The DASH Diet May Lower High Blood Pressure

By Margarita Nahapetyan

The DASH diet, in combination with regular exercise routine, can boost brainpower and help the mind function better in adults with extra weight and high blood pressure, the U.S. scientists claim.

The DASH diet comes from the Dietary Approaches to Stop Hypertension trial, carried out by the National Heart, Lung, and Blood Institute. The diet includes low-fat dairy products, carbs, fruits and vegetables as well as foods that are low in cholesterol. The new study was designed primarily to determine what effect such diet combined with exercise has on blood pressure.

For the study, the authors, led by James Blumenthal, a professor of psychology and neuroscience at Duke University Medical Center in Durham, N.C., recruited 124 male and female volunteers with mild to moderate high blood pressure who were 52 years of age and with a minimum of 15 pounds overweight, on average. All the participants were assigned into three groups. The first group had to follow the DASH diet combined with an aerobic exercise program (30 minutes of exercise, 3 times a week), the second group followed the DASH diet without any exercise program, and the participants in the third group did not follow a diet or exercise for a period of four months.

In addition, during the study, all the subjects were asked to complete a series of paper-and-pencil tests, such as crossing off specific digits on a page of number as fast as possible. These tests helped researchers assess the participants' brain functioning and mental skills, including manipulation of ideas and concepts and planning. The tests were given before and after the 4-month treatment program.

The results revealed that those in the first group who followed the DASH diet in combination with aerobic exercise program, showed a 30 per cent improvement in brainpower, as well as lower levels of blood pressure. These participants also demonstrated an improvement in their cardiovascular fitness, and lost an average of 19 pounds by the end of the study. On average, the participants in the first group had their systolic blood pressure (the top number in a blood pressure reading) reduced by 16 points and diastolic blood pressure (the bottom number) reduced by 10 points.

Modifications in a lifestyle, such as diet and physical activity, have been shown to lower the levels of blood pressure and improve mental functioning, but the experts say that this study is the first to analyze the combined effects of diet and exercise on brain activity in people with extra weight and high blood pressure.

According to Dr. Donald LeVan, the American Heart Association Spokesman, despite the fact that the study was well done, it may have some shortcomings. "It is entirely too small," LeVan said in an interview, and added that he would call it a keyhole study, suggestive but nothing definitive. More research with a longer duration and a control group for exercise alone will be needed in order to definitely confirm the new findings.

The study is published in the March 2010 issue of Hypertension: Journal of the American Heart Association.