Consumption of Different Egg-Based Diets Minimally, yet Differentially, Impacts Markers Insulin Resistance in Young Healthy Adults

OBJECTIVES: Previous epidemiological studies have reported conflicting associations between egg consumption and type 2 diabetes mellitus (T2DM) risk. However, many observational, survey-based studies do not fully characterize intake of additional egg-based foods or clearly differentiate between type of egg consumed. Thus, we investigated whether daily intake of whole eggs, egg whites, or an egg-free diet differentially altered markers of T2DM risk in young healthy adults. METHODS: Young, healthy men and women (18–35 y, BMI < 30 kg/m(2) or <30% body fat for men and < 40% body fat for women, n = 26) participated in a randomized, crossover intervention trial where they followed an egg-free diet for 4 weeks, then were randomized to consume either 3 whole eggs or 3 egg whites per day for 4 weeks. Participants then followed a 4-week egg-free diet washout period, before switching to the alternative whole egg or egg white diet treatment. Additional egg-based foods were restricted. Fasting serum samples were collected at the end of each diet period to measure markers of T2DM risk. RESULTS: Average fasting serum glucose was 90.7 mg/dL at baseline, and did not significantly change between the egg-free, egg white, or whole egg diet periods. Similarly, there were no changes in pro-inflammatory N-acetylglucosamine/galactosamine (GlycA), which is an independent predictor of insulin resistance (IR). Serum amino acids levels were further assessed, as elevated branched-chain amino acids and reduced glycine levels are predictors of prediabetes, IR, and future T2DM. Interestingly, isoleucine levels were increased following the egg white and whole egg diet as compared to the egg-free diet, whereas glycine levels were increased in by the whole egg diet only. Despite these differences, lipoprotein IR index (LP-IR) scores, which take into account NMR lipoprotein particle profiles, and diabetes risk index scores, which are calculated from LP-IR and branched-chain amino acid measures, did not change over the course of the intervention. CONCLUSIONS: Our findings indicate that eggs minimally impact IR markers in young healthy adults, with egg whites yielding more adverse changes than whole eggs. FUNDING SOURCES: This study was funded by an Agriculture and Food Research Initiative Grant from the USDA National Institute of Food and Agriculture.