When it comes to fighting high blood pressure, the average American diet delivers too much sodium and too little potassium. Eating to reverse this imbalance could prevent or control high blood pressure and translate into fewer heart attacks, strokes, and deaths from heart disease.
Normal body levels of potassium are important for muscle function. Potassium relaxes the walls of the blood vessels, lowering blood pressure and protecting against muscle cramping. A number of studies have shown an association between low potassium intake and increased blood pressure and higher risk of stroke. On the flip side, people who already have high blood pressure can significantly lower their systolic (top number) blood pressure by increasing their potassium intake when they choose to eat healthy foods.
Most Americans get barely half of the recommended amount of potassium — 4,700 milligrams (mg) a day. Fruits, vegetables, beans, and some seeds offer good ways to get more of it. Bananas (about 425 mg of potassium in a medium-sized one) are often held up as the poster child for potassium, but there are better sources.
Since people with high blood pressure may also be trying to lose weight, consider potassium rich foods that are low in calories and carbohydrates. Good examples include broccoli, water chestnuts, spinach, and other leafy greens. Also good—although slightly higher in carbs and calories—are butternut squash and sweet potatoes, and fruits such as cantaloupe, kiwi, and nectarines.
Potassium also carries a caveat. For people with kidney problems, loading up on the mineral may actually do harm. Also, don't take supplements without a doctor's advice—overly high levels of potassium can lead to dangerous irregular heart rhythms.