Eating a diet rich in fruits, vegetables, and low-fat dairy products, known as the DASH diet, is one of the most effective ways of controlling and reducing blood pressure, say reseachers.
In a new study, published in the April 2003 issue of Journal of the American Medical Association, researchers found that the greater the lifestyle changes, in particular to the diet, the greater control over blood pressure. High blood pressure is a major risk factor for heartdisease and the chief risk factor for stroke.
"This is the first time a host of behavioral steps toprevent or control high blood pressure has been puttogether in one intervention," said NHLBI director Dr Claude Lenfant.
"Past studies looked at one or two changes at a time, and it was thought that doing more would prove too hard. But Premier shows that an all-in-one approach works and can help Americans reduce their blood pressure, lowering their risk for heart disease and stroke."
Dr Lawrence J. Appel, Professor of Medicine at The Johns Hopkins Medical Institutions in Baltimore, Maryland, and a co-author of the article, said: "Those in the study who made the greatest lifestyle changes had the best blood pressure results."
He added that the approach should also be used to prevent high blood pressure in the first place.
In the study, 810 participants withblood pressures of 120-159 mm Hg systolic and 80-95 mm Hgdiastolic were randomly assigned to one of three groups: Advice-Only, Established, and Established Plus DASH. At the start of the trial, 38 per cent of participantshad hypertension, and most were overweight and sedentary. All three groups received printed materials about bloodpressure and lifestyle. The Advice-Only group received a 30-minute individual session with a nutritionist, which did not include counseling on how to make behavior changes. Those in the Established group had 18 counseling sessions in six months and kept track of their diet, including calorie and sodium consumption, and theirphysical activity. Those in the Established Plus DASH grouphad the same intervention schedule as those in theEstablished group, but also were taught to follow the DASHdiet and to record their daily servings of fruits,vegetables, dairy products, and fat.
After six months, blood pressure levels had declined in allthree groups but the reduction was significantly more inthe two intervention groups and most in the EstablishedPlus DASH group. Systolic blood pressure decreased onaverage by 11.1 mm Hg in the Established Plus DASH group,10.5 mm Hg in the Established group, and 6.6 in the Advice-Only group; diastolic blood pressure decreased on averageby 6.4 mm Hg in the Established Plus DASH group, 5.5 mm Hgin the Established group, and 3.8 in the Advice-Only group.
Those with hypertension dropped after sixmonths from 37 to 12 per cent in the Established Plus DASH group, from 37 to 17 per cent in the Established group, and from 38 to 26 per centin the Advice-Only group.
Those in the EstablishedPlus DASH group were also more able to control their blood pressure after six months with 77 per cent of hypertensives inthat group lowering their blood pressure to under 140/90, compared to only 48 per cent of hypertensives in the Advice-Only group able to bring theirhypertension under control.
"One of the key findings in Premier is that people can notonly follow the DASH diet on their own but also can loseweight on it, even though it calls for many more servingsof fruits and vegetables a day than Americans typicallyconsume," said Dr Eva Obarzanek, NHLBI nutritionist andproject officer for the project.
"The new findings mean that it'sfeasible for Americans to use the eating plan, lose weightif they're overweight, and protect themselves against therisks of high blood pressure."