, jelly, marmalade,
corn syrup, maple syrup, molasses,
sugar (brown and white), icing sugar
(confectioner’s)
Snack foods: Plain popcorn, nuts, and
soy nuts
Spreads, candies, chocolate
bars, chewing gum, and
lemon curd
Licorice and other candies made
with ingredients not allowed
Dry roasted nuts, flavored
potato chips, tortilla or taco
(corn) chips, and soy nuts
Seasoning mixes,
Worcestershire sauce
Pizza, unless made with ingredients allowed
Condiments: Plain pickles, relish,
olives, ketchup, mustard, tomato
paste, pure herbs and spices, pure
black pepper, vinegars (apple or cider,
distilled white, grape or wine, spirit),
gluten-free soy sauce
Other: Sauces and gravies made with
ingredients allowed, pure cocoa, pure
baking chocolate, carob chips and
powder, chocolate chips, monosodium glutamate (MSG), cream of
tartar, baking soda, yeast, brewer’s
yeast, aspartame, coconut, vanilla,
gluten-free communion wafers
Baking powder
Soy sauce (made from wheat),
mustard pickles (made from
wheat flour), malt vinegar
Sauces and gravies made from ingredients not allowed, hydrolyzed vegetable/plant protein
(HVP/HPP)*, communion
wafers
Modified by Case S, Molloy M, and Zarkadas M. From Canadian Celiac Association: Celiac disease needs a diet for life, October 2000. Further revisions by Case S,
April 2002 and June 2003.
*If the plant source in HVP/HPP (hydrolyzed vegetable protein/hydrolyzed plant protein) is not identified or if the source is from wheat protein, HVP/HPP
must be avoided.
Medical Nutrition Therapy
TABLE 30-4 Substitutions
Substitutions for 1 tbsp (15 ml) Wheat Flour
1
⁄ 2 tbsp
1
⁄ 2 tbsp
1
⁄ 2 tbsp
1
⁄ 2 tbsp
2 tsp
2 tsp
2 tbsp
Cornstarch
Potato starch
White rice flour
Arrowroot starch
Quick-cooking tapioca
Tapioca starch
Uncooked rice
7 ml
7 ml
7 ml
7 ml
10 ml
10 ml
30 ml
Substitutions for 1 c (250 ml) Wheat Flour*
Mix A:
Mix B:
2c
2c
2c
4c
11⁄ 3 c
1c
Brown rice flour
Sweet rice flour
Rice polish
White rice flour
Potato starch
Tapioca starch
500 ml
500 ml
500 ml
1L
325 ml
250 ml
Other Substitutions for 1 c (250 ml) Wheat Flour*
5
⁄8 c
⁄8 c
1c
1c
3
⁄4 c
5
⁄8 c
Potato starch
White or brown rice flour
Cornmeal
Fine cornmeal
Coarse cornmeal
White or brown rice flour
1
⁄3 c
1c
Potato starch
Soy flour
1
⁄4 c
3
⁄4 c
Potato starch
Rice flour
1
Cornstarch
Whole bean flour
7
150 ml
215 ml
250 ml
250 ml
175 ml
150 ml
PLUS
75 ml
250 ml
PLUS
50 ml
175 ml
It is important to correct the related anemias (see
Chapter 34). Nutritional deficiency may increase susceptibility to infectious agents, further aggravating
the condition.
INTESTINAL BRUSH-BORDER
ENZYME DEFICIENCIES
Intestinal enzyme deficiency states involve deficiencies of the brush-border disaccharidases that hydrolyze disaccharides at the mucosal cell membrane.
Disaccharidase deficiencies may occur as (1) rare congenital defects, such as the sucrase, isomaltase, or lactase deficiencies seen in the newborn; (2) generalized
forms secondary to diseases that damage the intestinal epithelium (e.g., Crohn’s disease or celiac disease); or, most commonly, (3) a genetically acquired
form (e.g., lactase deficiency) that usually appears after childhood but can appear as early as 2 years of
age. For purposes of this chapter, only lactose
maldigestion is described in detail (see Chapter 45
for a discussion of metabolic disorders).
PLUS
⁄4 c
7
⁄8 c
50 ml
215 ml
*Store in an airtight container and use 7⁄ 8 c (215 ml) of mix A or 1 c (250 ml) of
mix B for 1 c (250 ml) wheat flour. A combination of flours and starches gives
a better gluten-free product. For specific flour mixes see recipes in glutenfree cookbooks using a variety of gluten-free flours.
Modified from Case S: Gluten-free diet: a comprehensive resource guide, ed 2,
Saskatchewan, 2003, Case Nutrition Consulting.
Lactose Maldigestion and Lactose
Intolerance
Pathophysiology
Lactose intolerance is the most common carbohydrate intolerance, and it affects persons of all age
groups. Lactose maldigestion and intolerance to lac-
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
719
TABLE 30-5 Notes on “Foods to Question”
CATEGORY
FOOD PRODUCTS
NOTES
Milk products
Milk drinks
Cheese spreads or sauces
(e.g., nacho)
Flavored or frozen yogurt
Chocolate milk and other flavored drinks may contain wheat starch or barley malt.
May be thickened or stabilized with wheat.
Flavorings and seasonings may contain wheat.
May be thickened or stabilized with a gluten source.
May contain granola or cookie crumbs.
Some low-fat or fat-free may contain modified food starch.
Pure buckwheat flour is gluten-free. Sometimes buckwheat flour may be mixed
with wheat flour.
May contain barley malt extract.
May contain oat syrup or barley malt extract.
Some “soba” pastas contain pure buckwheat flour, which is gluten-free, but others
may also contain wheat flour.
Multigrain often contains barley and/or oats.
Some contain soy sauce (may be made from wheat).
Some are thickened with wheat flour.
May contain fillers made from wheat starch.
May contain wheat.
May contain fillers made from wheat.
May contain HPP or HVP made from wheat.
Often contain wheat or oats.
Dates and other dried fruits may be dusted with wheat flour to prevent sticking.
Some may be thickened with flour.
Grains
Sour cream
Buckwheat flour
Rice cereals
Corn cereals
Buckwheat pasta
Meats/
alternatives
Fruits and
vegetables
Soups
Fats
Desserts
Miscellaneous
Rice cakes, corn cakes,
rice crackers
Baked beans
Imitation crab
Dry-roasted nuts
Processed meat products
Imitation meats
Dried fruits
Fruits/vegetables with
sauces
Fruit pie fillings
French fries
Canned soups, dried soup
mixes, soup bases and
bouillon cubes
Salad dressings
Milk puddings/mixes
Beverages
Lemon curd
Potato, tortilla chips, and
soy nuts
Baking powder
Seasoning mixes
Worcestershire sauce
May contain wheat as an ingredient.
May contain noodles or barley.
Cream soups are often thickened with flour.
May contain HPP or HVP (from wheat).
Seasonings may contain wheat flour, wheat starch or hydrolyzed wheat protein.
Seasonings may contain wheat flour or wheat starch.
Starch source may be from wheat.
Some instant teas, herbal teas, coffee substitutes and other drinks may have grain
additives.
Nondairy substitutes (e.g., rice drinks and soy drinks) may contain barley, barley
malt extract or oats.
Usually thickened with flour.
Some potato chips contain wheat.
Seasoning mixes may contain wheat flour, wheat starch or hydrolyzed wheat
protein.
Contains starch, which may be from wheat.
May contain wheat flour, wheat starch or hydrolyzed wheat protein.
May contain malt vinegar which is not gluten-free.
From Case S: Gluten-free diet: a comprehensive resource guide, ed 2, Saskatchewan, 2003, Case Nutrition Consulting.
HPP, Hydrolyzed plant protein; HVP, hydrolyzed vegetable protein.
tose are caused by a deficiency of lactase, the enzyme
that digests the sugar in milk. Lactose that is not hydrolyzed into galactose and glucose in the upper
small intestine passes into the colon, where bacteria
ferment the lactose to SCFAs and gases, carbon dioxide, and hydrogen gas. Consumption of small
amounts should be of little consequence because
both the SCFAs are readily absorbed and the gases
can be absorbed or passed. Larger amounts, usually
greater than 12 g, consumed in a single food (the
amount typically found in 240 ml of milk), may result
in more substrate entering the colon than can be disposed of by normal processes. As is the case with any
malabsorbed sugar, the lactose may act osmotically
and increase fecal water, and rapid fermentation by
intestinal bacteria may result in bloating, flatulence,
and cramps. In some cases loose stools or diarrhea
may occur.
Seventy percent of the adult worldwide population, especially blacks, Asians, and South Americans,
are lactase deficient, which implies that decline of the
lactase enzyme after early childhood is the more normal state and lactase sufficiency is abnormal. Although it has been suggested that lactase persistence
is induced by the continuation of milk in the diet after weaning, no evidence has been found to support
this theory. It is more likely that the maintenance of
lactase throughout adulthood reflects the continuation of an ancient genetic mutation (see Focus on: Lactose Tolerance—An Uncommon Anomaly?).
Typically, lactase activity declines exponentially at
weaning to about 10% of the neonatal value. Even in
adults who retain a high level of lactase levels (75% to
85% of white adults of Western European heritage), the
quantity of lactase is about half that of other saccharidases, such as sucrase, -dextrinase, or glucoamylase
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5 / MEDICAL NUTRITION THERAPY
(Gray, 1993). The decline of lactase is commonly
known as hypolactasia; the adult form is the most
common type of lactase deficiency (Srinivasan and
Minocha, 1998).
Secondary lactose intolerance can also develop as a
consequence of infection of the small intestine, inflammatory disorders, HIV, or malnutrition. In children, it is typically secondary to viral or bacterial infections. Lactase activity may also be slow to return
after prolonged parenteral nutrition. Lactose maldigestion with all its symptoms may also occur in adults
with irritable bowel syndrome or in children with recurrent abdominal pain, even though they have normal lactase activity (Srinivasan and Minocha, 1998).
Lactase deficiency is typically diagnosed on the
basis of (1) a history of GI symptoms occurring after
milk ingestion, (2) a test for abnormal hydrogen levels in the breath, or (3) an abnormal lactose tolerance
test. The lactose tolerance test was originally based
on an oral dose of lactose equivalent to the amount in
1 quart of milk (50 g). If the patient has insufficient
lactase enzyme, blood glucose produced from the
lactose increases less than 25 mg/100 ml of serum
above the fasting level, and GI symptoms may appear. Because hydrogen production in the colon increases significantly if lactose is not digested in the
small intestine, hydrogen absorbed into the bloodstream and exhaled through the lungs can be used as
another test of malabsorption. The breath hydrogen
test shows increased levels 60 to 90 minutes after in-
gestion. Recently, doses lower than 50 g of lactose
have been used to approximate more closely the
usual consumption of lactose from milk products.
Medical Nutrition Therapy
Management of lactase insufficiency requires dietary
changes. The symptoms of lactose intolerance are
alleviated by reduced consumption of lactosecontaining foods. Persons who avoid dairy products
should take calcium supplements and should read ingredient labels carefully (Srinivasan and Minocha,
1998). A completely lactose-free diet is not necessary
in lactase-deficient persons. Most lactose maldigesters
can consume some lactose (6 to 12 g) without major
symptoms, especially when taken with meals or in the
form of cheeses or cultured dairy products. Many
adults with intolerance to moderate amounts of milk
can ultimately adapt to and tolerate 12 g or more of
lactose in milk (equivalent to 240 ml of full-lactose
milk) when introduced gradually, in increments, over
several weeks (Srinivasan and Minocha, 1998).
Apparently, incremental or continuous exposure
to increasing quantities of fermentable sugar can lead
to improved tolerance, not as a consequence of increased lactase enzyme production but perhaps by
altered colonic flora. This has been shown with lactulose, a nonabsorbed carbohydrate that is biochemically similar to lactose (Bezkorovainy, 2001). Individual differences in tolerance may relate to the state of
FOCUS ON
Lactose Tolerance—An Uncommon
Anomaly?
hen lactose intolerance was first described in
1963, it appeared to be an infrequent occurrence,
arising only occasionally in the white population. Because the capacity to digest lactose was measured in
people from a wide variety of ethnic and racial backgrounds, it soon became apparent that disappearance
of the lactase enzyme shortly after weaning, or at least
during early childhood, was actually the predominant
(normal) condition in most of the world’s population. With
a few exceptions, the intestinal tracts of adult mammals
produce little, if any, lactase after weaning. (The milk of
pinnipeds—seals, walruses, and sea lions—does not
contain lactose.)
The exception of lactose tolerance has attracted the
interest of geographers and others concerned with the
evolution of the world’s population. A genetic mutation
favoring lactose tolerance appears to have arisen
around 10,000 years ago, when dairying was first introduced. Presumably, it would have occurred in places
where milk consumption was encouraged because of
some degree of dietary deprivation and in groups in
which milk was not fermented before consumption. (Fermentation breaks down much of the lactose into mono-
W
saccharides.) The mutation would have selectively endured, because it would promote greater health, survival, and reproduction of those who carried the gene.
It is proposed that the mutation occurred in more than
one location and then accompanied migrations of populations throughout the world. It continues primarily
among whites from northern Europe and in ethnic
groups in India, Africa, and Mongolia. The highest frequency (97%) of lactose tolerance occurs in Sweden
and Denmark, suggesting an increased selective advantage in those able to tolerate lactose related to the limited exposure to ultraviolet light typical of northern latitudes. (Lactose favors calcium absorption, which is
limited in the absence of vitamin D produced by skin exposure to sunlight.) (See Chapter 4.)
Dairying was unknown in North America until the arrival of Europeans. Thus, Native Americans and all of
the non-European immigrants are among the 90% of the
world’s population who tolerate milk poorly, if at all. This
has practical implications with respect to group feeding
programs, such as school breakfasts and lunches. Fortunately, most lactose-intolerant people are able to digest milk in small to moderate amounts.
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colonic adaptation. Regular consumption of milk by
lactase-deficient persons may increase the threshold
at which diarrhea occurs.
Often solid or semisolid milk products, such as
aged cheeses, are well tolerated because gastric emptying of these foodstuffs is slower than for liquid
milk beverages, and the lactose content is low. Tolerance of yogurt may be the result of a microbial galactosidase in the bacterial culture that facilitates
lactose digestion in the intestine. The presence of
galactosidase depends on the brand and processing
method. Because this microbial enzyme is sensitive
to freezing, frozen yogurt may not be as well tolerated, but the addition of probiotics may change this
in the future (Davidson et al, 2000).
Lactase enzyme and milk products treated with
lactase enzyme (e.g., Lactaid) are available for lactase
maldigesters who have discomfort with milk ingestion. Commercial lactase preparations may differ
somewhat in their effects on both hydrogen breath
excretion and symptom reduction (Ramirez et al,
1994) and in their effectiveness (Srinivasan and
Minocha, 1998).
INFLAMMATORY BOWEL DISEASES
The two major forms of inflammatory bowel disease
(IBD) are Crohn’s disease and ulcerative colitis. The
onset of IBD occurs most often in patients 15 to 30
years of age, but some persons have first onset of the
disease later in adulthood. Both sexes are equally affected. The cause of IBD is not fully known, but it appears to involve the interaction of environmental factors, host microflora, genetic predisposition, and an
abnormal immune or autoimmune response in the
intestinal wall. At least part of the susceptibility (and
perhaps behavior and complications) of IBD have
been mapped to gene mutations on different chromosomes. The specific genes and their roles, however,
have not been completely elaborated (Ahmad et al,
2001; Hugot et al, 2001).
The overzealous inflammatory response with local
and systemic involvement of leukocytes results in the
release of proteases, prostaglandins, leukotrienes,
eicosanoids, and oxygen free radicals. The exaggerated immune response appears to be largely responsible for the GI tissue damage incurred (Laroux and
Grisham, 2001; van Dullemen et al, 1997).
Triggers for the initial onset and subsequent exacerbations likely include an exaggerated inflammatory response to a specific microbe or combinations
of microbes in the lumen of the GI tract (Beutler, 2001;
Podolsky, 2002) (Figure 30-3).
Food allergies and other immunologic reactions to
specific foods may have been considered in the
pathogenesis of IBD and certainly its symptoms;
however, the incidence of documented food allergies,
compared with food intolerances, is relatively small.
721
In one objective evaluation of 375 patients with GI
disease, adverse reactions to foods occurred in 32% of
patients, allergies were suspected in 14.4%, and allergies were confirmed in 3.2% of patients (Bischoff et
al, 1996). The permeability of the intestinal wall to
molecules of food and cell fragments is likely increased in inflammatory states, allowing heightened
interaction of antigens with host immune systems.
Food intolerances of various types occur more
than twice as often in persons with IBD than in the
population at large (Ballegaard et al, 1997). Except for
a small increase in the occurrence of lactose intolerance, however, the patterns are not consistent among
individuals, or even from one time to the next. Reasons for specific and nonspecific food intolerances
are abundant and are likely related to the stage, location, and manifestations of the disease process. Partial GI obstructions, malabsorption, diarrhea, altered
GI transit, increased secretions, food aversions, and
associations are but a few of the problems experienced by persons with IBD (Reif et al, 1997). Neither
food allergies nor intolerances, however, fully explain the onset or overall pathologic or clinical manifestations in all patients (see Chapter 32).
Normally, when an antigenic challenge or trauma
occurs, the immune response rises to the occasion; it
is then turned off (and continues to be held in check)
after the challenge resolves. In IBD, either the regulatory mechanisms are defective or the factors stimulating the immune and acute-phase response are enhanced, leading to tissue fibrosis and destruction.
The clinical course of the disease may be mild and
episodic, or severe and unremitting.
Both Crohn’s disease and ulcerative colitis share
some clinical features. For example, food intolerances, diarrhea, fever, weight loss, anemias, malnutrition, growth failure, and extraintestinal manifestations (arthritic, dermatologic, and hepatic) occur in
both diseases. The diseases, however, also have distinctive features in terms of their genetic characteristics, clinical presentation, and treatment (Table 30-6).
Persons with IBD are at risk for several forms of
malnutrition, and nutrition is a major consideration
in each stage of the disease. Although malnutrition
can occur in both forms of IBD, it is more likely to be
a major and lifelong concern in patients with Crohn’s
disease. In both forms of IBD, the risk of malignant
disease is increased with long-standing disease. The
reasons for the increased risk are not firmly established but may be associated with the increased proliferative state and nutritional factors.
Crohn’s Disease
Pathophysiology
Crohn’s disease may involve any part of the GI tract,
from mouth to anus. The most common pattern of involvement (about 50% to 60% of cases) is the combination of both the distal ileum and the colon; 15% to
25% of cases involve only the small intestine or only
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5 / MEDICAL NUTRITION THERAPY
INFLAMMATORY BOWEL DISEASE
Unknown
"irritant"
Viral?
Bacterial?
Autoimmune?
Genetic
predisposition
CAUSE
Abnormal activation
of the mucosal immune
response. Secondary
systemic response
PATHOPHYSIOLOGY
Damage to the
cells of the small
and/or large
intestine with
malabsorption,
ulceration, or
stricture
Diarrhea
Weight loss
Poor growth
MEDICAL MANAGEMENT
NUTRITIONAL MANAGEMENT
Corticosteroids
Antiinflammatory agents
Immunosuppressants
Antibiotics
Anticytokine medications
Oral enteral
formula
(tube-feed if
necessary)
Use of
foods that
are well
tolerated
FIGURE 30-3
•
Parenteral
nutrition in
patients with
severe disease
or obstruction
Pathophysiology algorithm: inflammatory bowel disease. (Algorithm content developed by John Anderson, PhD, and San-
ford C. Garner, PhD, 2000. Updated by Peter L. Beyer, MS, RD, LD, 2002.)
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723
TABLE 30-6 Differences Between Crohn’s Disease and Ulcerative Colitis
REGIONAL ENTERITIS
(CROHN’S DISEASE)
ULCERATIVE COLITIS
Young
Young to middle-aged
Transmural (all layers of submucosa)
50%
Frequent
Involved; ileum narrowed
Segmental
Chronic and extensive
Common
Edema and hyperplasia
Occasional
Frequent
Rare
Common
Mucosa and submucosa
95%
Occasional
Usually normal
Continuous
Rare (crypt abscess)
Absent
Not involved
Occasional
Absent
After 10 yr
Absent
Slowly progressive
Occasional
Colicky (45%)
Unusual or absent
Present (65%-85%)
Present (35%)
Common
Present (60%-70%)
Present (35%)
Common (75%)
Common (80%)
Remissions and relapses
Common (90%-100%)
Predefecation (60%-70%)
Almost always present
Early and frequent (80%-95%)
Present (15%)
Common
Present (20%-50%)
Present (10%)
Occasional (10%)
Rare (10%-20%)
Arthritis
Peripheral sacroiliitis
Hepatobiliary involvement
Present (20%)
18%
Uncommon
Skin: erythema nodosum, pyoderma gangrenosum
Nephrolithiasis
Common
Occasional
Uncommon (10%)
18%-20%
15% cholestatic dysfunction
19%-38% fatty liver
30%-50% pericholangitis
Present (5%-10%)
Rare
CHARACTERISTIC
General Description
Age at onset
Pathology and Anatomy
Depth of involvement
Rectal involvement
Right colon involvement
Small bowel involvement
Distribution of disease
Inflammatory mass
Cobblestone-like mucosa and granuloma
Mesentery lymph involvement
Toxic megacolon
Steatorrhea
Malignant disease
Fibrous stricture
Clinical Manifestations
Course of disease
Rectal bleeding
Abdominal pain
Hematochezia
Diarrhea
Vomiting
Nutritional deficit
Weight loss
Fever
Anal abscess
Fistula and anorectal fissure fistula
Systemic Manifestations
Modified from Black J, Matassarin-Jacobs E, editors: Luckmann & Sorensen’s medical-surgical nursing, ed 4, Philadelphia, 1993, WB Saunders.
the colon (Kornbluth et al, 1998). In the portions of intestine involved, the inflammation may skip areas,
and so these healthy segments of bowel separate inflamed portions. Mucosal involvement in Crohn’s
disease is transmural in that it affects all layers of the
mucosa. As inflammation, ulceration, abscesses, and
fistulas resolve, fibrosis, submucosal thickening, and
scarring may result, leading to narrowed segments of
bowel, localized strictures, and partial or complete
obstruction of the intestinal lumen.
Medical Treatment
Surgery may be necessary to repair strictures or remove portions of the bowel when medical management fails. About 50% to 70% of persons with Crohn’s
disease will undergo surgery related to the disease
(Hyams, 1996; Patel et al, 1997). Surgery does not
cure the disease; recurrence often occurs within 1 to 3
years of surgery, and the chance of reoperation sometime in the patient’s life is about 30% to 70%, depending on the type of surgery and the age at first opera-
tion. Major resections of the intestine may result in
varying degrees of malabsorption of fluid and nutrients. In extreme cases, patients may have extensive or
multiple resections, resulting short-bowel syndrome,
and dependence on parenteral nutrition to maintain
adequate nutrient intake and hydration.
Ulcerative Colitis
Pathophysiology
Ulcerative colitis involves only the colon, and the disease always extends from the rectum. Microscopic
examination shows diffusely inflamed mucosa, usually with small ulcers. Continuous disease (rather
than skipped areas) is characteristic. Serosal involvement, strictures, and significant narrowing are uncommon, but rectal bleeding or bloody diarrhea is
relatively common (Jenkins, 2001; Jewell, 1998) (see
Table 30-6 and Figure 30-4).
Ulcerative colitis occurs most commonly in young
people 15 to 30 years of age, with a secondary peak
at 50 to 60 years of age, although no age group is ex-
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5 / MEDICAL NUTRITION THERAPY
Medical Nutrition Therapy
FIGURE 30-4 • Crohn’s disease (left) and ulcerative colitis
(right). Whereas Crohn’s disease typically involves the small and
large intestine in a segmental manner, with intervening “skip” areas, ulcerative colitis is generally a contiguous disease process
that starts in the rectum and progresses in a retrograde fashion to
involve varying lengths of the colon. (Modified from Cotran KS, Kumar V, Robbins SI: Robbins’ pathologic basis of disease, ed 4, Philadelphia, 1989, WB Saunders.)
empt. Persons with long-standing disease are at increased risk for cancer. In severe disease and with increased risk of cancer, complete removal of the colon
is recommended, with creation of an ileostomy, ileal
pouch, or ileoanal anastomosis.
Medical Management
The goals of treatment in IBD are to induce and maintain remission and to maintain nutritional status.
Treatment of the primary GI manifestations appears
to correct most of the extraintestinal features of the
disease as well. The most effective medical agents
during the acute stages of the disease are corticosteroids, although antiinflammatory agents (aminosalicylates), immunosuppressive agents (cyclosporine, azathioprine, mercaptopurine), and antibiotics
(metronidazole) may be used for maintaining remission. Each carries the potential for medical and nutritional consequences (Regueiro, 2000). One of the
newest therapeutic agents is monoclonal anti–tumor
necrosis factor (anti-TNF) (infliximab), an agent that
inactivates one of the primary inflammatory cytokines. It is normally used in more severe cases of
Crohn’s disease and in the management of fistulas,
but it has not been shown to be effective in ulcerative
colitis. Figure 30-5 shows an algorithm for reversing
pediatric growth failure.
Investigations of various treatment modalities for
the acute and chronic stages of IBD are ongoing and
include new forms of existing drugs as well as new
agents targeted to regulate cytokines, eicosanoids, or
other mediators of the inflammatory/acute-phase cascade response (Holtmann et al, 2001; Panes, 2001;
Regueiro, 2000). Use of prebiotics and probiotic cultures have been considered plausible because each has
the potential to alter the GI microflora as well as the
immunologic response at the gut level (Madsen, 2001).
Persons with IBD are at increased risk of nutrition
problems for a host of reasons related to the disease
and its treatment, so the primary goal is to restore and
maintain the nutritional status of the individual patient (Box 30-5). Foods, dietary and micronutrient
supplements, enteral and parenteral nutrition may all
be used to accomplish that mission. Diet and the other
means of support may change during remissions and
exacerbations of the disease. Persons with IBD often
have fears and misconceptions regarding the significance of minor or major GI symptoms and the role of
foods and nutrition. Patients are also often confused
by advice from associates, various media, and health
care providers. Education is a key form of therapy.
Diet and specific nutrients may play a role in
maintaining or bringing on the remission of IBD. The
ability of parenteral or enteral nutrition to induce remission of IBD has been debated for several years,
and the issue is still not entirely resolved. At least in
theory, the use of low-residue, low-fiber liquid diets
can decrease the antigenic load or reduce microbial
populations in the colon. Clinical trials with parenteral and enteral nutrition and other supplements
have been confounded by small numbers of patients,
differences in study design, severity and location of
the disease, differences in the nutritional formulas,
and whether an oral diet was continued. Evaluation
is further confounded by the fact that the natural
course of IBD is one of exacerbations and remissions.
Results of reviews and metaanalyses of several
studies have generally concluded that (1) “bowel
rest” with parenteral nutrition is not a major requirement for achieving remission, (2) enteral nutrition
may be the preferred means of nutritional support,
and (3) at least in some cases, enteral nutrition is
more successful at inducing remission than parenteral nutrition (Han et al, 1999; Messori et al, 1996).
Commitment from the patient and caretaker to the
sole use of oral enteral formulas must be high, or the
formula must be fed by tube; however, current enteral or parenteral nutrition formulas do not appear
to be as consistently effective as corticosteroids or
combination medical therapy in inducing remission.
Regardless of whether or not current forms of parenteral or enteral nutrition induce remission, timely
nutritional support is a vital component of therapy to
restore and maintain nutritional health (Beyer, 2001).
Currently available parenteral solutions are not as
complete or well suited as enteral nutrition, but parenteral nutrition may be required to restore nutrition
in patients with obstructions, fistulas, severe disease,
and major GI resections.
Malnutrition itself compromises digestive and absorptive function and may increase the permeability
of the GI tract to potential inflammatory agents (Han
et al, 1999). Energy needs of patients with IBD are not
greatly increased (unless weight gain is desired), but
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725
Pediatric patient has limited
nutrient intake and absorption
due to Crohn’s disease.
Plot the patient’s growth curves
(height for age, height for weight).
Perform anthropometric measurements.
Has the patient
reached maturity
by bone age (x-ray)?
Yes
Yes
Does examination of
growth parameters
reveal growth failure?
No
No
Has the patient had
acute weight loss while
maintaining growth?
No
Yes
Apply supplemental
nutrition
intravenously.
Potential for catch-up
growth is dependent
on bone age.
Nutritional intervention
is imperative before
bones mature and
epiphyses fuse.
To achieve catch-up
growth, calculate intake
of an enteral elemental
diet based on ideal
weight for height.
Is growth failure
severe or bone age
advanced?
After 3 months,
reassess the patient’s
nutritional status and
growth parameters.
Yes
No
Is Crohn’s disease
acute?
Advise oral
supplementation with a
calorically dense
polymeric formula.
Administer enteral elemental
diet nocturnally via
continuous nasogastric
infusion, 60–80 kcal/kg
body weight, until patient
reaches maturity or normal
growth levels. The patient
should not be taking steroids.
No
Yes
Is the child younger
than age 2?
Yes
Administer a protein
hydrolysate infant
formula with MCT and
added amino acids.
No
Steroids can be used
to control symptoms,
but dosage should be
tapered under strict
monitoring with
initiation of elemental
diet therapy.
FIGURE 30-5
•
Administer enteral elemental
diet nocturnally via
continuous nasogastric
infusion, 60–80 kcal/kg
body weight, for 1 month
out of 4 for at least 1 year.
Algorithm for reversing growth failure in pediatric patients with Crohn’s disease. MCT, Medium-chain triglycerides.
(Modified from RD 11:5, 1991, Norwick-Eaton Pharmaceuticals, New York, N.Y.)
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5 / MEDICAL NUTRITION THERAPY
protein requirements may be increased by 50%, especially during active stages of the disease. Supplemental vitamins and minerals and trace elements may be
needed to replace stores or for maintenance because
of maldigestion, malabsorption, drug-nutrient interactions, or because the patient cannot eat a complete
diet. Diarrhea can aggravate losses of zinc, potassium, and selenium stores in particular.
During acute and severe exacerbations of the disease, the diet is tailored to the individual patient. A
minimal-residue diet that limits poorly absorbed or
hyperosmolar sugars, caffeine, and excess fiber might
be used initially to reduce diarrhea. During either
acute or chronic stages, inflammation or scarring may
result in a partially obstructed bowel; and, in that
case, fiber may have to be restricted or limited to
minute particles to pass through the narrowed lumen.
Small, frequent feedings may be tolerated better than
large meals, and small amounts of isotonic, liquid,
oral supplements may be valuable in restoring intake
without provoking symptoms. In cases in which fat
malabsorption is likely, supplementation with foods
made with MCT may be valuable in adding calories
and serving as a vehicle for fat-soluble nutrients.
Box 30-5. Potential NutritionRelated Problems
Associated
With Inflammatory
Bowel Disease
Anemias related to blood loss and poor food
intake
Gastrointestinal (GI) narrowing and strictures
leading to bloating, nausea, bacterial overgrowth, and diarrhea
Inflammation and surgical resections resulting
in diarrhea and malabsorption of bile salts
and micronutrients and macronutrients
Increased GI secretions with inflammation and
increased transit leading to diarrhea and
malabsorption
Abdominal pain, nausea, vomiting, bloating,
diarrhea
Food aversions, anxiety, and fear of eating related to experiences with abdominal pain,
bloating, nausea, or diarrhea
Associations of foods, or the simple ingestion of
foods, with adverse symptoms of the disease
(leading to anxiety and avoidance of food,
which further limits intake)
Drug-nutrient interactions
True and perceived food allergies
Dietary restrictions, both iatrogenic and selfimposed
Growth failure, weight loss, micronutrient deficiencies, and protein-calorie malnutrition
Whether dietary factors cause exacerbations is not
clear, but they certainly can aggravate symptoms. Although study results are inconsistent, the dietary
factors commonly noted before exacerbations include increased sucrose intake, lack of fruits and
vegetables, a low intake of dietary fiber, and altered
omega-6/omega-3 fatty acid ratios (Reif et al, 1997;
Shoda et al, 1996). In a small number of patients, specific food allergies may be identified. The significance
of these factors is not clear, but they may simply reflect an overall poor-quality diet that may have increased the overall susceptibility of the GI tract to the
disease process. Modification of oral diets and nutritional formulas with omega-3 fatty acids, specific
amino acids (e.g., glutamine), and antioxidants and
the use of fermentable fibers (prebiotics) or probiotics
are therapeutic strategies being evaluated for management of IBD (Han et al, 1999; Jacobasch et al, 1999;
Madsen, 2001; Panes, 2001).
In everyday life, patients may have intermittent
“flares” of the disease characterized by partial obstructions, nausea, abdominal pain, bloating, or diarrhea. Patients can be taught to manage their disease
by selecting appropriate foods and beverages. For example, patients might be taught to restrict foods during bouts of diarrhea (see Table 30-1) or to limit fiber
(especially large particles) if partial obstruction is
suspected. They can also be shown how to increase
omega-3 fats with food choices and supplements so
as to benefit from their antiinflammatory effect.
Probiotic foods or supplements may hold promise
by modifying the microbial flora. In animal models of
inflammatory GI disease and in preliminary studies
of humans with IBD, ingestion of specific strains or
mixtures of probiotic organisms has been shown to
alter the GI flora and to prolong periods of remission
(Linskins et al, 2001; Madsen, 2001). Prebiotic foods
(e.g., oligosaccharides, fermentable fibers, and resistant starches) can serve as fuels for colonic flora and
result in altered microflora and increased production
of SCFAs. The altered flora and SCFAs produced may
also serve to attenuate the inflammatory process, especially in ulcerative colitis. Additional study continues to identify the dose and most effective prebiotic
and probiotic foods, the form in which they can be
used for therapeutic and maintenance purposes, and
their relative value compared with other forms of
therapy (Fukuda et al, 2002; Jacobasch et al, 1999).
Food intolerances are common in patients with
IBD, but the foods are variable among patients and
may not be incriminated consistently from one time
to the next. Patients are sometimes advised simply to
eliminate the foods that they suspect are responsible
for the intolerance. Often, however, the patient becomes increasingly frustrated as the diet becomes
more and more limited, and symptoms may not resolve. One study (Pearson et al, 1993) revealed no significant differences in the duration of remission between patients who did or did not identify food
sensitivities.
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Confirming true allergic GI reactions to foods is a
difficult and painstaking process (see Chapter 32).
The patient must be willing to consume either an
amino acid diet or a very restricted diet composed of
only three or four foods, with the addition of each of
the suspected foods one at a time. The allergen is
identified on the basis of subjective and objective
symptoms related to the repeated addition and elimination of the food. Circulating antibodies to food
proteins have been considered a sign of allergy but
may in fact be a sign of increased permeability rather
than local GI allergy.
The same foods that are most consistently responsible for GI symptoms (gas, bloating, and diarrhea) in a
normal healthy population are likely to be the triggers
for at least the same symptoms in patients with mild
stages of IBD or those in remission. Patients receive
nutritional information from a variety of sources, including support groups, Internet news groups, the
audio and printed media, well-meaning friends, and
food supplement salespersons. The information is
sometimes inaccurate or exaggerated, or it may pertain only to one individual’s situation. The health care
provider can help patients sort out the role of foods in
normal everyday GI disturbances and the role of foods
in IBD and teach them how to evaluate valid nutrition
information from unproved or exaggerated claims. Patients’ participation in the management of their disease may help to reduce not only the symptoms of the
disease but the associated anxiety level as well.
727
pain), but patients may describe combinations of GI
complaints. GI discomfort after meals or with psychosocial distress, bloating, gas, heightened gastrocolic response, lowered threshold for normal GI discomfort, and abnormal bowel movements are all
common with IBS.
The diagnosis is based on international consensus
criteria (ROME I or II criteria) and diagnostic algorithms that help to rule out other GI or surgical disorders that may manifest with similar symptoms
(Drossman, 1997; Thompson et al, 1999). According
to the criteria, symptoms of abdominal discomfort
must be present for at least 12 weeks of the past year
and include at least two of three features: discomfort
relieved by defecation, onset associated with a
change in frequency of stool, and onset associated
with a change in form of the stool.
The diagnosis is usually further refined to categorize the syndrome into subtypes, such as predominant
patterns of alternating constipation and diarrhea,
painless diarrhea, or constipation. The most common
symptoms are alternating diarrhea and constipation,
abdominal pain (typically relieved by defecation),
and bloating; but perception of excessive flatulence,
sensation of incomplete evacuation, rectal pain, and
mucus in the stool may also occur (Figure 30-6).
Anxiety
Psychogenic stress
Life stressors
DISORDERS OF THE LARGE
INTESTINE
Specific foods
Excess food
and beverages
Irritable Bowel Syndrome
Pathophysiology
Irritable bowel syndrome (IBS) is not a disease but a
common syndrome involving altered intestinal
motility, increased sensitivity of the GI tract, and increased awareness and responsiveness of the viscera
to enteral and external stimuli. The disorder likely involves more than the large intestine, but most of the
early speculation regarding the pathology of IBS focused on the colon. In IBS no obvious tissue damage,
no inflammation, and no immunologic involvement
are present. In all persons, the enteric nervous system
is sensitive to the presence, chemical composition,
and volume of foods, and the GI tract receives various types of input from the brain and the autonomic
nervous system (see Chapter 1).
Persons with IBS tend to overrespond to many of
these stimuli (Mayer, 2001; Simren et al, 2001). The
mediators may be abnormal secretion of peptide hormones or signaling agents (e.g., neurotransmitters secreted in response to the hormones). The syndrome
typically involves one of three predominant symptom patterns (diarrhea, constipation, or abdominal
Heightened GI response to enteric stimuli
Heightened awareness of GI activity
Heightened sensation of GI discomfort
FIGURE 30-6
teric stimuli.
•
Heightened gastrointestinal response to en-
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5 / MEDICAL NUTRITION THERAPY
Symptoms typically first occur between adolescence and the fourth decade of life, but many persons
do not bring the problem to the attention of a physician. In the United States, IBS occurs in about 20% of
women and 10% to 15% of men. It represents about
12% of visits to family medicine clinics and 20% to
40% of visits to gastroenterologists, and it is one of
the most common reasons for which patients first
seek medical care (Drossman et al, 1997; Olden and
Schuster, 1998). Persons with IBD often have increased absenteeism from school and work, decreased
productivity, increased health care costs, and decreased quality of life as a result of their symptoms.
Persons with IBS appear to have altered enteric
sensitivity and motility in response to usual GI and
environmental stimuli. They react more significantly
than normal persons to intestinal distention, dietary
indiscretions, and psychosocial factors (Drossman et
al, 1997). Normal persons may experience mild GI disturbances in response to all the situations mentioned,
but they appear to have a milder response. Life stressors, such as employment changes, travel, relocation,
or uncomfortable social situations, may trigger the onset or worsen symptoms and may override many
therapeutic efforts. A history of psychosocial trauma,
such as physical or sexual abuse, has been reported in
32% to 44% of cases, but the higher estimate may be
somewhat exaggerated as a result of sampling.
In addition to stress and dietary patterns, factors
that may worsen symptoms include (1) excess use
of laxatives and other over-the-counter medications,
(2) antibiotics, (3) caffeine, (4) previous GI illness, and
(5) lack of regularity in sleep, rest, and fluid intake. In
patients with a strong family history of allergy, hypersensitivity to certain foods may be the cause of
IBS (Bischoff et al, 1996). A trial of food elimination
and challenge may be justified under these circumstances (see Chapter 32).
Medical Management
Management includes a combination of approaches
to deal with the symptoms and the factors that may
trigger them. Education, medications, counseling,
and diet all play a role in the care. Depending on the
predominant pattern and severity of the symptoms,
medications may include antispasmodic, anticholinergic, antidiarrheal, prokinetic, or antidepressive
agents. Newer agents are being evaluated to target
specific neurotransmitters, peptides, or other mechanisms involved in the GI motility and enteric nervous
system. Biofeedback, relaxation, and stress reduction
techniques may also be useful (Drossman, 1997;
Villanueva et al, 2001).
Medical Nutrition Therapy
Unlike IBD, IBS is not life threatening and does not
result in maldigestion or malabsorption of nutrients.
However, dietary practices of persons with IBS may
result in a less than complete diet, insufficient nutrient intake, and less enjoyment of foods. Dietary selections and patterns are also important in controlling
symptoms.
The aim of nutritional care is to ensure adequate
nutrient intake, to guide the patient toward a diet
that is not likely to contribute to symptoms, and to
explain the role of ordinary dietary practices in producing or avoiding GI symptoms. The recommendations made for all persons for a good-quality diet are
probably even more important in IBS. Excesses of dietary fat; caffeine; sugars such as lactose, fructose,
and sorbitol (Rumessen and Gudmand-Hoyer, 1998);
large meals; and alcohol are less well tolerated than
in normal persons. Dietary fiber intake in adolescents
and adults is typically about half that recommended.
Excessive use of bran or coarse fibers is not needed or
recommended, but increasing dietary fiber to the recommended 25 g or so per day may help to normalize
bowel habit in all types of IBS patterns. If the patient
is not able to consume fiber from food sources or
does not respond adequately, fiber in the form of bulk
laxatives (e.g., psyllium) may be helpful. Consumption of adequate fluid is recommended, especially
when powdered fiber supplements are used. Large
doses of wheat bran are no longer recommended and
may exacerbate symptoms in some persons with IBS.
Foods with fiber, resistant starches, and oligosaccharides may also serve as prebiotic foods, which favor the maintenance of “healthy” microflora and resistance to pathogenic infections (Madsen, 2001;
Nobaek et al, 2000). Results of initial studies on the
use of prebiotic and probiotic supplements have been
mixed, but additional studies with different products, doses, and subtypes of IBS are needed. The nutrition practitioner can work with the person with
IBS to identify his or her concerns and perceptions,
review the characteristics of the disease and the potential role of foods, and teach the client how to reduce the food-related symptoms associated with the
syndrome. Sometimes clients become trapped in a vicious cycle in which anxiety about food, GI distress,
and social embarrassment leave them with an unnecessarily restrictive diet, worsening nutritional status,
increasing anxiety, and worsening symptoms. Calming reassurance and gradual return to a good diet
with limitations of only items that likely will exacerbate symptoms will often greatly improve the quality
of life.
Diverticular Disease
Pathophysiology
Diverticulosis is a situation of saclike herniations (diverticula) of the colonic wall, thought to result from
long-term constipation and increased colonic pressures (Figure 30-7). The incidence of diverticulosis increases with age. Thirty percent of persons older than
50 years of age, 50% of those older than 70 years, and
66% of those 85 years of age and older develop diver-
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729
FIGURE 30-8 • Actual internal photograph of diverticular
pouch. (Courtesy Pitt County Memorial Hospital, Greenville, N.C.)
FIGURE 30-7 • Mechanism by which low-fiber, low-bulk diets
might generate diverticula. Where the colon contents are bulky
(top), muscular contractions exert pressure longitudinally. If the fecal contents are small in diameter (bottom), contractions can produce occlusion and exert pressure against the colon wall, which
may produce a diverticular hernia.
ticulosis (Simmang and Shires, 1998). Sigmoid involvement occurs in almost all cases; right-sided
colonic involvement occurs in Asians, but it is rare in
whites).
The cause is not known for certain, but studies in
animals and humans relate the disorder to constipation and lifelong increased intracolonic pressures.
The pressures result from attempts to propel small,
dry, hard fecal material through the lumen of the
bowel. Theoretically, circular muscles completely
close around the fecal material when the stools are
small and longitudinal muscles contract, attempting
to push the contents distally. Increased pressures result in the opportunity for herniations of the mucosal
wall to develop through weaker segments of the
colon (Simmang and Shires, 1998) (see Figures 30-7
and 30-8). This theory is supported by epidemiologic
studies of populations consuming high- and lowfiber diets, prospective cohort studies in men, and experimental studies in animals fed low-fiber diets
throughout their lifetimes (Scheppach et al, 2001). An
abnormal pattern of excitatory innervation of the
colon has been associated with intraluminal pressures and the presence of diverticulosis, but it is not
known whether the pattern is a consequence of the
disorder or related to the cause (Tomita et al, 1999).
In general, diverticular disease is (1) relatively rare
in countries where a high-fiber diet is part of the lifelong pattern, and (2) increasing where “westernization” of the diet and increased intake of refined foods
of the diet have begun (Camilleri et al, 2000; Scheppach et al, 2001). Lack of exercise may also contribute
to the development of diverticular disease, presumably because of the more sluggish movement of GI
contents (Peters et al, 2001).
Medical and Surgical Treatment
Complications of diverticular disease range from
painless, mild bleeding and altered bowel habits to
diverticulitis, which may include its own clinical
spectrum of inflammation, abscess formation, acute
perforation, acute bleeding, obstruction, and sepsis.
About 10% to 25% of patients with diverticulosis develop diverticulitis, and about one third of those admitted to hospitals for diverticular disease require
surgery. Death rates in patients requiring surgical intervention may be as high as 10% (Deckman and
Cheskin, 1993).
Medical Nutrition Therapy
At one time it was thought that “roughage” (dietary
fiber) aggravated diverticular disease, so the classic
diet therapy was one that was low in fiber. It is now
recognized that a high-fiber diet promotes soft, bulky
stools that pass more swiftly, require less straining
with defecation, and result in lower intracolonic pressures (Scheppach et al, 2001). High-fiber intakes have
been found to relieve symptoms for most patients,
and exercise appears to aid in both constipation and
diverticular disease (Cheek and Radley, 1999; Peters,
2001; Sheppach et al, 2001).
Patients who have followed a low-fiber diet for
years may require extensive encouragement to adopt
the high-fiber approach. Fiber intake should be increased gradually because it may cause bloating or
gas; however, these side effects usually disappear
within 2 to 3 weeks. In cases in which the patient cannot consume the necessary amount of fiber, methylcellulose and psyllium fiber supplements have been
used with good results. Adequate fluid intake (e.g., 2
to 3 L daily) should accompany the high-fiber intake.
For patients with an acute flareup of diverticulitis,
a low-residue diet, elemental diet, or, in complicated
cases, total parenteral nutrition may be required initially, followed by a gradual return to a high-fiber
diet. Colonic smooth-muscle contractions, which in-
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5 / MEDICAL NUTRITION THERAPY
tensify after a high-fat meal, may contribute to the
discomfort felt by persons with diverticular disease
(Snape, 1994). Therefore, a low-fat diet may be reasonable to suggest for these patients, at least initially.
The question of whether the consumption of
seeds, nuts, or skins of plant matter should be
avoided to prevent complications of diverticular disease or after bouts of diverticulitis to aid in healing
remains unresolved. Common sense tends to favor
avoiding consumption of very coarse materials such
as husks (not necessarily seeds) like those surrounding sunflower seeds and peanuts. Whether seeds or
normal fibrous materials play any role in the onset of
symptoms or actually harm the diverticula has not
been determined. In patients with clear cases of perforation or obstruction, large pieces of coarse plant
matter might be restricted and patients should be encouraged to chew fibrous foods thoroughly.
preparation methods may also influence the carcinogenic potential of meats and fatty foods (Giovannucci
and Goldin, 1997; Parodi, 1997) (see Chapter 40).
The use of prebiotics and probiotics alters colonic
microflora, induces glutathione transferase, increases
butyrate content of the stool, reduces toxic and genotoxic compounds, and in animal models reduces the
development of some precancerous lesions (Brady et
al, 2000; Wollowske et al, 2001).
Medical Management
Patients diagnosed with colorectal polyps or cancer
may require moderate to significant interventions,
including medications, radiation therapy, chemotherapy, colonic surgery, and parenteral nutritional
support.
Medical Nutrition Therapy
Colon Cancer and Polyps
Pathophysiology
In the United States, colon cancer is the second most
common cancer in adults (after lung cancer) and is
also the second most common cause of death. The
number of new cases of colorectal cancer in 2002 was
estimated to be about 148,000 cases (American Cancer Society, 2002). Worldwide, it is the third most
common malignant neoplasm and the second leading cause of cancer deaths. Colon cancer occurs more
commonly in men than in women (52 versus 38 cases
per 100,000 population, respectively). The highest
rates are seen in whites of northern European origin.
Rates in Africa and Asia are lower, but they tend to
rise with migration and westernization.
Factors that increase the risk of colorectal cancer
include family history, occurrence of IBD (both
Crohn’s disease and ulcerative colitis), familial polyposis, adenomatous polyps, and several dietary components. Polyps are considered precursors of colon
cancers (see Chapter 40).
Use of aspirin and nonsteroidal antiinflammatory
agents and exercise appear to be protective against
colon cancer (Peters et al, 2001; Reddy, 2000; Slattery,
2000). Dietary risk factors may include increased
meat or fat intake and inadequate intake of several
micronutrients. Protective factors include intake of
fruits, vegetables, several phytochemicals, high-fiber
grains, omega-3 fatty acids, and carotenoids; maintenance of acceptable weight; the vitamins D, E, and folate; and the minerals calcium, zinc, and selenium
(Garland et al, 1999; Reddy, 2000; Wollowske et al,
2001).
The role of dietary fat in colon carcinogenesis is not
entirely clear because different dietary lipids may have
different effects. Red meats, such as beef, pork, and
lamb, along with their fats, may be incriminated more
than other types of meats; poultry, fish, and dairy fats
appear to have less of a role in carcinogenesis. Food
Most Americans consume far less than the recommended amounts of fruits, vegetables, legumes,
whole grains, and dairy products. Therefore the best
advice for many patients might be to improve their
diet based on recommendations from the American
Cancer Society or the National Research Council or
the Dietary Guidelines for Americans. These recommendations promote the consumption of adequate
amounts of whole-grain breads and cereals, calciumcontaining foods, fruits and vegetables, adequate micronutrient intake, and reasonable amounts of omega3 fatty acids (from marine sources and other sources,
such as flaxseed oil) along with adequate exercise.
Cancer survivors should also be encouraged to follow
these same nutrition and exercise guidelines.
INTESTINAL SURGERY
Small-Bowel Resections and ShortBowel Syndrome
Short-bowel syndrome (SBS) refers to the malabsorption of fluid and nutrients associated with significant
resections of the small intestine, which results in only
3 to 5 feet of intact small bowel remaining. The
healthy small intestine has significant reserve, but resections of 40% to 60% may lead to several consequences of SBS, depending on the site of the resection
and other factors. Resection of the distal ileum has
the most significant impact on risk of SBS. Colonic resections alone do not produce SBS, but the risk of dehydration, electrolyte disorders, and malnutrition is
increased after distal small-bowel resections or colon
removal. The most common reasons for major resections of the intestine in adults include Crohn’s disease,
radiation enteritis, mesenteric infarct, malignant disease, and volvulus (Beyer, 2001). In the pediatric pop-
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ulation, most cases of SBS result from congenital
anomalies of the GI tract, atresia, volvulus, or necrotizing enterocolitis (Sigalet, 2001).
Obvious complications of short-bowel syndrome
include malabsorption of micronutrients and macronutrients, fluid and electrolyte imbalances, weight
loss, and growth failure (in children). Gastric hypersecretion, oxalate renal stones, cholesterol gallstones,
and rarely d-lactic acidosis may also occur (Sundarum
et al, 2002). The severity of malabsorption, the extent
of complications, and the degree of dependence on
parenteral nutritional support reflect the length and
location of the resection, the age of the patient at the
time of the operation, and the health of the remaining
GI tract (Beyer, 2001; Wilmore et al, 1997) (Box 30-6).
Jejunal Resections
Normally most digestion and absorption of food and
nutrients occurs in the first 100 cm of small intestine.
What remains to be digested or fermented and absorbed are small amounts of sugars, resistant starch,
fiber, lipids, dietary fiber, and fluids. After jejunal resections, the ileum is able to perform the functions of
the jejunum, especially after a period of adaptation.
The motility of the ileum is comparatively slow, and
hormones secreted in the ileum and colon help to
slow gastric emptying and secretions. Because jejunal
resections result in reduced surface area and shorter
intestinal transit than normal, the functional reserve
for absorption of micronutrients, excess amounts of
sugars (especially lactose), and lipids is reduced.
factor complex and bile salts, and the ileum normally absorbs a major portion of the several liters of
fluid ingested and secreted into the GI tract (see
Chapter 1). Although malabsorption of bile salts
may appear to be a rather benign problem, it creates
a potentially serious cascade of consequences (Beyer,
2001) (Box 30-7).
If the ileum cannot “recycle” bile salts secreted
into the GI tract, hepatic production cannot maintain
a sufficient bile salt pool or the secretions to emulsify
lipids. The gastric and pancreatic lipases are capable
of digesting some triglycerides to fatty acids and
monoglycerides, but without adequate micelle formation facilitated by bile salts, lipids are poorly absorbed. This can result in significant malabsorption
of fats and fat-soluble vitamins A, D, and E. In addition, malabsorption of fatty acids results in their combination with divalent cations, such as calcium, zinc,
and magnesium, to form fatty acid–mineral “soaps.”
This results in malabsorption of these nutrients. To
compound matters, colonic absorption of oxalate,
which normally is bound to the divalent cations, is
increased, leading to hyperoxaluria and increased renal oxalate stones. Relative dehydration and concentrated urine, which are common with ileal resections,
may further increase the risk of stone formation.
If the patient has any colon left, malabsorption of
what bile salts are secreted can act as irritants to the
mucosa, resulting in increased fluid and electrolyte
secretion and increased colonic motility rather than
absorption. Consumption of high-fat diets with ileal
Ileal Resections
Significant resections of the ileum, especially the
distal ileum, generally produce major nutritional
and medical complications. The distal ileum is the
only site for absorption of the vitamin B12/intrinsic
Box 30-6. Factors Affecting the
Course of Short-Bowel
Syndrome
Length of remaining small intestine
Loss of ileum, especially distal one third
Loss of ileocecal valve
Loss of colon
Disease in remaining segment(s) of gastrointestinal tract
Radiation enteritis
Coexisting malnutrition
Older age at surgery
731
Box 30-7. Consequences of Ileal
Resection
Rapid transit of intestinal contents
Decreased fluid absorptive area
Malabsorption of vitamin B12/intrinsic factor
complex
Malabsorption of bile salts
Inadequate bile salts for lipid solubilization, digestion, and absorption, leading to loss of fat
and fat-soluble nutrients
Loss of secreted bile salts into colon because of
decreased reabsorption
Formation of hydroxy fatty acids by colonic bacteria from malabsorbed fat, resulting in decreased fluid and electrolyte absorption
Malabsorption of Ca2, Mg2, and Zn2 because
of formation of insoluble “soaps” with malabsorbed free fatty acids
Increased risk of oxalate stones because of increased colonic absorption of oxalate, which
normally binds to Ca2, Zn2, and Mg2
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5 / MEDICAL NUTRITION THERAPY
resections and retained colon may also result in the
formation of hydroxy fatty acids, which also can increase fluid secretion. Cholesterol gallstones may occur more often because the ratio of bile acid, phospholipid, and cholesterol in biliary secretions is
altered as a result of ileal resections. Dependence on
parenteral nutrition may further increase the risk of
biliary “sludge” secondary to decreased stimulus for
evacuation of the biliary tract.
Lactic acidosis is a relatively rare complication
that occurs only with severe SBS and remaining
colon. The problem results from excessive intake and
malabsorption of carbohydrate. Metabolic acidosis
and production of d-lactate result from fermentation
of carbohydrate, production of SCFAs, reduced
colonic pH, and proliferation of acid-resistant colonic
microbes that produce d-lactate (Bongaerts et al,
1997). The problem is resolved by treating the metabolic acidosis and reducing the intake of sugars and
total carbohydrates.
Medical and Surgical Management
of Resections
Medications are prescribed to retard gastric emptying, decrease secretions, slow GI motility, and treat
bacterial overgrowth. Recently, somatostatin and somatostatin analogs and other hormones with antisecretory, antimotility, or trophic actions have been
used to retard both motility and secretions (Drucker,
2002; Sundarum et al, 2002). Surgical procedures, including reversal of segments of bowel to slow transit
of GI contents, creation of reservoirs (“pouches”) to
serve as a form of colon, intestinal lengthening, and
intestinal transplant, have been performed to help
patients with major GI resections (Pirenne et al,
2001). Intestinal transplant is still one of the most difficult organ transplants and is typically reserved for
gut failure and when patients develop significant
complications from TPN.
Medical Nutrition Therapy
Most patients who have significant bowel resections
require TPN initially to restore and maintain nutritional status (Sundaram et al, 2002). The duration of
TPN and subsequent nutrition therapy is based on
the extent of the bowel resection, the health of the patient, and the condition of the remaining GI tract. In
general, older patients with major ileal resections, patients who have lost the ileocecal valve, and patients
with residual disease in the remaining GI tract do not
fare as well. Some may require lifetime supplementation with parenteral nutrition to maintain adequate
fluid and nutritional status.
The two general principles for resuming enteral
nutrition after small-bowel resections are (1) to start
enteral feedings early and (2) to increase feeding concentration and volume gradually over time (Beyer,
2001; Vanderhoof and Young, 2001). The role of en-
teral feedings is to provide a trophic stimulus to the
GI tract; parenteral nutrition is used to restore and
maintain nutrient status. The more severe the problem, the slower the progression. Small, frequent, minimeals (6 to 10 per day) are likely to be better tolerated
than larger feedings. If enteral feedings are used,
gradual introduction of feedings stimulates GI adaptation; TPN provides the major source of fluid and
nutrients. More nutrients are gradually added enterally, and the volume or concentration of TPN decreases accordingly. Because of malnutrition and disuse of the GI tract, the digestive and absorptive
functions of the remaining GI tract may be compromised, and malnutrition itself will delay adaptation
(Cronk et al, 2000). The transition to more normal
foods may take weeks to months, and some patients
may never tolerate normal concentrations or volumes of foods.
Maximal adaptation of the GI tract may take up to
a year after surgery. Adaptation improves function,
but it does not restore the intestine to normal length
or capacity. Whole foods are some of the most important stimuli to the GI tract, but other nutritional
measures have been considered as a means of hastening the adaptive process and decreasing malabsorption. Glutamine, for example, is the preferred fuel for
small intestinal enterocytes and so may be valuable
in enhancing adaptation. Nucleotides may also enhance mucosal adaptation, but unfortunately they
are often lacking in parenteral and enteral nutritional
products. SCFAs (e.g., butyrate, propionate, acetate),
produced from microbial fermentation of carbohydrate and fibers, are major fuels of the colonic epithelium (Mortensen and Clausen, 1996).
Patients with jejunal resections and an intact ileum
and colon will likely adapt quickly to normal diets. A
normal balance of protein, fat, and carbohydrate
sources is satisfactory. Six small feedings, with avoidance of lactose, large amounts of concentrated
sweets, and caffeine, may help to reduce the risk of
bloating, abdominal pain, and diarrhea. Because the
typical American diet may be nutritionally lacking
and utilization of some micronutrients may be marginal, patients should be advised that the quality of
their diet is of utmost importance. A multivitamin
and mineral supplement may be required to meet nutritional needs.
Patients with ileal resections require increased
time and patience in the advancement from parenteral to enteral nutrition. Because of losses, fatsoluble vitamins, calcium, magnesium, and zinc may
need to be supplemented. Dietary fat may need to be
limited, especially in those with remaining colon.
Small amounts at each feeding are more likely to be
tolerated and absorbed. MCT products add to the
caloric intake and serve as a vehicle for lipid-soluble
nutrients.
Because boluses of MCT oil (e.g., taken as a medication in tablespoon amounts) may add to the patient’s diarrhea, it is best to divide the doses equally
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
in feedings throughout the day. Fluid and electrolytes, especially sodium, should be provided in
small amounts and frequently.
In patients with massive resections (e.g., when the
duodenum and a few inches of jejunum are anastomosed to segments of colon), an oral diet will be able
to nourish only partially. In some cases, overfeeding
in an attempt to compensate for malabsorption results in further malabsorption, not only of ingested
foods and liquids but also of the significant amounts
of GI fluids secreted in response to food ingestion.
Patients with an extremely short bowel are typically
nutritionally dependent on parenteral solutions for at
least part of their nutrient and fluid supply. Small,
frequent snacks provide some oral gratification for
these patients but typically can supply only a portion
of their fluid and nutrient needs.
733
nutritional support is mandatory to permit spontaneous or surgical closure of the fistula and wound.
Medical Nutrition Therapy
Either TPN or defined liquid formula diets have been
used successfully in patients with fistulas (see Chapter 23). The success rate of either method depends on
the location and the cause of the fistula and the patient’s overall condition.
Ileostomy or Colostomy
Pathophysiology
Blind-loop syndrome is a disorder characterized by
bacterial overgrowth resulting from stasis of the intestinal tract as an outcome of obstructive disease, radiation enteritis, fistula formation, or surgical repair
of the intestine. Bacteria deconjugate bile salts, which
besides being cytotoxic in this form, are also less effective as micelle formers. Poor fat absorption and
steatorrhea result. Carbohydrate malabsorption occurs because of injury to the brush border secondary
to the toxic effects of the products of bacterial catabolism and consequent enzyme loss. The expanding
numbers of bacteria use the available vitamin B12 for
their own growth.
Patients with severe ulcerative colitis, Crohn’s disease,
colon cancer, or intestinal trauma frequently require
the surgical creation of an opening from the body
surface to the intestinal tract to permit defecation
from the intact portion of the intestine. When the entire colon, rectum, and anus must be removed, an
ileostomy, or opening into the ileum, is performed. If
only the rectum and anus are removed, a colostomy
can provide entrance to the colon. In some cases, a
temporary opening may be made to allow surgery
and healing of more distal parts of the intestinal tract.
The opening, or stoma, eventually shrinks to the
size of a nickel. The output from the stoma depends on
its location, as shown in Figure 30-9. The consistency of
the stool from an ileostomy is liquid, whereas that from
a colostomy ranges from mushy to fairly well formed.
Stool from a colostomy on the left side of the colon is
firmer than that from a colostomy on the right side.
Odor is a major concern of the patient with an ileostomy or colostomy; however, an ileostomy stool usually
has a weakly acidic odor that is not unpleasant.
Medical Treatment
Medical Treatment
Treatment is directed toward the removal of the blind
loop or control of the bacterial growth with antibiotics.
Patients with a permanent colostomy or ileostomy require sympathetic understanding from the entire
health care team. Acceptance of the condition and the
problems involved in maintaining bowel regularity is
usually difficult. Nursing personnel, especially ostomy specialists, can play a major role in supporting
and teaching patients with ostomies. Having these
patients meet other people who have undergone similar surgery may help with the adjustment. Eventually, they may be encouraged by the realization that,
in the future, they will not have the multiple hospitalizations or chronic disabilities that accompanied
their intestinal disease.
Blind-Loop Syndrome
(Bacterial Overgrowth)
Pathophysiology
Medical Nutrition Therapy
Use of a lactose-free diet, along with MCT and parenteral vitamin B12, may be useful.
Fistula Repair
Pathophysiology
Fistulas occur as a result of prenatal developmental
error, trauma, or inflammatory or malignant disease
processes. Fistulas of the intestinal tract can be serious threats to nutritional status because large
amounts of fluid and electrolytes are lost, and malabsorption and infection can occur.
Medical Treatment
Fluid and electrolyte balance must be restored; infection must be brought under control; and aggressive
Medical Nutrition Therapy
Malodorous stool is usually caused by steatorrhea or
bacteria acting on particular foodstuffs to produce
odorous gas. Because an individual patient may have
different flora, types and amounts of gases and odors
may differ among patients and with different dietary
practices. Patients learn to observe their stools to de-
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5 / MEDICAL NUTRITION THERAPY
Poor motility can cause
greater absorption. Hard
feces in the transverse
colon can cause constipation.
Semi-fluid
Semi-mush
Mush
Fluid
Solid
Ileocecal valve
Hard solid
Excess motility can
cause less absorption,
which results in diarrhea
or loose feces.
FIGURE 30-9 • As the feces move from the ileocecal valve to
the anus, water is absorbed and the feces become more solid. The
characteristics of the output from a colostomy depend on its location in the colon.
termine which foods to eliminate, and this differs
from one patient to the next. Foods that tend to cause
odor from a colostomy are legumes, onions, garlic,
cabbage, highly spiced foods, fish, antibiotics, and
some vitamin and mineral supplements. Persistent
odor may be attributable to poor stoma hygiene or to
an ileostomy complication that allows bacterial overgrowth in the ileum. Deodorants are available, and
modern pouch appliances are odor proof. Gas production may cause the pouch to become tense and
distended, and accidental dislodgment is likely. The
nutritional recommendations for reducing flatulence,
presented at the beginning of this chapter, may be
helpful for patients with colostomies.
The normal output from the ileum to the colon is
in the range of 750 to 1.5 L in the intact GI tract. After
a colectomy and creation of an ileostomy, adaptation
occurs within 1 to 2 weeks. Fecal output will lessen
and stools will become less liquid. Reduction in stool
volume may not occur to the same extent in patients
who have had an ileal resection in addition to a colectomy. Depending on the amount of ileum resected,
their ileal output may be 1.5 to 5 times greater than
that of the patient who has had only a colectomy. Patients with ileostomies have an above-average need
for salt and water to compensate for excessive losses
in stool. Inadequate water intake can result in small
urine volumes and a predisposition for renal calculi.
A normal diet provides adequate sodium, and patients should be instructed to drink at least 1 L more
than their ostomy output daily.
The patient with a normal, functional ileostomy
usually does not become nutritionally depleted. Surgical procedures, such as ileostomy, may require specific dietary changes but no greater energy intake;
caloric expenditures in these patients are similar to
those of normal subjects. Those who also undergo resection of the terminal ileum need vitamin B12 supplementation or intravenous injections. Patients with
an ileostomy may have low vitamin C and folate intakes because of low fresh vegetable and fruit intakes, and they require supplementation. Patients
with ileostomies should be guided by physiologic
reasons for intolerance of foods, not by anecdotal reports. Because it is possible for a food bolus to get
caught at the point where the ileum narrows as it enters the abdominal wall, it is important to warn the
patient to avoid very fibrous vegetables and to chew
all food well. Other than this, patients with either an
ileostomy or a colostomy should be encouraged to
follow their normal diet, omitting only those foods
known to cause problems.
Ileal Pouch After Colectomy
Pathophysiology
As an alternative to creation of an ileostomy for persons who have had their colons removed, surgeons
can create a reservoir using a portion of the distal
ileum (ileal pouch). Folds of the ileum are joined together to create a small pouch, which is then connected to the rectum and ileum. This is called an ileal
pouch–anal anastomosis (IPAA). The most common
pouch is the J pouch, but S and W pouches are
sometimes created using additional folds of ileum
(Pemberton and Phillips, 1998). Like the colon, the
pouch develops a microflora capable of at least partially fermenting fiber and carbohydrate (Alles et al,
1997). Because the reservoir is smaller than the colon,
bowel movements are likely to occur more frequently
than normal, between four and eight times daily.
Medical Treatment
Vitamin B12 injections are usually required because,
as in blind loop syndrome, the microbes may compete for and bind intraluminal vitamin B12. Other
problems commonly reported include obstruction,
“pouchitis,” and increased stool output, frequency,
and gas (Thompson-Fawcett et al, 1997; Pemberton
and Phillips, 1998).
The incidence of obstruction may be lessened with
attention to particle size of fibrous foods, chewing
thoroughly, and consuming small meals frequently
throughout the day. Stool frequency and volume do
not return to normal, however. The normal, intact
colon absorbs 80% to 90% of the liter or so of fluid entering from the ileum, leaving only 100 to 200 ml. After surgery, the remaining ileum does adapt to a
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30 / Medical Nutrition Therapy for Lower Gastrointestinal Tract Disorders
small degree by increasing efficiency of fluid absorption, but even after adaptation, fluid output is always
in the range of 300 to 600 ml.
Pouchitis, as implied by the name, is an inflammation of the mucosal tissue forming the pouch. The associated pathologic changes have been described as
being somewhat similar to that of IBD (e.g., ulcerative colitis) (Goldstein et al, 1997). The cause of pouchitis is not entirely clear, but it may be related to selected bacterial overgrowth, bile salt malabsorption,
or insufficient SCFA production. Antibiotics are the
primary form of therapy, but experiments with different types of dietary fiber, prebiotics and probiotics,
and other nutrient components are being investigated (Alles et al, 1997; Sandborn et al, 2000).
735
Clinical Scenario 1
Suzanne is a 33-year-old teacher with Crohn’s disease who
has been referred for evaluation because of abdominal
pain, bloating, and occasional nausea and diarrhea. The
physician suspects a distal small-bowel stricture. Suzanne
is seeking information about what to eat to prevent the
problem from worsening during the 3-day period before her
appointment at the clinic.
1. What information would be appropriate to gather about
this patient before you advise her about a nutritional
plan?
2. What, in terms of Suzanne’s symptoms, makes the
physician suspect a stricture?
3. What kind of dietary advice, based solely on her presumed problem, might be warranted?
Medical Nutrition Therapy
The same dietary measures that are used by others to
reduce excessive stool output (reduced caffeine, lactose avoidance in lactose-intolerant persons, avoidance of sorbitol ) will likely reduce stool volume and
frequency in persons with pouches. Adequate fluid
and electrolyte intake are especially important because of the increase in intestinal losses.
Rectal Surgery
Nutritional care after rectal surgery, such as hemorrhoidectomy, should be directed toward maintaining
an intake that will allow wound repair and prevent
infection of the wound by feces. The frequency of
stools is minimized by the use of constipating drugs
and a minimal-residue diet (see Table 30-1). Chemically defined diets are low in residue, and their use
can reduce stool volume and frequency to as little as
50 g every 6 days, making the surgical construction
of a temporary colostomy unnecessary. A normal
diet is resumed after healing is complete, and the patient is instructed about the benefits of eating a highfiber diet to avoid constipation in the future (see
Table 30-1).
SUMMARY
The GI tract is one of the largest sites of exposure to
the outside environment. The function of the GI tract
in monitoring and sealing the host interior (gut barrier) plays an important role in health maintenance.
Disruptions in the gut barrier following injury from
nonsteroidal antiinflammatory drugs and oxidative
stress have been linked to multiorgan system failure
in sepsis and immune dysregulation (DeMeo et al,
2002). Contribution of gut barrier dysfunction to GI
disease is an evolving concept. As evidence for the
role of gut barrier dysfunction in disorders such as
Crohn’s disease, celiac disease, food allergy, and related disorders mounts, new treatments and medical
nutrition therapies will be developed.
Clinical Scenario 2
Mrs. Smith has IBS with a pattern of alternating constipation and diarrhea. She comes to you requesting dietary advice for (1) day-to-day management and (2) what might be
“safest” to eat when she is getting ready to present weekly
to biweekly reports to the executives in her large consulting
company.
1. What do you want to know about Mrs. Smith’s diet, perspectives, and lifestyle?
2. What foods or eating patterns would be best (or best to
avoid) for Mrs. Smith for her day-to-day activities?
3. Why might she be asking for advice during stressful
periods?
■
R e l e v a n t We b S i t e s
Celiac Disease
www.niddk.nih.gov/health/digest/pubs/celiac/
Crohn’s Colitis Foundation
www.ccfa.org/
Gastrointestinal Disorders and Treatment
www.niddk.nih.gov/health/digest/digest.htm
Gluten Enteropathy Resources
www.gluten.net
www.glutenfreediet.com
www.niddk.nih.gov/health/digest/pubs/celiac/
■
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