Relationship between gut microbiota and intestinal permeability reflected by serum zonulin in women. Microbiota and serum zonulin

Purpose: Increased gut permeability causes the trespass of antigens into the blood stream which leads to inflammation. In this cross-sectional study, we investigated a potential relationship between zonulin, a marker of intestinal permeability and gut microbiota of a female cohort of different BMI groups and activity levels (represented by athletes). Methods: 102 women were included (BMI range 13.24-46.89 kg m-2): Anorexia nervosa patients (n=17), athletes (n=20), normal weight (n=25), overweight (n=21) and obese women (n=19). DNA was extracted from stool samples and subjected to 16S rRNA gene analysis (V1-V2). Quantitative Insights Into Microbial Ecology (QIIME) was used to analyze data. Zonulin was measured with ELISA. Nutrient intake was assessed by repeated 24-hour dietary recalls.Results: We used the median of serum zonulin concentration to divide our participants into a “high zonulin” (>53.64ng/ml) and “low zonulin” (<53.64ng/ml) group. The alpha-diversity (Shannon-Index, Simpson-Index, equitability) of the gut microbiome was not significantly different between the groups. There were small positive correlations between the zonulin concentration and total calorie, protein, carbohydrate, sodium and vitamin B12 intake. Linear discriminant analysis Effect Size (LEfSe) identified Ruminococcaceae (LDA= 4.163, p=0.003) and Faecalibacterium (LDA=4.151, p=0.0002) as significantly more abundant in the low zonulin group. Conclusion: The diversity of the gut microbiota in women does not seem to be correlated with zonulin concentration. The enhanced abundance of Faecalibacteria in the low zonulin group could be related to their anti-inflammatory effects affecting gut permeability. Further studies are needed to investigate zonulin as a biomarker for gut permeability.