Fotherby M D, Williams J C, Forster L A, Craner P, Ferns G A
University Division of Medicine for the Elderly, University of Leicester, The Glenfield Hospital, UK.
J Hypertens. 2000 Apr;18(4):411-5. doi: 10.1097/00004872-200018040-00009.
To determine the effect of oral vitamin C supplements on ambulatory blood pressure and plasma lipids.
A 6-month double-blind randomized placebo-controlled cross-over study with a 1 -week washout between cross-over periods.
Vitamin C 500 mg daily or matching placebo was given to 40 men and women aged between 60 and 80 years for 3 months each in a cross-over fashion. Clinic and 24-h ambulatory blood pressure, plasma ascorbate and lipids were measured at baseline and at the end of each cross-over phase.
Clinic blood pressure did not change between placebo and vitamin C phases. Daytime ambulatory blood pressure showed a small but significant fall in systolic blood pressure (2.0 +/- 5.2 mmHg; 95% confidence interval 0-3.9 mmHg) but not in diastolic blood pressure. Regression analysis showed that with increasing baseline daytime blood pressure the fall in blood pressure with vitamin C supplementation increased. Regression analysis of the change in high-density lipoprotein (HDL) cholesterol showed a significant effect of sex on the change in HDL cholesterol. In women, but not men, HDL cholesterol increased significantly by 0.08 +/- 0.11 mmol/l, P=0.007. There was no change in low-density lipoprotein cholesterol between treatment periods.
In older adults high intakes of ascorbic acid have modest effects on lowering high systolic blood pressure, which could contribute to the reported association between higher vitamin C intake and lower risk of cardiovascular disease and stroke.
确定口服维生素C补充剂对动态血压和血脂的影响。
一项为期6个月的双盲随机安慰剂对照交叉研究，交叉期之间有1周的洗脱期。
40名年龄在60至80岁之间的男性和女性，以交叉方式分别服用每日500毫克维生素C或匹配的安慰剂，各为期3个月。在基线时以及每个交叉阶段结束时测量诊所血压、24小时动态血压、血浆抗坏血酸和血脂。
安慰剂阶段和维生素C阶段之间诊所血压没有变化。日间动态血压显示收缩压有小幅但显著下降（2.0±5.2毫米汞柱；95%置信区间0 - 3.9毫米汞柱），但舒张压没有下降。回归分析表明，随着基线日间血压升高，补充维生素C导致的血压下降幅度增加。对高密度脂蛋白（HDL）胆固醇变化的回归分析显示，性别对HDL胆固醇变化有显著影响。在女性中，而非男性中，HDL胆固醇显著增加0.08±0.11毫摩尔/升，P = 0.007。治疗期间低密度脂蛋白胆固醇没有变化。
在老年人中，高剂量摄入抗坏血酸对降低高收缩压有适度作用，这可能有助于解释所报道的维生素C摄入量较高与心血管疾病和中风风险较低之间的关联。
