Monday, October 4, 2010;
Replacing processed with whole-grains foods may help lower blood pressure
THE QUESTION Eating whole grains has been linked to better health. Might that include a positive effect on blood pressure?
THIS STUDY involved 206 healthy but overweight adults, most in their early 50s, who had been eating a "refined diet" (including refined, or processed, cereals and white bread). They were randomly assigned to continue the refined diet or to replace three servings of refined foods with three servings of whole-wheat foods, or to substitute with one serving of whole-wheat foods and two servings of oats daily. After three months, systolic blood pressure (the first, or top, number) had fallen five to six points (measured as millimeters of mercury, mmHg) for those eating whole-grain foods, compared with about a one-point drop for the others.
WHO MAY BE AFFECTED? Adults who are concerned about their blood pressure and who eat foods containing grains. High blood pressure can contribute to heart disease, heart attack, stroke, kidney disease and more. In refined foodstuffs, such as white rice and white flour, the bran and germ have been removed in the milling process. The entire kernel is used in whole-grain products, making them a better source of fiber and other nutrients. The study authors suggested that lowering blood pressure by eating three servings of whole-grain foods daily could reduce the risk of coronary artery disease by at least 15 percent and stroke by 25 percent or more.
CAVEATS The study data did not include precise measurements of participants' intake of sodium and potassium, which could affect blood pressure. The mechanism by which whole grains may contribute to blood pressure decline was not determined.
FIND THIS STUDY October issue of the American Journal of Clinical Nutrition.
LEARN MORE ABOUT high blood pressure at www.nhlbi.nih.gov/health. Learn about the health benefits of whole-grain foods at www.hsph.harvard.edu/nutritionsource (click "what should you eat," then "whole grains" in the first nutrition tip).
- Linda Searing
The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.