Since 1928, nearly 60 studies have shown that potassium can help reduce blood pressure. A recent meta-analysis (pooled study review) considering 33 of these past studies confirms this hypothesis.

The meta-analysis, conducted by Paul Whelton, M.D., dean of the School of Public Health, Tulane University, New Orleans, involved 2,609 hypertensive and nonhypertensive adults ranging in age from 18 to 79. The majority of participants were white males, with blacks represented in 14 trials and women in 21. Participants who consumed, on average, 2,340 mg of potassium per day from diet or supplements showed a median decrease of 4.4 mm/mercury (mm/Hg) in systolic blood pressure and a 2.4 mm/Hg decrease in diastolic blood pressure.

Most study participants took potassium chloride (74 percent). Twenty-five percent received it in their diets, and the remaining 1 percent took supplemental potassium citrate and potassium bicarbonate. There is no RDA for potassium, but according to representatives from the Institute of Medicine in Washington, the minimum daily requirement for healthy adults is 1,600 to 2,000 mg.

Whelton found that potassium was particularly effective at lowering the blood pressure of participants who did not decrease their daily sodium intake--leading him to conclude that potassium supplements may help treat people who have a hard time changing their diets. Supplementation could also benefit blacks, who are at high risk for developing hypertension, Whelton says.

CAUTION: People who have kidney disease or take diuretics such as spironolactone, triamterene or amiloride should not consume excess potassium.