Abstract
About half of dietary salt intake comes from salt containing seasoning such as salt, soy sauce and miso (soybean paste) in Japan. We conducted a randomized, placebo-controlled, double-blind cross-over study to examine the effect of low sodium soy sauce and soybean paste on salt intake. The subjects were 1 man and 16 women between 34 and 76 years of age in a district. During a one week period, the intervention group received low sodium soy sauce (25 % lower in sodium compared with common soy sauce) and soybean paste (20 % lower in sodium compared with common soybean paste), and controls received common soy sauce and soybean paste for both table and cooking use. Changes in urinary salt excretion during 24 hours with proportional sampling method were evaluated.
Salt excretion decreased by 2.3 g in the intervention group and increased by 0.6 g in the controls, and the difference between two groups was 2.9 g. No statistically significant difference was found in urine volume and urinary excretions of creatinine, potassium, calcium and magnesium. Taste scores of low sodium soy sauce and soybean paste did not differ much compared with the control soy sauce and soybean paste. Feasibility for long-term use of low sodium soy sauce and soybean paste and their effect on blood pressure should be further investigated for application in community-based intervention trials of salt and blood pressure in Japan.
