Why are people dyeing their poo blue?
Social media users have been posting pictures of vibrant-blue cupcakes with the unique hashtag #bluepoopchallenge. Yep, that’s right. Blue. Poop. Challenge. This didn’t start off as a viral social media trend, but as research into how well your digestive system and gut microbiome are working. And it’s something we can all try.
The time it takes from eating food to excreting it is called the “gut transit time”. Researchers gave participants muffins dyed with strong blue food colouring, turning their poo blue, to make it easy to identify the transit time.
“Slower transit time is associated with less favourable gut bacteria and a faster transit time is associated with a better gut bacteria profile”, explains dietitian and intestinal specialist Sophie Medlin (who wasn’t involved with the study). However, a transit time that’s too fast (suggesting you have diarrhoea) may indicate a less healthy gut microbiome.
The median gut transit time in the study was 28.7 hours, but it can take less than 12 hours and up to several days. “A gut transit time of 14–58 hours is a good place to be, and indicates that your gut is working as it should”, says the website of ZOE , a health science company linked to the research and encouraging people to take up the challenge. But ZOE and Medlin stress “it’s important to know what is normal for you”, as transit time is affected by many factors.
