What changed after a low-FODMAP diet in IBS patients with high fecal zonulin?

Details

Many patients with irritable bowel syndrome (IBS) have a compromised intestinal barrier associated with low-grade inflammation. Polyunsaturated fatty acids (PUFAs) are potential mediators of inflammation: omega-6 PUFAs are pro-inflammatory, while omega-3 PUFAs are antioxidant and anti-inflammatory. Zonulin is a potential biomarker of small-intestinal permeability (s-IP).

The study investigated the relationship between PUFAs and gastrointestinal barrier integrity in patients with diarrhea-predominant IBS (IBS-D). Researchers evaluated gastrointestinal barrier function indicators in urine and blood and the PUFA composition of erythrocyte membranes in 38 IBS-D patients: 5 men and 33 women, aged 44.11 ± 1.64 years. At baseline, patients were grouped by fecal zonulin levels as high (≥107 ng/mL, H-FZ) or normal (<107 ng/mL, N-FZ). Evaluations took place before and after a 12-week low-FODMAP diet (LFD).

At baseline, the H-FZ group had s-IP significantly higher than the reference value. Compared with the N-FZ group, H-FZ patients had lower omega-3 PUFA levels and higher omega-6-to-omega-3 and arachidonic acid (AA)-to-eicosapentaenoic acid (EPA) ratios. After the LFD, the H-FZ group showed a significant increase in omega-3 PUFAs, decreases in omega-6 PUFAs and the omega-6-to-omega-3 and AA-to-EPA ratios, and improved s-IP. Across all subjects, the omega-6-to-omega-3 PUFA ratio was positively correlated with fecal zonulin levels.

The researchers concluded that the findings highlight a relationship between PUFAs and the intestinal barrier, suggesting a role for PUFAs in IBS-D pathophysiology and supporting positive effects of the LFD in IBS-D management.