In repudiation of reports that tacitly posit grave consequences from drinking coffee regularly , comes new research helmed by Dr. Li Jiao, who is also an associate professor of medicine–gastroenterology at the Baylor College of Medicine in Houston, TX, and a researcher at the Center for Innovations in Quality, Effectiveness, and Safety at the Michael E. DeBakey VA Medical Center. More specifically, the new study highlights coffee’s effects on the gut microbiota living in our stomach, another relatively new area of interest for dietary science. 

To examine this more concretely, the researchers recruited a group composed of 34 individuals. Before the study began, these individuals underwent a colonoscopy and endoscopy screening,  had photos taken of segments of their colons, and had microbial DNA extracted, before  the experts performed a 16s rRNA sequencing analysis. Following these precursor tests, the participants were tasked with a questionnaire so that the researchers could get a gauge on how much coffee each individual partook a day. The group was then assigned to two groups based on their responses: the high intake group (at least 82.9 milligrams) and the low intake group: (less than 82.9 mg grams a day). The results instanced a higher amount of Faecalibacterium and Roseburia, and a lower amount of Erysipelatoclostridium in the high-intake coffee group.

Faecalibacterium and Roseburia, have been independently noted for their strong anti-inflammatory properties. Faecalibacterium is widely considered to be one of the most important commensal bacteria found in the human gut community and Roseburia has been rewarded a handsome association with weight loss and improved glucose tolerance on several occasions. 

Excessive levels of Erysipelatoclostridium, on the other hand, is believed to surge diet-induced obesity via up-regulating of small intestinal glucose and fat transporters, in addition to being adversely linked to metabolic syndrome.

Although a slew of other healthy bacteria was present in the gut’s of the high coffee intake group, and even though these positive results remained consistent irrespective of age or diet outside of coffee intake, the study did have a few notable limitations. For one, the study was not specific to the brand of coffee or preparation methods but instead relied on self-reporting metrics.  All of the participants in the study group were also men with otherwise healthy colons.

Dr. Juan continues, “Higher caffeine consumption was associated with increased richness and evenness of the mucosa-associated gut microbiota, and higher relative abundance of anti-inflammatory bacteria, such as Faecalibacterium and Roseburia and lower levels of potentially harmful Erysipelatoclostridium.We cannot tease out whether polyphenol or other compounds in coffee may also partially explain the association. We need [to] learn more about the interaction between the host and gut microbiome in diverse populations. More research is needed to understand what these bacteria (such as Alistipes) do in our body.