Ask the Expert: Caffeine
Q: Does drinking coffee or caffeinated beverages increase cancer risk?
A: According to a 1997 report by the World Cancer Research Fund, “Most evidence on coffee suggests that coffee drinking has no relationship with cancer risk.” Nonetheless, interest in this topic persists not only because coffee is such a popular beverage, but also because news reports are always raising possible concerns. For example, in early 2006, a study was released suggesting that coffee is responsible for as much as a third of daily consumption of the cancer-causing chemical acrylamide, which occurs possibly as a result of the roasting of coffee beans.
Earlier studies linked coffee consumption to increased risks of two types of cancer—bladder and pancreatic—and to a decreased risk of colon cancer. Subsequent studies have not supported the link to pancreatic cancer. In addition, part of the association of coffee with bladder cancer may have been due to cigarettes. Smokers not only drink more coffee than average but they also have higher rates of bladder cancer. When smoking is accounted for, there is still a link between coffee and bladder cancer, but it is a much weaker one. However, the data on colon cancer, while mixed, lean toward a possible protective effect from coffee. Clearly, more research is needed.
Regarding another very common malignancy—breast cancer—there is no evidence linking coffee consumption to an increased risk. However, caffeine may increase symptoms of fibrocystic breast disease, a common but benign breast condition. In terms of bone health, excess caffeine consumption causes calcium to be leached from bones and excreted in the urine. Caffeine can also increase the heart rate, a concern in individuals with certain types of cardiac arrhythmias.Therefore, it is probably best to keep caffeine intake to a minimum.
World Cancer Research Fund. Food, nutrition and the prevention of cancer: a global perspective; 1997.
Tavani A, La Vecchia C. Coffee and cancer: a review of epidemiological studies, 1990-1999. Eur J Cancer Prev. 2000;9(4):241-256. Review.
Chow WH, Swanson CA, Lissowska J, et al. Risk of stomach cancer in relation to consumption of cigarettes, alcohol, tea and coffee in Warsaw, Poland. Int J Cancer. 1999;81(6):871-876.