LOW-CHO & HIGH-CHO, HIGH-FIBER DIETS & RISK MARKERS FOR THE METABOLIC SYNDROME

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this study is to compare an ad libitum low-carbohydrate diet with an libitum high-carbohydrate, high-fiber diet with regard to insulin sensitivity and blood markers for cardiovascular disease risk in men and women with the metabolic syndrome. In a randomized crossover design, 24 men and women with the metabolic syndrome will consume each of two diets: a low-carbohydrate diet (15-20% carbohydrate; 55-60% fat; 25-30 protein) and a high-carbohydrate, high-fiber diet (55-60% carbohydrate; 20-25% fat; 15-20% protein; > 30 grams fiber per day). Each diet period will last 4 weeks, with a 4-6 week wash-out period. All meals will be prepared in the General Clinical Research Center (GCRC) kitchen for pick-up three days per week by the participants, and will contain 150% of daily energy requirements estimated by the Harris-Benedict equation. Participants will be instructed to eat only until no longer hungry, and to return uneaten food to the GCRC. We hypothesize that that the ad libitum high-carbohydrate, high-fiber diet will significantly improve insulin sensitivity assessed by the Quantitative Insulin sensitivity Check Index (QUICKI), enhance arterial endothelial and smooth muscle function (as measured by flow-mediated dilation); increase blood concentration of adiponectin; and reduce blood concentrations of total and LDL-cholesterol, C-reactive protein, homocysteine, fibrinogen, cytokines (IL-1, IL-2, IL-6 and TNF-alpha), leukocyte adhesion molecules(E-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1)), and blood pressure; whereas the ad libitum low-carbohydrate, low-fiber diet will not.