Why Does Coffee Make Me Poo?

If you are reading this post, then you are most likely in 1 of 2 camps:

Camp 1. OMG that’s me! Sometimes I don’t even get to finish a full cup before the sh*ts kick in!


Camp 2. Coffee makes you poo? HA! Nonsense. You are talking absolute sh*t!

It’s true, coffee can have a laxative effect on some people, but not everybody. Some people are more susceptible to coffee’s natural laxative effects than others, and some people do not feel any effect whatsoever.

So, here’s a bit of science as to why your morning cup of coffee might be keeping you regular as clockwork.

  • It’s common knowledge that coffee is a general stimulant because of it’s high caffeine content; improving alertness and cognitive function. Studies have also shown that caffeine stimulates your digestive system, more specifically the lower GI tract and the colon. Increased activity in the GI tracts will speed up the digestion process and push waste food etc. out the ‘other end’ much sooner.
  • Drinking coffee also encourages a hormonal response within the body. Coffee triggers the release of Gastrin into the blood system. Gastrin is a peptide hormone which stimulates the release of Gastric acid (HCL) into the stomach to aid in the digestion of food. The Gastric acid promotes stomach contractions in various forms which increases the rate food is emptied from the stomach into the small intestines.
  • It’s not just regular caffeinated coffee either; studies have shown that decaf also has similar effects. Although not quite as potent as the caffeinated version, decaf still increased colonic activity significantly more than regular coffee.

So, what else could be causing this effect?

  • Studies supporting the fact that it is not just caffeine affecting your bowel movements have highlighted compounds such as N-alkanoyl-5-hydroxytryptamides (C-5HT) and N-Methylpyridinium (NMP) as possible culprits. (Don’t worry, you are not supposed to understand what they are, we don’t have a clue, just that they are present in all coffee). In a study carried out by Nestle, they found that C-5HT causes gastric irritation, and NMP decreases stomach acid secretion. That means that theoretically they cancel each other out. As the C-5HT starts to irritate your bowels the NMP should be working to reduce bowel irritation.
  • However, they found that different roast levels of coffee beans either increased or decreased the amount present.
    • For a light roast coffee C-5HT levels remained high, but NMP levels were extremely low.
    • For a dark roast coffee C-5HT levels were low, and NMP levels were high.
  • Therefore, Lighter roasts are more likely to cause stomach irritation than dark roasts as dark roasts have more of the stomach friendly NMP present.


The Bottom Line

It’s true, coffee is likely to make you poo. It contains a variety of compounds which can stimulate your digestive system and push food through your system faster. It is still out for discussion which of the above factors has the most significant impact, and whether it affects all people in the same way, or if regular coffee drinkers become less susceptible to the effects over time. But for the moment, the studies and data available say coffee and toilet trips are definitely linked.

Next time you are in the office, half way through your morning pick me up and the panic sets in as you think you might suddenly sh*t yourself; you now know why.

Plus, it’s a much more enjoyable way to stay regular than eating prunes!







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