Double-blind randomized controlled trial of low sodium seasonings on salt intake and blood pressure

在日本，大约一半的膳食盐来自盐、酱油和味噌（大酱）等含盐的调味料。对于日本人来说，要吃传统的日本饮食并减少食盐的摄入量是非常困难的。减少膳食盐摄入量的一种实际和简单的方法将有助于预防日本的心血管疾病。[方法]采用两项双盲、随机安慰剂对照试验，研究低钠酱油和味噌对24小时尿盐排泄的影响（n=17，交叉设计），并评估日本普通人群长期使用低钠酱油和味噌的可行性及其对血压的影响（低钠组n=32，对照组n=32，平行设计）。<RESULTS>在第一次试验中，低钠组尿盐排泄量减少2.3 g，对照组尿盐排泄量增加0.6 g，干预1周后两组尿盐排泄量差异为2.9 g。尿量和尿中肌酐、钾、钙、镁的排泄量差异无统计学意义。在第二次试验中，干预前低钠组与对照组在年龄、性别、体重指数、血压和高血压方面均无显著差异。干预六周后，所有参与者的血压没有明显变化。然而，在40岁及以上的人群中，低钠组舒张压净降低6.4毫米汞柱，收缩压无明显变化。低钠组的味觉评价。低钠调味料的口感评价相当好。在普通人群中，将酱油和味噌从普通钠型改为低钠型是可行的，这可能是日本饮食中减盐策略的基础。

<BACKGROUND> About half of dietary salt comes from salty seasoning such as salt, soy sauce and miso (soybean paste) in Japan. It is very difficult for Japanese people to eat a traditional Japanese diet and achieve reduction in dietary salt intake. A practical and easy manner for reducing dietary salt intake would contribute to the prevention of cardiovascular disease in Japan.<METHODS> Two double-blind, randomized placebo-controlled trials were conducted to examine the effect of low sodium soy sauce and miso on urinary salt excretion during 24 hours (n=17, cross-over design) and to evaluate the feasibility of long-term use of low sodium soy sauce and miso in general Japanese population and its effect on blood pressure (low sodium group n=32, controls n=32, parallel design).<RESULTS> In the first trial, urinary salt excretion decreased by 2.3 g in the low sodium group and increased by 0.6 g in the controls, and the difference between two groups was 2.9 g after one-week intervention. No statistically significant difference was found in urine volume and urinary excretions of creatinine, potassium, calcium and magnesium. In the second trial, no significant differences in age, sex, body mass index, blood pressure and hypertension were found between low sodium groups and controls before intervention. After six-week intervention, no significant change in blood pressure was observed in all of the participants. However, in those aged 40 years and older, 6.4 mm Hg net reduction in diastolic blood pressure with no significant change for systolic blood pressure was noted in the low sodium group. Taste evaluation for the low sodium group. Taste evaluation for the low sodium seasoning was considerably good.<CONCLUSION> Replacing soy sauce and miso from common sodium type to low sodium type is feasible in the general population and it could be the basis for a salt reduction strategy in the Japanese diet.