Influence of the DASH diet and other low-fat, high-carbohydrate diets on blood pressure.

The Dietary Approaches to Stop Hypertension (DASH) and DASH-sodium trials were controlled feeding dietary trials that lowered blood pressure in the absence of weight loss. The beneficial aspect of DASH appears to be the low saturated fat content (< 7%). Sodium restriction added additional blood pressure lowering to the low saturated fat DASH diet. Sodium restriction was more effective with increasing age and more effective than increasing fruit and vegetable content. When achievement of sodium restriction, exercise, and weight loss goals were reached in the outpatient setting with subjects making their own food choices (as in the PREMIER study), adding the DASH diet with an average fruit and vegetable intake of 7.8 servings daily had no additional benefit in those younger than 50 years of age or in ethnic/gender subgroups, but did have a benefit for the total group older than age 50 years. Because many hypertensive subjects are overweight, hypocaloric versions of DASH geared toward weight loss are appropriate. Mechanisms for dietary beneficial effects are related to inflammation and insulin sensitivity.