Comparison of the effect of soya protein and whey protein on body composition: a meta-analysis of randomised clinical trials

Abstract

Background: Essential amino acids (EAAs) promote the process of regulating muscle synthesis. Thus, whey protein that contains higher amounts of EAA can have a considerable effect on modifying muscle synthesis. However, there is insufficient evidence regarding the effect of soy and whey protein supplementation on body composition. Thus, we sought to perform a meta-analysis of published Randomized Clinical Trials that examined the effect of whey protein supplementation and soy protein supplementation on body composition (lean body mass, fat mass, body mass and body fat percentage) in adults. Methods: We searched PubMed, Scopus, and Google Scholar, up to August 2020, for all relevant published articles assessing soy protein supplementation and whey protein supplementation on body composition parameters. We included all Randomized Clinical Trials that investigated the effect of whey protein supplementation and soy protein supplementation on body composition in adults. Pooled means and standard deviations (SD) were calculated using random-effects models. Subgroup analysis was applied to discern possible sources of heterogeneity. Results: After excluding non-relevant articles, 10 studies, with 596 participants, remained in this study. We found a significant increase in lean body mass after whey protein supplementation weighted mean difference (WMD: 0.91; 95% CI: 0.15, 1.67. P= 0.019). Subgroup analysis, for whey protein, indicated that there was a significant increase in lean body mass in individuals concomitant to exercise (WMD: 1.24; 95% CI: 0.47, 2.00; P= 0.001). There was a significant increase in lean body mass in individuals who received 12 or less weeks of whey protein (WMD: 1.91; 95% CI: 1.18, 2.63; P<0.0001). We observed no significant change between whey protein supplementation and body mass, fat mass, and body fat percentage. We found no significant change between soy protein supplementation and lean body mass, body mass, fat mass, and body fat percentage. Subgroup analysis for soy protein indicated there was a significant increase in lean body mass in individuals who supplemented for 12 or less weeks with soy protein (WMD: 1.48; 95% CI: 1.07, 1.89; P< 0.0001). Conclusion: Whey protein supplementation significantly improved body composition via increases in lean body mass, without influencing fat mass, body mass, and body fat percentage.

Protein intake and body weight, fat mass and waist circumference: an umbrella review of systematic reviews for the evidence-based guideline on protein intake of the German Nutrition Society

“…Some of the primary studies were incorporated more than once into different SRs, but overall there was only a “slight” overlap of primary studies of 2.2%, determined as corrected covered area according to Pieper et al [ 15 ], see Supplementary Material 5. BW was addressed in 29 SRs [ 18 – 20 , 22 , 23 , 26 – 35 , 37 – 50 ], FM in 21 SRs [ 18 , 23 – 25 , 27 , 29 , 32 – 34 , 36 – 43 , 45 , 46 , 49 , 50 ] and WC in 13 SRs [ 18 , 21 , 30 , 32 – 35 , 40 , 42 , 43 , 48 – 50 ].…”

“…The included SRs contained healthy participants [ 18 , 25 , 27 , 33 , 45 ] and subjects with risk factors of cardiometabolic diseases [ 20 , 21 , 23 , 26 , 29 , 36 , 42 , 48 ], one SR focused on nursing home residents [ 22 ] and another on older adults with frailty [ 29 ]. In most SRs, specific restrictions on the participants’ health status were lacking [ 19 , 22 , 24 , 28 , 30 – 32 , 34 , 35 , 37 – 41 , 43 , 44 , 46 , 47 , 49 , 50 ].…”

“…In most SRs, specific restrictions on the participants’ health status were lacking [ 19 , 22 , 24 , 28 , 30 – 32 , 34 , 35 , 37 – 41 , 43 , 44 , 46 , 47 , 49 , 50 ].…”

“…In seven out of 13 SRs with MA, the duration of protein intervention was defined as inclusion criteria with ≥ 2 weeks [ 21 , 42 ], ≥ 4 weeks [ 25 , 40 , 49 ], ≥ 6 weeks [ 24 ] and ≥ 12 months [ 32 ]. Intervention was conducted by supplementation with whey protein [ 18 , 21 , 24 , 27 , 40 , 42 , 46 ], soya protein [ 45 , 46 , 48 ], beef protein [ 25 ] or dietary proteins without further specification [ 32 , 33 , 35 , 47 , 49 ].…”

Effects of Whey Protein Supplement on 4-Week Resistance Exercise-Induced Improvements in Muscle Mass and Isokinetic Muscular Function under Dietary Control

“…Similar results have been reported in previous studies. The most recent meta-analysis reported no significant effect of whey protein supplementation on body mass, body fat mass, or body fat percentage [ 25 ]. Considering that decreases in body fat mass and body fat percentage are well-known effects of resistance exercise [ 26 ], it is possible that the significant decreases in body composition in both groups in this study may be mainly due to resistance exercise.…”