DASH diet shown to lower blood pressure levels
An analysis of a government-sponsored study has revealed that blood pressure can be reduced in most people by a diet rich in fruits and vegetables and limited in sodium and total and saturated fats.
The diet also is rich in potassium, calcium, magnesium, fiber, and protein.
The Dietary Approaches to Stop Hypertension (DASH) study is supported by the National Heart, Lung, and Blood Institute (NHLBI).
Previous studies have found that besides blood pressure, the DASH diet lowers blood levels of low-density lipoprotein-cholesterol (LDL-C), the “bad” cholesterol, and the amino acid homocysteine, both of which may increase the risk of heart disease. Earlier research also has found that reducing dietary sodium alone lowers blood pressure.
The latest analysis showed that the DASH diet, plus reduced dietary sodium, lowers blood pressure in a wide variety of people, including those with and without hypertension or a family history of hypertension, older and younger adults, men and women, and obese and non-obese individuals.
In addition, the combination lowered blood pressure in people with high or low physical activity levels, large or small waist circumferences, and high or low annual family incomes or education levels.
“This new study underscores the blood pressure-lowering effects of a reduced intake of salt and other forms of dietary sodium,” says NHLBI Director Claude Lenfant, M.D.
“Earlier research on the link between sodium and blood pressure had given conflicting results in various population groups. Now we can say that cutting back on dietary sodium will benefit Americans generally and not just those with high blood pressure.”
While the combination of the DASH diet and reduced dietary sodium produced the biggest reductions, each intervention also lowered blood pressure for all groups when used alone.
“Adopting these measures could help millions of Americans avoid the rise in blood pressure that occurs with advancing age,” says Frank Sacks, M.D., a professor of cardiovascular disease prevention at the Harvard School of Public Health and chairman of the DASH steering committee.
The new data come from the DASH-Sodium study, a multicenter, 14-week randomized “feeding” trial. In this trial, 412 participants, 22 years of age and older, had systolic blood pressures between 120 and 160 mm. Hg. and diastolic blood pressures between 80 and 95 mm. Hg. Forty-one percent had hypertension and 59 percent did not; 52 percent of the participants were women, and 48 percent were men.
For three months, participants ate either the DASH diet or a typical American diet. Weight was kept stable. During the study period, each group followed three different intakes of dietary sodium for one month, each in random order:
* 3,300 milligrams (mg.) a day (the average level consumed by Americans)
* 2,400 mg. a day (the upper limit currently recommended by the National High Blood Pressure Education Program)
* 1,500 mg. a day.
The largest differences in blood pressure occurred with subjects following the DASH diet (daily sodium intake, 1,500 mg., compared with those following the “typical” diet (daily sodium intake, 3,300 mg.).
(Source: Annals of Internal Medicine, December 18, 2001.)
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