Soy Protein and Reduced C-Reactive Protein Levels

Research synthesisLow evidenceMixed effect size3 studies · 1 beneficial · 2 neutral · 0 harmful

Across 3 studies, one meta-analysis reported a moderate beneficial effect of soy protein on reducing C-reactive protein (CRP) in adults with chronic inflammatory diseases, while two other studies (a meta-analysis and an RCT) found no significant effect. The predominant effect size is mixed (small to moderate). The median study duration was 90 days, and the most studied dose was 40 g/day.

Studied populations: Adults with chronic inflammatory diseases

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance, suggesting the effect may be inconsistent. The beneficial effect was observed only in a meta-analysis of patients with chronic inflammatory diseases; the effect may not generalize to other populations.

Generated Jul 11, 2026

Doses used in studies

g/day: 40 (median 40, IQR 40–40) — 1 study

Time to effect

Median: 3 months · IQR 3 months–3 months · Range 3 months–3 months — Reported in 1 of 3 studies

3 of 3 papersPopulation:

Can soy isoflavones in combination with soy protein change serum levels of C-reactive protein among patients with chronic inflammatory diseases? A systematic review and meta-analysis on randomized controlled trials.
- 2025-05-12
- Meta-Analysis
- Journal of health, population, and nutrition 44(1)
- - Ali Gholami
  - Bahareh Amirkalali
  - Mitra Hariri
- PubMed: 40355968
- DOI: 10.1186/s41043-025-00902-6
1 Insight on
- Reduced C-Reactive Protein Levels
- High evidence
- Clinical
The overall estimates revealed that soy isoflavones containing soy protein significantly decreased serum levels of CRP in comparison with control group (weighted mean difference (WMD)= -0.49 mg/L; 95% confidence interval (CI): -0.74, -0.25; P=0<0.001).
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis.
- 2022-06-16
- Meta-Analysis
- 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
3 Insights on
- Reduced C-Reactive Protein Levels
- High evidence
- Clinical
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
Significant
No
Is soy protein effective in reducing cholesterol and improving bone health?
- 2020
- RCT
- Food & function 11(1)
- - Kelli S George
  - Joseph Muñoz
  - Neda S Akhavan
  - Elizabeth M Foley
  - Shalom C Siebert
  - Gershon Tenenbaum
  - Dania A Khalil
  - Sheau C Chai
  - Bahram H Arjmandi
- PubMed: 31848551
- DOI: 10.1039/c9fo01081e
8 Insights on
- Reduced C-Reactive Protein Levels
- High evidence
- Rigorous Journal
- Mixed
Neither treatment affected total cholesterol, HDL cholesterol, LDL cholesterol, or C-reactive protein
Effect
Neutral
Effect size
Small
Significant
No
Dose
40 g/day

Soy Protein and Reduced C-Reactive Protein Levels

Can soy isoflavones in combination with soy protein change serum levels of C-reactive protein among patients with chronic inflammatory diseases? A systematic review and meta-analysis on randomized controlled trials.

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

Is soy protein effective in reducing cholesterol and improving bone health?