Table 3.
Plant-derived proteins: effects on muscle in relation to age, exercise, energy restriction and source.
| Reference | Study Design | Protein Composition | Measurements | Key Outcomes |
|---|---|---|---|---|
| Hartman et al., 2007 [106] | Randomised, controlled, parallel intervention design Soy protein (n = 19) vs. milk (n = 18) vs. carbohydrate (CHO) control (n = 19) Healthy young males (M) (18–30 years). 12 weeks 5 d/week whole-body resistance exercise training (RET) |
Soy protein—17.5 g isoenergetic/nitrogenous milk—17.5 g protein CHO—isoenergetic 2 × supplement, post exercise + 1 h |
Fat- and bone-free mass (FBFM), fibre cross (CSA), plasma amino acid (AA) profile | No increased FBFM in soy group Soy protein increased type I fibre CSA after 12 weeks, however milk greatly increase type I + II CSA Soy protein increased post-ingestion plasma leucine and EAA profiles similar to milk Increased plasma insulin immediately after ingestion similar to milk |
| Tang et al., 2009 [97] | Randomised, controlled, parallel intervention design Soy vs. whey vs. casein protein All groups n = 6 Healthy young M (22.8 ± 3.9 years, mean ± standard error of the mean (SEM)) Unilateral leg press and knee extension (4 sets, 10–12 repetition maximum (RM)) |
Soy protein—22.2 g protein, 1.8 g leucine Whey protein—21.4 g protein, 2.3 g leucine Casein protein—21.9 protein, 1.8 g leucine All provided ~10 g EAA Protein drink post exercise. |
Rest and exercise muscle fractional synthesis rates (FSR), plasma AA profile | Soy and whey protein increased rest muscle FSR above casein Soy protein + exercise muscle FSR increased above casein protein, however a greater increase was seen in whey protein + exercise Soy protein ingestion increase EAA + leucine profiles above casein protein, with whey protein ingestion increasing both to a greater degree |
| DeNysschen et al., 2009 [105] | Randomised, double-blind, controlled parallel intervention design Soy protein (n = 10) vs. whey protein (n = 9) vs. CHO placebo (n = 9) Overweight males (21–50 years, mean 38 years, body mass index (BMI) 25–30) 12 weeks 3 d/week whole-body RET |
Soy protein—25.8 g Whey protein—26.6 g CHO placebo—0.6 g protein Supplement ingested post-resistance exercise (RE), daily |
Body composition, strength, fasting blood measures | All groups increased strength pre to post Total cholesterol decreased in all groups No differences between groups for any measures |
| Wilkinson et al., 2007 [103] | Randomised cross-over intervention design Soy protein vs. milk n = 8 Healthy young M (21.6 ± 0.3 years, mean ± SEM) Unilateral standardised leg workout, 80% 1-RM |
Soy protein—18.2 g Isoenergetic/nitrogenous milk—18.2 g protein Protein drink post RE |
AV balance-based FSR and fractional breakdown rate (FBR), net balance, plasma AA profile | A significant, but lower increase in total AA and muscle FSR after consumption of soy protein vs. milk Soy protein ingestion resulted in a shorter period of positive net protein balance and area under the curve compared to milk Total AA net balance remained elevated after milk consumption vs. soy protein |
| Luiking et al., 2011 [108] | Randomised, single-blind parallel intervention design Soy protein (n = 10) vs. casein protein (n = 12) Healthy young adults (M/females (F) 50:50, 22 ± 1 years, mean ± SEM) |
Soy protein—3.4 g protein/100 mL Isonitrogenous casein protein—2.95 g/100 mL Enteral ingestion (2 mL/kg/bw/h) |
AV balance based FSR & FBR, net balance, plasma AA profile | Greater net uptake of glutamate, serine, histidine and lysine from casein vs. soy protein Reduced intramuscular branch AA concentrations from soy ingestion compared to casein No differences in muscle protein synthesis (MPS) or muscle protein breakdown between protein sources |
| Joy et al., 2013 [23] | Randomised, double-blind, parallel intervention design Rice protein vs. whey protein isolate All groups n = 12 Healthy young males (21.3 ± 1.9 years, mean ± standard deviation (SD)) Periodic whole-body RET |
Rice protein—48 g protein, 80 mg/g leucine Isonitrogenous whey protein isolate—48 g protein, 115 mg/g leucine Ingested post exercise 3 d/week Control diet provided |
Muscle thickness, body composition, strength measures | Both groups increased lean mass (LM), bicep/quadricep thickness, with no differences between groups |
| Babault et al., 2015 [107] | Randomised, double-blind, controlled parallel intervention design Pea protein (n = 53) vs. whey protein (n = 54) vs. placebo (n = 54) Healthy young M (21.9 ± 3.7 years, mean ± SD) 6 weeks 3 d/week progressive strength training, elbow flexor/extensor |
Pea protein—26.6 g protein, 2.9 g leucine Whey protein—23.9 g protein Placebo—3.9 g maltodextrin Ingested twice daily morning/afternoon (post exercise) for 6 weeks |
Bicep thickness, maximal voluntary torque, 1-RM | All groups increased bicep thickness compared to baseline after 42 and 82 days, no difference between groups Baseline weakest volunteers supplemented with pea protein demonstrated increased bicep thickness between 42 and 84 days |
| Candow et al., 2006 [104] | Randomised, double-blind, controlled parallel intervention design Soy protein vs. whey protein vs. placebo All groups n = 9 Healthy young adults (M/F 1:2, 23 ± 6 years, mean ± SD) 6 weeks 3 d/week whole-body RET |
Soy and whey protein—1.2 g/kg Placebo—1.2 g/kg maltodextrin, isocaloric Ingestion split between 3 equal daily doses pre/post-training and evening |
Body composition, strength measures, muscle FBR | Both soy and whey protein groups increased LM and strength greater than the placebo group All groups increased muscle FBR similarly |
| Yang et al., 2012 [71] | Parallel intervention, controlled design Soy protein 20 g or 40 g vs. whey protein 20 g or 40 g vs. water All groups n = 10 Healthy older M (71 ± Unilateral knee extension (3 sets, 10-RM). |
Soy protein—20 g protein, 1.6 g leucine Soy protein—40 g protein, 3.2 g leucine Whey protein—20 g protein, 2 g leucine Whey protein—40 g, 4 g leucine Water control Protein drink post exercise |
Myofibrillar FSR (rest and RE) plasma AA profile, leucine oxidation | No increase in rest myofibrillar FSR in either 20 or 40 g soy protein groups Increased RE myofibrillar FSR in 40 g soy protein group Significant increases in myofibrillar FSR for all whey protein groups, rest + RE 20 and 40 g soy protein increased leucine oxidation to similar degrees |
| Deibert et al., 2011 [109] | Randomised controlled intervention design Whole-body RET with/without soy protein Healthy moderately overweight older M (55.7 ± 4.6 years, BMI 27.7 ± 2.1, mean ± SD) 12 weeks 2 d/week progressive whole-body RET |
50 g soy protein yoghurt—26.7 g protein Control—RET only Consumed after evening training |
Skinfold measures, BMI, strength measures, blood biomarkers | Decreased waist circumference and fat mass and increased fat free mass in soy protein supplemented group Improved glycaemic control and metabolic markers in soy protein-supplemented group Both groups increased in strength and coordination |
| Gorissen et al., 2016 [99] | Randomised, double-blind, controlled parallel intervention design 35 g wheat protein vs. 35 g or 60 g wheat protein hydrolysate vs. 35 g micellar casein protein, 35 g whey protein All groups n = 12 Healthy older M (71 ± 1 years, mean ± SEM) Single protein drink ingestion |
Wheat protein—35 g Wheat hydrolysate protein—35 g Wheat hydrolysate protein—60 g Micellar casein protein—35 g Whey protein—35 g Single ingestion |
Myofibrillar FSR, plasma AA profile | Ingestion of 35 g wheat protein did not increase myofibrillar FSR as much as 35 g whey or 35 g casein protein 60 g wheat hydrolysate stimulated myofibrillar FSR to a greater degree than 35 g whey protein 2–4 h post-ingestion Whey protein ingestion had a greater plasma leucine increase compared to 60 g wheat hydrolysate protein Plasma AA content was more persistent following 60 g wheat hydrolysate ingestion |
| Oikawa et al., 2020 [102] | Single blind, parallel group design 24 F randomised to potato protein (n = 12, 20 ± 3) or control (n = 12, 21 ± 3) diet for 2 weeks plus unilateral RET (3 ×/weeks) (mean ± SD) |
Potato protein—25 g 2 ×/d (1.6 g/kg/d total protein) Control—0.8 g/kg/d total protein (breakdown of AA composition within each supplement can be found in original article) |
Myofibrillar protein synthesis, cell signalling, baseline body composition and strength, dietary analysis | No difference in total kcals or percentage fat intake between groups Protein intake was significantly greater in the potato protein group compared to control MPS increased above baseline at rest in the potato protein, but not control, group MPS increased similarly above baseline with exercise in both groups In response to exercise, total protein kinase B (PKB/Akt) increased compared to baseline Main effect of time for total mechanistic target of rapamycin and ribosomal protein s6 |
Abbreviations: AA, amino acids; BMI, body mass index; CHO, carbohydrate; CSA, cross-sectional area; EAA, essential amino acid, FBFM, fat- and bone-free mass; F, females; FBR; fractional breakdown rate; FSR, fractional synthesis rate; LM, lean mass; M, males; MPS, muscle protein synthesis; RE, resistance exercise; RET, resistance exercise training; RM, repetition maximum; SD, standard deviation; SEM, standard error of the mean.