Potassium2026-06

Are changes in the urinary sodium-to-potassium ratio associated with changes in blood pressure in a healthy population with low urinary sodium-to-potassium ratios? Eight-year follow-up results from the KOBE Study.

Kawahara Mizuki, Tsukinoki Rumi, Miyamatsu Naomi, Kuwabara Kazuyo et al. — Hypertension research : official journal of the Japanese Society of Hypertension

Summary

A long-term study followed healthy Japanese adults for eight years to see if changes in their sodium-to-potassium balance, measured in urine, affected their blood pressure. Researchers found that even small increases in the sodium-to-potassium ratio over time were linked to higher blood pressure, suggesting that maintaining a good balance is important for heart health.

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Key points

This study tracked healthy individuals to understand how changes in their sodium-to-potassium ratio relate to blood pressure over time.
Even in people starting with a healthy sodium-to-potassium balance, an increase in this ratio was linked to higher blood pressure.
Maintaining a lower sodium-to-potassium ratio appears beneficial for long-term blood pressure control, even for healthy individuals.
The findings highlight the importance of dietary choices that favor more potassium and less sodium for cardiovascular health.

What the study looked at

This study explored whether shifts in the balance of sodium and potassium in the body, as indicated by urine tests, were connected to changes in blood pressure over time, even in healthy individuals who initially had good levels. Researchers from the KOBE Study followed 567 healthy Japanese adults, aged 40-74, for eight years. They regularly measured participants' blood pressure and collected urine samples to determine their sodium-to-potassium ratio. The study specifically looked at how changes in this ratio over the eight-year period related to changes in blood pressure, accounting for various other health and lifestyle factors. The study found that while participants' blood pressure generally increased over the eight years, and their average sodium-to-potassium ratio remained stable, individual increases in this ratio were significantly linked to increases in both systolic and diastolic blood pressure. This suggests that even small shifts towards a higher sodium-to-potassium ratio can predict long-term blood pressure elevation, even in people who started with healthy blood pressure and a good sodium-potassium balance.

Dietary takeaway

These findings suggest that paying attention to your sodium and potassium intake is important for blood pressure control, even if you're currently healthy. Aim to increase your intake of potassium-rich foods like fruits, vegetables, and legumes, while also being mindful of reducing high-sodium processed foods. Remember, this is one study, and dietary advice should always be personalized and discussed with a healthcare professional.

Abstract

Little is known about the associations between changes in the urinary sodium-to-potassium (Na/K) ratio and blood pressure (BP) in healthy individuals. Using survey data, urinary data, and BP data from the KOBE Study, this longitudinal study aimed to assess the associations between changes in the urinary Na/K ratio and BP in a healthy Japanese population over an 8-year follow-up period. We analyzed 567 participants aged 40-74 years who did not initiate antihypertensive or cardiovascular disease treatment during follow-up. Changes in the spot urinary Na/K ratio and BP were calculated by subtracting the baseline values from the follow-up measurements, and their associations were examined using a multivariable linear regression analysis that adjusted for sex, age, body mass index, baseline Na/K ratio and BP, low-density lipoprotein, hemoglobin A1c, ethanol intake, smoking status, salt taste sensitivity, years of education, employment status, baseline survey season, and 8-year follow-up survey season. The study cohort had a mean spot urinary Na/K ratio of 2.1 at baseline. While BP increased significantly over the 8-year follow-up period, the urinary Na/K ratio remained unchanged. However, urinary Na/K ratio changes were positively associated with changes in systolic BP (β = 1.48, p = 0.001) and diastolic BP (β = 0.76, p = 0.004). In conclusion, increases in spot urinary Na/K ratios were predictive of long-term BP elevation in a healthy, normotensive population with near-optimal urinary Na/K ratios at baseline. These findings indicate that maintaining a low urinary Na/K ratio is important for BP control, even among healthy individuals.

View on PubMed →DOI: 10.1038/s41440-026-02621-9