Whey concentrates, isolates, hydrolysates, pea proteins, beef isolates, casein, milk protein, soy protein...the list goes on. Todays supplement market is saturated with various protein powders, but which one is the 'best'?
To dissect this common question, we will need to take a look at some of the scientific literature. But first, it is important to explain the concept of Muscle Protein Synthesis (MPS). In short, MPS is the process of building new muscle proteins. This is an ongoing process, which is upregulated shortly after eating protein rich foods/supplements and resistance training. MPS works in synergy with protein breakdown to complete a cyclical process called protein turnover. This essentially means that your body is constantly breaking down old muscle tissue and replacing it with new tissue. When the rate of synthesis consistently exceeds the rate of breakdown, a net gain of muscle is achieved.
Considering this process, researchers in the field of protein metabolism have attempted to identify which protein supplements induce the greatest postprandial elevations in MPS. In a controlled trial, Tang et al. (2009) split 18 young men into groups of 6 and made them complete a unilateral leg extension exercise. Upon completing the exercise, the groups consumed a protein matched bolus (20g) of either whey hydrolysate, casein or soy isolate. Despite each protein source containing 10g of essential amino acids (the building blocks of proteins which must be obtained through the diet), it was found that the whey hydrolysate produced a significantly greater MPS response than the casein protein (122% greater) and soy isolate (31% greater). It was suggested that the rapid digestibility of whey hydrolysate could be responsible for producing a greater MPS response. However, the variation in MPS may also be attributed to each source containing different amounts of Leucine (the essential amino acid which is most important for triggering MPS).
A more recent study by Mitchell et al. (2015) observed the MPS rate of 16 middle aged men following the consumption of either 20g of whey protein or milk protein. Despite the participants not taking part in an exercise session, both the whey protein and milk protein significantly increased MPS. There were no differences between groups in the protein synthetic response, despite whey protein having a faster absorption rate and higher leucine content. This goes against Tang et al.'s (2009) theory that absorption rate and leucine availability is responsible for the magnitude of MPS responses. However, it is possible that the age of the participants had an effect on the observed MPS rate, with 20g of protein being enough to maximally stimulate MPS in this cohort.
Nonetheless, whilst these studies provide a valuable insight into what is happening to MPS on an acute level, in order to gain meaningful amounts of muscle, synthesis rates must chronically exceed breakdown rates. However, it is often impractical to directly measure chronic changes in MPS, therefore to assess the efficacy of protein supplements studies tend to observe changes in muscle mass over long periods.
You will pleased to know that dietary protein supplementation in general invokes a positive increase in muscle mass when paired with resistance exercise (Morton et al., 2018). Furthermore, all of the forms of proteins which we stock at The Little Supplement Company have robust data to suggest they are efficacious in supporting skeletal muscle adaptations to resistance exercise (Babault et al., 2015; Bergia et al., 2018).
Whilst is it easy to get bogged down by the technical nuance of protein supplementation and synthesis rates, my overall recommendation is that the individuals choses a protein which suits their unique needs. Having a protein shake which you enjoy the taste/texture of and sits well in your stomach are important factors for helping you consistently hit your daily protein goals. For most individuals who are looking to optimise muscle growth, daily protein intake should sit between 1.6g-2.2g per kilogram of bodyweight per day (Morton et al., 2018).
Robert E Bergia, III, Joshua L Hudson, Wayne W Campbell, Effect of whey protein supplementation on body composition changes in women: a systematic review and meta-analysis, Nutrition Reviews, Volume 76, Issue 7, July 2018, Pages 539–551, https://doi.org/10.1093/nutrit/nuy017
Mitchell, C.J.; McGregor, R.A.; D’Souza, R.F.; Thorstensen, E.B.; Markworth, J.F.; Fanning, A.C.; Poppitt, S.D.; Cameron-Smith, D. Consumption of Milk Protein or Whey Protein Results in a Similar Increase in Muscle Protein Synthesis in Middle Aged Men. Nutrients 2015, 7, 8685-8699. https://doi.org/10.3390/nu7105420
Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med, 2018; 52: 376-384
Nicolas Babault, Christos Païzis, Gaëlle Deley, Laetitia Guérin-Deremaux, Marie-Hélène Saniez, Catherine Lefranc-Millot & François A Allaert (2015) Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein, Journal of the International Society of Sports Nutrition, 12:1, 3, DOI: 10.1186/s12970-014-0064-5