Download Malnutrition results from imbalance between the body`s needs and

KUWAIT UNIVERSITY
FACULTY OF MEDICINE
CLINICAL MEDICINE AND PATHOLOGY (316)
Dr. T. Chacko Mathew
NUTRITIONAL AND ENVIRONMENTAL DISORDERS
NUTRITIONAL DISORDERS
Nutrition is the science of food and its relationship to health.
Nutrients are chemical compounds in foods that are absorbed by the body. Nutrients are
divided into essential and non-essential nutrients. Essential nutrients cannot be
synthesized by the body and thus must be derived from the diet. The essential nutrients
include vitamins, minerals, amino acids, fatty acids, and some carbohydrate. Nonessential
nutrients are those that the body can synthesize from other compounds, although they
may also be derived from the diet.
Macronutrients
Nutrients are generally divided into macronutrients and micronutrients. Macronutrients
constitute the bulk of the diet and supply energy as well as essential nutrients needed for
growth, maintenance, and activity. Carbohydrates, fats (including essential fatty acids),
proteins, macrominerals, and water are macronutrients.
During the process of digestion, carbohydrates are converted to glucose and other
monosaccharides; fats, to fatty acids and glycerol; and proteins, to peptides and amino
acids. These macronutrients are interchangeable as sources of energy; fats yield 9 kcal/g;
proteins and carbohydrates yield 4 kcal/g.
Biological Value of proteins
The amino acid composition of proteins varies widely. The extent to which a protein
matches the amino acid composition of animal tissues determines its biologic value (BV).
A perfect match is egg protein, with a value of 100. Animal proteins in milk and meat
have a high BV (~90), whereas proteins in cereal and vegetables have a lower BV (~40),
and some derived proteins, such as gelatin, which lack tryptophan and valine, have a BV
of 0.
Essential amino acids and fatty acids
Essential amino acids (EAAs) are the components of proteins that make them essential in
the diet. Of the 20 amino acids in proteins, 9 are essential, ie, they cannot be synthesized
in the body. Therefore, they must be obtained through diet. Eight EAAs are required by
all humans. Infants require one more, histidine.
Essential fatty acids (EFAs) must be provided by the diet. However, some EFAs can be
made from others. EFAs are polyunsaturated fatty acids (PUFAs), but not all PUFAs are
EFAs.
Protein- calorie deficiency disorders
Kwashiokor: Deficient protein intake despite normal or nearly normal calorie intake. It
is characterized by edema of the abdomen, enlarged liver, decreased blood pressure, low
pulse rate, lower than normal body temperature and sometimes mental retardation.
Marasmus: It is due to protein-calorie under nutrition. Characterized by retarded growth,
low weight, muscle wasting, dry skin and dull hair.
The macrominerals
Sodium, chloride, potassium, calcium, phosphorus, and magnesium are required in gram
quantities per day by humans. Water is also considered a macronutrient because it is
required in amounts of 1 mL/kcal of energy expended, or about 2500 mL/day.
Micronutrients
Vitamins, which are classified as water-or fat-soluble, and trace minerals are
micronutrients.
Water-soluble vitamins are vitamin C (ascorbic acid) and eight members of the vitamin
B complex-thiamine (vitamin B1), riboflavin (vitamin B2), niacin, pyridoxine (vitamin
B6), folic acid, cobalamin (vitamin B12), biotin, and pantothenic acid.
Fat-soluble vitamins include retinol (vitamin A), cholecalciferol and ergocalciferol
(vitamin D), alpha-tocopherol (vitamin E), and phylloquinone and menaquinone (vitamin
K). Only vitamins A, E, and B12 are stored to any significant extent in the body.
VITAMIN DEFICIENCY DISEASES
Night blindness: the inability to see in dim light.
Beriberi usually begins with mild symptoms, including muscle cramps, irritability, loss of
appetite, and prickling or burning sensations in the skin
Pellagra: Severe cases include three basic symptoms - diarrhea, skin problems, and
dementia or learning difficulties. Advanced pellagra can cause death.
Scurvy: Symptoms of include swollen gums, loose teeth, and small black-and-blue spots
on the skin.
Rickets: The deficiency results in the body not having enough calcium to maintain
healthy bone structure and leads to softening of bones and serious bone deformities.
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Vitamin E deficiency: It causes difficulty with walking, lack of reflexes, and paralysis of
eye muscles. Vitamin E is protects cell structures from free radical damage.
Vitamin K deficiency: Vitamin K helps promote clotting of blood.
Folic acid deficiency: Folic acid is needed to prevent anemia. It also is needed by
pregnant women to help prevent neural tube defects in the fetus.
Vitamin
A
B1
(thiamine)
B2
(riboflavin)
Niacin
B6
B12
C (ascorbic
acid)
D
E
K
Deficiency
disease
Night blindness
Beriberi
Ariboflavinosis
Pellagra
Vitamin B6
deficiency
Pernicious
anemia
Scurvy
Rickets
Vitamin E
deficiency
Vitamin K
deficiency
Food sources of vitamin
Eggs, whole milk, cream, cheese, liver, green and
yellow vegetables (carrots, squash, sweet potatoes,
spinach, kale, and broccoli)
Milk, fortified cereals, peanuts, liver, yeasts
Liver and other organ meats, milk, green
vegetables, fortified cereals, yeast
Peanuts, lean meats, poultry, fish, bran, yeast, liver
Whole-grain cereal, fish, legumes, liver and other
organ meats, yeast
Eggs, milk, liver
Fresh fruits and vegetables (oranges and other
citrus fruits, brussels sprouts, cabbage, etc.)
Fortified milk, fish liver oil
Vegetable seed oil, egg yolk, cereals, beef liver
Leafy green vegetables, liver
Essential trace elements
Essential trace minerals include iron, iodine, fluorine, zinc, chromium, selenium,
manganese, molybdenum, and copper. Except for iron and zinc, micromineral
deficiencies are uncommon in industrialized countries. Other trace minerals implicated in
animal nutrition (ie, aluminum, arsenic, boron, cobalt, nickel, silicon, and vanadium)
have not been established as being required by humans. All trace minerals are toxic at
high levels, and some (arsenic, nickel, and chromium) have been implicated as causes of
cancer. In the body, lead, cadmium, barium, and strontium are toxic, but gold and silver
are inert as components of teeth.
Obesity
The excessive accumulation of body fat.
Traditionally, obesity has been defined as a body weight of > 30% above ideal or
desirable weight on standard height-weight tables. Now, it is usually defined in terms of
the body mass index (BMI)--weight (in kilograms) divided by the square of the height (in
meters).
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ENVIRONMENTAL DISORDERS
Exposure to severe heat
Direct exposure of the skin to severe heat produces burns. The severity of the burn
depends on the degree and the length of exposure to heat. Two major factors that
determine the outcome of burn injury are the depth of burn and the surface area of skin
affected.
Classification of burns
Burns may be classified as major or minor, according to extent and depth.
First degree burns: This type burns the epidermal layer of the skin. It is usually
superficial.
Second degree burns: In this type of burns, there are damage to the epidermis and the
dermis of the skin (partial thickness burns). The immediate consequence of a seconddegree burn to more than 20% of the body is extravasation of fluid, including high
protein exudate, from the burn site.
Third degree burns: There is a destruction of all the epidermis and dermis. It goes to the
root of the hair. It is called full thickness burns. Skin grafting is recommended.
Fourth degree burns: In these burns, the tissue beneath the skin is destroyed. That
includes the muscles, tendons, ligaments and bones. Skin grafting is usually required.
Other injuries of fire
They are airways injury by heat, carbon monoxide inhalation, and chemical inflammation
of lung caused by inhalation of toxic smoke. There may be secondary bacterial infection
of the burn.
Hypothermia
Hypothermia occurs most commonly at very cold environmental temperatures, but can
occur even at cool temperatures (above 40°F) if a person becomes chilled from rain,
sweat, or submersion in cold water.
Frostbite: Frostbite is an injury to the body that is caused by freezing. Frostbite causes a
loss of feeling and colour in affected areas. Usually, it affects the nose, ears, cheeks, chin,
fingers, or toes. Frostbite can permanently damage the body, and severe cases can lead to
amputation.
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Exposure to ultraviolet (UV) radiation
Ultraviolet (UV) radiation is defined as that portion of the electromagnetic spectrum
between x rays and visible light, i.e., between 40 and 400 nm. Accidental UV
overexposure can injure unaware victims due to the fact UV is invisible and does not
produce an immediate reaction. After irradiation, vascular changes occur, which lead to
secondary ischaemic damage to tissue.
UV radiation is known to damage DNA in epidermal cells, and several malignant
tumours of skin in Caucasians are believed to be caused by exposure to this type of
radiation.
Mechanical injury
The most frequent types of mechanical trauma are skin and soft tissues injuries. Injuries
to bone and tendon may be acute or chronic.
Other environmental factors
Toxic chemicals
Toxic chemicals can gain access to the body by many routes including skin contact,
inhalation, ingestion, and injection.
Metals
Metals cause disease as a result of environmental, occupational and therapeutic exposure.
Many metals have adverse effects if present in high levels.
Insecticides
Insecticides and herbicides are frequently implicated in disease. For example, chlorinated
hydrocarbons (DDT, dieldrin) are insecticides, chronic exposure leading to accumulation
in the liver. Although toxicity to certain birds and carcinogenicity in rats is established,
there is little evidence of toxicity in man.
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