Knowledge-behaviour gap in potassium intake for blood pressure: A Japanese cross-sectional study

Background

Increasing potassium intake, alongside salt reduction, is essential for blood pressure (BP) management. However, potassium intake in Asia, including Japan, is considerably lower than in Europe. The relationship of potassium-BP is reportedly less known than the relationship of salt-BP. Therefore, we examined how awareness of the potassium-BP relationship affects knowledge and actual intake of potassium-rich foods.

Methods

This study used health check-up and questionnaire data from a Japanese retail company in 2025. Participants with lactose intolerance were excluded. They were grouped by awareness of the potassium-BP relationship (Aware vs Unaware). Logistic regression analyses were performed to examine the associations between each group and (1) knowledge of which foods are rich in potassium (vegetables, fruit, soy products, and dairy products) and (2) their intake frequency (vegetables ≥2 times/day; others ≥1 time/day). Models were adjusted for age, sex, and antihypertensive use, and results were presented as odds ratios (ORs) with 95% confidence intervals.

Results

We analysed 5,305 individuals (mean age 46.8±12.3 years, men 32.2%). The Aware group (n = 2,769) showed higher recognition of vegetables (OR 3.08 [2.68-3.60], p < 0.001), fruit (OR 2.27 [2.00-2.56], p < 0.001), and soy products (OR 2.09 [1.88-2.34], p < 0.001) than the Unaware group (n = 2,536), while no association was observed for dairy products. Furthermore, awareness that dairy products are potassium-rich was notably low in both groups (25.5% and 23.1%) compared to other foods. Regarding intake frequency, associations were observed only for vegetables (OR 1.17 [1.04-1.31], p = 0.008) and fruit (OR 1.13 [1.01-1.27], p = 0.035).

Conclusions

Awareness of the potassium-BP relationship is strongly associated with knowledge of potassium-rich foods other than dairy products, but its impact on actual intake frequency is attenuated. A limitation is reliance on intake frequency rather than absolute amounts.

Key messages

• In a working-age population, a knowledge-behaviour gap appears to exist: awareness of the potassium-BP relationship and potassium-rich foods is not fully reflected in actual intake.

• Future BP interventions could benefit from bridging this gap by not only educating on diverse potassium sources but also providing practical strategies to facilitate actionable dietary changes.