Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 35706399 · doi:10.1017/S0007114522001787
What was done
A systematic review and random-effects meta-analysis of randomized controlled trials (RCTs) identified via MEDLINE, Web of Science, Scopus, and Cochrane Library through September 2021. The review evaluated the effects of isolated whey and soy protein supplementation on circulating C-reactive protein (CRP), IL-6, and TNF-α in older adults.
What was found
Thirty-one RCTs were included: - Whey protein significantly reduced circulating IL-6 (Mean Difference [MD]: -0.79, 95% CI: -1.15 to -0.42, I² = 96%). - In a subgroup of individuals with sarcopenia and pre-frailty, whey protein significantly reduced IL-6 (MD: -0.98, 95% CI: -1.56 to -0.39, I² = 0%). - Soy protein significantly reduced TNF-α (MD: -0.16, 95% CI: -0.26 to -0.05, I² = 68%), with an additional reduction when soy isoflavones were added (MD: -0.20, 95% CI: -0.31 to -0.08, I² = 34%). - No numerical estimates were reported for CRP in the abstract.
Why it matters
Because systemic low-grade inflammation impairs muscle proteostasis in aging, isolating differential cytokine responses to whey versus soy protein informs targeted nutritional strategies in older adults.
Limits
High between-study heterogeneity was present in the primary analyses (I² = 96% for IL-6 with whey; I² = 68% for TNF-α with soy). Total participant sample size, specific supplement doses, intervention durations, and pooled quantitative results for CRP were not reported in the abstract.
Cited by
- supports Randomized controlled trials show that whey protein supplementation has either a neutral or positive (reducing) effect on inflammatory markers.