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Maximizing protein anabolism in young and aging muscle: a dose response to dietary protein ingestion
Author(s) -
Symons T. Brock,
SheffieldMoore Melinda,
Wolfe Robert R.,
PaddonJones Douglas
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1095.10
Subject(s) - anabolism , ingestion , muscle protein , lean body mass , lean meat , medicine , zoology , endocrinology , chemistry , skeletal muscle , biology , body weight
We have recently shown that a single moderate serving of a protein‐rich food (113 g of lean beef; 30 g protein) acutely increases muscle protein synthesis by 51% in both young and elderly. PURPOSE: To quantify the age‐ and dose‐response to nutrient ingestion by measuring muscle protein synthesis following a single large serving of a protein‐rich food (340 g lean beef; 90 g protein; ~1.2g/kg/day for 70kg individual) in young (n=7; 29±3yrs) and elderly (n=7; 66±2yrs) individuals. METHODS: Venous blood and vastus lateralis muscle biopsy samples were obtained during a primed (2.0 μmol/kg) constant infusion (0.08 μ mol·kg −1 min −1 ) of L‐ [ring‐ 13 C 6 ] phenylalanine. Mixed muscle fractional synthesis rate (FSR) was calculated during a 3 h post‐absorptive period and for 5 h following ingestion of 340 g of 90% lean ground beef. RESULTS: Mixed muscle FSR increased by approximately 46% in both the young (pre: 0.082±0.010; post: 0.119±0.012) and the elderly (pre: 0.086±0.008; post: 0.125±0.014 %/h) following ingestion of 340 g of lean beef. These data were similar to the response to ingestion of 113 g lean beef in the young (pre: 0.074±0.005; post: 0.113±0.005 %/h) and elderly (pre: 0.072±0.004; post: 0.108±0.006). CONCLUSION: A large serving of protein increases muscle protein synthesis by 46% in both young and elderly, but provides no additional anabolic stimulus above that afforded by a more moderately sized 113 g serving. These data have implications for the dose and distribution of dietary protein over the course of a day.