Greater Stimulation of Postexercise Muscle Protein Synthesis after Consumption of Whole Eggs versus Egg Whites in Healthy Young Men

Abstract

The majority of protein consumed in the diet is obtained from whole food sources that contain a mixture of macro‐ and micronutrients. Whereas the majority of research investigated the effect of isolated protein sources on protein metabolism, our aim was to assess the muscle anabolic potential of consuming a complete protein within its naturally occurring, nutrient dense food matrix during recovery from resistance exercise in young men. In crossover trials, 10 healthy resistance‐trained men (21±1 y; 88±3 kg; bodyfat: 16±1%) received primed continuous L‐[ring‐2H5]phenylalanine and L‐[1‐13C]leucine infusions. Repeated blood and muscle biopsies were collected before and after a single bout of resistance exercise (4 sets of 10 repetitions at 80% of 10‐RM for both leg press and leg extensions). Immediately after resistance exercise, participants ingested intrinsically L‐[5,5,5‐2H3]leucine labeled whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat) cooked in scrambled form. Exogenous leucine appearance rates increased (P<0.001) after protein ingestion with peak values of 513±57 nmol leucine·kg−1·min−1 occurring at 75 min after egg white ingestion compared with 496±38 nmol leucine·kg−1·min−1 at 120 min after whole egg ingestion. The total amount of protein derived leucine that became available in circulation over the 300 min postprandial period was similar (P=0.53) between whole egg (75±2.3%) and egg white ingestion (77±1.7%). Whole egg ingestion supported greater post‐exercise myofibrillar protein synthesis rates when compared to egg white ingestion (0.034%/h and 0.024%/h respectively; P=0.02). We conclude that whole egg ingestion stimulates the muscle protein synthetic response more effectively than the consumption of isonitrogenous amounts of egg whites during recovery from resistance exercise in healthy young men. This effect is not attributed to divergent postprandial protein‐derived amino acid availability, suggesting that some intrinsic factor within whole eggs and/or the divergent macronutrient profile may have modified the anabolic potential of this complete protein.Support or Funding InformationVision 20/20 Grant, Division of Nutritional Sciences, University of Illinois, Urbana‐Champaign