King Grub
2016-04-05, 21:00
Skeletal muscle is critical for human health. Protein feeding, alongside resistance exercise, is a potent stimulus for muscle protein synthesis (MPS) and is a key factor that regulates skeletal muscle mass (SMM). The main purpose of this narrative review was to evaluate the latest evidence for optimising the amino acid or protein source, dose, timing, pattern and macronutrient coingestion for increasing or preserving SMM in healthy young and healthy older adults. We used a systematic search strategy of PubMed and Web of Science to retrieve all articles related to this review objective. In summary, our findings support the notion that protein guidelines for increasing or preserving SMM are more complex than simply recommending a total daily amount of protein. Instead, multifactorial interactions between protein source, dose, timing, pattern and macronutrient coingestion, alongside exercise, influence the stimulation of MPS, and thus should be considered in the context of protein recommendations for regulating SMM. To conclude, on the basis of currently available scientific literature, protein recommendations for optimising SMM should be tailored to the population or context of interest, with consideration given to age and resting/post resistance exercise conditions.
On the basis of published literature collated in this review, we propose the following evidence-based implications for practice.
Protein guidelines should be customised to the population (young or older adults) and situation (resting or post-exercise condition) of interest. For example, (a) the optimal dose of protein for maximal stimulation of MPS during exercise recovery is greater for older compared to young adults and (b) whey protein has been shown to stimulate a greater response of MPS compared with soy protein during exercise recovery, but not at rest.
Chronic periods of leucine supplementation will not necessarily facilitate long-term improvements in SMM, given that a full complement of EAA is critical for stimulating a maximal and sustained response of MPS.
Manipulating the leucine content of a protein source that lacks quality (i.e., the protein source constitutes a low leucine composition) and/or quantity (i.e., an insufficient protein dose for the maximal stimulation of MPS) effectively rescues a submaximal resting postprandial stimulation of MPS. This phenomenon has particular implications for older adults or other populations that often experience difficulties in consuming a sufficiently large dose of protein in each meal serving to stimulate a maximal response of MPS.
Timing protein intake in close temporal proximity to exercise is recommended, although not critical, for stimulating a maximal response of MPS.
Coingesting CHO with a suboptimal dose of amino acids/protein may be an effective strategy for “rescuing” a submaximal response of MPS associated with a suboptimal dose of amino acids/protein. However, no additional benefit is gained from adding CHO to a dose of amino acids/protein known to saturate the response of MPS.
Any beneficial impact of fat coingestion on MPS is likely mediated by the anabolic action of the LC n-3 PUFA.
Nutrients. 2016 Mar 23;8(4). Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults.
http://www.mdpi.com/2072-6643/8/4/181/htm
On the basis of published literature collated in this review, we propose the following evidence-based implications for practice.
Protein guidelines should be customised to the population (young or older adults) and situation (resting or post-exercise condition) of interest. For example, (a) the optimal dose of protein for maximal stimulation of MPS during exercise recovery is greater for older compared to young adults and (b) whey protein has been shown to stimulate a greater response of MPS compared with soy protein during exercise recovery, but not at rest.
Chronic periods of leucine supplementation will not necessarily facilitate long-term improvements in SMM, given that a full complement of EAA is critical for stimulating a maximal and sustained response of MPS.
Manipulating the leucine content of a protein source that lacks quality (i.e., the protein source constitutes a low leucine composition) and/or quantity (i.e., an insufficient protein dose for the maximal stimulation of MPS) effectively rescues a submaximal resting postprandial stimulation of MPS. This phenomenon has particular implications for older adults or other populations that often experience difficulties in consuming a sufficiently large dose of protein in each meal serving to stimulate a maximal response of MPS.
Timing protein intake in close temporal proximity to exercise is recommended, although not critical, for stimulating a maximal response of MPS.
Coingesting CHO with a suboptimal dose of amino acids/protein may be an effective strategy for “rescuing” a submaximal response of MPS associated with a suboptimal dose of amino acids/protein. However, no additional benefit is gained from adding CHO to a dose of amino acids/protein known to saturate the response of MPS.
Any beneficial impact of fat coingestion on MPS is likely mediated by the anabolic action of the LC n-3 PUFA.
Nutrients. 2016 Mar 23;8(4). Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults.
http://www.mdpi.com/2072-6643/8/4/181/htm