Estrogen-induced cycles occurring during the menstrual cycle increase the risk of developing breast cancer by prompting cells to divide and multiply. Increased levels of estrogen are related to breast cancer, though the American Cancer Association says a direct link has yet to be established. Caffeine can increase estrogen levels, leading to theories that it can indirectly contribute to the development of breast cancer. More research is needed to determine the true relationship between caffeine, estrogen and breast cancer.
Estrogen
Higher levels of estrogen are associated with higher risks of contracting endometriosis, ovarian and breast cancer. Estrogen does not cause breast cancer, but prompts the duplication of cells; if cells already have a mutation, that increases the risk of developing breast cancer. According to the American Cancer Society, 5 to 10 percent of women with breast cancer have a hereditary predisposition to cell mutation. A woman's predisposition to cell mutation, however, does not necessarily mean she will develop the disease.
Caffeine
An October 2008 study from the Harvard School of Health revealed that the consumption of caffeine in commonly consumed substances such as coffee, tea and chocolate was not associated with overall risk of breast cancer. The study, however, showed caffeine caused a 68 percent increased risk of cell mutation during the estrogen-receptor and progesterone receptor process that takes place during a woman's menstrual cycle. Caffeine also increased the risk of breast tumors larger than 2 cm by 79 percent.
Coffee
Caffeinated coffee has been associated with health risks including ovarian and breast cancer. A study reported by the Health Sciences Institute showed women who drank 1 cup of coffee daily had higher hormone and estrogen levels. Women who drank 4 to 5 cups of coffee had 70 percent higher levels of estrogen than women whose caffeine consumption was under 100 mg per day. Further research needs to be conducted to determine the relationship between caffeine and substances containing caffeine to determine the effect -- if any -- on breast cancer.
Decaffeinated Coffee
Drinking decaffeinated coffee might be a good alternative to preventing breast cancer, but might cause other health concerns. According to the Health Sciences Institute, women who drink 4 or more cups of decaffeinated coffee daily are more than two times as likely to develop rheumatoid arthritis. It is unclear why the decaffeinated coffee causes these concerns, though scientists are examining the decaffeination process as a contributing factor. This might be an additional concern when drinking tea that contains caffeine as opposed to drinking herbal teas that do not contain caffeine.
References
- National Cancer Institute: Understanding Cancer Series: Estrogen Receptors/SERMs
- Harvard School of Public Health; Coffee, tea, caffeine and risk of breast cancer: a 22-year follow-up; May 2008
- American Cancer Society: What are the risk factors for breast cancer?
- The Health Sciences Institute; Is that Morning Cuppa Joe Really Worth it?; November 2001
