Effect of a Potassium-Rich Local Food on Sodium Excretion and Dietary Behavior in Young Adults: A Stratified Randomized Controlled Exploratory Trial

Hypertension is a major health issue, both globally and in Japan. Potassium-rich foods help prevent hypertension by promoting sodium excretion. We evaluated whether dadacha-mame (a local potassium-rich edamame variety) improves sodium excretion and influences dietary behavior. This 2-week stratified randomized exploratory trial included 54 (mean age: 20.5±1.4 years; 53.7% females) adults assigned to an intervention group [15 g/day of dried dadacha-mame; n = 27] or a control group [usual diet; n = 27]. Urinary sodium-to-potassium (Na/K) ratios were compared. Shifts in dietary behavior-change stages (pre-contemplation and contemplation) were assessed at baseline and post-intervention. No significant between-group baseline differences were observed. While no overall effect on the Na/K ratio was observed, subgroup analysis showed a significant reduction in the Na/K ratio in the intervention group (4.39 vs. 5.91 in Control, p=0.020). The intervention prompted positive dietary behavior changes, with the proportion of participants in the pre-contemplation stage decreasing from 50.0% at baseline to 33.3% post-intervention. Dietary intervention with dadacha-mame can significantly improve sodium excretion in individuals at a higher risk of hypertension and encourage healthier dietary behaviors. Utilizing local potassium-rich foods may be a valuable public health strategy, creating added value for agricultural products and benefiting community health.