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Chapter 16
Nutrition and Drugs for
Metabolism
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Chapter 16
Topics
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Physiology of Nutrition
Micronutrient Abnormalities
Enteral and Parenteral Nutrition
Obesity
Herbal and Alternative Therapies
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Physiology of Nutrition
Evaluating Nutrition Status
• Both external and internal physiological processes are
involved in weight maintenance
• To evaluate nutrition status, compare “normal” body
weight for a patient’s age and development with ABW
 Someone within the normal range
 Shows no signs of vitamin or nutrient deficiency
 Maintains an appropriate body weight and makeup
• Best indicator of nutrition status in children is appropriate
growth (including height and weight by age)
 Growth charts with population averages are used
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Physiology of Nutrition
IBW (Adults)
• IBW is the weight for a given height that is associated with
maximum longevity and health
• To assess basic nutritional status, compare patient’s ABW
with IBW
• Many times, IBW is used to determine proper weightbased dose (sometimes ABW can be used)
To Calculate IBW in Adults
Males: IBW (kg) = 50 + (2.3 × height in inches over 5 feet)
Females: IBW (kg) = 45.5 + (2.3 × height in inches over 5 feet)
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Physiology of Nutrition
BMI
• Another way to assess appropriate weight for height
 Used to identify both undernutrition and overnutrition
• Due to increased muscle mass, some males and athletes
may not be considered overweight until BMI reaches 27
• In children and teens, BMI must be compared to averages
in growth for age to be interpreted correctly
To Calculate BMI
BMI = weight (kg) / [height (m)]2
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Physiology of Nutrition
Calories
• Good nutritional status is maintained through appropriate
energy intake and expenditure
• Energy intake is measured in calories (kcal/kg)
• Appropriate daily caloric needs depend on age
 For adults, an intake of 25 kcal/kg of body weight a day
is usually adequate to maintain basal metabolic rate
 Malnourished and critically ill patients need more
calories
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Physiology of Nutrition
Nutrients
• In addition to calories, the body needs appropriate
amounts of protein, carbohydrates, fluids, micronutrients
• Protein needs vary depending on age, disease state, and
clinical condition
• Micronutrients include vitamins and minerals (electrolytes
and trace elements); key role in many metabolic processes
• In 2005, federal government published RDIs for vitamins
and essential trace elements
 RDI values of micronutrients measured in mg, mcg, IU
 Vitamins, hormones, and other medications are in IU
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Physiology of Nutrition
Obesity and Malnutrition
• Obesity is overnutrition; an obese body composition has
significantly more fat than is considered normal or healthy
• Malnutrition is a lack of adequate nutrient intake to supply
basic metabolic needs; related to two conditions
 Overall lack of calorie or protein consumption
 Specific micronutrient (vitamins, minerals) deficiency
• Malnutrition is most prevalent in underdeveloped
countries and in children.
• In the U.S., malnutrition is associated with disease states,
acute illness, and sometimes drug therapy.
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Physiology of Nutrition
Malnutrition Conditions
• Marasmus is a chronic condition caused by inadequate
caloric and protein intake over a prolonged time
• Cachexia is the wasting away of muscle and fat tissue due
to starvation and the effects of cancer
• Kwashiorkor is a condition in which caloric intake is
adequate, but protein intake is deficient
 Patients appear well nourished, but fluid accumulates
in the abdomen and feet
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Micronutrient Abnormalities
About Micronutrients
• Deficiencies or excesses of vitamins, minerals, and
essential fatty acids can cause significant morbidity
• Fat-soluble vitamins (A, D, E, and K) accumulate in fatty
tissue and can build up in the body over time
• Water-soluble vitamins (eight B vitamins and vitamin C)
are easily excreted in urine; overdose is uncommon
• Vitamin and mineral deficiencies measured with lab tests
• Vitamins and minerals are dietary supplements used to
treat or prevent malnutrition; they are not regulated
• For signs of deficiency and toxicity, see Table 16.4
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Micronutrient Abnormalities
Vitamin A
• Part of a family of compounds called retinoids
• Necessary for vision, growth, bone formation,
reproduction, immune system function, and skin health
• Sources: eggs, whole milk, butter, meat, and fish
 One compound, beta carotene, can be found in
vegetables (especially carrots) and fruits
• Indications: cases of deficiency; cataracts; reducing
complications of HIV, measles, and malaria
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Micronutrient Abnormalities
Thiamin (B1)
• Important coenzyme involved in carbohydrate metabolism
• Sources: pork, cereal, grains, peas, beans, and yeast
• Indications: cases of deficiency, which are most common
during pregnancy and during alcohol withdrawal
Riboflavin (B2)
• Coenzyme in tissue respiration and normal cell metabolism
• Sources: milk, cereal, green vegetables, and some meats;
made in the intestines by bacteria
• Indications: cases of deficiency, migraine headaches
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Micronutrient Abnormalities
Niacin (B3) or Nicotinic Acid
• Essential vitamin B complex for body reactions that
produce adenosine triphosphate (molecule in cellular
energy production)
• Necessary for the regulation of cholesterol production and
activity
• Sources: yeast, lean meats, peanuts, peas, beans, whole
grains, and potatoes
• Indications: cases of deficiency, lowering of cholesterol
(lowers triglycerides and LDL and raises HDL)
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Micronutrient Abnormalities
Pantothenic Acid (B5)
• Precursor of coenzyme A
• Necessary for the proper metabolism of carbohydrates,
proteins, and lipids
• Sources: vegetables, yeast, cereal, organ meats (liver,
kidney, heart)
• Indications: cases of deficiency
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Micronutrient Abnormalities
Pyridoxine (B6)
• B vitamin that the body converts to the coenzymes
responsible for amino acid metabolism
• Sources: most foods of plant or animal origin
• Indications: cases of deficiency; types of anemia and
seizure disorders; alcoholic patients with nerve damage;
patients with TB who take isoniazid, which depletes B6
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Micronutrient Abnormalities
Biotin (B7)
• Coenzyme involved in metabolism
• Deficiencies of it are associated with altered absorption,
such as short gut syndrome
• Sources: green leafy vegetables, liver, carrots, almonds
• Indications: cases of deficiency
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Micronutrient Abnormalities
Folate (B9) or Folic Acid
• Essential for intracellular metabolism and the breakdown
of homocysteine (amino acid associated with CV disease);
involved in serotonin (a neurotransmitter) production
• Deficiencies cause anemia and neural tube defects in a
developing fetus; deleterious effects on the cardiovascular
system
• Sources: green leafy vegetables, red meat; food additive
• Indications: cases of deficiency, pregnant women or those
planning to get pregnant, end-stage kidney disease,
depression, chronic fatigue syndrome, vitiligo
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Micronutrient Abnormalities
Cyanocobalamin (B12)
• Coenzyme necessary for cell reproduction, normal growth,
and red blood cell production
• Necessary for proper use of folate in the body; deficiency
causes pernicious anemia
• Sources: meats, fish, milk, bread
• Indications: cases of deficiency (common in elderly, strict
vegetarians); pernicious anemia; end-stage renal disease
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Micronutrient Abnormalities
Vitamin C (Ascorbic Acid)
• Important in immune system function and as an
antioxidant (reduce DNA mutations that lead to cancer)
• Sources: vegetables and fruits, especially citrus fruits
• Indications: cases of deficiency (scurvy), improvement of
iron absorption
• Indications (other): protein metabolism in premature
infants, macular degeneration, seasonal allergies,
prevention of the common cold
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Micronutrient Abnormalities
Vitamin D
• It maintains calcium and phosphate levels in the blood;
enhances intestinal absorption of calcium (bone health)
• Possible role in cardiovascular health, development of
cancer, and respiratory disease
• Two active forms: ergocalciferol and cholecalciferol
 Ergocalciferol is in plants and yeasts; cholecalciferol is
made in the skin in response to sunlight
• Sources: fortified milk, some eggs, tuna, sardines
• Indication: maintenance of bone health
• Taken with calcium supplements to improve absorption
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Micronutrient Abnormalities
Vitamin E (Alpha Tocopherol)
• Fat-soluble vitamin
• Sources: vegetable oils, cereals, grains, animal fat, meat,
poultry, eggs, fruits, and vegetables
• Indications (topical): improvement of skin health
• Indications (supported by studies): macular degeneration,
Alzheimer’s disease, reduction of risk for some types of
cancer and dementia
• Indications (controversial): improvement of immune
system function, diabetic retinopathy, cardiovascular
disease
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Micronutrient Abnormalities
Vitamin K or phytonadione
• Coenzyme for hepatic production of blood clotting factors
• Sources: green leafy vegetables, broccoli, brussels sprouts,
plant oils, margarine
• Deficiency can be caused by drug therapy
• Indication: cases of deficiency, enhanced blood clotting,
reversal of the effects of warfarin (an anticoagulant)
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Micronutrient Abnormalities
Vitamins: Side Effects and Cautions
• Side Effects: most result from excess intake and mimic
conditions of vitamin toxicity (see Table 16.4)
• Side Effects (niacin products, common): flushing, hot
flashes, a sensation of prickly skin
• Cautions: doses higher than the RDI of vitamin A are
category X (contraindicated) in pregnant women
 Vitamin A in excess of 800 mcg a day has been
associated with birth defects
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Your Turn
Question 1: A patient who is undergoing chemotherapy and
radiation says food does not taste good, and he seldom feels
hungry. He is not eating enough calories and protein, and his
muscle and fat tissue are disappearing. What is the likely
diagnosis of this condition?
Answer: This condition is called cachexia.
Question 2: A patient is trying to get pregnant. Her physician
recommends that she take folate (B9) supplements. What is the
purpose of these supplements?
Answer: Taking folate as a fetus develops can greatly reduce
birth defects such as neural tube defects.
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Micronutrient Abnormalities
Trace Elements
• Essential minerals needed for normal physiologic functions
• RDI is low; easy to obtain from normal food consumption
• Supplements are used mainly as additives to enteral and
parenteral nutrition formulas
Trace Elements: Chromium
• Part of a complex of molecules that help regulate glucose
tolerance and insulin levels
• Sources: canned foods, meat, fish, brown sugar, coffee,
tea, whole wheat bread, rye bread
• Indications: case of deficiency (parenteral nutrition)
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Micronutrient Abnormalities
Trace Elements: Copper
• Catalyst and coenzyme in various chemical reactions
• Without copper, RBCs and WBCs would decline and cause
anemia, leukopenia, neutropenia
• Sources: organ meats, seafood, nuts, seeds, wheat bran
cereals, grains, cocoa
• Indications: cases of deficiency (parenteral nutrition)
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Micronutrient Abnormalities
Trace Elements: Iodine
• Used to make thyroid hormones, which regulate metabolic
rates
• Sources: seafood, seaweed; added to salt in developed
countries
• Indications: cases of deficiency such as thyroid conditions,
radiation emergencies in which radioactive iodides were
used
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Micronutrient Abnormalities
Trace Elements: Iron
• Iron is in hemoglobin of RBCs and in myoglobin of muscle
• Cofactor for neurotransmitter production; part of the
functional groups of many important enzymes
• Without iron, RBC production and oxygen-carrying
capacity are reduced
• Sources: red meat, poultry, fish; in some vegetables (but
many cooking and storage methods reduce its availability)
• Indications: anemia (chronic disease and iron-deficiency)
• Too much iron can cause hemochromatosis (a liver
condition)
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Micronutrient Abnormalities
Trace Elements: Manganese
• Cofactor in many metabolic and enzymatic reactions
• Sources: legumes, seeds, tea, whole grains, green leafy
vegetables
• Indication: cases of deficiency
Trace Elements: Selenium
• Incorporated into amino acids; reduces oxidative stress
• Sources: broccoli, garlic, onions
• Indication: additive parenteral nutrition
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Micronutrient Abnormalities
Trace Elements: Zinc
• Cofactor in many physiologic processes, including the
synthesis of DNA and protein
• Important role in immune function, wound healing, blood
clotting, reproduction, and appropriate growth
• Sources: meat, seafood, dairy products, nuts, legumes,
whole grains
• Indications: cases of deficiency, immune function booster,
wound healing catalyst, Wilson’s disease
• Indications (lozenges): symptoms of common cold
• Indication (topical): healing of burn and skin wounds
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Micronutrient Abnormalities
Trace Elements: Side Effects
• Most side effects result from excess intake
• Side effects mimic conditions of toxicity (see Table 16.4)
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Enteral and Parenteral Nutrition
Nutritional Needs of Patients
• Alternative ways to supply nutrition must be used when a
patient cannot be fed normally
• Malnutrition will occur if a patient goes longer than 7 to 10
days without food or nutrition
Enteral Nutrition
• Feeding a patient through a tube into the GI tract
• Liquid nutrient is put through the tube in bolus doses
(mimics eating a meal) or continuously with enteral pump
• Indications: bowel obstruction, short gut syndrome,
Crohn’s disease
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Enteral and Parenteral Nutrition
Enteral Nutrition (continued)
• Indication: patients in long-term care who cannot swallow
food voluntarily due to stroke or coma
• IV fluids are usually given in addition to enteral feeding to
maintain hydration status
• Technicians often order enteral feeding formulas
 Requirement: label enteral feeding preparations with a
warning not to administer them through an IV
• Enteral feeding is preferred to parenteral feeding; keeps
the GI tract functional and prevents abdominal infections
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Enteral and Parenteral Nutrition
Enteral Tube Feeding
Sites
• A manually inserted
NG tube is not
comfortable ; this tube is
used on a short-term
basis
• A surgically placed G
tube or J tube delivers
enteral nutrition via the
stomach or jejunum,
respectively
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Enteral and Parenteral Nutrition
Parenteral Nutrition
• Often called TPN
• Involves feeding a patient through an IV when the
digestive tract cannot be used
 Used for severe burns, intolerance to enteral feeding,
anorexia nervosa, IBD, pancreatitis, severe diarrhea
 Sometimes used in pregnancy, AIDs, cancer
• Supplies all needed fluids, electrolytes, nutrients
(carbohydrates, proteins, and fats), vitamins, minerals
• Technicians in specialty or home-infusion pharmacies mix
TPN solutions
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Enteral and Parenteral Nutrition
Mixing of Parenteral Nutrition Solutions
• Order of mixing is important
 Mix all clear ingredients before cloudy ingredients
 Add some electrolytes and trace minerals separating to
reduce precipitating out of solution
 Precipitates occur when minerals bind together
and form specks that could block capillary flow
 Add vitamins last, just before administration
• Important to properly agitate and mix each TPN bag
• TPN solutions usually administered through a surgically
placed central line
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Enteral and Parenteral Nutrition
Mixing of Parenteral Nutrition Solutions (continued)
Two-in-one
Mixtures
Three-in-one
Mixtures
• Contain proteins (amino acids) and
carbohydrate (dextrose)
• Good for 21 days if refrigerated and 7 days at
room temperature
• Contain proteins, carbohydrates, lipids (fats)
• Lipids are cloudy; can hide precipitates
• Less stable solutions as two-in-one
• Good for 7 days if refrigerated and 24 hours
at room temperature
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Obesity
About Obesity
• The CDC estimates that approximately 34% of adults in the
United States are obese
 Obesity in males: ABW is 25% or more above IBW
 Obesity in females: ABW is 35% or more above IBW
• Morbid obesity is when ABW is more than twice IBW
• Causes of obesity: environmental, genetic, physiological,
and psychological factors
• Obesity is associated with serious health risks and
mortality (see Table 16.5)
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Obesity
About Obesity (continued)
• Centrally distributed fat is adipose tissue that accumulates
in the abdominal area vs. in the hips, thighs, or buttocks
 Linked to heart disease and diabetes
• Obese people have more depression and psychological
disturbances
Drugs for Obesity
• Preferred treatment for obesity is lifestyle and dietary
changes; changes must be permanent to control weight
• Indication (prescription): BMI over 30 (or over 27 if other
risk factors)
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Obesity
Drugs for Obesity: Appetite Suppressants
• Mechanism of Action: stimulate CNS; stimulate dopamine
and norepinephrine and prevent reuptake of serotonin;
signal sense of fullness and satisfaction
• Route: oral; all CNS stimulants are controlled substances
• Side Effects (common): headache, stomachache, insomnia,
nervousness, irritability
• Side Effects (other): difficulty urinating, constipation
• Caution: do not take with other drugs that also increase
serotonin (e.g., antidepressants)
 Could cause serotonin syndrome (dangerous condition)
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Obesity
Drugs for Obesity: Lipase Inhibitor
• Mechanism of Action: prevents enzymes in the intestines
from breaking down fats into a form that can be absorbed
 Fat then passes through intestines out of the rectum
• Indication: patients who are overweight
• Routes: all are oral
• Side Effects (common): fatty or oily stools, fecal
incontinence or urgency, gas, diarrhea
• Caution: potential vitamin deficiencies
 Technicians can help patients locate a supplement
containing fat-soluble vitamins
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Your Turn
Question 1: What is the reason enteral feeding is preferred to
parenteral feeding?
Answer: Enteral feeding keeps the GI tract functional and
prevents abdominal infections.
Question 2: A physician is writing an order for drug therapy for a
morbidly obese patient who wants to lose weight. The patient is
already taking an antidepressant that works by increasing the
amount of serotonin in the brain. What drug therapy will not be
prescribed? Why?
Answer: An appetite suppressant will not be prescribed. If
taken with the antidepressant, serotonin syndrome, a
serious side effect, could result.
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Herbal and Alternative Therapies
• Fiber is a natural substance in fruits and vegetables
 Creates a sense of fullness and speeds GI motility; this
limits fat and calorie absorption
 Produces laxative effects, lowers cholesterol, promotes
colon health
• Ephedra (also known as ma huang) is banned from sale in
the United States
 It is a CNS stimulant with anorexiant effects
 Serious effects, and even death, occurred from OTC use
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Summary
• Estimate body composition by comparing ABW to a
calculated IBW or by determining BMI
• Recommended daily intake values are published for all
vitamins and minerals
• A lack of vitamins can cause illness
• Toxicity can occur with excess of fat-soluble vitamins or
some minerals
• Enteral and parenteral nutrition used for malnutrition
• Appetite suppressants and lipase inhibitors are for obesity
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