- A new study funded by the coffee industry concludes that coffee may help protect against digestive tract issues such as gallstones, but some experts say the evidence is inconclusive.
- The new report also suggests coffee can help relieve constipation. Some experts say coffee can cause muscle movement that can help with this condition, but other experts aren’t convinced.
- Experts do say that coffee has a number of health benefits as long as you don’t drink too much on a daily basis.
A new report suggests coffee may be protective against gallstones and pancreatitis, but experts are divided on whether the research backing the claims is solid.
The study, a review of research studies into coffee and digestion, comes from the Institute for Scientific Information on Coffee, whose members are six major European coffee companies.
The paper’s author, Carlo La Vecchia, a professor in the department of clinical sciences and community health at the University of Milan in Italy, argues there is evidence to suggest coffee could be protective against a variety of gastrointestinal issues and diseases.
“The effect of coffee on digestion is an evolving area of research. Data indicates benefits against common digestive complaints such as constipation, as well as a potential reduction in the risk of more serious conditions like chronic liver diseases, from non-alcoholic fatty liver disease (NAFLD), gallstones, and related pancreatitis,” he said in a press release.
The report references a few studies that suggest daily consumption of coffee with caffeine may reduce risk of gallstones and gallstone disease. In the United States, 10 to 15 percent of the population is affected by gallstones.
“To my knowledge, there are no high quality, interventional, controlled studies that can support this claim. Most of these studies show associations which do not allow any conclusion about causality between coffee and these diseases,” Mayer told Healthline.
The report also concludes that coffee drinking may be linked to a reduced risk of chronic constipation.
Lauri Wright, PhD, an assistant professor in public health at the University of South Florida, says that coffee can indeed cause muscle contractions in the digestive tract, which in turn could promote bowel movements.
“Coffee stimulates movement of the muscles in the colon, which promotes peristalsis, thus causing bowel movements. Coffee has been shown to stimulate motility in the digestive tract which can improve digestion and excretion,” Wright told Healthline.
However, Mayer emphasizes that although the caffeine in coffee may stimulate intestinal contractions, it shouldn’t be considered a solution to constipation.
“Coffee is definitely not considered a treatment for constipation nor any of the other diseases,” he said.
More than 60 percent of people in the United States drink coffee daily with the average coffee drinker consuming about three cups every day.
According to the report, this might not be a bad thing.
It notes “a moderate caffeine consumption, of around 400 [milligrams (mg) of] caffeine per day (the equivalent of up to 5 cups of coffee), can be enjoyed as part of a healthy balanced diet and an active lifestyle.”
Dana Hunnes, PhD, a senior dietitian at the University of California Los Angeles Medical Center, says up to 400 mg of caffeine per day is safe.
“Much more caffeine than that could be potentially hazardous to health from the stimulation from the caffeine, but yes, up to 400 mg per day seems to be generally fine. Good thing too as I love coffee,” Hunnes told Healthline. “Any more than that though and you potentially run into negative effects on sleep, attitude, overstimulation, and jitteriness.”
Mayer notes coffee does contain some health-promoting ingredients.
“In my opinion, the main health-promoting ingredients in coffee are the polyphenols chlorogenic acid and caffeic acid,” he said. “The polyphenol content of coffee is about 2.5 times the amount in tea. Polyphenols have a wide range of health-promoting effects, many of which appear to be dependent on the metabolism of these large molecules by gut microbes in the colon. I have not seen a controlled study however that tested this hypothesis in humans.”
“If you drink coffee for health reasons, and to increase your intake of chlorogenic acid, it’s best to drink four cups a day. I personally believe it can be part of a healthy diet, but it is not essential,” he explained. “Green tea may give you the same benefit, providing you with caffeic acid in addition to the polyphenol catechin.”
Studies cited in the report suggest coffee consumption may support good bacteria in the gut.
Wright says this area of study is complex and requires much more research.
“Two research studies have found an increase in one type of helpful bacteria in the gut from consuming coffee. However, research on the microbiome is very complicated and much more research is needed before any benefit can be proven,” she said.
Although the benefits of coffee on the digestive system are inconclusive, there are known benefits in other parts of the body.
“There is clearly a significant amount of evidence that consumption of a moderate amount of coffee has a positive effect on cardiovascular health, with a reduction of the incidence of heart attacks, heart failure, and stroke,” Mayer said.
Mayer is a daily coffee drinker. He argues from a general health standpoint, drinking coffee daily is safe.
“There are currently few if any serious side effects of regular coffee consumption, and if anything, there appear to be a few benefits,” he said. “In my personal view, you should probably switch to decaf coffee if you are anxious and if you have sleep problems.”