Why do some people need the bathroom constantly while others rarely do. Turns out your genes—and specifically how your body handles vitamin B1—might have a lot to do with it.
Researchers analyzing genetic data from nearly 270,000 people across Europe and East Asia have identified 21 regions of the human genome linked to bowel movement frequency. The finding that stood out most: two genes involved in how your body transports and activates thiamine (vitamin B1) appear to play a surprising role in gut motility.
How They Found It
The international team, led by Mauro D'Amato at LUM University and CIC bioGUNE in Spain, used advanced genetic analysis to search for DNA differences associated with stool frequency. They confirmed what scientists already knew—that bile acids (which help digest fat) and nerve signaling in intestinal muscles influence how your gut moves. But the vitamin B1 connection was unexpected.
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Start Your News DetoxWhen the researchers looked at dietary data from over 98,000 people in the UK Biobank, they found something interesting: people who consumed more thiamine tended to have more frequent bowel movements. But here's the catch—this wasn't true for everyone equally. The effect depended on each person's genetic makeup at two specific genes called SLC35F3 and XPR1. Some people's bodies simply process vitamin B1 differently, which means the same amount of the vitamin affects them in different ways.
"We used genetics to build a roadmap of biological pathways that set the gut's pace," explained Dr. Cristian Diaz-Muñoz, the study's lead author. "What stood out was how strongly the data pointed to vitamin B1 metabolism, alongside established mechanisms like bile acids and nerve signaling."
This matters beyond bathroom habits. The same biological pathways linked to bowel frequency also appear in irritable bowel syndrome (IBS), a condition affecting millions worldwide. Understanding how vitamin B1 influences gut movement could eventually help researchers develop better treatments for IBS and other motility disorders—conditions where the underlying biology has been frustratingly difficult to pin down.
The next phase involves lab experiments and clinical studies to test whether targeting vitamin B1 metabolism could actually help people with gut problems. For now, the research gives scientists a concrete biological lead to follow, which is exactly what's needed when you're trying to solve a puzzle that's been unsolved for decades.
