May 23, 1997
Media Contact: Michael Purdy
Hopkins scientists have crunched data from 33 previous studies to authoritatively answer an enduring public health question: can potassium lower blood pressure? The answer is yes.
The Hopkins team found potassium supplements decreased blood pressure by 3.1 mm Hg systolic and 2.0 mm Hg diastolic. In persons with hypertension, the blood pressure reductions were even greater, 4.4 mm Hg (systolic) and 2.5 mm Hg (diastolic).
"That's about half the reduction in blood pressure you can typically expect from treatment with drug therapy," says Lawrence Appel, M.D., an author of the study in this week's Journal of the American Medical Association. A systolic blood pressure of less than 120 and diastolic less than 80 mm Hg is desirable. Systolic blood pressure occurs when the heart is contracting; diastolic when it relaxes between contractions.
Scientists also found evidence that potassium supplements were more helpful for those with severe high blood pressure and high salt intakes, and slightly more helpful for African-Americans. "Still, potassium supplements even helped persons with normal blood pressure," says Appel. "Even if your blood pressure is already normal, potassium can potentially help keep it that way."
Appel notes that taken individually, the prior studies of potassium and blood pressure left people with mixed signals. "By combining the results of over 30 studies that together enrolled more than 2500 persons, we conclusively demonstrated that potassium can reduce blood pressure," he says. "While this research evaluates potassium in the form of pills or supplements, it is likely that similar benefits would occur from potassium-rich foods."
The study, supported in part by the National Institutes of Health, was led by Paul Whelton, M.D., a former Hopkins faculty member now at Tulane University, and Jiang He, M.D., Ph.D., a visiting scientist at the Hopkins School of Public Health and Hygiene.
About 40 million Americans have high blood pressure, which is particularly common in African Americans and among people over 50. Hypertension is important because it is a powerful risk factor for cardiovascular disease, stroke and kidney disease.
The new findings could have a "widespread impact," according to Appel, particularly if adopted with other steps already recognized as affecting blood pressure, including lowering salt and alcohol intake and exercising regularly.
Other authors on the study were Jeffrey Cutler, M.D. and Dean Follman, Ph.D., both of the National Heart, Lung and Blood Institute; and Frederick Brancati, M.D. and Michael Klag, M.D., of Hopkins.