Who hasn’t experienced it: After the first sip of coffee in the morning, your stomach starts to rumble and your digestion gets a boost. But anyone who thinks it’s due to caffeine is wrong. Two experts say what the real reason is.

A quick coffee and then sprinting into a meeting, train or lecture wide awake – a common tactic. However, this short-term wake-up action can take its toll after just a few minutes.

This is when the digestive tract starts to rumble and a trip to the toilet, although highly inappropriate, can no longer be avoided.

But why does coffee actually make you have to go to the bathroom so much faster than usual?

Coffee does indeed have a laxative effect. However, researchers are divided as to why this is the case. What is clear is that the caffeine contained in coffee increases blood pressure and thus also stimulates the metabolism.

An old study from 1998 underlines this. It turned out that caffeinated coffee had a 23 percent stronger stimulating effect on the colon than decaffeinated coffee.

In contrast, another study made it clear that it cannot be caffeine alone that triggers the immediate urge to defecate after a cup of coffee. In this study, the researchers gave their subjects either black, caffeinated coffee, decaffeinated coffee or hot water to drink.

It turned out that caffeinated and decaffeinated coffee had a similar stimulating effect, while pure hot water triggered significantly less of the urge to go to the toilet.

Another suspected trigger for stimulated digestion is the body’s own hormone gastrin.

This digestive hormone is produced in the body itself and released as soon as food enters the stomach to stimulate muscle contraction in the stomach wall. After drinking coffee, gastrin secretion is particularly high. This means that the food in the stomach is broken down more quickly and released into the intestine.

Pascale M. White, associate professor of gastroenterology at Mount Sinai Health System (New York) and director of the Department of Gastroenterology, also cites another aspect that can affect digestion: the addition of additives such as artificial sweeteners and milk to coffee, which can irritate the stomach.

Especially with regard to dairy products, the doctor warns that some people may be lactose intolerant, which affects the intestinal tract and can lead to both increased and loose stools.

Basically, a slightly increased urge to go to the toilet after a coffee is completely normal and there are no known long-term negative consequences – apart from bad timing in the short term.

The original of this article “Why coffee really boosts digestion” comes from FitForFun.