Golan memorial lecture. Nutritional regulation of immunity and infection: from epidemiology to phenomenology to clinical practice.

Malnutrition is the most common cause of acquired immune dysfunction worldwide. Nutritional deficiencies, excesses, and imbalances influence specific components of the immune system. The severity of immunological impairment depends upon the extent and nature of undernutrition, the presence of infection, and the age of onset of nutritional deprivation. Profound immunological changes occur in children with marasmus and kwashiorkor as well as in deficiencies of vitamins A, E, B6, folate, zinc, iron, copper, and selenium. On the other hand, obesity and excessive intake of several vitamins, minerals, cholesterol, and polyunsaturated fatty acids also impair immunocompetence. These epidemiological observations and immunological phenomena are of practical significance in clinical practice.