Drinking red wine is often touted as beneficial to your health, so it makes sense why people might be confused about alcohol’s relationship to breast cancer. Alcohol, as a substance, is quite a chameleon.
By definition, alcohol is “a colorless volatile flammable liquid that is produced by the natural fermentation of sugars and is the intoxicating constituent of wine, beer, spirits, and other drinks, and is also used as an industrial solvent and as fuel” (1). It also contains chemical properties that enable it to function to some degree as a disinfectant of small surfaces and occasionally external surfaces of equipment (2).
However, despite its seeming versatility, careful investigation is required when it comes to determining whether alcohol consumption is appropriate for an individual, especially in regard to cancer status, with the cancer continuum including all phases of cancer prevention, treatment, and/or survivorship. This is in stark contrast to alcohol often being purported as beneficial for health.
The Link Between Cancer & Drinking
Due to the link between alcohol intake and cancer development, The World Cancer Research Foundation’s American Institute for Cancer Research (AICR) has included a recommendation to “limit alcohol consumption. For cancer prevention, it’s best not to drink alcohol.” AICR elaborates,
“…the evidence is clear and convincing; alcohol in any form is a potent carcinogen. It’s linked to six different cancers. The best advice for those concerned about cancer is not to drink. If you do choose to drink alcohol, however, limit your consumption to one drink for women and two for men per day.” (3)
Breast cancer has been identified as one of the six cancers referenced (with head, neck, esophageal, liver, and colorectal comprising the other five) and, furthermore, evidence is accumulating that alcohol is associated with increased risks of melanoma and of prostate and pancreatic cancers (4).
Alcohol Increases Breast Cancer Risks
Specific to breast cancer, epidemiologic studies have reported a consistent but modest association of alcohol consumption and breast cancer risk (5). Alcohol has been associated with a 7-10% increase in breast cancer risk for each 10 grams alcohol consumed daily by adult women; this is roughly equivalent to one drink, while moderate alcohol consumption has been linked to an approximate 30-50% increase in breast cancer for each 15-30 grams alcohol consumed daily; this is equivalent one to two drinks per day. Strikingly, consuming two or more alcoholic drinks per day for five years has been associated with an 82% increased breast cancer risk compared with no alcohol intake (6).
This seems to lend tremendous perspective to the above noted AICR recommendation, and discussion with one’s healthcare team is therefore essential to determine all considerations regarding the choices involved. The good news is that we can exercise control over alcohol intake, which is the most consistently modifiable risk factor for breast cancer.
How Does Alcohol Cause Cancer?
The mechanism of action for how alcohol causes cancer is related to the body’s ability to metabolize alcohol. Alcohol (ethanol alcohol, the form that is consumed) is converted by an enzyme, alcohol dehydrogenase (ADH) to acetaldehyde and then by an enzyme aldehyde dehydrogenase (ALDH) to acetate. If a small of alcohol is ingested, the body can process it without doing much damage, however, if a large amount of alcohol is ingested, the body cannot process it fast enough so there is a build-up of acetaldehyde which can cause derangements of the cellular level including mistakes in DNA (interference of the replication of healthy DNA as well as by inhibiting a process by which the body repairs damaged DNA), chromosome rearrangements, and damage to stem cells.
In this regard, research suggests that genetics also may determine how vulnerable an individual is to alcohol’s carcinogenic effects. People with mistakes in the genetic code of ALDH cannot break down acetaldehyde and are therefore more prone to certain cancers, particularly certain cancers of the mouth, throat, upper respiratory tract, liver, colon, rectum, and breast. However, acetaldehyde is not the only carcinogenic byproduct of alcohol metabolism. Studies show that when alcohol is metabolized other highly reactive molecules form that can damage DNA or interact with other substances to create carcinogenic compounds (8).
BRCA Genetics & Alcohol Consumption
Utilizing the topic of genetics as a springboard, it is worth mentioning that limited studies conducted in BRCA gene carriers have not shown alcohol consumption to pose an increased breast cancer risk in women carrying the BRCA (BRCA1 or BRCA2) gene mutation (9). In one study, an alcohol consumption was associated with a modest reduction in the risk of breast cancer among women with BRCA1 mutations. This association was restricted to consumers of wine exclusively. It is interesting to speculate if such were due to the phytochemical (plant compound) resveratrol found in grapes (and consequently in wine), however, further studies are needed to determine a more concrete connection based on all variables involved.
Pregnancy & Alcohol
An added layer of concern is the timing of alcohol consumption. Alcohol consumption before first pregnancy has been associated with a significant increase in risk (10), and a prolonged alcohol consumption before first pregnancy confers excess risk of breast cancer (6). These are noteworthy considerations as the current trends support an expected future increase in breast cancer incidence for young women.
Cardiovascular Disease & Cancer
And lastly, as overlap exists between cancer risk and cardiovascular disease risk (11), it is important to know which risk factors overlap and how they apply to one’s own personal health history and family history. These include alcohol intake, age, diet, family history, hormone replacement, overweight and obesity, physical activity, and tobacco use.
As a lack of cardioprotective effect on part of alcohol has been identified (12), we need to recognize which side of the fence alcohol truly sits on. It is now appearing that, regarding “relationship status,” alcohol and breast cancer are dysfunctional and should be terminated.
- Alcohol, Merriam Webster
- Infection Prevention and Control of Epidemic- and Pandemic-Prone Acute Respiratory Infections in Health Care, World Health Organization, 2014
- Cancer Prevention Recommendations, American Institute For Cancer Research (AICR)
- Alcohol and Cancer Risk, National Cancer Institute
- Alcohol Intake and Breast Cancer Risk: Weighing the Overall Evidence, Current Breast Cancer Reports, 2013
- Moderate Alcohol Consumption During Adult Life, Drinking Patterns, and Breast Cancer Risk, Journal of the American Medical Association, 2011
- Alcohol Metabolism and Cancer Risk, Alcohol Research & Health, 2007
- Alcohol Alert, National Institute on Alcohol Abuse and Alcoholism
- Alcohol Consumption and the Risk of Breast Cancer Among BRCA1 and BRCA2 Mutation Carriers, The Breast, 2010
- Alcohol Intake Between Menarche and First Pregnancy: A Prospective Study of Breast Cancer Risk, Journal of the National Cancer Institute, 2013
- Cardiovascular Disease and Breast Cancer: Where These Entities Intersect: A Scientific Statement From the American Heart Association, Circulation, 2018
- Risk Thresholds for Alcohol Consumption: Combined Analysis of Individual-Participant Data for 599 912 Current Drinkers in 83 Prospective Studies, The Lancet, 2018