Relationship between megadose vitamin supplementation and immunological function in a healthy elderly population.

We studied the immunological effects of 'megadose' vitamin or mineral supplementation by comparing the immunological functions of healthy elderly subjects taking large amounts of specific nutrients to similar subjects not on supplements. There was a non-significant trend for those subjects taking megadoses of vitamin C to have increased cell-mediated immune responses as measured in vivo by skin test reactivity but not by in vitro mitogen responses. In addition, subjects taking megadoses of vitamin E or any of several B vitamins (B1, B2, B6, folate and niacin) had lower absolute circulating lymphocyte counts than did the rest of the population. The relative lack of effect of megadose vitamins on immunological function in this population compared to reports of short term trials of mega nutrients raises the possibility that some of the previously reported immuno-enhancing properties of megadose vitamins may be due to a non-specific adjuvant effect that disappears with time.