The Effects of Probiotic/Synbiotic on Serum Level of Zonulin as a Biomarker of Intestinal Permeability: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis was conducted to obtain a conclusive result on the influence of probiotics/synbiotic on serum levels of zonulin. Data related to serum levels of zonulin were extracted to determine the effects of probiotic/synbiotic on intestinal permeability.

The literature search was conducted across the Cochrane Central Register of Controlled Trials, PubMed, Scopus and ISI Web of Science, Search up to Nov 2018. Clinical trials evaluating the effect of probiotic/synbiotic on serum zonulin levels of all human subjects were included.

Nine studies (including 496 intervention and 443 control subjects) met the inclusion criteria for the meta-analysis. According to the meta-analysis, probiotic/synbiotic has a significant effect on serum zonulin reduction (WMD=-10.55 [95% CI: -17.76, -3.34]; P=0.004). However, the high level of heterogeneity was observed among the studies (I2=97.8, P<0.001). The subgroup analysis suggested study quality, blinding, study duration, Participants age, subject's health status and supplement type as sources of heterogeneity.

Probiotic/synbiotic have favorable effects on serum levels of zonulin as a measure of intestinal permeability. However, the results should be interpreted with caution due to the high heterogeneity and further evidence is required before definitive recommendations can be made.