There have been many medical research papers showing a strong improvement in blood pressure, stroke and cardiovascular disease from eating high potassium foods. Recently one (J. Am. Coll. Cardiol. 2011;57;1210-1219) compiled a group of eleven papers that were done in a high quality manner, prospectively with at least 4 years of follow-up. It included 247,000 people.
The study first looked through over 3200 papers mentioning potassium intake and stroke or cardiovascular disease. It eliminated papers until it found those that were prospective and that included enough information to evaluate.
Six of the studies were on Americans, and five came from other countries. None came from the countries that are traditionally those having the highest potassium intake.
The papers looked at strokes and cardiovascular events, and correlated these events with potassium intakes. They found that those with the highest intakes of potassium had a 21% lower risk of stroke or cardiovascular events.
These particular studies did not estimate sodium, so it is impossible to say if changes in sodium intake occurred also. Because of the many studies on sodium showing that a reduction in sodium reduces strokes and cardiovascular disease, it would have been nice to know if it played a role in the present study.
The study was able to correct for some of the other factors influencing strokes and cardiovascular events, such as obesity and hypertension. They were able to show that potassium had an influence separate from these other factors.
Together with many other basic science and epidemiological studies, the evidence for the benefits of potassium in the diet are becoming ever stronger. There are probably multiple mechanisms that potassium uses to improve health, but for those who do not need to restrict potassium, the more foods high in it, the better.
More and more studies are pointing to the advantages of a high potassium diet to reduce blood pressure, stroke and cardiovascular disease. This one was particularly worthwhile because of the quality of the studies it assessed, and the large number of people included in the study.