- Thiamine, or vitamin B1, is linked to more frequent bowel movements.
- A new study found that your genes can determine the impact of thiamine on your gut.
- Foods like black beans, pork and cereal can help you reach your daily value for thiamine.
Our gut motility, which is the coordinated muscle contractions that move food through the digestive tract, is at the heart of our digestive systems. This process is essential for digesting food, absorbing nutrients and eliminating waste. When gut motility is disrupted, it can lead to uncomfortable and often debilitating conditions, most notably irritable bowel syndrome (IBS).
For years, alterations in gut motility have been recognized as a hallmark of IBS, yet the underlying “how” and “why” have remained somewhat mysterious. This lack of understanding has made it difficult to develop targeted treatments that address the root causes rather than just the symptoms.
However, a groundbreaking new study published in Gut is shedding light on the genetic factors that control the gut, all using a simple daily metric: stool frequency. And one vitamin, thiamine, may have a surprising impact on our gut motility.
How Was the Study Conducted?
The researchers used data from several large studies around the world to investigate stool frequency and how genetics might play a role. Each study, or cohort, collected information about participants’ health, lifestyle and genetics. For example, in the UK Biobank, 500,000 people were asked how many times they have a bowel movement daily, and their genetic data was analyzed. Similar approaches were taken in other countries, like the Netherlands, Canada, Belgium, the U.S. and China, though the exact questions and methods varied slightly.
Next, they ran a genome-wide association study (GWAS), where they looked for differences in DNA that might be linked to stool frequency. Each study did this separately, and then the researchers combined all the results to get a clearer picture.
After identifying genetic regions linked to stool frequency, they dug deeper to determine which genes might be involved and what those genes do. They also determined if these genes are active in tissues related to digestion, like the gut.
To test if stool frequency might actually cause certain diseases (rather than just being associated with them), they used a method called Mendelian randomization, which uses genetics to determine cause-and-effect relationships.
Finally, they looked at how diet might interact with genetics. For example, they studied how vitamin B1 (thiamine) intake affects stool frequency and whether certain genes make this relationship stronger or weaker. They also explored whether any existing drugs might target the genes they found, which could lead to new treatments.
Ultimately, the researchers combined genetic data, health surveys and advanced statistical methods to understand how genes and diet influence stool frequency and their connection to health conditions. Let’s break down the results.
What Did the Study Find?
The researchers discovered that how often we go to the bathroom is partly influenced by our genes. They found that genetic factors account for about 7% of gut motility in those of European descent and 5.6% in those of East Asian descent. While these percentages might seem small, they’re similar to the genetic influence seen with conditions like IBS. These findings indicate that our genes do play a noticeable role in shaping our bathroom habits.
Through their analysis, the team identified 21 independent genetic signals associated with stool frequency, nearly doubling the number of known locations in the genome linked to this trait. Ten of these were completely novel discoveries.
The researchers also identified two key genes: SLC35F3 and XPR1. These genes are involved in the metabolism of thiamine, also known as vitamin B1. SLC35F3 is a thiamine transporter, while XPR1 helps convert thiamine into its active form.
The study revealed the following in relation to thiamine:
- Eating more foods with thiamine was linked to going to the bathroom more often in the general population.
- This relationship was modified by an individual’s genetics. People with specific variants of the SLC35F3 and XPR1 genes processed thiamine differently, which directly impacted their gut motility.
Beyond thiamine, the study found significant genetic overlaps between stool frequency and other conditions. There were strong genetic correlations with gastrointestinal issues like IBS, diverticular disease and gastroesophageal reflux disease (GERD). There were also significant links to cardiovascular traits, like blood pressure, and psychiatric traits, like anxiety and depression, reinforcing the concept of the gut-brain axis.
Limitations of the Study
This study has some important limitations to consider before downing high-thiamine foods to help support gut health. First, it relied on people reporting how often they go to the bathroom as a stand-in for gut movement. While this is somewhat related to how quickly food moves through the digestive system, it’s not a perfect measure and might not fully reflect the complexity of gut function for everyone.
Second, because the researchers used large datasets from biobanks, they didn’t always have detailed information about each person’s diet, medications or lifestyle. Things like how much fiber someone eats or what medications they take can greatly affect bathroom habits, and not being able to account for all of these factors is a challenge.
Lastly, while the genetic links they found are strong, we still don’t know exactly how these genes affect gut movement. Identifying a gene is just the first step; scientists still need to do lab experiments to figure out how these genes influence things like muscle contractions in the gut.
How Does This Apply to Real Life?
So, what does this mean for the average person, especially those managing IBS or other gut issues?
The study suggests that for some people, depending on their genetic makeup, thiamine metabolism might be a key dial that regulates their digestion. This finding opens the door for personalized nutritional interventions. In the future, along with the tried-and-true recommendations like eating fiber and moving, a healthcare provider might look at your genetic profile and recommend specific thiamine supplementation or dietary changes to help manage constipation or diarrhea.
Experts recommend that adult men aim for 1.2 mg of thiamine and adult women consume 1.1 mg each day. A serving of fortified breakfast cereal contains 100% of your daily recommended thiamine, and a serving of protein sources like pork chops, trout and black beans all contain around 33% of your daily recommended value.
Still, more data is needed before we can definitively suggest that thiamine consumption is something people should explore to help manage gut movement.
Our Expert Take
This large-scale study published in Gut suggests vitamin B1 (thiamine) metabolism may play a significant role in regulating gut motility. The study represents a major step forward in understanding the biological engine of our digestion. By analyzing data from more than 268,000 people, researchers not only confirmed that our bowel habits are partially written in our DNA but also pinpointed the specific genetic chapters involved.
While more research is needed to translate these genetic insights into daily medical practice, the study offers a hopeful glimpse into a future where treating gut disorders is as precise and personalized as the unique genetic code we all carry.
