by Laurie Wertich, updated by Dr.C.H. Weaver M.D. 5/2019
If you’re a slave to your morning cup of coffee research shows that you don’t necessarily need to hang up the habit just yet. In fact, the data shows that coffee may reduce the risk of many cancers and isn't associated with any specific cancer risk. Coffee contains hundreds of different compounds, some of which may have anticancer effects. Nevertheless, the exact mechanisms by which coffee may impact cancer risk are not well understood. So what do the studies show?
Postmenopausal women who drink coffee have a statistically significant reduced risk of developing estrogen receptor (ER)-negative breast cancer.
It turns out that coffee drinkers have a lower incidence of breast cancer overall than those who abstain; however, when researchers really dug into the correlation and corrected for other lifestyle factors—such as weight, level of physical activity, family history, and age at menopause—the protective effect of coffee was only measurable for ER-negative breast cancer. The results of the study showed a modest decrease in overall breast cancer risk and a significant reduction in the risk of ER-negative breast cancer.
This doesn’t mean that postmenopausal women who want to avoid breast cancer need only to slurp coffee to avoid the disease. What it means is that if you tend to avoid indulging in coffee based on the perception that it could harm your health—you may be able to enjoy this simple pleasure without the extra helping of guilt.
It’s still important to maintain a healthy weight, stay physically active, eat a nutrient-dense diet, and avoid smoking; however, if you do all those things and still want to enjoy your morning cup of coffee, it appears that you can do so without worry. The bottom line—balance is always best.(1)
Coffee May Decrease Risk of Skin Cancer
Coffee drinkers are less likely to develop basal cell skin cancers and malignant melanoma, and their risk decreases with every cup they drink.(2) Coffee has long been associated with a reduction in the risk of various cancers however the current study is the first to show a reduction in the risk of melanoma.(2-8)
In a study run by the U.S. National Institutes of Health and AARP a food questionnaire was sent to 3.5 million AARP members living in California, Florida, Louisiana, New Jersey, North Carolina, Pennsylvania, Atlanta and Detroit.
According to findings of the study which were published in the Journal of the National Cancer Institute, people who drank the most coffee every day enjoyed a lower risk of melanoma, compared with those who drank little to no coffee.
People who drank one to three cups a day had about a 10 percent decreased risk of melanoma compared with those who drank none at all, while those who drank four or more cups had a 20 percent decreased risk.
It is important to understand that the study only uncovered an association between coffee consumption and the risk of developing melanoma risk; it doesn’t prove a true cause and effect relationship but is certainly intriguing.
Some previous research has shown that coffee drinking may be protective against other skin cancer, apparently by mitigating the damage to skin cells caused by the sun’s ultraviolet rays.(6)
Caffeine could be the reason for the apparent protection. The researchers found a significant decrease in melanoma risk only among those who drank caffeinated coffee, and previous studies have indicated that caffeine could protect skin cells against ultraviolet-B radiation.
This is not the first study to suggest that coffee consumption may reduce the risk of cancer. Previous studies have suggested that coffee may decrease the risk of basal cell skin cancer, uterine, prostate, liver and other cancers
To evaluate the effects of coffee consumption on risk of prostate cancer, researchers evaluated information from the Health Professionals’ Follow-up Study. Information about coffee consumption was collected from nearly 50,000 men every four years between 1986 and 2006. During this same period, close to 5,000 of the men were diagnosed with prostate cancer.
- Overall, there was a weak association between coffee consumption and risk of prostate cancer. Compared with non-drinkers, men who consumed six or more cups of coffee per day were 19% less likely to develop prostate cancer.
- A larger benefit of coffee consumption was seen when the researchers focused on the most advanced prostate cancers. Men who drank the most coffee were 59% less likely than non-drinkers to develop lethal or advanced prostate cancer.
- Caffeinated and decaffeinated coffee had a similar effect on prostate cancer risk.
If confirmed in other studies, these results suggest that consumption of caffeinated or decaffeinated coffee may reduce the risk of lethal or advanced prostate cancer.(8)
Drinking More Coffee and Tea May Decrease Risk of Kidney Cancer
According to an article recently published in the International Journal of Cancer, increased intake of coffee and tea appears to decrease the risk of developing renal cell carcinoma.
Researchers from several institutions around the world were involved in a clinical study to evaluate associations between coffee, tea, milk, soda, and fruit and vegetable juice intake and risks of developing RCC. This study included results from 13 studies including 530,469 women and 244,483 men. Follow-up was between seven and 20 years. Information about diet was gathered at the beginning of the trial.
- Individuals who drank three or more 8-ounce cups of coffee per day had a reduced risk of developing RCC compared with those who drank less than one 8-ounce cup per day.
- Individuals who drank one or more 8-ounce cups of tea per day had a reduced risk of developing RCC compared with those who did not drink tea.
- There were no associations between milk, soda, or juice intake.
The researchers concluded that “greater consumption of coffee and tea may be associated with a lower risk of renal cell cancer.” These results add to existing evidence suggesting that intake of coffee and tea does not appear to contribute to the risk of developing cancers.(9)
Drinking caffeinated coffee may reduce the risk of cancers of the oral cavity (mouth) and pharynx
Head and neck cancers originate in the tissues in or around the mouth, nose, and throat. Risk factors for head and neck cancer include smoking, alcohol consumption, and infection with high-risk types of human papillomavirus (HPV).
To evaluate the relationship between coffee and tea consumption and risk of head and neck cancer, researchers combined information from previous studies. These studies included a total of 5,139 people with cancer and 9,028 people without cancer.
- Compared with people who didn’t drink coffee, people who drank four or more cups of caffeinated coffee per day were 39% less likely to have cancer of the oral cavity or pharynx. Caffeinated coffee did not affect risk of laryngeal cancer.
- Consumption of decaffeinated coffee was less common, and the effects on head and neck cancer risk remain uncertain.
- Tea intake did not affect risk of head and neck cancer.
These results do not conclusively prove that coffee reduces the risk of head and neck cancer. Factors other than coffee intake could explain the difference in cancer risk. Nevertheless, if confirmed, these results suggest that coffee may provide a benefit.(10)
Coffee Cuts Risk of Liver Cancer
Research has found that regular coffee consumption can reduce the risk of liver cancer by 40 percent. In fact, the study—published in Clinical Gastroenterology and Hepatology—found that people who consume more than three cups of coffee per day reduce their risk by more than 50 percent.(4)
Researchers conducted a meta-analysis of data collected between 1996 and 2012 and then selected 16 studies that involved a total of 3,153 liver cancer cases. They included data on 900 more recent cases of HCC published since their last detailed study from 2007.(5)
They found that individuals who consume any amount of coffee have a 40 percent reduced risk of HCC compared to those who drink no coffee. What’s more, the higher the consumption, the more the risk was reduced. Those who drank more than three cups per day had a 50 percent or more reduced risk. The association between coffee and reduced risk was consistent regardless of gender, alcohol consumption, or history of hepatitis or liver disease.
The researchers concluded that coffee appears to reduce the risk of liver cancer. They speculate that it might affect liver enzymes and the development of cirrhosis and therefore, could protect against liver cancer.
Coffee May Cut Uterine Cancer Risk
Coffee consumption may reduce the incidence of uterine cancer, especially among overweight and obese women, according to the results of a study published in the International Journal of Cancer.(11)
Researchers continue to evaluate the link between dietary intake and cancer. Several studies have shown a reduced risk of uterine cancer associated with coffee consumption.(11-14) Although the reasons for this are unclear, some evidence suggests that coffee consumption may lower insulin resistance, which has been associated with uterine cancer.
Researchers used data from the Swedish Mammography Cohort, which was a population-based cohort study that involved 60,634 women who were followed for an average of 17.6 years. During that time, 677 women were diagnosed with uterine cancer. The women self reported their coffee consumption at baseline (between 1987 and 1990) and then again in 1997.
Each additional cup of coffee per day was associated with a 10% reduction in the risk of developing uterine cancer. Interestingly, the association appeared to be related to body mass index, as it was confined to women who were overweight or obese. Each additional cup of coffee resulted in a 12% risk reduction in overweight women and a 20% risk reduction in obese women.
The researchers concluded that coffee consumption might decrease the risk of uterine cancer, especially among women who are overweight or obese.
Coffee and Soft Drinks Not Associated with Increased Risk of Colon Cancer
Consumption of coffee and sugary soft drinks does not increase the risk of colon cancer, according to the results of a study published early online in the Journal of the National Cancer Institute.(15) High tea consumption, on the other hand, might be associated with a modest increase in risk.
Researchers continue to study the link between diet and cancer, as diet is one easily identifiable and changeable lifestyle factor that may help prevent the development of the disease. Coffee, tea, and soft drinks are among the most commonly consumed beverages in the world. Some studies have suggested that they decrease the risk of cancer, whereas others have indicated that they increase the risk.
Researchers from Harvard analyzed the data from 13 studies conducted in North America and Europe. Combined, the studies included 731,441 subjects, 5,604 of whom developed colon cancer. The researchers found that individuals who drank large amounts of coffee (six or more 8-oz cups a day) were no more likely to develop colon cancer than those who drank less. Similarly, individuals who drank more than 18 oz of sugar-sweetened carbonated beverages did not have an increased risk of colon cancer. The results remained the same after adjusting for age, sex, smoking status, alcohol consumption, BMI, and tumor location.
High consumption of non-herbal tea (more than four 8-oz cups per day) was associated with a modest increase in colon cancer risk, however the researchers cautioned that more study is needed to verify those results.
The researchers concluded that drinking coffee and sugar-sweetened sodas was not associated with colon cancer risk; however, more study will be necessary, especially among younger subjects who most commonly consume sugary sodas.
- Li J, Seibold P, Chang-Claude J, et al. Coffee consumption modifies risk of estrogen-receptor negative breast cancer. Breast Cancer Research, 2011; 13:R49 doi:10.1186/bcr2879
- Coffee contains hundreds of different compounds, some of which may have anticancer effects. Nevertheless, the exact mechanisms by which coffee may increase or decrease cancer risk are not well understood.
- Loftfield E, Freedman N, Graubard B, et al. Coffee Drinking and Cutaneous Melanoma Risk in the NIH-AARP Diet and Health Study. JNCI J Natl Cancer Inst, 2015, 1–9.
- Bravi F, Bosetti C, Tavani A, et al. Coffee reduces risk for hepatocellular carcinoma: An updated meta-analysis. Clinical Gastroenterology and Hepatology. 2013; 11(11): 1413-1421.e1.
- Bravi F, Bosetti C, Tavani A, et al. Coffee drinking and hepatocellular carcinoma risk: a meta-analysis. Hepatology. 2007;46: 430–435.
- Song F, Qureshi AA, Han J. Increased caffeine intake is associated with reduced risk of basal cell carcinoma of the skin. Cancer Research. 2012; 72: 3282-3289.
- Je Y, Hankinson SE, Tworoger SS, DeVivo I, Giovannucci E. A prospective cohort study of coffee consumption and risk of endometrial cancer over a 26-year follow-up. Cancer Epidemiology, Biomarkers, & Prevention. Early online publication November 22, 2011.
- Wilson WM, Kasperzyk JL, Stark JR et al. Coffee consumption and risk of lethal and advanced prostate cancer. Presented at the 2009 AACR Frontiers in Cancer Prevention Research conference. December 6-9, 2009. Houston, TX. Abstract A106.
- Lee J, Hunter D, Spiegelman D, et al. Intakes of coffee, tea, milk, soda and juice and renal cell cancer in a pooled analysis of 13 prospective studies. International Journal of Cancer [early online publication]. June 21, 2007. DOI: 10.1002/ijc.22909.
- Galeone C, Tavani A, Pelucchi C et al. Coffee and Tea Intake and Risk of Head and Neck Cancer: Pooled Analysis in the International Head and Neck Cancer Epidemiology Consortium. Cancer Epidemiology, Biomarkers, and Prevention. 2010;19:1723-36.
- Friberg E, Orsini N, Mantzoros CS, et al. Coffee drinking and risk of endometrial cancer – A population-based cohort study. International Journal of Cancer. 2009; 125:2413-2417.
- Bravi F, Scotti L, Bosetti C, et al. Coffee drinking and endometrial cancer risk: a meta-analysis of observational studies. American Journal of Obstetrics and Gynecology. 2009; 200:130-134.
- Shimazu T, Inoue M, Sasaxuki S, et al. Coffee consumption and risk of endometrial cancer: A prospective study in Japan. International Journal of Cancer. 2009; 123:2406-2410.
- McCann Se, Heh M, Rodabough K, et al. Higher regular coffee and tea consumption is associated with reduced endometrial cancer risk. International Journal of Cancer. 2009; 134: 1650-1653.
- Zhang X, Albanes D, Beeson LW, et al. Risk of colon cancer and coffee, tea, and sugar-sweetened soft drink intake: Pooled analysis of prospective cohort studies. Journal of the National Cancer Institute. Published early online May 7, 2010.