© Karolina Grabowska
November 10, 2026
Marianne Waldenfels
Large observational studies link regular coffee consumption to a lower risk of certain cancers. The association is particularly strong for cancers of the mouth and throat, as well as liver cancer. But the findings vary by cancer type – and caffeine may not be the only factor involved.
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Coffee is part of daily life for millions of people. But can a beverage prized mainly for its stimulating effects also influence whether certain tumors develop?
An international research team explored this question using data from more than 25,000 people. Their findings show that the type of cancer matters — and that the effects of coffee apparently cannot be reduced to its most famous ingredient.
For an analysis published in the journal Cancer, an analysis by an international research team drew on data from 14 studies. In total, 9,548 people with head and neck cancer and 15,783 cancer-free control individuals were included.
The findings: people who drank more than four cups of caffeinated coffee per day had statistically 17 percent lower odds of head and neck cancer compared with people who did not drink coffee.
The differences were even more pronounced for specific tumor types. For oral cavity cancer, the odds were approximately 30 percent lower; for tumors of the middle pharynx, around 22 percent lower. For cancer of the lower pharynx, three to four cups per day was associated with a difference of approximately 41 percent.
Not all head and neck tumors showed equally favorable results, however. For laryngeal cancer, the study found no comparably clear association.
One particularly telling observation by the researchers: decaffeinated coffee was also associated with lower odds of oral cavity cancer in the analysis. The difference compared with people who did not drink decaffeinated coffee was approximately 25 percent.
This shifts the focus to other ingredients. Coffee contains hundreds of bioactive compounds, including chlorogenic acids and other polyphenols. In experimental studies, some of these substances have demonstrated antioxidant and anti-inflammatory properties.
Whether these ingredients actually influence the development of cancer in humans has not been proven, however. The findings with decaffeinated coffee simply suggest that caffeine is not the only possible explanation for the observed associations.
The signs of a possible health benefit from coffee are not limited to head and neck tumors. Liver cancer and endometrial cancer are among the most thoroughly studied.
Liver Cancer
For hepatocellular carcinoma, the most common form of primary liver cancer, the evidence is comparatively consistent.
A BMJ Open meta-analysis that included 18 cohort studies with more than 2.2 million participants and eight case-control studies found that two additional cups of coffee per day were associated with a 35 percent lower relative risk of liver cancer.
Decaffeinated coffee also showed a favorable association in some studies, though based on a considerably smaller body of data.
Endometrial Cancer
A pooled analysis of 19 studies involving more than 12,000 cases found that women who drank coffee had lower odds of endometrial cancer than women who did not.
Possible explanations under discussion include changes in insulin and hormone metabolism. However, no causal relationship has been established.
Colorectal and Breast Cancer
The picture is less clear for other cancer types. A meta-analysis of 26 prospective studies found no overall statistically significant association between coffee consumption and colorectal cancer, although some subgroups showed more favorable results.
The evidence for breast cancer is similarly inconsistent. No general protective effect from coffee can be derived from these findings.
Most studies on coffee consumption are based on observational data. They show how often certain diseases occur among people with different drinking habits. Whether coffee itself is responsible for these differences cannot be determined with certainty from such data.
In addition, information about past coffee consumption is often collected through questionnaires. Other lifestyle factors also cannot be fully accounted for statistically.
For head and neck cancer in particular, this limitation is significant. Smoking and alcohol are among the most important modifiable risk factors. For certain tumors, infection with human papillomaviruses (HPV) also plays a substantial role.
Coffee cannot offset these risks. Avoiding tobacco, keeping alcohol consumption as low as possible, and following recommended preventive measures are far better-supported ways to reduce cancer risk.
According to the European Food Safety Authority (EFSA), up to 400 milligrams of caffeine spread throughout the day is considered safe for healthy adults. Depending on size and strength, this corresponds to roughly three to five cups of coffee. For pregnant and breastfeeding women, the reference value is 200 milligrams per day.
Not everyone responds to caffeine in the same way, however. For some people, even smaller amounts are enough to cause sleep problems, nervousness, or heart palpitations.
The key takeaway from the research is not that we should drink more coffee. Rather, it is that an everyday beverage appears to have more complex effects on the body than was long assumed. The association between coffee and a lower cancer risk is now well documented. Why this is the case remains one of the more fascinating open questions in the field.
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