Are you Are you a coffee fan, but you are not sure if it is right for you? You may be aware of its well-known stimulant effects, but you are unsure about the other effects it has on your health. A recent study examines how regular coffee consumption affects the gut-brain axis, a two-way communication network that connects the digestive system with brain activity. The results reveal a very elaborate interaction that goes beyond caffeine.
“Public interest in gut health has increased tremendously,” said John Cryan, co-author of the published study this week in nature communication. “We are increasingly understanding the link between digestive health and mental health, but the mechanisms underlying coffee’s effects on the gut-brain axis remain unclear.”
Scientists from APC Microbiome Ireland, a research center at the University of Cork, compared 31 well adults who regularly drank coffee with 31 non-coffee drinkers. According to the European Food Safety Authority, a “regular” coffee drinker is someone who drinks three to five cups a day, which is a secure and moderate amount for most people.
The researchers also analyzed what happens when consumers suspend their coffee consumption for two weeks and then resume consuming either decaffeinated or decaffeinated coffee. This structure made it possible to distinguish the effects of caffeine from other compounds present in coffee.
“Coffee is more than just caffeine,” Cryan said in: press release“, “is a elaborate dietary factor that affects our gut microorganisms, our metabolism and even our emotional well-being. “Our findings suggest that coffee, whether caffeinated or decaffeinated, may affect health in different but complementary ways.”
The surprising effects of coffee
One of the most critical findings was that coffee consumption modifies the composition of the gut microbiome. Changes in the number of certain bacteria have been detected in people who drink regularly, e.g Eggertella species and Cryptobacterium curtumsuggesting that coffee promotes specific microorganisms. It is believed that the former contribute to the secretion of gastric and intestinal acid, while the latter are involved in the synthesis of bile acids. APC Microbiome Ireland explains that both bacteria contribute to the elimination of harmful gut bacteria, preventing infections.
On a behavioral level, the study found that people who regularly drank coffee showed higher levels of impulsivity and emotional reactivity compared to people who did not drink coffee. However, after stopping coffee drinking for two weeks, these features decreased, and some symptoms associated with regular consumption, such as fatigue and headache, occurred in the first days of abstinence.
The reintroduction of coffee had different effects depending on its type. Both caffeinated and decaffeinated coffee reduced perceived stress and some signs of depression. However, caffeinated coffee was associated with improvements in anxiety levels and some aspects of attention, while decaffeinated coffee showed benefits on memory, sleep quality and physical activity. This means that many of the effects of coffee do not depend solely on caffeine, but on other bioactive compounds such as polyphenols.
Another critical aspect was the response of the immune system. Coffee consumers showed lower levels of inflammatory markers and higher levels of anti-inflammatory molecules. Some inflammatory markers augment during abstinence, suggesting that coffee may have a protective effect in this area.
No significant differences were observed between consumers and non-consumers in terms of physiological stress as measured by the hormone cortisol. This suggests that, at least under normal conditions, coffee does not significantly alter the body’s response to stress, although it may influence the subjective perception of stress, as mentioned above.
A particularly captivating finding of the study was that some of coffee’s effects on the microbiome and metabolism occur independently of caffeine. Even decaffeinated coffee was able to induce rapid changes in microbial composition when reintroduced. This reinforces the idea that coffee is a elaborate mixture of compounds with multiple biological effects.
“Our findings reveal the response of the microbiome and nervous system to coffee, as well as the potential long-term benefits for a healthier microbiome,” concluded Cryan, principal investigator at APC Microbiome Ireland. “Coffee has the potential to modify the activity of microbes as a whole and the metabolites they use. As the population continues to consider dietary changes to ensure proper digestive balance, coffee may also be used as an additional intervention within a healthy, balanced diet.”
This story originally appeared on WIRED in Spanish and was translated from Spanish.