An adequate daily intake of potassium may be an important part of preventing high blood pressure. This idea was first explored in genetically engineered rats, whose incidence of stroke greatly declined when they were fed a diet rich in potassium. Because high blood pressure is the major risk factor for stroke, scientists suspected that the potassium was working to decrease the rats' blood pressure. This suspicion was ultimately shown to be true, and further research demonstrated that potassium has similar protective effects in humans. Today, we know that people with a low dietary intake of potassium (less than 40mEq/day) have increased risk for developing high blood pressure and for suffering a stroke.
How Does Potassium Lower Blood Pressure?
While scientists are able to demonstrate the positive blood pressure effects of diets rich in potassium, they have not yet been able to explain exactly how potassium accomplishes these effects. One school of thought says that the action of potassium somehow makes blood vessels less sensitive to compounds, like hormones, that normally cause blood vessel contraction. Less contraction leads to lower overall blood pressure. Other researchers suggest that potassium, rather than preventing blood vessel contraction, actually works to actively produce blood vessel relaxation. Regardless of which theory is correct, both agree that relaxed blood vessels are the ultimate effect of potassium.
Rich Dietary Sources of Potassium
Potassium is a relatively common mineral and can be found in many foods. Good dietary sources of potassium include:
- Vegetables such as potatoes
- Fruits like oranges and bananas
- Whole bran products like cereal and certain breads
Your Doctor Can Help
While getting the right amount of potassium provides positive health benefits, too much potassium can be dangerous. Too much potassium leads to a condition called hyperkalemia, which is serious and potentially deadly. It is always a good idea to make any diet changes slowly and to keep your doctor informed. This is especially important with regard to dietary supplements or vitamin pills, which can be dangerous in certain patients.
Linas, SL. The Role of Potassium in the Pathogenesis and Treatment of Hypertension. Kidney Int. 39)4):771-86.
Coca, et al. The Cardiovascular Implications of Hypokalemia. American Journal of Kidney Disease. 45(2):233-47.
Khaw, et al. Dietary Potassium & Stroke Associated Mortality: A 12-year Prospective Population Study. New England Journal of Medicine, 316(5):235-40.
Dickinson, et al. Potassium Supplementation for the Management of Primary Hypertension in Adults. Chocrane Database, Revision July 2006, 3; CD004641.