Project Number: 3062-51000-053-08-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Dec 31, 2015
End Date: Dec 31, 2019
The Mediterranean Diet has been shown to decrease atherogenic lipoproteins and reduce systemic inflammation. It is unknown how high cholesterol intake within a Mediterranean Diet will affect these parameters, although recent evidence implies that the fatty acid content of the diet is more important than the cholesterol content. Therefore, the objective of this project is to evaluate the daily inclusion of whole eggs in the Mediterranean Diet on lipid profiles, lipoprotein particle size and density, and biomarkers of systemic inflammation. We hypothesize that regular consumption of whole eggs in a Mediterranean Diet result in 1) improved lipoprotein profiles (particle number and density), and 2) reductions in systemic inflammation compared to a control diet and, that 3) responses will be similar to those of a Med Diet that does not contain added whole egg. Specific Aims: (1) Determine effects of regular intake of whole eggs on lipid profiles in individuals consuming a Mediterranean Diet, 2) determine the diet effects on lipoprotein metabolism including lipoprotein particle size and content, and 3) determine the effect of whole egg intake on markers of systemic inflammation and platelet activation.
Studies will be conducted at the Grand Forks Human Nutrition Research Center (GFHNRC). The GFHNRC has the capacity to perform well controlled feeding studies in a free-living population, having inpatient facilities, metabolic kitchens and the required laboratory facilities. Twenty (20) normal weight to obese (BMI 18-39.9kg/m2) men and women (ages 25-75) will be recruited for a randomized, cross-over designed clinical feeding study evaluating three test diets: a) control – composition of the usual American diet, b) Mediterranean Diet (Med Diet), or c) Med Diet plus whole eggs (~1 whole egg/1000 Kcal; Med Diet + Whole Egg). The control and Med Diets will be prepared with egg substitutes while the Med Diet + Whole egg will be planned with fresh, whole eggs. Diets will be planned as a 5 day rotating menus with the use of similar foods except for the fats/oils needed to meet dietary composition for each treatment and the use of Whole Eggs as a protein source on the Med Diet + Whole Egg. Volunteers will be screened to ensure eligibility. Those with established metabolic disease or elevated lipids (total cholesterol >240 mg/dl) or blood glucose (>126 mg/dl) will be excluded. Participants will be randomly assigned to one of the diets for 4 weeks followed by a 4-8 week washout period. Upon completion of the washout, they will be assigned to the alternate treatment until all three diets have been tested by the same individual. Testing will be performed at days 0 and 28 of each treatment. Pre- and post-treatment outcome variables to be evaluated include lipid metabolism (plasma fatty acids, cholesterol, LDL, HDL, TG); lipoprotein number and density (VLDL particles, LDL Particles, Non-HDL particles, Apo-B-100, and Lp(a),' platelet activiation; and measures of inflammation (insulin, homocysteine, high sensitivity C Reactive Protein) will also be assessed before and after each treatment phase. All meals will be prepared in the GFHNRC metabolic kitchen and distributed for home consumption. During and between treatments total dietary intake will be monitored by diet record keeping overseen by a registered dietitian. Dietary compliance will be assessed by frequent monitoring of skin carotenoid levels.