In 2001 the National Heart, Lung, and Blood Institute completed a 14 week study comparing the effects of the DASH diet, lower sodium and the DASH diet plus lower sodium intake on a group of 412 adults from varying races both with and without hypertension. Weight was kept stable so as to not affect the results.

DASH Diet Alone

The DASH diet has been shown to reduce blood pressure by about 6 points systolic and 2 points diastolic for non-hypertensives compared to those eating the typical American diet. For those with high blood pressure, average drops reported are 7 mm Hg systolic and 3 mm Hg diastolic.

Eating Less Sodium

When changing from the average American diet of 3,300 milligrams a day of sodium to 1,500 milligrams, hypertensives have been shown to lower their systolic blood pressure by 8.3 mm Hg and 4.4 mm Hg diastolic. In those without hypertension the reductions were 5.4 mm Hg systolic and 2.8 mm Hg diastolic.

DASH Diet plus Eating Less Sodium

Combining the DASH diet with a daily sodium intake of less than 1,500 milligrams daily, has been shown to reduce blood pressure in those without hypertension by 7/4 mm Hg (systolic/diastolic) and for those with high blood pressure by 12/6 mm Hg.

Dr. Denise Simons-Morton a DASH co-author said, “Following the DASH diet and reducing the intake of dietary sodium are two non-drug approaches that work to control blood pressure,” according to the National Institutes of Health Press Release.

Sources:

“NHLBI Study Finds DASH Diet And Reduced Sodium Lowers Blood Pressure For All.” December 17, 2001. National Institutes of Health.  Retrieved September 16, 2008 from http://www.nhlbi.nih.gov/new/press/01-12-17.htm.

The women in the study were between 48 and 83 years old and at the beginning of the study did not have a history of heart failure, diabetes mellitus or myocardial infarction. Using food-frequency questionnaires, the researchers compared participant’s diets to the Dietary Approaches to Stop Hypertension (DASH) diet guidelines. After adjusting for variables such as age and socioeconomic background, they discovered that the women whose diet most closely resembled the DASH diet had a significantly lower risk of heart failure.

When they compared the quarter of women whose diets were the furthest from the DASH guidelines, to the quarter whose diets were the closest to the DASH diet, they found that the 25% of women whose diets most resembled the DASH guidelines saw a 37% reduction in their risk of heart failure. Upon further analysis, the researchers found that the 10% of women whose diet was most like the DASH diet saw a full 50% decrease in their risk of heart failure.

Source:

“Consistency With the DASH Diet and Incidence of Heart Failure” Emily B. Levitan, ScD; Alicja Wolk, DrMedSci; Murray A. Mittleman, MD, DrPH. Arch Intern Med. 2009;169(9):851-857. Can be viewed online at http://archinte.ama-assn.org/cgi/content/short/169/9/851.