Ascorbate is depleted by smoking and repleted by moderate supplementation:a study in male smokers and nonsmokers with matched dietary antioxidant intakes

Background: Lack of reliable dietary data has hampered the ability to effec tively distinguish between effects of smoking and diet on plasma antioxidan t status. As confirmed by analyses of comprehensive food-frequency question naires, the total dietary intakes of fruit and vegetables and of dietary an tioxidants were not significantly different between the study groups in the present study, thereby enabling isolation of the effect of smoking. Objective: Our objective was to investigate the effect of smoking on plasma antioxidant status by measuring ascorbic acid, alpha-tocopherol, gamma-toc opherol, beta-carotene, and lycopene, and subsequently, to test the effect of a 3-mo dietary supplementation with a moderate-dose vitamin cocktail. Design: In a double-blind, placebo-controlled design, the effect of a vitam in cocktail containing 272 mg vitamin C, 31 mg all-rac-alpha-tocopheryl ace tate, and 400 mu g folic acid on plasma antioxidants was determined in a po pulation of smokers (n = 37) and nonsmokers (n = 38). The population was se lected for a low intake of fruit and vegetables and recruited from the San Francisco Bay area, Results: Only ascorbic acid was significantly depleted by smoking per se (P < 0.01). After the 3-mo supplementation period, ascorbic acid was efficien tly repleted in smokers (P < 0.001), Plasma alpha-tocopherol and the ratio of alpha- to gamma-tocopherol increased significantly in both supplemented groups (P < 0.05). Conclusions: Our data suggest that previous reports of lower concentrations of plasma vitamin E and carotenoids in smokers than in nonsmokers may prim arily have been caused by differences in dietary habits between study group s. Plasma ascorbic acid was depleted by smoking and repleted by moderate su pplementation.