Studies have shown that drinking alcohol elevates your risk of developing breast cancer, although other factors, such as smoking or diet, may have contributed to results.

How much alcohol is okay? Cutting out alcohol consumption entirely may be the best answer, but women who drink one alcoholic drink a day have less of a risk than women who drink two or more per day. The rate of breast cancer seems to be about 40% higher than the rate for non-drinkers according to Cornell University's Sprecher Institute for Comparative Cancer Research. This rate is comparable to other well-established risk factors such as early menarche (25% higher rate), or family history (50% or higher). Researchers suspect the amount of alcohol consumed during your life contributes to your risk, but are not sure whether the steady intake of alcohol (drinking a small amount every day) or a history of binge drinking (a large amount in a short period of time) creates a higher risk.

Estrogen has been linked to the development of breast cancer, and scientists believe there is a link between alcohol and an increased amount of estrogen in the body. According to a Specher Institute fact sheet, it is unclear whether alcohol causes an increase in the production of estrogen or contributes to the decrease in the breakdown of estrogen in the body. An additional consideration is the fact that the liver, which is affected by alcohol, may not function properly. The liver acts as a large filter for the body, and if it is not working properly, it may not filter out carcinogens (cancer-causing agents), which could also account for the higher level of estrogen.

References and Other Resources:

Napieralski, PhD., Julie A. and Devine, PhD, RD, Carol: "Fact Sheet #13: Alcohol and the Risk of Breast Cancer", Program on Breast Cancer and Environmental Risk Factors, Cornell University, March 1988.