TUESDAY, April 22, 2003 (HealthDayNews) -- A change of heart about your diet and exercise habits can help you keep a lid on your blood pressure -- but you have to be committed to the conversion.
New research shows people who cut down on salt and alcohol while losing weight and getting regular exercise do indeed control their blood pressure. Going a step further by adopting a low-fat diet high in fruits and vegetables works even better, but the added benefit isn't quite as great as many researchers may have suspected.
Even so, the scientists say, the results indicate people can pick and choose from a buffet of lifestyle changes to make a dent in their blood pressure. "You can combine all these things together, and that's pretty encouraging," says Victor J. Stevens, a psychologist at the Kaiser Permanente Center for Health Research in Portland, Ore., and a co-author of the study.
Nearly 50 million Americans, or about a quarter of the adult population, have high blood pressure -- defined as a reading of at least 140 millimeters of mercury (mmHg) for the systolic (the top number) and 90 mmHg for the diastolic (the bottom number). High blood pressure raises the risk of heart attacks and stroke and can seriously damage other organs, including the kidneys. The ideal blood pressure is 120/80.
"Reducing your blood pressure by even a few millimeters makes a difference," Stevens says. "The more pressure there is, the faster your circulatory system wears out."
The latest study, reported in the April 23/30 issue of the Journal of the American Medical Association, included 810 men and women with higher than optimal blood pressure, 38 percent of whom had clinical hypertension. Their average age was 50.
A third of the subjects received a single counseling session, typically with a registered dietitian, about the importance of diet in controlling their blood pressure. They were then left on their own to alter their behaviors.
The rest were assigned to two groups, both of which received much more intensive advice -- as many as 18 sessions over a six-month period -- about the link between lifestyle and hypertension. They were told to lose weight if they needed to, to get at least three hours a week of moderate exercise, and to cut down on their salt and alcohol intake.
Subjects in one of these two groups also were advised to adopt the so-called DASH (Dietary Approaches to Stop Hypertension) diet, a low-fat meal plan that emphasizes fruits and vegetables and cuts back on red meat. It has been shown to help lower blood pressure.
People in all three groups saw their blood pressure drop, but those who received intensive counseling reaped far more benefits. Their blood pressure came down more on average, and fewer developed high blood pressure. They were also more likely to lose a significant amount of weight, and less likely to require drugs to control their hypertension.
The improvement was best for those who had the intensive counseling and the DASH diet, with blood pressure falling twice as much, on average, compared with the first group. Yet the addition of the DASH diet to aggressive lifestyle counseling only slightly reduced blood pressure compared with lifestyle changes alone. Losing weight had the greatest impact on reducing blood pressure and keeping it in a healthy range.
The relatively weak impact of the DASH diet in the latest study points up the challenge of implementing behavioral programs outside the confines of a clinical trial, says Dr. Thomas Pickering, a physician at Mount Sinai Medical Center in New York. "When you are giving people food that is already prepared [as previous studies with DASH did], you can be pretty sure they're getting what you want them to have," says Pickering, author of an editorial accompanying the journal article. But when they do it themselves they often dilute the benefits of the diet.
Dr. Laura Svetkey, director of the Duke Hypertension Center at Duke University and a study co-author, says it's not clear why adding DASH to the counseling regime didn't have a bigger effect. It may be that when it comes to blood pressure, "maybe there's a maximum bang for the buck that you can get" by altering behavior. Another factor, she says, is that people in the study may not have eaten precisely the DASH diet prescribed in earlier trials with the meal program.
But Svetkey says there are plenty of good reasons to make the DASH diet part of a routine to control or prevent hypertension. It is rich in calcium and thus good for the bones, the low-fat content is easy on the heart, and the high doses of fruits and vegetables can reduce the risk of certain cancers.
Although the intensive counseling is just that, Svetkey says "there's nothing magic" about the regimen. All it requires is motivation, support and the willingness to set small goals. "We simply asked people to eat a healthy diet, eat reasonable portions, increase their physical activity to a moderate level, and reduce their salt intake to recommended levels," she says.
More information
Learn about high blood pressure from Medline plus or the American Heart Association. Meanwhile, the National Heart, Lung, and Blood Institute has a primer on the DASH diet.
