DIETARY PATTERNS AND BLOOD PRESSURE

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The aim of this study is to identify a diet pattern that will lower blood pressure. Past studies which have examined the blood pressure effect of the amount and type of dietary fat and protein have demonstrated no convincing effect. The diet pattern which has been most consistently associated with lower blood pressure is vegetarianism. We believe that the micronutrient combination of the vegetarian diet is the most likely mediator of its hypotensive effect. Although a vegetarian pattern is too extreme to recommend to our general population, the same micronutrient intake can be achieved along with sufficient meat, fish, and dairy products to make the overall pattern palatable. Therefore, our proposed multi-center trial would test the blood pressure effect of two diets high in micronutrients (potassium, calcium, and magnesium) vs a "typical" American control diet in 480 subjects (50:50 male:female and black:caucasian) with baseline diastolic blood pressure 80-99 mmHg. The treatment diets will differ in macronutrients: one with the "adverse" macronutrients of the control diet and the other with lower animal fat and a better polyunsaturated:saturated fat ratio. We hypothesize that both treatment diets will lower blood pressure (demonstrating that the hypotensive effect is related to micro- not macro-nutrient content), but only the low animal fat diet will also lower cholesterol levels. Thus, the high micronutrient, low fat diet would be optimal for overall cardiac risk reduction. Undoubtedly, some subjects will lower blood pressure substantially with this diet and some will not. To help identify the determinants of these "responders", we propose to characterize subjects at the trial's out set according to demographics, usual diet intake, and several "hypertensive" paradigms (renin status, salt-sensitivity, insulin resistance, and modulator/nonmodulators). Considering the sizable number of subjects which will be studied in this multi-center trial, and the even distribution of ethnicity and gender, this trial should definitively establish the importance of dietary pattern high in micronutrients as a means of lowering blood pressure. With appropriate pre-trial classification of subjects, it will also definitively demonstrate in which groups of subjects these diets might be most beneficial.