BIOLOGY Volume 1 - A Guide to General Biology - 2004

8. HETEROTROPHIC NUTRITION

8.9. Malnutrition

Malnutrition in the broad sense means poor Nutrition. The term encompasses both undernutrition and overnutrition. Below are four Examples of malnutrition. Two of them are typical of developed countries — anorexia nervosa and obesity — while two are characteristic of developing countries — general malnutrition and Protein deficiency. Two examples of deficiency diseases caused by a lack of Vitamins A and D were discussed earlier (see section 8.7.9).

8.9.1. Anorexia nervosa

Anorexia nervosa is sometimes referred to as the "slimness disease". It has become widespread over the last 30 years and is primarily associated with affluent Western societies, largely because thinness is often regarded as a standard of beauty in these cultures. The term anorexia nervosa literally means "nervous loss of appetite". Strictly speaking, however, this is not entirely accurate, as sufferers of this condition do not usually lose their appetite; rather, an overwhelming fear of gaining weight overrides the sensation of hunger.

Anorexia predominantly affects young women (with men accounting for only 10% of cases) and typically begins in adolescence. It most commonly starts as a consequence of dieting. Gradually, the diet becomes increasingly strict, and food intake diminishes until the fear of becoming fat turns into an obsession. Psychologically, at this stage, the individual still perceives herself as overweight, even though she is actually underweight and the physical signs of malnutrition are beginning to manifest.

Profound physical changes occur within the body, effectively causing a regression to a pre-pubescent developmental stage; for instance, menstruation may cease. Soft, downy Hair (lanugo) begins to grow on the face and shoulders, a characteristic symptom of severe emaciation (section 8.9.4). Starvation can lead to severe wasting, presenting various symptoms of marasmus as body mass drops to critically low levels. The body is deprived of essential nutrients, particularly CARBOHYDRATES and fats, which are precisely the components restricted by dieting. As a result, the body may begin to break down its own structural Proteins to use as an energy source. Since Skeletal Muscle contains the largest protein reserves, Muscles and other Tissues waste away. Other side effects include chronic constipation, low Blood pressure, tooth decay (dental caries), and heightened susceptibility to various infections. Deficiencies in VITAMINS AND MINERALS may also occur. In some cases, the condition can be fatal.

A more detailed Structure/133.html">Discussion regarding the psychology of this condition and its Treatment falls outside The Scope of this book. However, it is crucial for anorexia sufferers to recognize that they have a problem and that they need help. Such support can be obtained through specialized groups where experienced professionals are invited for consultation. There are also voluntary organizations that can help guide the correct approach to treating this illness. In certain cases, hospitalization is required.