Cheers (?) to the New Year
It is almost one week into 2025, and the scaremongering has already begun. Last week, the U.S. Surgeon General issued a report on Alcohol and Cancer risk. The report highlights the direct link between alcohol consumption and increased risk of cancer, stating that alcohol is identified as the third leading preventable cause of cancer in the United States, following tobacco use and obesity, and explicitly mentions breast cancer as one of the seven types of cancer that alcohol overuse elevates the risk of. While we do not promote alcohol use and/or abuse, before you empty your bar cart and pour out all your bottles of wine (unless you already have because of Dry January), it is helpful to understand the context missing from this report (and the subsequent numerous headlines hitting your feed right now): the amount of alcohol consumed that plays a role in elevating the risk of certain types of cancer.
Numerous studies have shown a clear association between alcohol consumption and an increased risk of breast cancer. The World Health Organization (“WHO”), the American Cancer Society, and other leading health organizations acknowledge that even moderate alcohol intake can raise breast cancer risk. The overall estimated association is an approximate 30-50% increased risk is associated with consuming 15-30 grams of alcohol per day (c.1-2 drinks)[1]. For each additional 10 grams/day, the relative breast cancer risk increases by 7%[2]. A summary of data for lighter drinking supported that even in women who drink ≤12.5 g/day (≤1 drink/day), there was a 5% increase in risk of breast cancer compared to non-drinkers (95% CI 1.02-1.08)[3].
Mechanisms Linking Alcohol and Breast Cancer
The exact mechanisms linking alcohol to breast cancer are complex but involve several biological processes:
Hormonal Changes: Alcohol elevates estrogen levels, promoting hormone-receptor-mediated cell proliferation and genetic alterations. These hormones promote the growth of hormone-receptor-positive breast cancer cells.
DNA Damage: When alcohol is metabolized by an enzyme called alcohol dehydrogenase (“ADH”), it produces acetaldehyde (“AA”), which is the primary ethanol metabolite suggested to have a possible role in breast cancer pathogenesis. While this mainly happens in the liver where approximately 97% of ADH is localized, AHD is also expressed and regulated in breast and other tissues. This toxic compound can damage DNA and hinder the body’s ability to repair genetic mutations.
Oxidative Stress: Alcohol can generate reactive oxygen species (“ROS”), which cause oxidative stress and damage cells, contributing to cancer development.
Nutritional Impact: Chronic alcohol consumption may lead to deficiencies in essential nutrients like folate, which plays a role in DNA repair and synthesis. Low folate levels have been linked to an increased risk of breast cancer.
Genetic Factors: Alcohol may downregulate the BRCA1 tumor suppressor gene, exacerbating genetic damage. Further, polymorphisms in alcohol-metabolizing genes (e.g., ADH1B, ADH1C) can modify breast cancer risk in certain populations, further supporting causality[4].
Risk Markers: Alcohol use is linked to higher mammographic density, a strong intermediate marker for breast cancer risk[5].
Risk and Moderation
Evidence supports a modest causal link between alcohol consumption and breast cancer. While the risk is modest, adhering to drinking guidelines or abstaining may benefit women, particularly those concerned about breast cancer. While complete abstinence from alcohol might not be practical for everyone, understanding what constitutes a low-risk level of consumption is crucial. Further, it is worth highlighting moderate alcohol drinkers were more likely to have higher caloric intake and are generally less likely to exercise, so the increased breast cancer risk may partially or even fully be explained by these other factors.
What Does “Safe” Drinking Look Like?
Experts generally recommend limiting alcohol intake to reduce cancer risk:
For Women: The Dietary Guidelines for America recommend no more than one standard drink per day, on average, or about seven drinks per week.
For Those at High Risk: Women with a family history of breast cancer or other risk factors may want to consider avoiding alcohol altogether.
Practical Steps to Reduce Risk
Track Your Intake: Keeping a record of your alcohol consumption can help you stay within recommended guidelines. There are several mobile apps, such as Reframe and Sunnyside, which are designed to help users cutback on alcohol through educational content, drinks tracking, forums, and shows the amount of money users have saved and the calories avoided. DrinkControl has an in-app calendar that allows users to designate specific days as “dry.”, as well as helps people track their alcohol consumption by the cost per drink and by the ounce over one-, seven- and 30-day periods, helping users to get a fuller picture of their alcohol intake over time and its impact on their wallets.
Seek Alternatives: Try a non-alcoholic beverage or mocktail when socializing.
Focus on Overall Health: Maintaining a healthy weight, staying physically active, and eating a balanced diet rich in fruits, vegetables, and whole grains can further reduce breast cancer risk.
Regular Screening: If you have risk factors for breast cancer, regular screenings and discussions with your healthcare provider are essential.
Raising Your Glass to Awareness
While moderate alcohol consumption has often been touted for its potential cardiovascular benefits and longevity, as someone of drinking age, you should use your own judgement to weigh these benefits against the risks, particularly when it comes to breast cancer. By staying informed and making mindful choices, we can all take proactive steps to protect our health, while enjoying the occasional glass of wine. Not one single behavior, food, drink, or activity in isolation will be the sole determinant of your physical health.
If you’re looking to make changes to your drinking habits or need support, consider speaking with a healthcare provider or exploring community resources designed to help.
[1] McDonald JA, Goyal A, Terry MB. Alcohol Intake and Breast Cancer Risk: Weighing the Overall Evidence. Curr Breast Cancer Rep. 2013 Sep;5(3):10.1007/s12609-013-0114-z. doi: 10.1007/s12609-013-0114-z. PMID: 24265860; PMCID: PMC3832299.
[2] Hamajima N, Hirose K, Tajima K, et al. Alcohol, tobacco and breast cancer--collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease. British journal of cancer. 2002;87(11):1234–45. doi: 10.1038/sj.bjc.6600596.
[3] Seitz HK, Pelucchi C, Bagnardi V, La Vecchia C. Epidemiology and pathophysiology of alcohol and breast cancer: Update 2012. Alcohol and alcoholism. 2012;47(3):204–12. doi: 10.1093/alcalc/ags011
[4] Druesne-Pecollo, Nathalie et al.; Alcohol and genetic polymorphisms: effect on risk of alcohol-related cancer. The Lancet Oncology, Volume 10, Issue 2, 173 - 180
[5] Martin LJ, Boyd NF. Mammographic density. Potential mechanisms of breast cancer risk associated with mammographic density: hypotheses based on epidemiological evidence. Breast cancer research : BCR. 2008;10(1):201. doi: 10.1186/bcr1831.