American mothers' often-ignored advice to eat fruits and vegetables, not cheeseburgers and doughnuts, now appears to substatially and quickly lower blood pressure, according to results of a study performed at Johns Hopkins and several other centers.
The findings offer more evidence that healthy diets can reduce the risk of heartdisease and stroke, the nation's first- and third-leading killers, respectively. About 40million Americans have high blood pressure, which is particularly common amongpeople over 50 and a major risk factor for cardiovascular disease and stroke.
Results of the study, supported by the National Heart, Lung and Blood Institute,are published in the April 17 issue of The New England Journal of Medicine.
"We already know that weight control and reduced salt and alcohol intake areimportant steps to prevent and treat hypertension," says Lawrence Appel, M.D., leadauthor and an associate professor of medicine at Hopkins. "Our findings show that a dietrich in fruits, vegetables and low-fat dairy products and reduced in saturated and total fatoffers an additional nutritional approach."
The Dietary Approaches to Stop Hypertension (DASH) study included 459 adultswith high-normal or stage 1-mild hypertension (systolic blood press of less than 160 mmHg and diastolic pressure of 80-95 mm Hg). Researchers examined the impact on bloodpressure of whole dietary patterns rather than individual nutrients or supplements.
Participants ate one of three diets for eight weeks: a control diet low in fruits,vegetables and dairy products and with a fat content typical of the American diet; a diet high in fruits and vegetables; or a "combination" diet low in saturated and total fat andhigh in fruits, vegetables and low-fat dairy products.
Among the 133 participants with high blood pressure, the combination dietreduced systolic and diastolic blood pressure by an average of 11.4 mm Hg and 5.5 mmHg, respectively. Systolic blood pressure, the higher of the two numbers, occurs when theheart is contracting; diastolic blood pressure occurs when the heart relaxes betweencontractions.
"These blood-pressure reductions are clinically important because they are similarto those reductions commonly achieved through use of one anti-hypertensivemedication," Appel says.
Among the 326 participants with high-normal blood pressure, the combinationdiet reduced systolic and diastolic blood pressure by an average of 3.5 mm Hg and 2.1mm Hg, respectively.
"These reductions are important from a public health perspective because theymay prevent hypertension from occurring," says Appel.
Among all participants, the diet high in fruits and vegetables reduced bloodpressure, but to a lesser extent than the combination diet. The reductions occurred withintwo weeks of the start of the study. The blood pressure reductions were independent ofbody weight, salt intake and alcohol consumption, which were held constant.
The DASH combination diet provided nine to 10 daily servings of fruits andvegetables (about twice the usual amount in Americans' diets) and three daily servings oflow-fat dairy products (about double the usual amount in Americans' diets). Moreinformation about the DASH diet is available on the World Wide Web athttp://dash.bwh.harvard.edu
Other investigators and institutions in the study were Thomas J. Moore, M.D., atBrigham and Women's Hospital, Thomas M. Vogt, M.D., at Kaiser Permanente Centerfor Health Research, Laura P. Svetkey, M.D., at Duke University Medical Center, GeorgeA. Bray, M.D., at the Pennington Biomedical Research Center, and Eva Obarzanek at theNational Heart, Lung and Blood Institute.
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Materials provided by Johns Hopkins Medical Institutions. Note: Content may be edited for style and length.
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