Luc J C VAN Loon, Jan-Willem van Dijk, Thorben Aussieker, Luuk Hilkens, Andrew M Holwerda, Cas J Fuchs, Lisanne H P Houben, Joan M Senden, Tim Snijders
Journal: Medicine and science in sports and exercise 2023;55(10):1792-1802
PMID: 37202878
Muscle protein synthesis after exercise is enhanced by the ingestion of high-quality protein post-exercise. The synthesis of muscle connective proteins, which are equally important for muscle strength, also increases after exercise, but the effect of protein ingestion on this is unclear. The aim of this double-blind, randomised, placebo-controlled trial, including 45 healthy male and female recreational athletes, was to evaluate the effects of collagen and whey protein supplementation on the formation of muscle connective proteins. Athletes were given 30 g whey protein, 30 g collagen or placebo following a resistance exercise workout, and blood and muscle tissue samples were taken regularly for 5 hours. Plasma levels of amino acids (AA) differed significantly between the 3 groups with levels of total and essential AA being highest in the whey group and levels of non-essential AA highest in the collagen group, with all lowest in placebo group. Levels of leucine were highest with whey supplementation whilst the AAs important for collagen synthesis (proline, glycine, hydroxyproline) were highest in the collagen group. Myofibrillar protein synthesis was significantly higher in the whey compared to the placebo group. There was no significant difference between groups in the synthesis of muscle connective tissue or in delayed onset muscle soreness. The authors concluded that neither whey nor collagen supplementation enhances muscle connective protein synthesis.
INTRODUCTION
Protein ingestion during recovery from exercise has been reported to augment myofibrillar protein synthesis rates, without increasing muscle connective protein synthesis rates. It has been suggested that collagen protein may be effective in stimulating muscle connective protein synthesis. The present study assessed the capacity of both whey and collagen protein ingestion to stimulate postexercise myofibrillar and muscle connective protein synthesis rates.
METHODS
In a randomized, double-blind, parallel design, 45 young male ( n = 30) and female ( n = 15) recreational athletes (age, 25 ± 4 yr; body mass index, 24.1 ± 2.0 kg·m -2 ) were selected to receive primed continuous intravenous infusions with l -[ring- 13 C 6 ]-phenylalanine and l -[3,5- 2 H 2 ]-tyrosine. After a single session of resistance type exercise, subjects were randomly allocated to one of three groups ingesting either 30 g whey protein (WHEY, n = 15), 30 g collagen protein (COLL, n = 15) or a noncaloric placebo (PLA, n = 15). Blood and muscle biopsy samples were collected over a subsequent 5-h recovery period to assess both myofibrillar and muscle connective protein synthesis rates.
RESULTS
Protein ingestion increased circulating plasma amino acid concentrations ( P < 0.05). The postprandial rise in plasma leucine and essential amino acid concentrations was greater in WHEY compared with COLL, whereas plasma glycine and proline concentrations increased more in COLL compared with WHEY ( P < 0.05). Myofibrillar protein synthesis rates averaged 0.041 ± 0.010, 0.036 ± 0.010, and 0.032 ± 0.007%·h -1 in WHEY, COLL and PLA, respectively, with only WHEY resulting in higher rates when compared with PLA ( P < 0.05). Muscle connective protein synthesis rates averaged 0.072 ± 0.019, 0.068 ± 0.017, and 0.058 ± 0.018%·h -1 in WHEY, COLL, and PLA, respectively, with no significant differences between groups ( P = 0.09).
CONCLUSIONS
Ingestion of whey protein during recovery from exercise increases myofibrillar protein synthesis rates. Neither collagen nor whey protein ingestion further increased muscle connective protein synthesis rates during the early stages of postexercise recovery in both male and female recreational athletes.
Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Sports Medicine.
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