Why Does Coffee Make Me Poop?

[left-of-center2012]

The speed of this effect suggests it’s mediated by the brain. Some studies on the topic — which tend to be small, old and limited — have suggested that it’s probably not the caffeine that triggers the urge to go. One paper published in 1998, for instance, found that decaffeinated coffee had a similar stimulatory effect on the colon as caffeinated coffee, whereas a cup of hot water did not.

One thing we do know is that coffee doesn’t affect everyone the same way. In one study published in 1990 in the journal Gut, 92 young adults filled out a questionnaire about how coffee affected their bowel habits; just 29 percent of the respondents said it “induced a desire to defecate,” and most of them — 63 percent — were female. (Though Dr. Martindale said that the percentage of people who have a bowel response after drinking coffee is likely much higher in the general population — he estimated that around 60 percent of his patients do — and he hasn’t noticed any differences between men and women.)

We also know that a gut response to coffee can happen fast. In the same study,
some volunteers agreed to have a pressure-sensing probe inserted into their colon to measure intestinal muscle contractions before and after drinking a cup of Joe. Among those who said that coffee usually stimulated a bowel movement, the probe showed a significant increase in pressure within four minutes of drinking coffee, while the so-called nonresponders had no change in colon activity.

That drinking a cup of coffee can stimulate the opposite end of the gastrointestinal tract within minutes means “it’s probably going through the gut-brain axis,” Dr. Martindale said. That is, the arrival of coffee in the stomach sends a message to the brain, which then “stimulates the colon to say, ‘Well, we’d better empty out, because things are coming downstream,’” he explained. The coffee itself would move through the intestines much more slowly, likely taking at least an hour to traverse the long path from the stomach through the small intestine and to the colon.

https://www.nytimes.com/2021/11/30/well/eat/why-does-coffee-make-you-poop.html

[Flo Mingo]

1. Things you never forget

Your Mother-in-law, who's retired from a 40 yr nursing career, telling you she's constipated and drinking coffee because caffeine stimulates the anus.

[left-of-center2012]

6. And the OP says ...

It's not the caffeine.

[Flo Mingo]

13. Maybe, maybe not

I'm no expert. Nor did I stay at a Holiday Inn Express.
All I'm saying is you never forget your MIL telling something stimulates the anus.

Hope it all works out.

[left-of-center2012]

14. Your MIL versus the scientists

okie dokie

[Flo Mingo]

15. I don't know how to respond

I'm not sure if you really think I'm supporting my MIL's statement. I drink coffee. I poop. I don't over think it.

It seems obvious to me that I'm just making light of a moment that was a bit awkward in a this-is-kinda-funny way. Maybe you had to be there.

[hlthe2b]

16. Not necessarily. There was a smaller study several years ago that looked at caffeine tablet intake

100-200mg--the equivalent in a large cup of brewed coffee. They found a similar effect. I don't have time to search for it, but I think this current research should have included an additional comparison group to better explore the caffeine link. Caffeine's stimulatory effects on the brain could still be quite compatible with the impacts on gastrocolic reflex. We DO know that caffeine is NOT the ONLY stimulatory chemical in coffee and tea (theanine, for example), so the old study mentioned that found that decaf coffee can have a similar effect to caffeinated coffee is not contradictory. There is nothing from this study that rules out stimulatory effects as being the cause.

[bucolic_frolic]

2. It's the abrupt change in acidity in the colon

The same thing can happen with small amount of magnesium, epsom salts, or so called ph drops - acid neutralizers - and even green powdered drinks.

[left-of-center2012]

8. Is that what the OP says?

[bucolic_frolic]

10. in my mind that article is full of it

[elias7]

3. How about the old gastro-colic reflex?

First thing in your stomach in the morning often triggers defecation in a process known as the gastro-colic reflex. It is not mediated by the brain. For many, the first thing in their stomach is coffee, but really any food (or a stimulant like tea or coffee) in your stomach begins the process of digestion, which is part chemical (secretion of digestive enzymes and bile) and part mechanical (intestinal peristalsis). Some of that peristaltic process is in the sigmoid colon which warehouses the stool for your next bowel movement. This colic peristalsis can also be induced by cigarettes (another stimulant), and I reckon you’ll find folks, especially those who are regular, that their first cigarette, first cup of coffee or first meal of the day will often be followed by a sh*t…

[hlthe2b]

17. Actually there is direct brain impact on gastric-colic reflex-- including circadian rhythms--

for which a central clock or “pacemaker” is located in the hypothalamic suprachiasmatic nucleus (SCN), which receives photic input via the retinohypothalamic tract. While peripheral tissues have some effect even with damage to these hypothalamic centers-- such that timed feedings can still induce gastric motility and thus some "regularity," there are impacts (and thus the issues frequently seen with gastric motility among shift workers).

The brain has influence on everything quite frankly. Thus, stimulants should not be expected to be unrelated to such signals. It is not merely local innervation detecting a "filling effect," though that surely has some impact as well.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950682/

[elias7]

18. Kewl...

The retinothalamic tract might help explain why every time I see TFG, I feel the urge to puke. Although, perhaps there are otic as well as photic input, since I feel that way whenever I hear him too. 🙂

[Lovie777]

4. Well a cup of coffee works for me . ....

it takes of an hour or longer but 99% of the time it works. If not, later that day 1/3 cup of prune juice.

[Tetrachloride]

5. say peristaltic 3x in a row.

i submit this is a better experiment.

[brewens]

7. Wake and bake works like a charm if that's a problem for anyone. In fact, I gotta run! LOL n/t

[Historic NY]

9. Ancestry collects worldwide data and thats one they survey...

they also looked at minutes for the effect.

Things are coming downstream....

[samnsara]

11. it actually makes me vomit if i drink it too early

[lastlib]

12. drink coffee, dump a trump.....

that's how it works for me. I'm fine with it. Caffeine IS a diuretic.

[elias7]

19. Dump a trump! That's a keeper...