May 18, 2021
Based on our research, recently published in the peer-reviewed journal Gut, the #bluepoopchallenge is a simple and inexpensive way for anyone to measure their gut transit time at home and learn more about their microbiome.
All you need are a couple of blue muffins and the spirit of curiosity to find out what’s going on in your gut!
Read on to learn about the science behind the #bluepoopchallenge, how to take part, and what your result might mean for your gut health and microbiome.
Your gut transit time - how long it takes for food to travel through your digestive system - is an important measure of gut health.
There are several scientific ways of measuring gut transit time, such as asking people to swallow special capsules and tracking them by X-ray or swallowing a tiny wireless device. But these methods are complicated and invasive, and can’t be done easily at home.
The simplest way to measure your gut transit time is to eat some distinctively colored food and see how long it takes to come out the other end. You may have even accidentally done this experiment before by eating beets and noticing your poop turns purple-ish a few days later.
To measure transit time as part of our PREDICT study - the world’s largest in-depth study of nutrition and the gut microbiome - we asked thousands of participants to eat specially-prepared blue muffins.
In our paper, published in Gut earlier this year, we found that normal transit times vary from quicker than 14 hours to more than 58 hours, with a typical time of around 29 hours.
We also found that the longer someone’s gut transit time, the less often they pooped and the more likely they were to be constipated.
But that wasn’t the only thing we discovered.
We already know that your diet, hydration, and lifestyle, such as how much exercise you do and any medications you take, can all affect how often you poop and how long it takes for food to move through your body.
But our research has revealed that your gut transit time is also affected by the trillions of bugs living in your gut, known as your gut microbiome.
To explore the links between transit time, gut microbes, and health, we analyzed the gut microbiomes of each study participant and collected lots of data about their diet and health.
We found that shorter transit times were generally associated with better health, having less belly fat, and healthier responses to food.
Our data showed that transit time is a better indicator of gut health than tracking poop appearance or frequency.
There was also a difference in diet and gut microbiome composition between people with shorter and longer transit times, with specific foods and strains of bacteria associated with speedier or slower poops.
With longer transit times, we often found more microbes that feed on protein and fewer fiber-loving bugs that produce helpful molecules called short-chain fatty acids that are linked to better gut health.
Interestingly, we also found that people with longer transit times were more likely to have a greater diversity of microbes in their gut, which is often associated with better gut health. This suggests that more microbiome diversity may not always be a sign of better health for people who don’t poop very often.
Finally, it’s not all about being first to the finish line! People with the very fastest transit times, suggesting they had diarrhea, tended to have a less healthy gut microbiome.
If you want to discover your own gut transit time and find out what it means for your gut health, all you need are a couple of blue muffins.
To start the challenge, simply eat two muffins for breakfast and note down the time or start a timer on your phone.
Then all you have to do is look out for blue-green poop in the toilet and note the time when you spot it.
Finally, head on over to bluepoopchallenge.com. Enter your transit time and answer a few simple health questions to get fascinating and fun insights into your gut health.