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

Study answer

What this study found

Overall, whey and soy protein showed modest, biomarker-specific anti-inflammatory effects rather than broad reductions across all markers. Whey protein was associated with lower IL-6 overall (MD -0.79 pg/ml, 95% CI -1.15 to -0.42), while effects on CRP, hs-CRP, and TNF-alpha were not statistically clear. Soy protein was associated with a reduction in TNF-alpha (MD -0.16 pg/mL, 95% CI -0.26 to -0.05), and adding isoflavones further lowered TNF-alpha (MD -0.20, 95% CI -0.31 to -0.08) but increased CRP in one subgroup analysis (MD 0.53, 95% CI 0.12 to 0.94). Benefits appeared more evident in…

Study & population

Systematic review and meta-analysis of 31 studies involving 3274 participants, with 1611 in intervention arms and 1663 in comparators.

Intervention

Included trials evaluated isolated whey protein or soy protein supplementation, usually taken orally once daily for 6 weeks to 24 weeks, with doses ranging from 15 g/d to 52 g/d.

Key limitation

Results were limited by substantial heterogeneity for several outcomes, especially whey IL-6 and CRP and soy CRP and hs-CRP.

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Original abstract