Does coffee make you poop?
Have you ever just been sitting, enjoying your morning cup of coffee and then, bam, suddenly you have the urgent need to head to the restroom? Well, if you’ve experienced this before, you’re not alone!
So, what exactly about coffee makes it a ‘colonic stimulant’ (the fancy word for it making you have to poop!)? Well, science has some answers for us! In a survey of 99 young, healthy volunteers, Brown and Read (1990) found that 29% of them stated that drinking coffee made them need to poop – and more than half of them were women! They then investigated exactly what regular, unsweetened black coffee did to the colon function of 14 people (12 men, 2 women). They found that in 8 of these people, both decaf and regularly caffeinated coffee make them feel like they needed to head to the restroom! To make sure it wasn’t just an effect of the hot drink, they also tested the impact of just plain, hot water – and found none of them needed to ‘go’!
Another study, Rao et al. (1998) also confirmed that both caffeinated and decaffeinated coffee gave respondents the urge to poop. In this study, they actually implanted probes that measure the colon’s movement into 12 healthy adults to determine the impact of caffeinated coffee, decaffeinated coffee, a large meal, and water on the stimulation of the colon. What they found was that both types of coffee and the large meal got the colon’s moving – but the water didn’t. Overall, their data showed that caffeinated coffee got the colon moving the same amount as a big meal, that it was 60% stronger than water, and 23% stronger than decaf coffee.
Alright, so now that we know coffee is a colonic stimulant for some people, let’s talk about what exactly is it about coffee that gets the colon ready to perform. To determine if just caffeine alone is enough, Lohsiriwat et al. (2008) gave 10 healthy adults the same amount of water and caffeine solution and measured (in a way I will spare you the details of) whether or not the volunteers needed to ‘go’! Overall, as you can guess, yup! Caffeine made everyone need to poop!
So, it seems like caffeine is definitely playing a role in why coffee makes some people need to poop. However, since decaffeinated coffee also gives some people the urge to go, some researchers think that other facets of coffee are also playing a role.