Alcohol consumption is one of the most well-documented risk factors for breast cancer. Consuming even as few as three to six drinks per week increases the risk of breast cancer by 15% compared to not drinking. What counts is the ethanol content, not the type of alcohol. The resveratrol content of red wine does not effectively counteract the harmful effects of its alcohol content.

Women who are fast metabolizers of alcohol (and therefore "can't hold their liquor") have a higher risk of breast cancer from alcohol consumption than slow metabolizers. Consuming several drinks over a short period of time appears to be more harmful than the same amount of alcohol consumed over a period of days. Alcohol is also associated with increased breast cancer recurrence and death, especially for postmenopausal and overweight or obese women.

Unlike some other risk factors that take decades to produce invasive breast cancer, alcohol consumption has been shown to increase the risk of breast cancer at a relatively young age. Girls who regularly drink during adolescence are more likely to develop benign breast disease and the risk increases in proportion with the amount of alcohol consumed. Teenage girls with a family history of breast cancer who consumed seven alcoholic drinks per week doubled their risk of benign breast disease in young adulthood in one study. Such breast disease is a known risk factor for breast cancer. The problem stems from the fact that teenage drinking takes place during a time in which breast tissue is going through stages of rapid proliferation. Now a new study has reported that substantial exposure to alcohol resulted in abnormal mammary gland structure and proliferation in an animal model of breast development.

Alcohol and breast cancer

The mechanism of action by which alcohol promotes breast cancer in adults is not fully understood. Alcohol consumption increases inflammation, as well as circulating estrogen and leptin (a fat hormone) levels, all of which are associated with increased breast cancer risk. Estrogen receptor signaling is involved in ethanol-induced stimulation of breast cancer cell proliferation. The metabolism of ethanol to acetaldehyde within cells results in DNA damage. In fact, heavy alcohol consumption has been linked to accelerated telomere shortening, which has also been associated with cancer risk.

Latest research finds alcohol proliferation and atypical development

The study referenced at the beginning of this news article was designed to investigate the effects of adolescent alcohol consumption on breast development. To conduct the study, the authors used an animal model that closely resembles breast development in humans. Pubertal female pigs were given alcohol (approximately 20% of total calories) for four to five weeks. This produced average blood alcohol concentrations of 115-130 mg/dL and increased liver mass, as would be expected. The alcohol diet also was found to promote the formation of distended ductules within lobular units. This was associated with increased epithelial proliferation. Alcohol consumption did not lead to precocious lactogenesis. The authors conclude that feeding alcohol to animals with similar physiology and mammary gland structure to humans during the equivalent of human adolescence promotes increased mammary gland proliferation and development of atypical lobular structures. The authors comment that these changes might mirror how alcohol intake increases the risk of developing breast cancer in humans.

Please see our article on protecting our daughters for more information on how to reduce breast cancer risk for our daughters.