A new genetic analysis has identified key DNA regions influencing how often people have bowel movements, with a surprising link to vitamin B1. Researchers analyzed data from over 268,000 individuals and found that higher thiamine intake correlates with more frequent stools, depending on genetic variations. The findings, published in Gut, suggest new pathways for studying gut disorders like irritable bowel syndrome.
Bowel movement frequency serves as a window into gut health, where disruptions can lead to conditions such as constipation, diarrhea, or irritable bowel syndrome. A study published on January 20 in the journal Gut offers fresh insights into the genetics behind intestinal motility. Led by Mauro D'Amato, a professor of medical genetics at LUM University and research professor at CIC bioGUNE in Spain, the international team examined genetic data and health surveys from 268,606 people of European and East Asian descent.
Their analysis pinpointed 21 genomic regions associated with stool frequency, 10 of which were previously unknown. Several signals aligned with established gut mechanisms, including bile-acid regulation—which aids fat digestion and gut signaling—and nerve pathways involving acetylcholine for muscle contractions. However, the most striking result involved vitamin B1, or thiamine, through two genes: SLC35F3 and XPR1, which handle thiamine transport and activation.
To explore real-world implications, the researchers reviewed dietary records from 98,449 UK Biobank participants. They observed that greater thiamine consumption was tied to increased bowel frequency, but this effect varied based on a combined genetic score from the two genes. Inherited differences in thiamine processing may thus influence how the nutrient affects digestion across populations.
Dr. Cristian Diaz-Muñoz, the lead author, noted: "We used genetics to build a roadmap of biological pathways that set the gut's pace. What stood out was how strongly the data pointed to vitamin B1 metabolism, alongside established mechanisms like bile acids and nerve signaling."
Professor D'Amato added: "Gut motility problems sit at the heart of IBS, constipation and other common gut-motility disorders, but the underlying biology is very hard to pin down. These genetic results highlight specific pathways, especially vitamin B1, as testable leads for the next stage of research, including lab experiments and carefully designed clinical studies."
The work involved collaborators from institutions in Spain, Italy, the Netherlands, the UK, Canada, and Australia, supported by various grants. It underscores potential roles for thiamine in gut health and calls for further clinical validation.
