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Pathology => Human Diseases => Malnutrition
Malnutrition
Malnutrition, dietary condition caused by a deficiency or excess of one or more essential nutrients in the diet. Malnutrition is characterized by a wide array of health problems, including extreme weight loss, stunted growth, weakened resistance to infection, and impairment of intellect. Severe cases of malnutrition can lead to death.
Children suffer from the effects of starvation more quickly than adults. According to the United Nations Children's Fund (UNICEF), malnutrition contributes to the deaths of more than 6 million children under age five each year. Typically, starving children develop a condition called protein-energy malnutrition (PEM). The two most common forms of PEM, marasmus and kwashiorkor, occur in all developing countries and are life-threatening conditions. Marasmus occurs when a child is weaned earlier than normal and receives foods low in nutrients. The child may also suffer repeated infections, such as gastroenteritis, due to poor hygiene. A child with marasmus is very underweight, with no body fat and wasted muscles. Kwashiorkor occurs when a child is weaned later than normal and receives starchy foods low in protein. In this disease, the child's abnormally low body weight is often masked by water retention, which makes the face moon-shaped and the belly swollen.
Deficiency diseases are usually associated with lack of vitamins or minerals. The effects of a vitamin or mineral deficiency on the body depend on the function of the particular nutrient lacking. For example, vitamin A is important for good vision, and severe deficiency of this vitamin may cause blindness. Because some vitamins and minerals have many functions, prolonged nutritional deficiencies can therefore have wide-ranging effects on health.
Diets that lack a wide variety of foods may result in vitamin deficiency diseases. For example, in countries where people eat maize as the staple food and only few other foods, diets may lack niacin, a B vitamin. Such diets may cause pellagra, a deficiency disease characterized by dermatitis, diarrhea, and dementia.
Some people find it difficult to meet their nutritional requirements. For example, women, due to their menstrual cycle, have a higher requirement for iron than do men. If their iron requirement is not met, women may develop anemia. Geographic factors can play a role in nutritional deficiencies. In some remote areas where the soil contains little iodine, the plants that grow there also contain little iodine. Since few foods contain significant amounts of iodine, people living in these areas may suffer prolonged iodine deficiency, resulting in disorders of the thyroid gland. In developed countries inadequate consumption of calories and protein is common in the elderly and in people with certain diseases, such as anorexia nervosa. However, the most common form of malnutrition in developed nations is overnutrition, which can lead to obesity. Obesity increases the risk of many diseases, including heart disease, diabetes, and arthritis.
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