Protein source and quality for skeletal muscle anabolism in young and older adults: a systematic review and meta-analysis
Morgan, Paul T ; Harris, Dane O ; Marshall, Ryan N ; Quinlan, Jonathan I ; Edwards, Sophie J ; Allen, Sophie L ; Breen, Leigh
Morgan, Paul T
Harris, Dane O
Marshall, Ryan N
Quinlan, Jonathan I
Edwards, Sophie J
Allen, Sophie L
Breen, Leigh
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University of Birmingham; University Hospitals Birmingham NHS Foundation Trust
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Publication date
2021-04-13
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Abstract
Background: There is much debate regarding the source/quality of dietary proteins in supporting indices of skeletal muscle anabolism.
Objective: We performed a systematic review and meta-analysis to determine the effect of protein source/quality on acute muscle protein synthesis (MPS) and changes in lean body mass (LBM) and strength, when combined with resistance exercise (RE).
Methods: A systematic search of the literature was conducted to identify studies that compared the effects of ≥2 dose-matched, predominantly isolated protein sources of varying "quality." Three separate models were employed as follows: 1) protein feeding alone on MPS, 2) protein feeding combined with a bout of RE on MPS, and 3) protein feeding combined with longer-term resistance exercise training (RET) on LBM and strength. Further subgroup analyses were performed to compare the effects of protein source/quality between young and older adults. A total of 27 studies in young (18-35 y) and older (≥60 y) adults were included.
Results: Analysis revealed an effect favoring higher-quality protein for postprandial MPS at rest [mean difference (MD): 0.014%/h; 95% CI: 0.006, 0.021; P < 0.001] and following RE (MD: 0.022%/h; 95% CI: 0.014, 0.030; P < 0.00001) in young (model 1: 0.016%/h; 95% CI: -0.004, 0.036; P = 0.12; model 2: 0.030%/h; 95% CI: 0.015, 0.045; P < 0.0001) and older (model 1: 0.012%/h; 95% CI: 0.006, 0.018; P < 0.001; model 2: 0.014%/h; 95% CI: 0.007, 0.021; P < 0.001) adults. However, although higher protein quality was associated with superior strength gains with RET [standardized mean difference (SMD): 0.24 kg; 95% CI: 0.02, 0.45; P = 0.03)], no effect was observed on changes to LBM (SMD: 0.05 kg; 95% CI: -0.16, 0.25; P = 0.65).
Conclusions: The current review suggests that protein quality may provide a small but significant impact on indices of muscle protein anabolism in young and older adults. However, further research is warranted to elucidate the importance of protein source/quality on musculoskeletal aging, particularly in situations of low protein intake.
Citation
Morgan PT, Harris DO, Marshall RN, Quinlan JI, Edwards SJ, Allen SL, Breen L. Protein Source and Quality for Skeletal Muscle Anabolism in Young and Older Adults: A Systematic Review and Meta-Analysis. J Nutr. 2021 Jul 1;151(7):1901-1920. doi: 10.1093/jn/nxab055.
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Article