Coffee and Cancer Prevention: Colorectal, Endometrial, Liver, and Melanoma

Table of Contents

  1. Overview
  2. Colorectal Cancer
  3. Liver Cancer
  4. Endometrial Cancer
  5. Melanoma and Skin Cancer
  6. Other Cancers with Inverse Associations
  7. Proposed Anti-Cancer Mechanisms
  8. Caveats and What Coffee Does Not Protect Against
  9. Sources
  10. Featured Videos

Overview

The World Cancer Research Fund and the International Agency for Research on Cancer (IARC) both reclassified coffee in 2016: IARC specifically removed coffee from its Group 2B "possibly carcinogenic" designation after extensive review, citing the accumulated evidence that regular coffee consumption is more often associated with reduced rather than increased cancer risk. For several cancers—most notably liver, colorectal, and endometrial—the inverse associations are strong enough that coffee is now considered one of the best-studied protective dietary exposures.

Coffee is a complex mixture of more than a thousand compounds, several of which have demonstrated anti-cancer activity in preclinical studies. Caffeine, chlorogenic acids, cafestol, kahweol, trigonelline, and melanoidins each contribute distinct effects, and together they may explain why the protective associations are observed across such a diverse range of tumor types.

Colorectal Cancer

Colorectal cancer is the second leading cause of cancer death globally. The evidence linking coffee to reduced colorectal cancer risk is among the strongest for any dietary factor. Sartini and colleagues' 2019 systematic review and meta-analysis in Nutrients pooled 21 prospective cohort studies and found a 15 to 20 percent lower risk of colorectal cancer among highest-versus-lowest coffee consumers. Micek and colleagues' 2019 dose-response meta-analysis reached similar conclusions, with the protective effect becoming apparent at two cups per day and plateauing around four.

Large individual cohorts have reinforced this finding. The Multiethnic Cohort Study found consistent inverse associations across five ethnic groups, and a pooled analysis from the European Prospective Investigation into Cancer and Nutrition (EPIC) reported similar reductions. Coffee also appears to protect against colorectal adenomas, the precancerous lesions from which most colorectal cancers arise, suggesting the effect operates early in carcinogenesis.

Liver Cancer

The coffee-liver cancer association is covered in detail on the Liver Disease page, but the headline finding bears repeating: Kennedy and colleagues' 2017 meta-analysis in BMJ Open found a 35 percent reduction in hepatocellular carcinoma risk per two cups per day, with the effect holding across caffeinated and decaffeinated coffee and across cirrhotic and non-cirrhotic populations. This is the single strongest coffee-cancer association in the epidemiological literature.

Endometrial Cancer

Endometrial cancer is the most common gynecologic cancer in developed countries, with type 2 diabetes and obesity as major risk factors. The 2012 meta-analysis by Je and colleagues in the International Journal of Cancer pooled 16 studies and found that the highest coffee consumers had roughly a 30 percent lower risk of endometrial cancer compared with non-drinkers. A prospective cohort analysis by Je and colleagues from the Nurses' Health Study found that women drinking four or more cups per day had a 25 percent reduction in endometrial cancer risk over 26 years of follow-up.

The protective effect is thought to operate via improved insulin sensitivity and reduced circulating estrogen levels, both of which mitigate the hormonal drivers of endometrial carcinogenesis.

Melanoma and Skin Cancer

A 2015 analysis of the NIH-AARP Diet and Health Study by Loftfield and colleagues found that adults drinking four or more cups of caffeinated coffee per day had about a 20 percent lower risk of malignant melanoma. A 2016 meta-analysis by Wang and colleagues pooled 12 studies and reported a 13 percent reduction in melanoma risk among higher coffee consumers. The effect appears specific to caffeinated coffee and may operate through caffeine's action on adenosine receptors and its ability to enhance UV-induced apoptosis of damaged keratinocytes.

For non-melanoma skin cancer, several prospective studies have also found inverse associations with basal cell carcinoma, though the evidence is more mixed for squamous cell carcinoma.

Other Cancers with Inverse Associations

Beyond the best-established associations above, coffee has shown inverse relationships—of varying strength—with several additional cancers:

Proposed Anti-Cancer Mechanisms

Caveats and What Coffee Does Not Protect Against

Coffee is not universally protective. Very hot beverages (above 65°C / 149°F) have been classified by IARC as probably carcinogenic to the esophagus, so the temperature of consumption matters. For most cancers, coffee is best described as neutral or modestly protective. The evidence does not support large protective effects against lung, pancreatic, stomach, or bladder cancers, and early reports of associations with pancreatic and bladder cancer have not held up in later meta-analyses that adjusted properly for smoking.

Coffee is not a substitute for proven cancer screening (colonoscopy, mammography, cervical cancer screening) or known risk-reduction strategies (tobacco cessation, alcohol moderation, physical activity). It is a reasonable dietary component to consider alongside these, not in place of them.

Sources

Video Thumbnail

Is Coffee Consumption Good for Advanced Colon Cancer? — Dana-Farber Cancer Institute

Video Thumbnail

Drinking Coffee Every Day Could Reduce Risk of Liver Cancer — FOX 4

Video Thumbnail

Coffee May Prevent Colon Cancer — F. Perry Wilson, MD

Back to Table of Contents