Increased gut motility improves nutrient absorption after feeding while also enhancing insulin secretion (Yabut et al., 2019), though excess serotonin has been shown to promote intestinal and colonic motility in rats, which induces pathophysiological conditions similar to those of irritable bowel syndrome (IBS) in humans (Waclawiková et al., 2021; Guzel and Mirowska-Guzel, 2022). This evidence concerns the gene INS and irritable bowel syndrome.