Lack of knowledge about the hypotensive effects of potassium and dairy: current hypertension-related knowledge and results of a knowledge intervention in Japanese workers.

Objectives: A high dietary sodium/potassium ratio with low potassium and high sodium intake, which is a risk factor for hypertension, is a characteristic of diets in East Asia, such as Japan. To promote prevention of hypertension among Japanese workers, knowledge of the antihypertensive effects of potassium, which is not limited to vegetables and fruits and include various potassium-rich foods, such as milk, is important. Thus, we investigated the knowledge of workers on the associations of potassium and milk intake with blood pressure and effective methods for communicating this association. Methods: The participants were 130 Japanese workers, most of whom were under 50 years old and were not using medication for hypertension. After distributing only free dairy products for 3 weeks, leaflets and stickers were distributed with the dairy products to communicate the knowledge about the hypotensive effect of potassium and milk for 3 weeks. At baseline, after distributing only free dairy products, and after providing knowledge, the participants responded to the same questionnaires on the association of potassium and milk intake with blood pressure. Questionnaire responses were analyzed using Cochran's Q test and multiple comparison analysis. Results: The percentage of the correct answers on the association of potassium and milk intake significantly improved with the knowledge intervention (35.4% at baseline, 50.8% after distributing only the dairy products, and 90.0% after distributing the knowledge regarding potassium). Conclusions: The participants had limited knowledge about the association between potassium and milk intake and blood pressure. Our intervention methods might be effective for improving knowledge of the association.