By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

There is a steadily increasing body of evidence that a high-potassium intake may help not only to control blood pressure but also to prevent its consequences such as strokes and heart attacks. This evidence comes both from human observations and experiments in animals. Here are some of the key points.

• Population studies have shown that people whose diet contains a lot of potassium (typically because they eat a lot of fruit and vegetables) tend to have lower blood pressure. In one such study, an increase of potassium equivalent to three servings of fruit or vegetables was associated with a 2-3 mmHg lower blood pressure.
• Adding potassium supplements to the diet has also been found to lower blood pressure, particularly in blacks, people on a high salt intake, and people with higher blood pressure.
• The DASH diet (which included 8-10 servings of fruit and vegetables per day, and which was high in potassium) produced a substantial lowering of blood pressure in people with mild hypertension.
• Observational studies in humans and experimental studies in animals both suggest that a high potassium intake may protect against stroke independently of the effect on blood pressure.
• A recent study in rabbits which were fed a high fat diet to induce coronary artery disease found that a diet low in potassium resulted in much more severe disease of the arteries.