For years, doctors have counseled patients with high blood pressure to cut back on sodium, or salt. That’s still good advice. But making sure you get enough potassium may be just as important.

In a study of 3,300 people who are part of the Dallas Heart Study, researchers this week report that low potassium levels are closely linked to hypertension risk. “The lower the potassium in the diet, the higher the blood pressure,” explained Dr Susan Hedayati, MD, of the University of Texas Southwestern Medical Center in Dallas, Texas.

The findings aren’t really new. Previous data from the Dietary Approaches to Stop Hypertension Study, commonly known as DASH, has already spotlighted the dangers of low potassium. This new study is important because half the volunteers were African Americans, who suffer disproportionately from hypertension—and whose diets appear to be particularly low in potassium. Adults should get 4.7 grams of potassium a day, according to current guidelines.

Many of us fall short. Abundant sources include spinach and other dark leafy vegetables, mushrooms, lima beans, avocados, papayas, cantaloupe, citrus and bananas.

Tags: high blood pressure, hypertension, potassium, salt, sodium