COMBINATION DIETS
A variety of studies have examined the effect of combined dietary approaches on blood pressure as nonpharmacological treatment of hypertension or for the prevention of hypertension in those at increased risk (high-normal blood pressure). These combined studies have been fraught with problems resulting from recidivism, inadequate achievement of dietary goals, or relatively short duration. In general, it can be stated that weight loss appears to be the most effective single intervention as long as the weight loss can be maintained. There does not appear to be an additive benefit when potassium supplementation is combined with modest dietary salt restriction beyond that seen with salt restriction alone. However, in the DASH trial, when a specific diet incorporating modest salt restriction with an increase in fresh fruits and vegetables and low-fat dairy products (presumably increasing potassium, calcium, and magnesium intake) was followed, a significant reduction in blood pressure was observed over the 8-wk study period.
This benefit appeared to be greatest among African-Americans and those with higher initial blood pressure levels. Another study exami ning multiple dietary changes was a subgroup of the Nurses Health Study II, which compared the effects of supplemental potassium, calcium, magnesium, or all three minerals to placebo in normotensive nurses in whom dietary deficiencies of these minerals were documented. As previously mentioned, potassium supplementation alone, but not combination supplementation, lowered blood pressure.
