Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis.

2022-06-16
The British journal of nutrition 129(5)
- Konstantinos Prokopidis
- Mohsen Mazidi
- Rajiv Sankaranarayanan
- Behnam Tajik
- Anne McArdle
- Masoud Isanejad

PubMed: 35706399
DOI: 10.1017/s0007114522001787

Study Design

Type: Meta-Analysis
Population: individuals with sarcopenia and pre-frailty
Methods: systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021; meta-analysis using a random-effects model

Background and aims

Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers.

Methods

We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603).

Results

Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I² = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I² = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I² = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I² = 0 %). These findings may be dependent on participant characteristics and treatment duration.

Conclusions

These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.

Research Insights

Soy→Reduced Tumor Necrosis Factor Alpha
The significant reduction was only observed for IL-6 with whey protein and TNF-α with soy protein; whey protein did not significantly reduce TNF-α.
Effect
Neutral
Effect size
Small
Soy Protein→Reduced C-Reactive Protein Levels
The abstract only reports significant effects on IL-6 and TNF-α; no significant effect on CRP is mentioned for soy protein.
Effect
Neutral
Effect size
Small
Soy Protein→Reduced Interleukin-6 Levels
The significant reduction was only observed for IL-6 with whey protein and TNF-α with soy protein; soy protein did not significantly reduce IL-6.
Effect
Neutral
Effect size
Small
Soy Protein→Reduced Tumor Necrosis Factor Alpha
The significant reduction was only observed for IL-6 with whey protein and TNF-α with soy protein; whey protein did not significantly reduce TNF-α.
Effect
Neutral
Effect size
Small
Whey Protein→Reduced C-Reactive Protein Levels
The abstract only reports significant effects on IL-6 and TNF-α; no significant effect on CRP is mentioned for soy protein.
Effect
Neutral
Effect size
Small
Whey Protein→Reduced Interleukin-6 Levels
The significant reduction was only observed for IL-6 with whey protein and TNF-α with soy protein; soy protein did not significantly reduce IL-6.
Effect
Neutral
Effect size
Small
Whey Protein→Reduced Tumor Necrosis Factor Alpha
The significant reduction was only observed for IL-6 with whey protein and TNF-α with soy protein; whey protein did not significantly reduce TNF-α.
Effect
Neutral
Effect size
Small