As society’s coffee addiction showed no sign of letting up, long-held concerns about its effects on gastrointestinal (GI) disorders also continued; however, evidence showed inconsistent evidence of harms and some indicators of possible protective benefits — with some key caveats.

Among leading GI conditions considered to be potentially caused and/or exacerbated by coffee consumption is gastroesophageal reflux disease (GERD). A 2020 analysis of Nurses’ Health Study II data found a higher risk for gastroesophageal reflux symptoms among coffee drinkers, with the highest risk (hazard ratio [HR], 1.34) among those who drank the largest amount (six or more 8-ounce servings a day) vs those who drank no coffee.

A new meta-analysis, published in Clinical and Translational Gastroenterology, also suggested some adverse effects — but only to a small degree.

The analysis of 39 studies and 121,625 patients, including 85,400 coffee drinkers and 36,674 nondrinkers, showed that coffee drinkers had a slightly increased risk for GERD (34.9% vs 30.7%; odds ratio [OR], 1.18), with the findings consistent across all preplanned sensitivity analyses, including those with adolescent patients and using an expanded definition of GERD.

It found no significant link between coffee intake and Barrett esophagus, a complication of chronic GERD seen as a potential precursor to esophageal cancer.

The minor difference in the GERD rate “is of unclear clinical significance,” the authors wrote. “The role of routine avoidance/reduction of coffee intake as universal lifestyle modification for GERD needs further evaluation.”

Prior epidemiologic studies in Norway and Japan found no significant link between coffee consumption and GERD, even among subgroups of patients drinking multiple cups per day, but the new meta-analysis “encompassed a much larger number of studies and sample size,” the authors noted. It also used “a more comprehensive search strategy to capture studies internationally, thus allowing more rigorous analyses,” they wrote.

Because there are so many variables to consider in coffee consumption studies, the finding of only a marginally higher risk for GERD is not surprising, said senior author Walter W. Chan, MD, MPH, director of the Center for Gastrointestinal Motility at Brigham and Women’s Hospital, Boston.

“Coffee likely increases reflux only in a specific subset of at-risk population, when specific types/amount/characteristics of coffee is ingested, with little to no impact on the rest of the population at large,” Chan told Medscape Medical News. “That may explain why the overall risk may appear marginal, when examining studies with very heterogeneous designs, patients included, and coffee used.” 

Instead of restricting coffee as a first-line strategy for all patients with GERD, Chan said, restriction may be most beneficial among patients who clearly indicate that coffee is a symptom trigger and who report improvement with coffee reduction or cessation, which is consistent with recommendations in the American Gastroenterological Association guidelines.

“While it is possible that coffee, or specific formulations/quantity, may be more relevant for subsets of patients with GERD, it is likely not a significant, universal factor for all patients,” he said. “Therefore, a blanket recommendation to cease coffee intake for all patients with reflux is likely not necessary or indicated.”

The study’s finding showing no increased risk for GERD complications, particularly Barrett esophagus, “further calls into question to the significance of the small association between coffee and GERD observed,” Chan added.

Sweetener a Culprit?

A 2025 study suggested that coffee may protect against development of some GI disorders — with the slightly bitter caveat of the benefits being strongest when coffee is unsweetened.

The researchers analyzed data of 147,263 participants from the UK Biobank who had no preexisting GI disorders at baseline. Over a median follow-up of 12.6 years, coffee consumption was found to have a U-shaped effect in which consumption of two to four cups of coffee per day was associated with the lowest risk for the development of GI disorders compared with drinking fewer than two or more than four cups per day (HR, 0.84; P < .001).

Notably, the effect was seen primarily with unsweetened coffee. The association was limited with consumption of naturally sweetened coffee and was inconsistent with artificially sweetened coffee compared with no coffee consumption.

The protective effects were observed for GERD, as well as gastritis/duodenitis, metabolic dysfunction-associated steatotic liver disease, and biliary diseases.

The findings remained robust across subgroup and sensitivity analyses, “emphasizing the potential role of coffee consumption, particularly unsweetened coffee, in reducing the burden of GI diseases,” the authors wrote.

Some of the strongest benefits were observed among those with a genetic risk for GI diseases and for diverticulosis and cirrhosis. However, no benefits were observed between unsweetened or other coffee types and the risk of developing irritable bowel syndrome or inflammatory bowel disease.

In addition, the role of cream in coffee was not assessed.

Nevertheless, “a key contribution of our work is the differentiation between unsweetened and sweetened coffee, which has often been overlooked in earlier studies that typically considered all coffee consumption as a single category,” the authors wrote.

The study also did not show any significant association between coffee consumption and the risk for GI cancers, which is consistent with the International Agency for Research on Cancer’s conclusion that coffee is “not classifiable as to its carcinogenicity to humans,” the authors added.

Commenting on that study, Chan noted that its limitations include the potential for various confounding effects.

“The fact that a similar pattern of moderate effect was found for coffee for a variety of GI conditions (from GERD to diverticulosis) that do not necessarily share similar pathophysiologic processes further raise concerns that other unaccounted common factors may be responsible for the relationships observed,” he added.

 Coffee and GI Cancer Risk — Does Diet Matter?

A new study, published in Cancer Medicine, probing the relationship with coffee and GI cancers suggested an individual’s diet plays an important role.

Because coffee comes into direct contact with the digestive tract and is absorbed through it, “the expected functioning of coffee is influenced by the environment in the gastrointestinal tract (physicochemical properties and intestinal flora), as well as by the interaction with other foods and nutrients, such as milk, fats, etc,” the authors wrote. “Given the critical role of the physicochemical environment and the food matrix in modulating the bioavailability of coffee’s active compounds, a pertinent question arises: Do different dietary backgrounds limit the well known antineoplastic effects of coffee?”

To investigate, they evaluated data of 29,422 adults enrolled in the US National Health and Nutrition Examination Survey from 2001 to 2018.

After a multivariate adjustment, the results showed that low and high levels of coffee consumption were positively associated with the overall prevalence of GI cancer (P < .001).

Among those with lower coffee consumption (up to 503.2 g or about 2.5 cups per day), the prevalence of GI cancer was 1.26 times higher than noncoffee drinkers, and the prevalence among those consuming 503.2 g or more per day was 1.2 times higher. These findings indicate that when diet isn’t considered, coffee represents a risk factor for GI cancer, the authors wrote.

In looking at dietary profiles, individuals following Western diets (dominated by solid fats, refined grains, cheese, added sugar, processed meats, and orange vegetables) or “balanced” diets (dominated by vegetable oils, starchy vegetables, other vegetables, eggs, and seafood) who regularly consumed coffee showed a reduced risk for GI cancers (OR, 0.753 and 0.963, respectively) compared with noncoffee drinkers.

However, those with a diet described as a “vegetarian pattern” (dominated by fruits, orange vegetables, dark green vegetables, other vegetables, whole grains, and yogurt) who regularly consumed coffee had a higher risk for GI cancers (OR, 1.707).

Of note, a subanalysis looking only at vegetable intake levels found that coffee consumption lowered the risk for GI cancer among people with high vegetable intake (OR, 0.581).

The difference between that finding and the higher GI cancer risk found among coffee drinkers following a vegetarian pattern is due to fruit being the most dominant component of the vegetarian diet, the authors wrote.

“Research has shown that polyphenols can form polyphenol-pectin complexes with pectin in fruits and juices, which have no ability to scavenge superoxide and have reduced hydroxyl radical scavenging activity,” they wrote. “This implies that the function of the active substances in coffee may be influenced by the food matrix of the plant-based diet.”

Collectively, the evidence suggests that clinicians should consider a range of individual factors in patients with GI before advising for or against coffee intake, Chan said.

“Rather than a one-size-fit-all approach to ask patients to completely cease coffee intake, clinicians should employ a more sensible, personalized approach and target patients whose symptoms may be more likely related to coffee use,” he said.

Chan had no disclosures to report.