Effect of a low beta-carotene diet on the immune functions of adult women.

We examined the effect of beta-carotene depletion and repletion on the immune status of nine healthy women who lived in the metabolic suite for 100 d. For the first 4 d all women were fed a basal diet supplemented with 1.5 mg beta-carotene/d (baseline). During the next 68 d, the basal diet without beta-carotene supplementation was fed to all subjects (depletion), and during the last 28 d the diet of each women was supplemented with 15.0 mg beta-carotene/d (repletion). Neither beta-carotene depletion nor repletion significantly (P < or = 0.05) altered proliferation of peripheral blood mononuclear cells cultured with phytohemagglutinin or concanavalin A, in vitro production of soluble interleukin 2 receptor, or the concentration of circulating lymphocytes and their subsets. Thus, in healthy adults consuming adequate vitamin A, beta-carotene depletion had no adverse effect on the indexes tested, nor was there any beneficial effect of modest beta-carotene supplementation.