Changes in serum zonulin in individuals with morbid obesity after weight-loss interventions: a prospective cohort study

Abstract

Background: Zonulin is a biomarker of impaired intestinal permeability, which has been associated with various disorders. The primary aim was to study serum zonulin (s-zonulin) in individuals with morbid obesity before and after a conservative weight loss intervention followed by bariatric surgery. The secondary aims were to explore predictors of s-zonulin, and the associations between the changes of the predictors and changes in s-zonulin, and to compare the associations in the two treatment periods. Methods: Individuals with morbid obesity were included. Data before any weight loss interventions, after a 6 months' conservative weight loss intervention, and 6 months after bariatric surgery were used. S-zonulin was measured with an ELISA method from Immundiagnostik AB, Bensheim, Germany. Data were analysed with mixed models. Results: The mean body mass index was 42.1 kg/m 2 (SD 3.8) at inclusion and was reduced to 38.7 kg/m 2 (SD 3.8) and 29.8 kg/m 2 (SD 3.8) after the conservative treatment and bariatric surgery respectively. S-zonulin was 63 ng/mL (SD 32) at inclusion and was reduced with 19 ng/ml (95% CI 12 to 26, p < 0.001) after conservative treatment and 11 ng/ml (95% CI 0 to 21, p = 0.04) after bariatric surgery. At inclusion, s-zonulin was significantly associated with factors including p-glucose (B = 2.21, 95% CI 1.09 to 3.33, p < 0.001), c-reactive protein (B = 1.02, 95% CI 0.45 to 1.58, p < 0.001) and the intake of proteins (B = 0.23, 95% CI 0.08 to 0.38, p = 0.003) and non-nutritive sweeteners (B = 0.68, 95% CI 0.19 to 1.17, p = 0.007). The reduction in s-zonulin after the conservative weight loss intervention was significantly associated with improvement in diarrhoea (B = 6.6, 95% CI 1.3 to 11.8, p = 0.02), HbA1c (B = 9.7, 95% CI 1.1 to 18.3, p = 0.03), p-glucose (B = 3.5, 95% CI 1.2 to 5.9, p = 0.004) and gamma-GT (B = 0.28, 95% CI 0.09 to 0.47, p = 0.004), but not associated with the change in body mass index (B = 0.9, 95% CI − 1.5 to 3.3, p = 0.46). Conclusions: S-zonulin was markedly reduced after the conservative weight loss intervention, and further reduced after bariatric surgery. The reduction in s-zonulin was associated with improvement of diarrhoea, markers of glucose intolerance and liver disease, but not associated with the change in body mass index.

Are Faecal Microbiota Analyses on Species-Level Suitable Clinical Biomarkers? A Pilot Study in Subjects with Morbid Obesity

“…The microbiota in subjects with morbid obesity is influenced by the high prevalence of comorbidity, their often unusual dietary habits, and use of drugs. Diabetes, use of metformin, intake of often high quantities of non-nutritive sweeteners, inflammation (measured as CRP), and increased gastrointestinal permeability (measured as zonulin), which were variables included in this study, are known causes of faecal dysbiosis [ 42 , 43 , 44 , 45 , 46 ]. In this study, none of these variables were associated with changes in the microbiota.…”

Synbiotic Supplementation Improves Obesity Index and Metabolic Biomarkers in Thai Obese Adults: A Randomized Clinical Trial

“…The zonulin level was found to be elevated above the reference value in individuals with morbid obesity. S-zonulin was partially controlled after a 6-month-long conservative weight loss intervention and further reduced after bariatric surgery [ 69 ].…”

Plasma and fecal zonulin are not altered by a high green leafy vegetable dietary intervention: secondary analysis of a randomized control crossover trial

“…Based on the results reported by Aasbrenn et al, which reported changes in serum zonulin that correlated with changes in gastrointestinal symptoms, a clinically significant 30% reduction in zonulin with a sample size of 19 would result in 0.808 power with an effect size of 0.686 at the 0.05 significance level [ 40 ].…”