Abstract
PurposeIncreased gut permeability causes the trespass of antigens into the blood stream which leads to inflammation. Gut permeability reflected by serum zonulin and diversity of the gut microbiome were investigated in this cross-sectional study involving female study participants with different activity and BMI levels.Methods102 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-h dietary recalls. We used the median of serum zonulin concentration to divide our participants into a “high-zonulin” (> 53.64 ng/ml) and “low-zonulin” (< 53.64 ng/ml) group.ResultsThe alpha-diversity (Shannon Index, Simpson Index, equitability) and beta-diversity (unweighted and weighted UniFrac distances) of the gut microbiome were not significantly different between the groups. Zonulin concentrations correlated significantly with 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.ConclusionButyrate-producing gut bacteria such as Faecalibacteria could decrease gut permeability and lower inflammation. The diversity of the gut microbiota in women does not seem to be correlated with the serum zonulin concentration. Further interventional studies are needed to investigate gut mucosal permeability and the gut microbiome in the context of dietary factors.
Highlights
The permeability of the intestinal mucosa depends on the junctional complex between the intestinal enterocytes, which includes tight junction proteins that regulate the transport of ions and water between the gut lumen and the blood stream [1].Increased gut permeability has been linked to diseases showing low-grade inflammation [2] caused by antigens trespassing the gut barrier which subsequently leads to an inflammatory immune response [3]
anorexia nervosa (AN) patients had a mean body mass index (BMI) of 15.22 ± 1.27, normal weight participants had a mean BMI of 21.94 ± 1.75, overweight participants had a mean BMI of 27.86 ± 1.08, adipose participants had a mean BMI of 34.66 ± 4.52 and athletes had a mean BMI of 22.14 ± 1.76
Since microbial alpha-diversity did not significantly differ between the high and low-zonulin groups investigated in this study, bacterial diversity cannot be solely responsible for strengthening the gut barrier
Summary
The permeability of the intestinal mucosa depends on the junctional complex between the intestinal enterocytes, which includes tight junction proteins that regulate the transport of ions and water between the gut lumen and the blood stream [1].Increased gut permeability has been linked to diseases showing low-grade inflammation [2] caused by antigens trespassing the gut barrier which subsequently leads to an inflammatory immune response [3]. The permeability of the intestinal mucosa depends on the junctional complex between the intestinal enterocytes, which includes tight junction proteins that regulate the transport of ions and water between the gut lumen and the blood stream [1]. The serum protein zonulin, which was first described by Fasano et al, can be used as a peripheral marker to assess gut permeability [3, 4]. High serum concentrations of zonulin, indicating a leaky gut, have been identified in obesity [2] and patients with high fasting glucose [5]. Low serum zonulin levels have further been observed in pregnant, overweight women showing high alpha-diversity (Chao-1 and number of observed species) [7]. There are no data available regarding non-pregnant women with different BMI values ranging from extremely lean to obese (including patients suffering from anorexia nervosa) and athletes
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