Drinking coffee is beneficial for gut health, regardless of whether it contains caffeine or is decaffeinated, according to a new study from researchers in Ireland. Even consuming just three cups per day can enhance mood and reduce stress levels, the researchers said, adding to a growing body of evidence supporting the health benefits of the popular morning beverage.
Positive Effects on Gut Bacteria
The study found that regular coffee drinkers had increased levels of healthy gut bacteria, including Firmicutes, which have been associated with positive emotions in women. The gut microbiome, composed of bacteria in the intestine, plays a crucial role in regulating the immune system, brain function, and heart health.
These findings could help coffee drinkers better understand the impact of coffee on their health beyond the stimulating effects of caffeine and may even encourage more people to drink coffee, although it is noted that coffee contains acid that can erode the stomach lining.
“Coffee is more than just caffeine — it’s a complex dietary factor that interacts with our gut microbes, our metabolism, and even our emotional well-being,” said Professor Cryan of University College Cork, the lead researcher, in a statement. “Our findings suggest that coffee, whether caffeinated or decaffeinated, can influence health in distinct but complementary ways.”
Study Methodology
Cryan and his colleagues studied the health of 31 coffee drinkers and 31 non-coffee drinkers over two years. Participants were asked to abstain from coffee for two weeks for physical assessments. The researchers examined stool and urine samples and found significant changes in the compounds produced by gut bacteria in coffee drinkers when they stopped drinking coffee. These compounds aid metabolism and digestion.
After the two-week abstinence, coffee was reintroduced to regular drinkers, but they did not know what type of caffeine they were receiving. Half were given decaf, and the other half received half-caf. Both groups reported lower stress, depression, and impulsivity, regardless of the type of coffee consumed.
Specific Bacterial Changes
Further tests revealed increased levels of the bacteria Eggerthella and Cryptobacterium curtum in coffee drinkers. Both types may help eliminate stomach infections and unhealthy gut bacteria that disrupt the gut’s balance.
However, not all benefits were universal. For instance, only decaf drinkers showed notable improvements in learning and memory, suggesting that other components in the drink, not found in caffeinated coffee, were responsible.
Broader Health Implications
“As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy balanced diet,” Cryan said.
This study follows recent research showing that drinking coffee can reduce the risk of dementia, slow biological aging, and lower the risk of death. Other studies have indicated that regular consumption of caffeinated beverages may reduce the likelihood of developing cardiovascular disease and certain cancers, including liver, endometrial, skin, and neck cancer.
Experts recommend that Americans limit their caffeine intake to a daily maximum of 400 milligrams. According to the National Coffee Association, two-thirds of American adults already drink coffee each day.
