Is coffee good or bad for the gut? Moderate consumption can promote intestinal motility.
Many people habitually use coffee to "boost their energy" and increase concentration because coffee contains caffeine, a central nervous system stimulant. Caffeine promotes the release of the neurotransmitter dopamine and can also inhibit the neurotransmitter adenosine, preventing adenosine from inducing drowsiness and thus achieving a stimulating effect. However, the effects of caffeine on the body last for about 5 hours, and as the caffeine concentration gradually decreases, fatigue can also occur.
In addition, caffeine promotes intestinal peristalsis (laxative effects).
Both caffeine and decaf coffee stimulate the production of gastrin; gastrin is a hormone that causes the stomach to release more hydrochloric acid and digestive enzymes, leading to increased stomach contractions and relaxation of the "gate" between the small and large intestines and the sphincter muscles between the stomach and small intestine, thereby promoting digestion. Therefore, drinking coffee can help with bowel movements.
A study as early as 1998 tested the effects of coffee, decaffeinated coffee, water, or consuming 1,000 calories of food on bowel movements. Research has found that caffeine makes coffee have a laxative effect, stimulating colonic activity in the same way as a 1,000-calorie diet; decaffeinated coffee is less effective, but still more stimulating than water. In a 2008 study, 10 participants drank water or had caffeine powder dissolved in water, and anorectal function was measured using a manometry method. Researchers found that caffeine intake led to stronger contractions of the anal sphincter and increased the urge to defecate.
Caffeine is a gastrointestinal stimulant, and the acidity of coffee can also stimulate the intestines. Both can accelerate peristalsis (the contraction of muscles as food passes through the digestive tract), thus speeding up intestinal transit. However, caffeine sensitivity varies from person to person. The International Gastrointestinal Foundation points out that drinking more than three cups of coffee or tea per day can easily lead to loose stools, and excessive consumption may cause discomfort such as headaches, irritability, and sleep disturbances. Moderation is advised.
Coffee Drinking Tips:
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For those experiencing stomach discomfort after drinking coffee, reducing caffeine intake and opting for half-caffeine or decaffeinated coffee is ideal.
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Dark (brown) roast coffee stimulates less stomach acid secretion than medium roast.
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Based on European and American dietary recommendations, the recommended daily coffee intake is 400 mg (approximately 4 cups). Additionally, pregnant women should not consume more than 200 mg per day.
References:
Lohsiriwat, S., Kongmuang, P., & Leelakusolvong, S. (2008). Effects of caffeine on anorectal manometric findings. https://doi.org/10.1007/s10350-008-9271-y
Rubach, M., Lang, R., Bytof, G., Stiebitz, H., Lantz, I., Hofmann, T., & Somoza, V. (2014). A dark brown roast coffee blend is less effective at stimulating gastric acid secretion in healthy volunteers compared to a medium roast market blend. Molecular nutrition & food research, 58(6), 1370–1373. https://doi.org/10.1002/mnfr.201300890
