The FM + IBS group exhibited the highest fecal zonulin levels (243.5 ± 16.33 ng/mL), showing a 35.9% increase compared to the FM group (172.8 ± 21.87 ng/mL, p = 0.04) and a 46.0% increase compared to the IBS group (160.80 ± 14.2 ng/mL, p = 0.01) (Figure 4B). This evidence concerns the gene HP and irritable bowel syndrome.