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/m2 (SD 3.8) at inclusion and was reduced to 38.7 kg/m2 (SD 3.8) and 29.8 kg/m2 (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: