Effect of a Potassium-enriched Diet on the Urinary Sodium-to-potassium Ratio

• Published in: Nihon Eiyō, Shokuryō Gakkai shi Vol. 76; no. 6; pp. 391 - 401
• Main Authors: Shimizu, Yukiko, Yamanaka, Saki, Ushida, Yusuke, Suganuma, Hiroyuki, Sato, Ikuo, Ishida, Hiromi
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Japan Society of Nutrition and Food Science 2023; Japan Science and Technology Agency
• Subjects: Blood pressure; Carbohydrates; Diet; Enrichment; Hypertension; low-sodium diet; Nutrient deficiency; Population studies; Potassium; Reduction; Sodium; urinary sodium-to-potassium ratio
• ISSN: 0287-3516; 1883-2849
• DOI: 10.4327/jsnfs.76.391

Salt reduction is important for prevention of hypertension, but is difficult in practice as it tends to approximate the Dietary Reference Intakes. In a study population of young female subjects, we comparatively evaluated the effects of a control diet with moderate salt reduction, a strictly low-sodium (Na) diet, and a potassium (K)-enriched diet on the urinary Na/K ratio, which is known to be positively correlated with blood pressure. The subjects in the three groups consumed three servings of each test meal per day for two weeks, and urinary Na/K ratios were measured before and after the intervention. The control, low-Na and K-enriched diets provided 3,277 and 1,743, 2,559 and 1,743, and 3,277 and 3,277 mg Na and K, respectively, per day. Otherwise, their energy, protein, fat, and carbohydrate contents were equal. The K-enriched diet intervention resulted in a significant decrease of the urine Na/K ratio (2.8±1.2→1.9±0.6). The low-Na diet also decreased the ratio, but not to a significant degree (3.2±2.0→2.5±1.0). In subjects with a preintervention urinary Na/K ratio of 2 or higher, comparison among the three groups showed that the K-enriched diet had reduced the urinary Na/K ratio to a significantly greater degree than the control diet. These results suggest that a K-enriched diet, as well as a Na-reduced diet, is effective for improving the urinary Na/K ratio, thus likely preventing hypertension.