N.M.M.P. de Hart1, Z.S. Mahmassani1, P.T. Reidy1, A.I. McKenzie1, J.J. Petrocelli1, L.S. Ward2, J.A. Maschek1, M.J. Bridge1, M.J. Drummond1

1University of Utah, Salt Lake City, UT; 2Glanbia Nutritionals, Twin Falls, ID

Dietary protein is fundamental to maintain muscle mass. Muscle protein synthesis transiently increases following protein ingestion; the magnitude and duration of which is dictated by the amino acid profile, type of protein, and protein digestion. No studies have evaluated the acute skeletal muscle protein response to cheese ingestion especially since it is rich in leucine content (~10%). PURPOSE: The purpose of this study was to determine the blood amino acid profile to the acute ingestion of cheddar cheese and how this responds to that of milk of the same protein amount. We hypothesized in healthy young male (n=12, 27 ± 4, 24.6 ± 3.8) and female (n=12, 26 ± 4, 21.9 ± 2.8) adults that a single dose of cheddar cheese, equivalent to 20g of protein, would acutely increase the blood branched-chain amino acids (particularly leucine) compared to baseline. Furthermore, we hypothesized that the blood branched-chain amino acid in response to cheese would demonstrate a similar response when compared to a single dose of an equivalent amount of protein in the form of 2% bovine milk. METHODS: We conducted a randomized cross-over clinical study in young men and women such that participants completed both nutrient product experiments within 1-4 weeks of each other. Blood samples were assessed in plasma for essential and non-essential amino acids before and repeatedly after nutrient ingestion (5h) following milk or cheese. RESULTS/CONCLUSION: We found that an acute ingestion of both cheddar cheese and milk (20g of protein) increased BCAA and NEAA plasma levels to a similar extent over a 5h period following ingestion in young healthy adults. Though milk demonstrated an acute peak response that was greater than cheese, cheddar cheese demonstrated a slow release of amino acids such that the total amino acid appearance over 5h was similar between the two products. Our next step is to evaluate the protein anabolic response in skeletal muscle following before and following the ingestion of these two protein-dense food products.

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