New research reveals what coffee really does to your gut—and it’s surprising

Is coffee actually good for you? Some experts tout its health benefits, such as lowering the risk of type 2 diabetes and Alzheimer’s disease. At the same time, excessive caffeine consumption has been linked to various health conditions, such as anxiety, headaches, faster heart rate, and in some cases, lower bone density in women. Although coffee is widely believed to improve digestion and mood, what is less clear is the mechanism for how this works in the body—namely, its effect on our gut-brain axis, which is the two-way communication system linking microorganisms in the digestive tract to the brain. To this end, researchers from the University College Cork’s APC Microbiome Ireland studied 31 regular coffee drinkers (who consumed three to five cups of coffee a day) and 31 non-coffee drinkers. They recorded their caffeine intake, diet, and changes to their gut microbes using stool and urine samples. Then, study participants were prohibited from drinking coffee for two weeks. That’s when researchers found something surprising in the guts of the coffee drinkers: Their metabolites had changed. After that two-week period, coffee was reintroduced, with half the study receiving regular …