Nutrition-oriented, non-pharmacologic therapies to reduce blood pressure (BP) are receiving considerable attention as safe, and potentially effective, modalities to treat and prevent hypertension (HTN). Of the numerous dietary factors known to influence BP, evidence is most convincing for sodium, alcohol and weight. While potentially effective, the influence of calcium, magnesium and potassium intakes and of diets modified in macronutrient intake (high/low protein, saturated fat, polyunsaturated fat, carbohydrate and fiber) is less persuasive. The goal of the proposed research effort is to elucidate the BP-lowering effect of dietary patterns which combine these promising, but incompletely evaluated, dietary factors. Based on our review of available evidence, diets modified in macronutrient and/or micronutrient intake appear most promising. The proposed study will be a multi-center feeding study in which eligible participants are randomized to one of four diets (typical, modified macronutrient, modified micronutrient, or combined modified macronutrient/modified micronutrient diet). The modified macronutrient diet will provide foods comparatively high in protein, low in saturated fat and high in omega-3 polyunsaturated fatty acids, while the modified micronutrient diet will provide a diet comparatively high in calcium, magnesium and potassium. The study population (55% Afro-American) will consist of men and women (ages 25-54) with a mean baseline diastolic B.P of 85-94 mmHg. The initial 12 months will be devoted to protocol development and will include a pilot of the proposed diets. During the next two years, 480 individuals, 120 at each of four clinical centers, will be randomly assigned to one of the above four dietary patterns. The duration of the intervention period will be three months. Substantial efforts will be devoted to monitoring and enhancing adherence to the assigned diets. The principal trial endpoint will be the net change in diastolic BP.