What does gut transit time have to do with our overall health? A lot! Let’s talk about poo.
If you know me, you know one of my favorite subjects is poo. Lest you think I’m weirdly obsessed with fecal matter, let it be known that my interest in topics like gut transit time and poo stems from an understanding that improved gut health is a key factor in overall wellness.
But more importantly, improving your digestive health is easy, affordable, and can reduce your risk of a myriad of symptoms and prevent a range of diseases.
So let’s talk about poo.
More specifically, let’s talk about gut transit time. ‘Transit time’ refers to the amount of time it takes for food to get through your digestive tract. It was from Dr. Greger of NutritionFacts.org that I first learned about this concept. I think this is one of the most interesting parts of the already-fascinating topic of gut health.
When you eat something, it should be out of your system within about 24-48 hours. How can you check your transit time to ensure things are moving smoothly along those eight meters of digestive tract? Dr. Greger recommends eating a bunch of beets, then checking to see when things become ‘pretty in pink’ in the toilet.
The longer food is in your gut digesting, the more at risk you are for certain diseases. Longer transit times are linked to higher rates of cancer (specifically breast cancer– estrogen binds with fiber, and thus a high-fiber diet flushes excess out of the body) and colon cancer. Longer transit times are also linked to appendicitis, diverticulitis, and general digestive discomfort, like constipation, bloating, and gas.
Dr. Greger has a fascinating look at the average transit time, and found that most non-vegetarian women have about a four-day intestine transit time, while non-vegetarian men have about 3-4 day transit time. What this means is that the food that you ate Monday is still making its way through your system on Thursday, which is just really gross. And, as a new study confirms, it’s pretty unhealthy too.
Related: 6 Ways to Eliminate Constipation
A new study from National Food Institute, Technical University of Denmark and published in Nature Microbiology shows that the longer food takes to travel through the gut (the colon), the higher the level of ‘harmful bacterial degradation products’ that are produced. Food that hangs out in our bellies feeds “bad” gut bacteria.
While is it often thought that high bacterial populations are good for gut health, this new study shows that high bacteria might be indicative of a slow transit time, and this would not be beneficial. Tine Rask Licht explains: ”We believe that a rich bacterial composition in the gut is not necessarily synonymous with a healthy digestive system, if it is an indication that food takes a long time to travel through the colon.” Furthermore, he says, “when the transit time is shorter, we find a higher amount of the substances that are produced when the colon renews its inner surface, which may be a sign of a healthier intestinal wall.”
In Denmark, where this study took place, approximately 20% of the population suffers from constipation from time to time. In the US this is even more relevant. Research suggests that more than 90 percent of Americans aren’t meeting our daily fiber requirement, which is 25 grams a day for women and 38 grams a day for men.
The solution to improving gut transit time is so simple: just eat more fiber. Fiber is found only in plant foods, and you can boost your fiber simply by eating more fruits, vegetables, whole grains, legumes. If your diet is really low in fiber or you’re continually constipated, you can supplement with fibers like psyllium husk or flax, and maybe add probiotics to improve movement further.
Licht emphasizes that people’s dietary habits can influence transit time:
“You can help food pass through the colon by eating a diet rich in [fiber] and drinking plenty of water. It may also be worth trying to limit the intake of, for example meat, which slows down the transit time and provides the gut bacteria with lots of protein to digest. Physical activity can also reduce the time it takes for food to travel through the colon.”
If you want to see me in action talking about my favorite subject, check out my three minute snippet of a talk from a few years ago called How to Build a Better Poo. To learn more, see the notes from another talk about probiotics and gut health.
poopy bunny image from Shutterstock