Why does coffee have a laxative effect? And why not with everyone? Let’s find out.
A cup of coffee in the morning gets many people’s metabolism going. Why is that actually? And why is that not the case with everyone? Many cannot do without it: the morning cup of coffee. Not only do morning grouches swear by the invigorating effect – many people appreciate the hot drink mainly because of its digestive effect.
In this article, we are going to discuss:
- Is coffee really a laxative
- What’s the mechanism of the bowel movements after drinking coffee
- Does coffee make you dehydrated
- Reasons why coffee doesn’t work as a laxative at some people
- Helpful tips to make use of the healing powers of coffee
Let’s get started!
Regular coffee consumption is said to reduce the risk of heart attacks, protect the body from oxidative stress and increase concentration. However, it is now quite well proven that coffee has a laxative effect on some people.
But what exactly does our favorite drink do that goes so well in the digestive tract?
Revving the metabolism: caffeine is not solely responsible
Pascale M. White, lecturer in gastroenterology at Mount Sinai Health System (New York) and director of the clinic for gastroenterology, told Popsugar that coffee has a laxative effect.
However, research disagrees as to exactly why this is. It is clear that the caffeine contained in coffee increases blood pressure and thus also stimulates metabolism.
A small study from 1998 underscores this. It found that caffeinated coffee had a 23 percent stronger stimulating effect in the colon than decaffeinated coffee.
Is it coffee or caffeine?
A 1998 study found that caffeinated coffee, the same as coffee without caffeine, and a 1,000 calorie meal stimulated the colon. However, caffeinated coffee stimulated the colon 23 percent more than coffee without coffee and 60 percent more than normal water.
While coffee can have a laxative effect on some people, it’s unclear whether it’s coffee or caffeine. The effects of coffee are not solely due to caffeine, since coffee without coffee has shown the same or an even greater effect.
Additionally, most people don’t need to poop after drinking other caffeinated beverages like soda or energy drinks.
International Foundation for Functional Gastrointestinal Disorders (IFFGD) says that excessive consumption of beverages containing caffeine can lead to loose stools or diarrhea. And the caffeine in coffee can act as a stimulant that can induce bile production and increase bowel movements.
Both caffeinated and decaffeinated coffee act as a laxative
In contrast, however, another study made it clear that it cannot be caffeine alone that triggers the immediate urge to visit the restroom after a cup of coffee.
In this 1990 study, the researchers gave their subjects either black, caffeinated coffee, decaffeinated coffee, or hot water.
It turned out that caffeinated and decaffeinated coffee had a similar stimulating effect, while pure hot water triggered significantly less urge to go to the toilet.
But a 2015 study indicated that decaffeinated coffee had a significant impact on bowel movements in patients with postoperative ileus compared to caffeinated coffee and water.
Postoperative ileus refers to digestive problems that occur after abdominal surgery. In this case, the patients studied had colon surgery.
In short, there are no current scientific studies on how coffee affects bowel habits.
Coffee triggers gastrin production
The body’s own hormone gastrin is suspected to be another trigger for stimulated digestion.
This digestive hormone is produced in the body itself and released as soon as food reaches the stomach to stimulate the muscle contraction of the stomach wall.
Nutrition scientist Birgit Warnecke from the German Coffee Association says that caffeine, even in decaffeinated coffee, stimulates the production of gastric acid. This breaks down the chyme before it can slip into the intestinal tract.
A trigger for acid production is the body’s own hormone gastrin, which is additionally stimulated by caffeine. Gastrin is released as soon as food reaches the stomach, where, among other things, it helps break down food proteins and stimulates the digestive muscle contraction of the stomach wall.
After consuming coffee, the gastrin volume is particularly high. The food in the stomach is broken down more quickly and released into the intestines.
Once the chyme gets from the stomach into the intestinal tract, it has to make its way about five meters to the exit. This is done with the help of bowel contraction.
Coffee also stimulates these wave-like muscle contractions in the colon wall.
The stimulating effect is also used by medicine: Doctors use coffee as a mild stimulant in patients after colon removal to stimulate bowel activity and prevent intestinal obstruction, explains the nutritionist.
Conclusion: Thanks to coffee, food moves faster through the intestines.
Effects of coffee on the gallbladder
The chlorogenic acid also contained in coffee is said to have a digestive effect. Among other things, it stimulates the flow of bile. Bile is a liquid produced in the liver and released into the duodenum after eating. There it mainly ensures that fat is digested.
Another effect that stimulates the gallbladder after drinking coffee: the digestive hormone cholecystokinin. It causes the gallbladder to contract, which promotes bile production.
Cholecystokinin is also responsible for the release of important digestive enzymes. Coffee, in turn, ensures that even more of this hormone is produced.
Conclusion: Coffee stimulates the gallbladder to work.
The diuretic effect of coffee
While not all people can report a laxative effect of coffee, a full bladder after coffee consumption is practically guaranteed. Because caffeine temporarily increases the filter function of the kidneys, so that more urine is formed. But this effect quickly subsides again.
The claim that coffee removes water from the body has meanwhile been refuted: calculated over the course of the day, we excrete 84 percent of the liquid in coffee. If we drink pure water, it is 81 percent. A difference that hardly matters. However, coffee is not recommended as a thirst quencher.
So if you drink coffee regularly, you cannot really add it to your daily water intake.
In Southern countries, you are usually given a glass of water with your coffee. However, the nice gesture is not used to top up liquid. Rather, the water should emphasize the taste of particularly fine types of coffee. If you want to do it right, you can quickly sip the water after every second sip of espresso.
Conclusion: Coffee hits on the bladder, but hardly draws water from the body.
Can lactose intolerance cause a laxative effect?
The US professor Dr. White also mentions another aspect that can affect digestion: the addition of additives such as artificial sweeteners and milk to coffee, which can irritate the stomach.
With regard to dairy products, in particular, the doctor warns that some people may be lactose intolerant, which affects the intestinal tract and can lead to both increased and loose bowel movements.
Basically, after a coffee, there is a slightly increased urge to go to the toilet, but completely normal and without any long-term negative consequences – apart from short-term bad timing – have been known.
That’s why we made a collection of best dairy-free milk alternatives for your coffee.
If coffee is a laxative, does it make you slim?
Black coffee is practically calorie-free and increases the basal metabolic rate slightly by stimulating the metabolism. However, whether that is enough to lose weight is not so clear. The chlorogenic acids already mentioned should also be responsible for a slimming effect through various mechanisms.
There are some promising studies on this that have shown, among other things, an antidiabetic effect of chlorogenic acids in animal models.
In addition, chlorogenic acids are said to slow down the absorption of sugar into the blood after a meal. But further research still needs to be done on this.
Conclusion: Coffee has a laxative effect and slightly increases the basal metabolic rate, but there is no evidence that you lose weight as a result.
Why doesn’t coffee work as a laxative for everyone?
Genetics plays an important role in the effects of coffee. On the one hand, people are equipped differently when it comes to adenosine receptors. The caffeine attaches to these receptors in order to develop its effect.
On the other hand, our genes also dictated whether we belong to the so-called fast or slow caffeine breakdowns. This, in turn, would be due to the different features of different enzyme systems in the liver. Whether and how much coffee drives us to the toilet is in our genes.
More tips on how coffee gets the bowels moving
Coffee stimulates digestion – more precisely the caffeine contained in coffee.
- If the body is supplied with caffeine, it releases the hormone cholecystokinin. This hormone in turn stimulates the formation of bile secretion – and bile juice promotes the digestion of fat.
- Coffee also contains a lot of fiber – hard to believe, but true. This is what researchers have found out, and it is particularly true of instant coffee. Since the hormone cholecystokinin also makes you feel full, you can even lose weight with coffee.
- Simply drinking coffee or another beverage in the morning stimulates a laxative reflex known as the gastrocolic reflex. This reflex helps get your bowels going while you eat or drink. There is no scientific evidence to suggest that this causes a bowel movement after drinking coffee.
- For people with irritable bowel syndrome who have an oversensitive gastrocolic reflex, research suggests that coffee’s potential laxative effects may stimulate bowel movements after drinking a cup of joe.
The consumption of coffee promotes digestion and helps with constipation. However, you should not overdo it: if consumed in large quantities, coffee leads to diarrhea due to its laxative effect.