If the timeless “little black” gives a boost for some or is synonymous with convivial moments for others, coffee also has a laxative effect, softening the stool and thus helping to fight against constipation. Since the 1990s, numerous studies have proven this. But how to explain this mechanism? A american study conducted by the University of Texas explains why: and surprise, it’s not related to caffeine at all!

To explain the laxative effect of coffee, researchers conducted an experiment on rats, for 3 days. A coffee-based solution mixed with intestinal bacteria was administered to a first group of rats. The second group was fed decaffeinated coffee also mixed with gut bacteria. Then, they studied their intestines using a probe. The third group of rats did not consume any coffee at all. Results :

• All muscles in the small intestine and colon contracted in rats after they ingested coffee.
• With or without caffeine, the contractile capacity of the rats’ small intestine muscles increased.
• The faeces of rats that drank coffee showed fewer bacteria than animals that did not drink coffee. The bacteria even stopped multiplying after ingesting coffee. Even if the coffee was decaffeinated.
• The same effect was more pronounced as the coffee concentration increased.

The laxative effect of coffee has long been thought to be caffeine-related. However, this experience shows thatlaxative effects are independent of caffeinesince caffeine-free coffee had similar effects to regular coffee“, explains Xuan-Zheng Shi, gastroenterologist and lead author of the study. The experiment also shows that coffee stimulates contractions of the small intestine and colonallowing better passage of solid food.

Moreover, “this experiment is really interesting, because it shows that coffee could be an antibacterial agentsays the researcher. But further research is needed to try to understand why coffee could have this inhibiting effect on the microbiome” and whether this mechanism is also visible in humans. If the results are confirmed, coffee consumption could in particular be considered as a an effective treatment for postoperative constipation or ileusin which the intestines stop working after abdominal surgery.