ABSTRACT
Epidemiological and experimental observations indicate that nutritional status is a critical determinant of immunocompetence. Intervention trials that attempted to correct nutritional deficiencies in the elderly demonstrated an improvement in immune responses, including antibody titer after prophylactic vaccination. Changes occurring in the immune system during the aging process have many similarities with the effects of some types of protein-calorie, or energy, malnutrition. Clinical malnutrition in humans is usually a complex syndrome of multiple nutrient deficiencies. However, observations in laboratory animals deprived of one dietary element and findings in rare patients with a single nutrient deficiency have confirmed the crucial role of several vitamins and trace elements in immunocompetence, and thus finding certain deficiencies in elderly persons may imply decreased immune competence. The critical role of nutrition in the modulation of immune responses has led to a few studies in which nutritional status has been correlated with immune responses in old age, although all studies have found such a difference.
