Vitamin E kinetics in smokers and nonsmokers

Does cigarette smoking increase vitamin E utilization in vivo? A trial was carried out in 6 smokers and 5 nonsmokers of comparable ages and serum lipids. Subjects consumed 75 mg each d3-RRR and d6-all rac-α-tocopheryl acetates (natural and synthetic vitamin E, respectively) daily for 7 d with a standardized breakfast. Fasting blood samples were drawn on days −7, −6, −5, −4, −3, −2, −1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 14, 21 (negative days indicate supplementation). In both groups, plasma d3-α-tocopherol concentrations were approximately double of d6-α-tocopherol. At day 0, the %d3 α-tocopherols (d3-α-tocopherol/total-α-tocopherol × 100) were similar in both smokers and nonsmokers. Subsequently, there was a trend toward a faster exponential disappearance of the plasma %d3 α-tocopherol in smokers compared with nonsmokers (0.30 ± 0.04 compared with 0.24 ± 0.05, p = .0565). The calculated %d3 half-lives were 55.6 ± 7.4 h in smokers and 72.1 ± 17.3 h in nonsmokers (p = .0630). By day 21, the %d3 in smokers had decreased to 1.4% ± 0.3% while it was 2.2% ± 0.7% (p = .0418) in the nonsmokers. These data suggest that smoking increases plasma vitamin E disappearance, but further studies are needed to confirm this finding and to assess its cause.