Schectman G
Division of General Internal Medicine, Medical College of Wisconsin, Milwaukee 53226.
Ann N Y Acad Sci. 1993 May 28;686:335-45; discussion 345-6. doi: 10.1111/j.1749-6632.1993.tb39197.x.
This analysis of a large, population based, cross-sectional survey demonstrates that the association of smoking with decreased serum ascorbic acid (AA) levels is independent of the reduced AA intake found in smokers. Smokers have a threefold higher incidence of low serum AA levels (< or = 11 mumol/L) which could place them at increased risk for the clinical manifestations of AA deficiency. Smokers not taking vitamin supplements who consumed less than 15 servings weekly of fruits and vegetables were especially prone to have serum AA levels less than 11 mumol/L. An AA intake of > or = 200 mg was necessary to provide smokers with equivalent protection from hypovitaminosis AA as had nonsmokers whose AA intake exceeded the recommended dietary allowance (RDA [60 mg]). This level of dietary AA intake is considerably higher than the newly increased RDA for smokers of 100 mg. Although the simplest and most direct method to increase the low serum vitamin C levels found in many smokers would be to stop smoking, markedly increasing dietary AA consumption is appropriate when this is unsuccessful. However, if dietary modification fails to sufficiently increase AA intake, then vitamin supplementation may be necessary to significantly reduce the high prevalence of hypovitaminosis AA present in smokers.
这项基于大规模人群的横断面调查分析表明，吸烟与血清抗坏血酸（AA）水平降低之间的关联独立于吸烟者抗坏血酸摄入量的减少。吸烟者血清AA水平低（≤11μmol/L）的发生率高出三倍，这可能使他们患AA缺乏临床表现的风险增加。每周食用水果和蔬菜少于15份且未服用维生素补充剂的吸烟者尤其容易出现血清AA水平低于11μmol/L的情况。要为吸烟者提供与抗坏血酸摄入量超过推荐膳食摄入量（RDA[60mg]）的非吸烟者同等的抗坏血酸缺乏保护，抗坏血酸摄入量需≥200mg。这一膳食抗坏血酸摄入量水平远高于吸烟者新提高的100mg的RDA。虽然增加许多吸烟者低血清维生素C水平的最简单、最直接方法是戒烟，但在戒烟不成功时，显著增加膳食抗坏血酸摄入量是合适的。然而，如果饮食调整未能充分增加抗坏血酸摄入量，那么可能需要补充维生素，以显著降低吸烟者中抗坏血酸缺乏的高患病率。
