Effect of Egg Consumption on Cardiometabolic Health in Prediabetic Subjects.

This is a randomized, crossover study that includes two screening visits and two 4-week test periods separated by a 4-week washout. Subjects will consume two eggs/day (12 eggs/week consumed over 6 days per week, provided as breakfast foods such as burrito-type roll-up, egg sandwich and omelet) or non-egg based control foods (provided as breakfast foods such as English muffins, bagels, ready-to-eat cereal, and flavored muffins). The background diet will be a habitual diet. The nutritional profiles of the egg and control breakfast foods will be designed such that the energy from eggs will be substituted for a mixture of carbohydrate, protein and fat in the control foods. Study foods will be dispensed with instructions to consume the assigned breakfast food starting on day 1. Subjects will be instructed to consume the breakfast foods in their entirety each day, for the duration of the 28 day test period, and to record daily study food intake. Subjects will receive diet instruction on the incorporation of food substitutions during the test period to maintain habitual energy intake. Compliance will be assessed using the Daily Log intake and number of foods consumed based on returned foods. An intravenous glucose tolerance test (IVGTT) will be completed at baseline and the end of each treatment period for evaluation of insulin sensitivity. Blood will be collected for a fasting lipid profile (at all visits), glucose and insulin, high-sensitivity C-reactive protein (hs-CRP), vertical auto profile (VAP) for cholesterol carried by lipoprotein fractions (at baseline and end of each treatment period), with additional blood samples collected for storage and archived for possible future analysis of non-genetic indicators of metabolism. Assessments of vital signs and body weight, review of concomitant medication/supplement use and inclusion and exclusion criteria for relevant changes, and evaluation of adverse effects will be performed throughout the study.