Does Your Morning Coffee Send You Running To The Loo ?
Many of us rely on our morning cup of coffee to kick-start our brains into high gear and give us a boost to get the day started. But it’s not just the brain that receives a kick-start; coffee can get your digestive system up and running too, with many coffee drinkers relying on their morning coffee to keep them regular. In fact, it’s such a well-known side-effect of coffee that you can even buy various mugs proclaiming loud and proud, “Coffee makes me poop”. Seriously, google it, it’s a thing.
If you’ve ever wondered exactly WHY you can often time your toilet trips for shortly after your coffee breaks, you’re not alone. Scientists have studied this over the years and, although they haven’t found the definitive, go-to answer, they have managed to narrow it down a bit and offer up some interesting facts to ponder.
Firstly, if it’s your morning coffee that sends you racing to the porcelain telephone to make a call, your coffee might not actually be to blame. After a night of inaction, it only takes a bite of food to stimulate the digestive system into activity; so, the fact that you’re up and moving, eating and drinking is enough to get that traffic moving along the intestinal highway – not to mention the fact that in the morning the colon is twice as active as normal, due to the natural circadian rhythms the body follows.
Most of the results cited in today’s research are from a study done back in 1990, the results of which were published in “Gut” magazine. This particular research program took some brave participants, wired them up with some anal probes, and studied the reaction of their colonic muscles to various beverages.
Not all coffee drinkers experience this digestive phenomenon: the study showed that only three out of ten coffee imbibers experience this laxative effect, and many regular coffee drinkers build up so much of a tolerance to the daily dose that the effect may wear off. For the lucky (or unlucky?) minority, a cup of coffee causes the digestive system to react in the same way as it would if they were to ingest a large meal, all within four minutes of ingestion. Research also found that a cup of coffee stimulated peristalsis 60% more than a glass of water.
Let’s take a pause here and fill in the blanks with some basic education about the far end of our digestive system. Food, which later becomes stool, after some advanced magic in the upper digestive system, is moved through the lower intestinal tract and colon by peristalsis, which is the contraction of the walls of the stomach and intestinal tract. When you eat something, this triggers the gastrocolic reflex to kick in, which gets things moving right along. If those contractions move things along more quickly than normal, as can be the case with a strong cup of coffee, then the resulting stool can tend to be a bit looser than one would expect. This is because it hasn’t spent enough time in the colon, where the excess moisture would normally be reabsorbed.
Many people assume that it’s the caffeine in the coffee that causes this effect; however, the results from the study mentioned above provided proof that decaffeinated coffee has the same effect, although to a slightly lesser extent, and that high-caffeine energy drinks and sodas do not have the same outcome. So, having ruled out the caffeine aspect, that only leaves, oh, about 1000 other chemical components to sift through, all of which are contained in a single cup of coffee.
Now, scientists haven’t narrowed down exactly which compound/s do the dirty work (so to speak), but they do know that something in your cuppa joe triggers the release of two key hormones: motilin, which stimulates those gut contractions, and gastrin, which triggers the secretion of acid in the stomach.
Which leads to the second theory: coffee itself is quite acidic. An average cup of coffee has a pH of about 4.7 (with 1.0 being the highest acidity possible, and 14 being the lowest). For comparison, lemon juice has a pH of 2.0 and water a pH of 7.0. This higher acidity, along with the extra acid stimulated by gastrin, in turn gives the distal colon a wee push-start, leading to faster excretion of wastes from the body.
So, there you have it! If you’re one of the special few who experience the coffee/poo chain of events, you now know exactly what’s happening as your coffee works its way from the mouth on downward, and why your favourite beverage helps to keep you regular. You can now impress your co-workers during your coffee break with your newfound colonic knowledge, and maybe even go ahead and buy a “coffee makes me poop” mug for your next office Secret Santa.