To compare the effects on blood pressure and plasma lipids of three different diets--a carbohydrate-rich diet, a protein-rich diet, or a diet rich in unsaturated fat.

BACKGROUND: While there is widespread consensus that the optimal diet to reduce cardiovascular risk should be low in saturated fat, the type of macronutrient that should replace saturated fat (carbohydrate, protein or unsaturated fat) is a major, unresolved research question with substantial public health implications. The study will evaluate these three dietary approaches by studying their effects on established coronary risk factors and a selected group of emerging risk factors.

DESIGN NARRATIVE: The study design is a randomized, three period cross-over feeding study that compares the effects on blood pressure and plasma lipids of a carbohydrate-rich diet (the DASH diet) to two other diets, one rich in protein and another rich in unsaturated (UNSAT) fat, predominantly monounsaturated fat. The DASH diet has been shown to reduce blood pressure and LDL-cholesterol substantially, and is currently recommended by policy makers. During a one week run-in, all participants will be fed samples of the three study diets (DASH, PROTEIN and UNSAT). Using a three period cross-over design, participants will then be randomly assigned to the DASH, PROTEIN OR UNSAT diet. Each feeding period will last six weeks; a washout period of at least two weeks will separate each feeding period. Throughout feeding (run-in and the three intervention periods), participants will be fed sufficient calories to maintain their weight. Trial participants (n=160, approximately 50 percent female, approximately 50 percent African-American) will be 20 years of age or older, with systolic blood pressure of 120-159 mmHg and diastolic blood pressure of 80-95 mmHg. Primary outcomes variables will be blood pressure and the established plasma lipid risk factors (LDL-C, HDL-C and triglycerides). Secondary outcomes will include apolipoproteins VLDL-apoB and VLDL-apoCIII, which should be superior to triglycerides as predictors of cardiovascular events, as well as total apolipoprotein B, non-HDL cholesterol, and lipoprotein(a).

Ages Eligible for Study:  20 Years and above,  Genders Eligible for Study:  Both

Criteria