Selenium. Some studies have suggested that people with low selenium levels are at greater risk of bladder, breast, colon, rectum, lung, and prostate cancers. A large-scale, multiyear study is currently in progress to look at the effects of combining selenium and vitamin E on prostate cancer prevention.
Vitamin A. Experts have long known that vitamin A plays a role in infection and maintaining mucosal surfaces by influencing certain subcategories of T cells and B cells and cytokines. Vitamin A deficiency is associated with impaired immunity and increased risk of infectious disease. On the other hand, according to one study, supplementation in the absence of a deficiency didn’t enhance or suppress T cell immunity in a group of healthy seniors.
Vitamin B2. There is some evidence that vitamin B2 enhances resistance to bacterial infections in mice, but what that means in terms of enhancing immune response is unclear.
Vitamin B6. Several studies have suggested that a vitamin B6 deficiency can depress aspects of the immune response, such as lymphocytes’ ability to mature and spin off into various types of T and B cells. Supplementing with moderate doses to address the deficiency restores immune function, but megadoses don’t produce additional benefits. And B6 may promote the growth of tumors.
Vitamin C. The jury is still out on vitamin C and the immune system. Many studies have looked at vitamin C in general; unfortunately, many of them were not well designed. Vitamin C may work in concert with other micronutrients rather than providing benefits alone.
Vitamin D. For many years doctors have known that people afflicted with tuberculosis responded well to sunlight. An explanation may now be at hand. Researchers have found that vitamin D, which is produced by the skin when exposed to sunlight,