Sourced from NYT | December 01, 2021
It's not clear
if coffee can stimulate a bowel movement, but the speed to which it does suggests it's mediated by the brain.
A cup of coffee gets us going in the morning, in more ways than one. This brew revs energy levels with a dose of caffeine, but for many, it hits us hard and gets us jumpy and going, and also increases our need to poop.
It's surprising if you think about it, how little we know about how it affects the gastrointestinal tract.
Some studies have suggested that caffeine triggers the urge for us to go. A finding showed that decaffeinated coffee had also a similar stimulatory effect on the colon as caffeinated coffee, whereas a cup of hot water did not.
Coffee is a complex beverage containing more than 1,000 chemical compounds, which has many antioxidant and anti-inflammatory properties.
Coffee doesn't affect everyone the same way. In one study published, the journal Gut, 92 young adults filled out a questionnaire about how coffee affected their bowel habits. 29% of respondents said it "induced a desire to defecate" — 63% of which were female.
A gut response to coffee can happen quite quickly. In a study published in 1990, 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 coffee. Among those who said that coffee usually stimulated 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.
Drinking a cup of coffee can stimulate the opposite end of the gastrointestinal tract within minutes. The arrival of coffee in the stomach sends a message to the brain, which then heads to the colon to say "we better empty out now".
The communication between the stomach, brain, and colon is called the gastrocolic reflex, a response to eating. Coffee seems to have an outsize effect; a study published in 1998 found that eight ounces of coffee stimulates colonic contractions similar to someone who induced a 1000 calorie meal.
While the mechanism remains murky, coffee's effects on guts could be helpful for those who are recovering from certain types of surgery. Impaired bowel function is common after abdominal surgeries, which can lead to bloating, pain, and an inability to pass gas or tolerate food. A 2020 analysis showed the results of several clinical trials and found that drinking coffee allowed patients who had undergone colorectal or gynecological surgery to tolerate solid foods an average of 10 and 31 hours sooner.
A couple of sips of coffee can do it. It doesn't take much to have an effect. Brewed coffee also contains a small amount of fiber, about one gram per eight-ounce cup.
Others find that coffee causes an upset stomach and loose stools, as well as side effects linked to excess caffeine, like insomnia, anxiousness, heart palpitations, and headache. The Food and Drug Administration says that it's safe for most people to drink 400 milligrams of caffeine, the amount in about four or five cups each day. Though keep in mind that everyone metabolizes caffeine differently so the threshold can vary from person to person.
For the rest of us, coffee can be a part of a comforting morning routine, waking us up and getting us up and going every day, especially in a bustling city like NYC.
