Vitamin B1 Intake and Genetics Linked to Bowel Movement Frequency

New research published in January 2026 examined how genetic factors and vitamin B1 intake relate to bowel movement frequency in large population groups.

The study, led by Mauro D’Amato, professor of medical genetics at LUM University and research professor at CIC bioGUNE, focused on genetic and health data from 268,606 individuals of European and East Asian backgrounds. Researchers aimed to identify genetic signals that influence how often people have bowel movements.

Scientists found 21 distinct genomic regions associated with stool frequency, with 10 of these not previously connected to digestive processes. Two genes, SLC35F3 and XPR1, which are involved in the transport and activation of vitamin B1 (thiamine), showed particularly strong associations with bowel movement patterns.

Analysis of nearly 98,449 participants from the UK Biobank indicated that higher dietary vitamin B1 intake was linked to more frequent bowel movements. However, the relationship between vitamin B1 consumption and stool frequency varied depending on genetic differences in the SLC35F3 and XPR1 genes.

What the numbers show

• 268,606 individuals’ genetic and health data were analyzed
• 21 genomic regions were identified as associated with stool frequency
• 98,449 UK Biobank participants contributed dietary data on vitamin B1 intake

The study used self-reported dietary information to assess vitamin B1 intake among participants. Researchers scanned millions of genetic markers to identify links between genes and digestive function, expanding the understanding of how genetics and nutrition interact in gut motility.

The findings were published in the journal Gut on January 20, 2026. The research highlighted the importance of considering both genetic background and nutrient intake when examining digestive health.

Fox News reported on the study, noting the connection between vitamin B1 metabolism and gut motility based on the analysis of over 268,000 people. The coverage also emphasized that while genetic associations were found, the results do not conclusively demonstrate that taking vitamin B1 supplements will alter bowel habits.

According to Fox News, the research identified new genomic regions related to stool frequency and clarified that genetic associations do not establish causation. The study’s use of self-reported dietary data was also noted as a limitation in interpreting the results.

* This article is based on publicly available information at the time of writing.