Vitamin B1 may influence digestion speed, study says

A genetic analysis of more than 268,000 people linked thiamine (vitamin B1) metabolism to self-reported bowel movement frequency, and data from nearly 100,000 UK Biobank participants showed higher dietary B1 was associated with more frequent bowel movements, with the effect differing by genetic profile.

Researchers report a connection between thiamine (vitamin B1) metabolism and how often people reported bowel movements. The international team, led by Mauro D'Amato with first author Dr. Cristian Diaz-Muñoz, analyzed genetic and health data from more than 268,000 people of European and East Asian ancestry. Stool frequency was used as a practical measure of gut motility. The investigators also examined dietary data from nearly 100,000 UK Biobank participants and noted genetic differences in the observed associations. Key findings: - The study scanned millions of genetic markers and identified 21 genetic regions linked to reported stool frequency. - Many signals involved known digestive pathways, including bile acid metabolism and nerve signaling that influence intestinal muscle contractions. - Two genes tied to thiamine transport and regulation showed unexpected, strong associations with stool frequency. - In UK Biobank data, higher self-reported vitamin B1 intake was associated with more frequent bowel movements, but the association varied by genetic makeup. - The study, published in the journal Gut, noted limitations such as reliance on self-reported dietary data, use of stool frequency as an indirect measure of motility, and that genetic associations do not prove causation. Summary: The research links thiamine metabolism to reported bowel movement frequency and highlights that genetic variation may alter that relationship. The findings add biological clues about gut motility but do not establish a causal pathway. Undetermined at this time.