drink Coffee without eating something together in the morning can attack the mucous membrane stomach? For many people, enjoying a fresh cup of coffee in the morning is a nonnegotiable way to start their day. But the notion that a sip without some other food could harm you colon — or contributing to other ailments like bloating, acne, hair loss, anxiety, thyroid issues, or pain, as some have claimed on social media — has garnered as much popularity as distrust.
Researchers have been studying the benefits and harms of coffee consumption, particularly as it relates to the gut, since the 1970s, said Kim Barrett, a professor of membrane physiology and biology at the University of California (Davis School of Medicine) and a board member of directors for the American Gastroenterological Association . Fortunately, the stomach can withstand all kinds of irritants, including coffee.
“The stomach has so many ways to protect itself,” Barrett said. For example, it expels a thick layer of mucus that forms a strong protective shield between your stomach lining and whatever you eat. This protective shield also protects the stomach from its own natural acidic environment, which is needed to break down food, she explained.
You would have to consume a very hard substance “for the stomach’s defenses to be broken down because they’re constantly in a very adverse and harmful environment,” she said. “This is exactly how the stomach does its job.”
Therefore, drinking coffee, especially if it’s black, without a meal can lower stomach pH more than drinking it with milk or other foods, the doctor said. Photo: Joyce Lee/The New York Times
How does coffee affect the gut?
Irritants like alcohol, cigarette smoke, and nonsteroidal antiinflammatory drugs like ibuprofen (Advil, Motrin) or naproxen (Aleve) are known to alter our stomach’s natural defense mechanisms and injure its lining, said Byron Cryer, chief of medicine at Baylor University Medical Center at Dallas.
Her research lab specializes in understanding how different drugs and other chemicals can damage the stomach and small intestine. While certain substances can make the stomach more prone to acid formation and ulcers, several large studies have found that this is not the case with coffee.
For example, a 2013 survey of more than 8,000 people living in Japan found no significant association between coffee consumption and the development of stomach or intestinal ulcers — even among those who drank three or more cups a day.
“Coffee, even in concentrated form, is unlikely to cause objective damage to the stomach,” Cryer said. “And certainly not with the typical shots in the usual drinks.” However, coffee does have an effect on the gut — it can speed up the colon and stimulate a bowel movement — and it also increases acid production in the stomach. Outside the gut, caffeine is known to increase heart rate and blood pressure. And if you drink it too close to bedtime, it can disrupt your sleep. But those changes are temporary, Cryer said.
Does increased stomach acid cause any problems?
Drinking coffee on an empty stomach probably doesn’t harm the digestive tract, but theoretically it could trigger heartburn, Barrett said.
We know that coffee triggers the production of stomach acid, but having food in your stomach or drinking your coffee with milk or cream helps create a buffer that helps neutralize that acid. Drinking coffee, especially if it’s black, without a meal can lower your stomach’s pH more than drinking it with milk or other foods, Barrett said.
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While a slightly lower pH doesn’t affect the stomach lining, it could pose a problem for the lining of the esophagus, which is much more susceptible to acid damage.
Additionally, some studies have shown that coffee can relax and open the sphincter muscle that connects the esophagus to the stomach, which could hypothetically allow stomach acid to spurt up the esophagus more easily and cause uncomfortable heartburn symptoms.
But even there, the data is mixed. A 2014 analysis of 15 studies in Europe, Asia and the United States found no association between coffee consumption and heartburn symptoms, while a 2020 study using data from more than 48,000 nurses identified a higher risk rate of heartburn symptoms among them coffee drinker.
To understand how coffee might affect the esophagus, scientists are also studying a condition called Barrett’s esophagus, which occurs when the organ is damaged by chronic exposure to stomach acid, such as in people with longstanding acid reflux problems.
In this condition, the cells lining the esophagus turn into tougher, stomachlike cells to protect themselves from the acid. These changes can increase the risk Cancer Esophagus, especially if you have a family history of the condition or if you smoke. But reassuringly, a 2016 study among veterans in the United States found no similar association with coffee consumption. The authors concluded that avoiding coffee is unlikely to be helpful in Barrett’s esophagus.
So what should I do?
As a gastroenterologist, I often ask my patients in the office to be aware of their symptoms. If you experience a constant burning chest pain or a sour taste in your mouth after drinking coffee, you should eliminate it from your diet — or consider an antacid. Adding a little milk or cream or a small piece of food with your morning cup can also help. But if you don’t notice any symptoms, chances are you’re someone who doesn’t have significant postcoffee reflux and is able to continue drinking in peace.
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Cryer regularly enjoys his coffee as a latte or cappuccino — frothed milk cuts off the bitterness, he said. And overall, he added, drinking coffee has many health benefits, including compounds to longevityreduced risk of cardiovascular disease and protection against many types of cancer, including liver, prostate, breast and colon cancer.
“There’s a lot more evidence of coffee’s benefits than harm,” Cryer said — something worth keeping in mind, he added, when flipping through social media stories promoting the drink’s harm protest./ TRANSLATION STÉPHANIE ARAÚJO