Johnston C S, Meyer C G, Srilakshmi J C
Department of Family Resources and Human Development, Arizona State University, Tempe 85287.
Am J Clin Nutr. 1993 Jul;58(1):103-5. doi: 10.1093/ajcn/58.1.103.
We examined the effect of supplemental ascorbic acid on red blood cell glutathione. Subjects consumed self-selected vitamin C-restricted diets, and, under double-blind conditions, ingested placebo daily for week 1 (baseline), 500 mg L-ascorbate/d for weeks 2-3, 2000 mg L-ascorbate/d for weeks 4-5, and placebo daily for week 6 (withdraw). Mean red blood cell glutathione rose nearly 50% (P < 0.05) after the 500-mg period compared with baseline, and the changes from baseline for individual subjects ranged from +8% to +84%. However, the increases in plasma vitamin C and red blood cell glutathione were not correlated (r = 0.22). At the 2000-mg dosage, mean red blood cell glutathione was not significantly different from the value obtained at the 500-mg dosage. After the placebo-controlled withdraw period, red blood cell glutathione did not differ from baseline. These data indicate that vitamin C supplementation (500 mg/d) maintains reduced glutathione concentrations in blood and improves the overall antioxidant protection capacity of blood.
我们研究了补充抗坏血酸对红细胞谷胱甘肽的影响。受试者采用自行选择的限制维生素C饮食，在双盲条件下，第1周（基线期）每日摄入安慰剂，第2 - 3周每日摄入500毫克L - 抗坏血酸盐，第4 - 5周每日摄入2000毫克L - 抗坏血酸盐，第6周（撤药期）每日摄入安慰剂。与基线相比，在摄入500毫克阶段后，红细胞谷胱甘肽平均升高近50%（P < 0.05），个体受试者相对于基线的变化范围为 +8%至 +84%。然而，血浆维生素C的升高与红细胞谷胱甘肽的升高不相关（r = 0.22）。在2000毫克剂量时，红细胞谷胱甘肽的平均值与500毫克剂量时获得的值无显著差异。在安慰剂对照的撤药期后，红细胞谷胱甘肽与基线无差异。这些数据表明，补充维生素C（500毫克/天）可维持血液中还原型谷胱甘肽的浓度，并提高血液的整体抗氧化保护能力。
