Acute Effects of Cheddar Cheese Consumption on Circulating Amino Acids and Human Skeletal Muscle

Abstract

Cheddar cheese is a protein-dense whole food and high in leucine content. However, no information is known about the acute blood amino acid kinetics and protein anabolic effects in skeletal muscle in healthy adults. Therefore, we conducted a crossover study in which men and women (n = 24; ~27 years, ~23 kg/m2) consumed cheese (20 g protein) or an isonitrogenous amount of milk. Blood and skeletal muscle biopsies were taken before and during the post absorptive period following ingestion. We evaluated circulating essential and non-essential amino acids, insulin, and free fatty acids and examined skeletal muscle anabolism by mTORC1 cellular localization, intracellular signaling, and ribosomal profiling. We found that cheese ingestion had a slower yet more sustained branched-chain amino acid circulation appearance over the postprandial period peaking at ~120 min. Cheese also modestly stimulated mTORC1 signaling and increased membrane localization. Using ribosomal profiling we found that, though both milk and cheese stimulated a muscle anabolic program associated with mTORC1 signaling that was more evident with milk, mTORC1 signaling persisted with cheese while also inducing a lower insulinogenic response. We conclude that Cheddar cheese induced a sustained blood amino acid and moderate muscle mTORC1 response yet had a lower glycemic profile compared to milk.

Cheese Ingestion Increases Muscle Protein Synthesis Rates Both at Rest and During Recovery from Exercise in Healthy, Young Males: A Randomized Parallel-Group Trial

“…In agreement, the postprandial increase in plasma amino acid availability (iAUC) was substantially less following cheese when compared with milk protein ingestion. These findings seem to be in line with previous work ( 28 ) reporting a more delayed increase in plasma amino acid availability following cheddar cheese compared with milk ingestion. Our data further support the understanding that the food matrix in which protein is provided strongly affects protein digestion and amino acid absorption, and modulates the subsequent postprandial plasma amino acid profile.…”

“…Consequently, we hypothesized that ingestion of a meal-sized amount of cheese increases circulating plasma amino acid concentrations and subsequently stimulates muscle protein synthesis. Recent work has reported substantial differences in postprandial circulating amino acid concentrations following ingestion of dairy protein isolates, concentrates, and various dairy whole foods ( 27 , 28 ). Whether such differences in postprandial plasma amino acid concentrations modulate the capacity to stimulate postprandial muscle protein synthesis remains to be established ( 28 ).…”

“…Recent work has reported substantial differences in postprandial circulating amino acid concentrations following ingestion of dairy protein isolates, concentrates, and various dairy whole foods ( 27 , 28 ). Whether such differences in postprandial plasma amino acid concentrations modulate the capacity to stimulate postprandial muscle protein synthesis remains to be established ( 28 ). The food matrix of cheese and the greater amount of casein protein in cheese when compared with milk protein ( 26 ) could theoretically result in an attenuated postprandial rise in circulating essential amino acid (EAA) concentrations, and plasma leucine concentrations in particular.…”

The skeletal muscle fiber periphery: A nexus of mTOR-related anabolism

“…Protein-dense whole foods offer distinct amino acid profiles and anabolic responses that are not contingent on the protein dose or extent of aminoacidemia. 62 , 63 For instance, no changes in mTOR-LAMP2 colocalization were observed in individuals consuming either cheese or milk containing 20 ​g protein. 62 Again, mTOR-WGA colocalization was elevated, indicative of peripheral translocation, albeit only following cheese ingestion.…”

“… 62 , 63 For instance, no changes in mTOR-LAMP2 colocalization were observed in individuals consuming either cheese or milk containing 20 ​g protein. 62 Again, mTOR-WGA colocalization was elevated, indicative of peripheral translocation, albeit only following cheese ingestion. 62 It is therefore possible that the source of protein ingested may impact mTOR translocation, albeit more clarifying research is needed in this area.…”