It is generally agreed that ageing is associated with impaired immune responses and increased infection-related morbidity. In 1992, an eminent immunologist from Newfoundland, Canada and Johns Hopkins assessed the effect of physiologic amounts of vitamins and trace elements on immunocompetence and occurrence of infection-related illness.1 He assigned 96 independently living ambulatory healthy elderly individuals to receive either routine daily maintenance vitamin supplementation or placebo. Nutrient status and immunologic variables were assessed at baseline and at 12 months, and the frequency of illness due to infection was ascertained.

http://orthomolecular.org/library/jom/1998/articles/1998-v13n04-p223.shtml