If you ever find yourself suddenly running to the bathroom following a lovely cup of coffee – you are not alone. According to a study published in the medical journal Gut, coffee was found to induce a desire to crap in some 29 percent of all participants.
The observed laxative effects of coffee kick in within four minutes of taking your first sip and can last up to half an hour after finishing your cuppa. But what causes coffee’s bowl-blasting effect? And why does it leave some people turtle heading and others excrementally unmoved?
The answer, it turns out, is far from clear. But there are a number of working theories as to why coffee can have such a cathartic effect.
Caffeine is crap-tastic
Several experts have pointed the finger at caffeine. Not only does the magic molecule keep you awake and alert – its stimulant properties also affect your intestinal and colonic muscles, speeding up their rate of movement. This sets of a chain reaction of muscle movements through your gut known as peristalsis, which squeezes material through the digestive tract and into the business end of the colon – giving you the sudden urge to go.
But the effect of caffeine might be overstated, as one 2015 study found that decaffeinated coffee drinkers also reported the same poop-inducing benefits as caffeinated coffee consumers. Indeed, the same effect has not been observed among drinkers of caffeinated fizzy pop or energy drinks suggesting there is more to coffee’s poo-factor than caffeine alone.
Bowl dropping acid
Another culprit could be the large quantity of chlorogenic acid contained within coffee beans. Coffee beans are in fact, one of the largest natural sources of the acid – as are another well known natural laxative – prunes.
Scientists are still researching the effect of chlorogenic acid, but it is thought that the compound causes higher acidity levels in the stomach as it is digested. An overall rise of acidity within the stomach stimulates the production of bile and causes the stomach it to empty it’s contents into the intestine quicker.
It’s the hormones, stupid
Researchers aren’t quite sure which specific compound, or combination of compounds, found in coffee are responsible, but drinking coffee boosts the production of motilin and gastrin – two hormones which play an important role in digestion.
Motilin and gastrin are the chemicals that enhance the process of bowl vacation during digestion – and their presence in enhanced following a cup of coffee – both decaf and regular!
Building a resistance
It is thought that regular coffee drinkers over time will build up a resistance to the chemical compounds that give coffee its laxative effects. This means occasional coffee drinkers are likely to experience a more pronounced ‘explosive’ effect when they drink coffee.
“Hang on,” you say. “My morning bowel movement happens at 8.30 am sharp – as soon as I finish my first cup!”
Well you’re not alone and science just might have an answer as to why…
Timing is everything
Researchers have also pointed out that the observed laxative effects of coffee may well be down to the time of day that most people drink it.
The colon is twice as active after waking up – which is when most people reach for a cup of joe. Healthy human bowels tend to get busy as soon as you take your first bite of breakfast as the digestive system starts working again after much lower levels of activity during sleep.
Warm drinks – not necessarily coffee – are very effective at widening the blood vessels in the gastro intestinal system, making them good at awakening your bowels up too. Depending on how much you want to ascribe coffee’s crap-factor too the bowl shattering effects of early morning warm liquids, coffee’s perceived laxative effects could largely be coincidence.
It’s all in your head?
Perhaps coffee’s reported laxative effects are little more than placebo.
If over the years you have woken up and had a coffee, followed by a number two – it’s fairly obvious that with time the act of drinking coffee is going to illicit some kind of physical response in anticipation of what is going to happen next.
In fact, drinkers who experience coffee’s laxative effect widely report getting the urge as soon as they hear the percolator dripping and smell their first cup of the day….
This response is similar to the way Ivan Pavlov’s dogs learned to salivate upon hearing a bell because they were already thinking about the food that Pavlov was about to feed them,
The precise mechanisms behind coffee’s laxative effects are the still unknown and more studies will need to be done before we know exactly where to point the finger. Coffee may well be the third most consumed beverage on the planet – but we still have much to learn about it.
Take solace in the fact that if coffee makes you poop – you are perfectly normal. Just remember to time your coffee’s sensibly so as not to be caught short at an inappropriate moment!