Sarcopenia should be thought of as a disease; acute or chronic muscle failure. The disease process is complex and not fully understood but we have come a long way in the decade between EWGSOP 1 and 2. If you haven’t come across sarcopenia before then definitely take time to read about it in the European Consensus on Definition and Diagnosis of Sarcopenia. Sarcopenia isn’t just for people working with older adults as it is very relevant in numerous clinical specialities. If your interest is piqued then take a look at a summary I wrote for Physiospot earlier in the year.
For a long time now we’ve known that resistance training is the most effective tool at combating weakness, atrophy and failure of our muscles. There is also robust evidence which demonstrates that protein consumed pre- and post- (and even during) exercise brings about more protein synthesis than if you didn’t have protein. Somewhere around the 1.5g/kg/day mark is the suggested level of protein intake advised for active individuals. So for an 85 kg individual this is 127.5g of protein a day this is equivalent to 4 whole chicken breasts or 700g of cashew nuts. The target is more than achievable in a normal well-balanced diet – supplementation is not always necessary – but of course we are talking about healthy individuals in the early-middle stages of their life. Does this change in those with sarcopenia, co-morbidities and disability?
The article by Liao et al published in Nutritients last month, attempts to answer this question from the perspective of frailty and older adults with sarcopenia. They did this through a systematic review and meta-regression analysis of RCTs and their search strategy is easily accessible in the paper which is available for free from the link below.
The results of this review conclude that yes, protein supplementation alongside muscle strengthening is effective at improving muscle mass which then has positive effects in terms of QoL and walking ability – of course muscle strengthening will have this effect anyway. What this article doesn’t tell us is if the protein supplementation is essential or not they suggest that supplementation augments the muscle growth but not by how much. In terms of the right amount of protein to use the 1.5g/kg/day is the number recommended by this study for limiting muscle mass loss and appears to be what this study is telling us.
In terms of clinical implications this probably doesn’t change a huge amount but on the balance of things protein supplementation is worth it for most older adults performing exercise, however it is worth considering the implications of protein supplementation for some individuals. Increased levels of protein isn’t good for everyone and discussion with dietetics is worthwhile for those with bowel disorders or complex medicine regimes. Also it is worth thinking about the concept that not all calories (and nutrients) and made equally for everyone.
A chocolate bar of 300 calories for me might not mean 300 calories for you as we all digest things differently as we have different gut microbiomes and anatomy. As with everything things are often more complicated than first thought. The question of whether protein supplementation is essential for muscle growth in sarcopenia has been hotly contested for a while now and it will continue to rumble on.