Intake of a Mediterranean Diet Reduces Atherogenic Lipid Profiles but the Effect Is Diminished by Daily Egg Intake

Abstract

Abstract Objectives A Mediterranean diet (Med Diet) decreases atherogenic lipoproteins and cardiovascular disease (CVD) risk. It is unknown how high cholesterol intake within a Med Diet will affect these parameters. The objective of this project was to evaluate the daily inclusion of whole eggs, a high cholesterol food, in the Med Diet on lipid and lipoprotein profiles. Methods Overweight to obese men (8) and women (25) were recruited into a randomized, cross-over designed, controlled feeding study evaluating three isocaloric test diets: a) Control –average American diet from What We Eat in America, b) Med Diet, and c) Med Diet plus whole, fresh eggs (1 whole egg/1000 kcal; Med Diet + Egg). The Control and Med Diet contained egg substitute. Participants were directed to consume only those foods provided during each 4-week diet treatment period. Each treatment period was separated by > 4-week washout period. Fasting blood was taken pre- and post-treatment for determination of lipid concentrations, lipoprotein particle size and number. Results Intake of the Control and Med Diet, but not the Med Diet + Egg, decreased (time effect, P < 0.05) total cholesterol and low density lipoprotein (LDL) concentrations, but an overall diet treatment effect did not occur. Med Diet, but not Control or Med Diet + Egg, reduced (time effect, P < 0.05) triglyceride concentrations, but an overall treatment effect did not occur. Particle numbers (P < 0.05) were reduced (P < 0.05) for intermediate density lipoprotein (26%) and total LDL (8%) by Med Diet intake but not by the other diets, and an overall treatment effect was not observed. Very low density lipoprotein size was reduced (P < 0.05) by Med Diet intake and an overall treatment effect occurred (P = 0.04). Variability in responses was assessed by hierarchical clustering heatmap analysis of blood lipid responses. Three main categories of responses types were present but not defined by dietary treatment. Conclusions Daily intake of a Mediterranean diet meal pattern or an average American diet without whole eggs reduced blood lipid and/or lipoprotein concentrations associated with CVD risk; addition of daily egg intake blunted these reductions. However, the variability in the study population responses warrants further nutrigenomic exploration. Funding Sources USDA-ARS 3062-53000-001-00D and the American Egg Board.