It's well established that a sufficient protein intake is necessary to see the full extent of benefits from a resistance training programme. Dietary protein increases post-exercise muscle protein synthesis rates and inhibits muscle protein breakdown, allowing enhanced muscle protein accretion during the post-exercise recovery period. As such, it is commonly endorsed for weightlifting enthusiasts to complement their diets and maximise their workouts with protein supplements.
But here's the question: for a healthy individual already achieving relatively high protein intakes from diet alone, say in excess of 90-100 grams/day (the British Dietetic Association recommends levels of 55 grams a day), is there any merit in advocating additional supplementation?
Until now, the evidence has been equivocal. Whereas some studies report greater gains in fat-free mass, muscle fibre size, and/or muscle strength from protein supplementation during resistance training regimes, many others have failed to observe any benefit. When such ambiguity exists in the literature the best approach is often to take the most rigorously performed studies and conduct a meta-analysis i.e., combine them all together and investigate the overall result.
Such an analysis was recently carried out by nutrition science researchers in the Netherlands. Analysing 22 randomised controlled trials of participants on a resistance-type exercise training intervention (>six week) with one subject group receiving a protein supplement or a modified higher protein diet (>1.2g/kg/day), it was found that protein supplements significantly augment the adaptive response of our muscles; increasing skeletal muscle mass and strength compared to non-consumers . The average supplemented protein amount was 50 grams a day (on top of the relatively high protein diet) and typically it was consumed before or after training.
In 'younger' individuals (under 50 years) the introduction of protein supplements to resistance training regimes produced a staggering greater than fourfold increase in fat free mass accumulation, and an impressive demonstration of 20% greater strength in one rep max leg press compared to the placebo groups
The results for the over fifties were intriguing. Examined individually, every study failed to observe a significant benefit on fat free mass gain from protein supplementation. But when compiled together, bringing about an increase in one's power to detect an effect, it was found that supplementation actually increased fat free mass by 38%, compared to placebo, after three months of training. This is an important finding; protein supplements are more often consumed by the younger generations, but with the age related loss of muscle mass reducing functional capacity and increasing disease risk, recommending protein supplements is potentially a very useful lifestyle therapeutic strategy to mitigate this. Considering that dietary intakes of protein by the more elderly are lower than the general population this is an especially important intervention offering a robust and effective strategy for promoting healthy aging.
1. Cermak NM, Res PT, de Groot LC, Saris WH, van Loon LJ (2012) Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. Am J Clin Nutr 96: 1454-1464.