Sacks F M, Willett W C, Smith A, Brown L E, Rosner B, Moore T J
Department of Nutrition, Harvard School of Public Health, Brigham and Women's Hospital, Boston, Mass 02115, USA.
Hypertension. 1998 Jan;31(1):131-8. doi: 10.1161/01.hyp.31.1.131.
In populations, dietary intakes of potassium, calcium, and magnesium each have been inversely associated with blood pressure. However, most clinical trials in normotensive populations have not found that dietary supplements of these minerals lowered blood pressure. We tested the hypothesis that normotensive persons who have low habitual intake of these minerals would be particularly responsive to supplementation. Three hundred normotensive women in the Nurses Health Study II (mean age, 39 years), whose reported intakes of potassium, calcium, and magnesium were between the 10th and 15th percentiles, received for 16 weeks' duration daily supplements of either potassium 40 mmol, calcium 30 mmol (1200 mg), magnesium 14 mmol (336 mg), all three minerals together or placebos. At baseline, mean (+/-SD) 24-hour ambulatory blood pressures were 116+/-8 and 73+/-6 mm Hg systolic and diastolic, respectively, and mean dietary intakes of potassium, calcium, and magnesium were 62+/-20 mmol/d, 638+/-265 mg/d, and 239+/-79 mg/d, respectively. The mean differences (with 95% confidence intervals) of the changes in systolic and diastolic blood pressures between the treatment and placebo groups were significant for potassium, -2.0 (-3.7 to -0.3) and -1.7 (-3.0 to -0.4), but not for calcium, -0.6 (-2.2 to 1.0) and -0.7 (-2.0 to 0.6), or for magnesium, -0.9 (-2.6 to 0.8) and -0.7 (-2.2 to 0.8). The administration of calcium and magnesium with potassium did not enhance the effect of potassium alone, and the changes in blood pressure were not significant -1.3 (-3.0 to 0.4) and -0.9 (-2.2 to 0.4). In conclusion, potassium, but not calcium or magnesium supplements, has a modest blood pressure-lowering effect in normotensive persons with low dietary intake. This study strengthens evidence for the importance of potassium for blood pressure regulation in the general population.
在人群中，钾、钙和镁的膳食摄入量均与血压呈负相关。然而，大多数针对血压正常人群的临床试验并未发现补充这些矿物质能降低血压。我们检验了这样一个假设：这些矿物质习惯性摄入量低的血压正常者对补充剂会有特别明显的反应。护士健康研究II中的300名血压正常的女性（平均年龄39岁），她们报告的钾、钙和镁摄入量处于第10至第15百分位数之间，接受了为期16周的每日补充剂，分别为40毫摩尔钾、30毫摩尔钙（1200毫克）、14毫摩尔镁（336毫克），这三种矿物质一起补充或服用安慰剂。在基线时，24小时动态血压平均值（±标准差）收缩压和舒张压分别为116±8和73±6毫米汞柱，钾、钙和镁的平均膳食摄入量分别为62±20毫摩尔/天、638±265毫克/天和239±79毫克/天。治疗组和安慰剂组之间收缩压和舒张压变化的平均差异（95%置信区间），钾具有显著性，分别为-2.0（-3.7至-0.3）和-1.7（-3.0至-0.4），但钙不显著，分别为-0.6（-2.2至1.0）和-0.7（-2.0至0.6），镁也不显著，分别为-0.9（-2.6至0.8）和-0.7（-2.2至0.8）。钙和镁与钾一起补充并没有增强钾单独补充的效果，血压变化不显著，分别为-1.3（-3.0至0.4）和-0.9（-2.2至0.4）。总之，对于膳食摄入量低的血压正常者，补充钾而非钙或镁有适度的降压作用。这项研究强化了钾对普通人群血压调节重要性的证据。
