Vitamin Supplements

Folate / B-12 and Immunity

Very little published information addresses the role of folate and Vitamin B-12 in immunity. Folate deficiency causes anergy to DNCB in pregnant women and impaired lymphocyte proliferation. Folate deficiency causes lymphoid organ atrophy, reduced T-cell numbers, and lymphocyte proliferation in laboratory animals. Vitamin B-12 deficiency, but not folate, reduces phagocytosis and bacterial killing by neutrophils in humans.

Folate and Vitamin B-12 in AIDS

Although these two vitamins are not considered to play a key role in immunity, have received considerable attention in HIV disease because of vitamin B-12's potential role in neurologic disease. Numerous studies detected low serum levels of the nutrient in this population. The mechanism of these deficiencies is not known, although gastrin was elevated in one study population -- a sign of defective B-12 absorption. Vitamin B-12 deficiency may be an important cause of neurological disorders and anemia in people with HIV, leading some physicians to offer periodic B-12 injections to their patients. The clinical efficacy of this intervention remains unproved, however. Folate levels may be increased in HIV-infection, according to several studies. One study suggested that IV-drug users may have reduced folate levels because of poor access to fresh fruits and vegetables -- key sources of folate. Gay men, the authors speculate, probably do not have reduced folate because of better access to fresh foods, although they present no evidence to support this hypothesis.

Vitamin C

Vitamin C (ascorbic acid) is found in many foods, including citrus fruits, green vegetables, berries, and organ meats. Most animal and plant species do not need to consume Vitamin C in their diet as they are able to produce sufficient quantities naturally. Humans and guinea pigs are the only animals that can not produce Vitamin C naturally and thus must consume it. Vitamin C is critical to electron transport, collagen synthesis, and various metabolic processes. The deficiency of Vitamin C produces connective tissue disorders, impaired wound healing, bleeding gums, and other serious symptoms. The deficiency of Vitamin C is called scurvy, the bane of sailors for hundreds of years.

Unlike other vitamins, marginal Vitamin C deficiency is somewhat better characterized. It may produce fatigue, muscle weakness, and impaired wound healing.

Vitamin C and Immunity

Vitamin C supplementation has not been shown to delay progression or improve survival in people with HIV.

Vitamin C deficiency does not impair lymphocute proliferation or CD4 and CD8 levels in humans. In guinea pigs, Vitamin C deficiency impairs tuberculin skin reactions, cell-mediated cytotoxicity, and decreases the bactericidal capacity of neutrophils. Vitamin C can induce interferon production in vitro. Animal and human studies demonstrate conflicting results on Vitamin C's impact on antibody formation. Several in vitro and animal studies indicate, however, that Vitamin C may play a more significant role in cellular immunity.