Research & Your Health is a series of articles written in accessible, everyday language, focused on the latest scientific research of natural health products.
On February 10, 2015
Background: A stroke is a sudden loss of brain function that occurs due to a ruptured blood vessel in the brain (hemorrhagic stroke) or, an interruption of blood flow to the brain (ischemic stroke). In both of these scenarios the brain is damaged due to a lack of oxygen and nutrient delivery to the affected area. Though previous research has shown that higher dietary potassium intake is associated with lower risk of stroke, only 16.6% of subjects in the World Health Organization cohort met the daily recommended potassium intake.
Objective: This study aimed to determine if higher levels of dietary potassium intake were associated with a decreased risk of ischemic/hemorrhagic stroke, and all-cause mortality.
Methods: Over 90,000 women aged 50-79 were included in this prospective cohort study. Potassium intake was estimated with a food frequency questionnaire administered at the beginning of the study and again three years later. Follow-up time was 11.1 years on average. To remove outliers, data from subjects in the top and bottom 1% of caloric intake were not included in the analysis. Potentially confounding variables were also included in the statistical analysis (e.g. body mass index (BMI), blood pressure, alcohol consumption, smoking history, physical activity, and medical history).
Results: Compared to the lowest quartile of potassium intake, those in the highest quartile had lower risk of all types of stroke (12%), ischemic stroke (15%), and all-cause mortality (15%). Women without hypertension saw the most benefit of a high potassium diet on ischemic stroke risk reduction (27%). A similar association was seen in those who had a healthy BMI (30% reduction in stroke risk), while those who were obese and were in the highest quartile of potassium consumption did not see a reduction in stroke risk.
Conclusion: In this large study population, higher intake of potassium was associated with lower risk of ischemic and hemorrhagic stroke, as well as all-cause mortality. These associations were strongest in healthy-weight, and nonhypertensive women.
The Findings in Perspective: These findings suggest significant benefit from higher levels of dietary potassium. Previous research has shown that a habitually low potassium diet was associated with increased arterial stiffness, even in subjects with normal blood pressure. To keep the circulatory system in top shape, make sure to eat potassium rich foods such as organic potatoes, tomatoes, beet greens, and bananas.