| Background & aim: The results of studies about the effect of soy products on serum highly sensitive Creactive
protein (hs-CRP) are inconsistent. The aim of this systematic review and meta-analysis of randomized
clinical trials (RCTs) was to investigate the effect of soy products intake on serum hs-CRP
concentration.
Methods: We searched PubMed, EMBASE, Science Direct, ISI Web of Science, Google Scholar and
Cochrane Central Register of Controlled Trials up to December 2016 without language restrictions.
Random-effect model was used for quantitative data synthesis.
Results: Thirty-six studies were included in our analyses. A meta-analysis revealed a non-significant
reduction in serum hs-CRP concentrations following soy products consumption, 0.19 (mg/L) (95%
CI: 0.49 to 0.09; I2
¼ 95.6%). Subgroup analyses suggested that natural soya products may reduce plasma
levels of CRP by 0.18 mg/L (95% CI: 0.28 to 0.08; I2: 11.6) in comparison to other source of isoflavones
(soya extracts, supplements). Moreover, the effect was stronger among subjects with baseline hs-CRP concentrations
of less than 2.52 mg/L, 0.15 (95% CI: 0.27 to 0.02; I2: 34.6). A meta-regression analysis
revealed that dosage of isoflavones seems to be a strong predictor of the effect of soya on serumhs-CRP levels.
Conclusion: Present review of RCTs published up to December 2016 did not provide strong evidence
regarding the beneficial effect of soya products consumption on blood hs-CRP concentrations. However,
it appears that natural soya products may reduce plasma levels of hs-CRP in comparison to other source
of isoflavones. Large and well-designed studies are recommended to confirm this conclusion.
Systematic review registration: PROSPERO CRD42018069371. |