Table 1.
Studies aimed to identify the best protein supplementation in inducing muscle protein synthesis or accretion, after acute administration.
| Author, Year | Number Participants, Gender | Age (Mean or Range) | Type of Study: Intervention Arms | Main Endpoints | Results |
|---|---|---|---|---|---|
| Paddon-Jones, 2006 [30] | 14, 7 ♀/7 ♂ | 68 | RCT: 15 g WP vs. 15 g EAA | Muscle FSR for 3.5 h after ingestion | Both supplementations stimulated FSR, with greater increase in EAA arm |
| Katsanos, 2008 [31] | 15, 6 ♀/9 ♂ | 60–85 | RCT: 15 g WP vs. 6.72 g WP’s EAA vs. 7.57 WP’s Non-EAA | blood phenylalanine, insulin, glucose concentration, muscle biopsy | WP improves MP accrual through mechanisms beyond its EAA content |
| Koopman, 2009 [32] | 10, ♂ (cross over) | 64 | Case-control study: 35 g intact casein vs. 35 g hydrolyzed casein | blood phenylalanine concentration, muscle biopsy (FSR) | Hydrolysate accelerates protein digestion and absorption, increase AA availability and FSR |
| Pennings, 2011 [33] | 48, ♂ | 74 | RCT: 20 g WP vs. 20 g casein vs. 20 g casein hydrolysate | Postprandial Muscle FSR | MP accretion more effective in WP arm |
| Burd, 2012 [34] | 14, ♂ | 71 | RCT: 20 g micellar casein vs. 20 g WP | Rate of MPS at rest and after exercise | Greater rates of MPS in WP arm |
| Groen, 2012 [35] | 16, ♂ | 74 | RCT: intra-gastric administration during sleep of 400 mL of water with vs. without 40 g casein | BPB, MPS | Casein administration during sleep improves BPB and stimulates MPS |
| Pennings, 2012 [36] | 33, ♂ | 73 | RCT: 10 g vs. 20 g vs. 35 g WP | AA absorption, BPB, MPA | 35 g WP reaches best values in all endpoints |
| Wall, 2013 [37] | 24, ♂ | 74 | RCT: 20 g casein vs. 20 g casein + 2.5 g leucine | MPA | Leucine co-ingestion improves MPA |
| Luiking, 2014 [38] | 19, 10 ♀/9 ♂ | 69 | RCT: 20 g WP vs. 6 g milk protein, both arms after unilateral resistance exercise | MPS | Higher MPS with WP, without further enhance with exercise |
| Churchward-Venne, 2015 [39] | 32, ♂ | 71 | Parallel group study: 25 g casein in milk matrix vs. 25 g casein in water | Post-prandial MPS | Milk matrix delays casein digestion and absorption without affecting MPS |
| Borack, 2016 [40] | 20, ♂ | 55–75 | RCT: 30 g WP isolate vs. 30 g soy-dairy protein blend (25% soy, 25% WP and 50% casein); both arms after resistance exercise | Blood and muscle AA concentration; FSR | No differences in endpoints among arms |
| Gorissen, 2016 [41] | 60, ♂ | 71 | RCT: 35 g WhP vs. 35 g WhPH, vs. 35 g micellar casein vs. 35 g WP vs. 35 g WPH vs. 60 g WhP | Post-prandial AA concentration and MPS | Greater AA concentration after WP, greater MPS after micellar casein |
| Walrand, 2016 [42] | 31, ♂ | 72 | RCT: 10-day period of AP or HP diet followed by ingestion of 15 g or 30 g casein vs. 15 g or 30 g of soluble milk proteins | FSR | Greater increase in FSR after ingestion of soluble milk proteins only in the AP group |
| Kouw, 2017 [43] | 48, ♂ | 72 | RCT: before sleep administration of 40 g casein vs. 20 g casein vs. 20 g casein + 1.5 g leucine vs. placebo | MPS | Ingestion of 40 g casein increases MPS better than other arms |
| Hamarsland, 2019 [44] | 21, 8 ♀/13 ♂ | 74 | RCT: 20 g WP vs. 20 g native WP vs. milk (ingested after 2 h of resistance training) | Serum leucine concentration; FSR | Greater increase in serum leucine in native WP arm, but no difference with WP in FSR (only superior to milk) |
♀: females; ♂: males; RCT: Randomized Clinical Trial; WP: Whey Proteins; EAA; Essential Amino Acids; FSR: Fractional Synthetic Rate; MP: Muscle Protein; MPS: Muscle Protein Synthesis; BPB: Body Protein Balance, AA: Amino Acids; MPA: Muscle Protein Accretion; WhP: Wheat Protein; WhPH: Wheat Protein Hydrolysate; WPH: Whey Protein Hydrolysate; Adequate Protein; HP: High Protein.