ABSTRACT

Experiments with nutritional intervention in animal and cell culture models are essential to gaining an understanding of the roles and mechanisms of individual nutrients. However, these studies may or may not be directly applicable or relevant to clinical or public health conditions. Thus, this review of recent studies emphasizes clinical trials in which beneficial effects of vitamins on immunity have been reported. Specific and nonspecific immune responses can be severely compromised when the B complex vitamins are deficient as a result of inadequate dietary intake or disease processes. The involvement of the B complex vitamins in immune function are not unexpected, since they are essential to many aspects of cellular metabolism including sugar, protein, lipid, and nucleic acid synthesis and degradation. The role of vitamin A in resistance to infection is well established, whereby its deficiency significantly increases risk of systemic morbidity and mortality, especially in children.