You probably know the old adage that says that drinking coffee helps you have a bowel movement . In the same vein, in a more popular version, we know the triple C saying “coffee, cigarette, poop”, which implies that after drinking a coffee and smoking a cigarette, we go straight to the toilet. But does drinking coffee, whether it is in the form of an espresso, a long coffee, or an instant coffee, really help us fight constipation? Or at least, trigger the urge to have a bowel movement? William Berrebi, gastroenterologist and author of the book Mission Ventre Plat, La méthode microbiotique alimentaire et sportive (Mission Ventre Plat, The Microbiotic Nutritional and Sports Method) published by Marabout, answers this question.
It's not a myth, coffee does help with bowel movements. At least that's what American scientists revealed in a study conducted on rats in 2019. "When the rats were treated with coffee for three days, the ability of the muscles of the small intestine to contract appeared to increase," said Xuan-Zheng Shi, PhD, lead author of the study and associate professor of internal medicine at the University of Texas Medical Branch, Galveston. However, it turns out that the effects of this beverage are also valid for humans. This can be explained by three reasons, which the gastroenterologist explains to us.
The Qastrocolic reflex From constipation
We often drink coffee in the morning for breakfast. And this therefore occurs after a long period of rest for our digestive tract. When we ingest something after this break, constipation, a gastro-colic reflex occurs . It is simply the "response" of the colon when we eat, which contracts to make room and accommodate food again. This is what allows it to move what it stores, and makes us evacuate it by going to the toilet . "This is valid for any solid or liquid food, including coffee, therefore. The arrival of food in the stomach leads to hormonal production that creates these contractions", underlines the gastroenterologist.
The role of caffeine on the colon
The second explanation for why coffee triggers our urge to go to the toilet is that caffeine “stimulates peristalsis in the colon. That is, it has the power to activate the muscles of our digestive organ ,” explains the doctor. He adds that the third reason is the production of gastrin, which results from taking caffeine . The Academy of Medicine describes it as follows: “a hormonal polypeptide secreted by the G cells of the gastric mucosa at the level of the pyloric antrum, which stimulates the secretion of gastric juice and hydrochloric acid by the lining cells of the stomach.” Specifically, “gastrin plays a role in the digestion process, which helps us to have the urge to go to the toilet,” concludes William Berrebi.
Can coffee give us diarrhea?
However, the doctor reassures: if coffee can contribute to triggering the urge to go to the toilet, it does not have the power to make us sick . “In someone who does not have digestive problems and who does not have diarrhea, coffee is not likely to facilitate transit to this point. On the other hand, if you already have liquid stools, coffee can speed up the process. To limit the risk of inconvenience, I recommend consuming it in reasonable quantities, i.e. around 3 to 4 espressos per day.”