Alcohol and Breast Cancer: Are you aware of your risk?

You may not have heard that alcohol is a well-established and leading risk factor for female breast cancer. Since the 1980’s well over 100 epidemiological studies that include hundreds of thousands of women internationally have examined the effects of alcohol on the incidence of breast cancer, consistently producing similar results. There is strong evidence, including data from numerous landmark studies, that suggests that any amount of alcohol drinking can increase a women’s risk of developing breast cancer.

Therefore, no safe lower limit for recommended intake has been established. The collective data suggests intake as low as 10 grams per day, which is the equivalent of a small glass of wine or beer, is associated with an increased risk of disease. Several studies have found alcohol intake to be the most significant contributor to breast cancer risk compared to other well known risk factors and some have gone as far as to suggest a causal relationship. 

As a result of this research, the International Agency for Research on Cancer (IARC) and The World Cancer Research Fund (WCRF) joined by the American Institute for Cancer Research (AICR) has warned that alcohol likely causes female breast cancer. The IARC has further classified alcohol as a Group 1 carcinogen, placing it in the category of chemicals having the strongest evidence of cancer-causing potential.

The Group 1 classification means that alcohol can be as carcinogenic to humans as arsenic, benzene, asbestos, cigarette smoke, and plutonium. While the theory of causality is still up for debate and several questions remain unanswered regarding the various aspects of alcohol as it relates to breast cancer, the association between alcohol and breast cancer is firmly established and universally accepted.

Regardless of age, ethnicity, or sociocultural background, alcohol even at low to moderate levels of intake, can substantially increase a woman’s risk of developing breast cancer. It is recommended that all women control their intake. 

Alcohol-related breast cancer risk has been recognized in both premenopausal as well as postmenopausal women and is found to increase substantially with quantity consumed. So, while there may be risk associated with even small amounts of consumption, that risk increases greatly the more you drink, making the risk-relationship between alcohol and breast cancer dose dependent.

Breast tissue has been shown to be particularly vulnerable to alcohol’s carcinogenic effects, and these effects can accumulate over a lifetime. Age of exposure and cumulative lifetime risk continue to be studied and considered significant and independent risk factors with episodes of binge drinking contributing heavily to the risk of lifetime drinkers.

It has been observed that exposure during certain stages of development, especially adolescence, can increase a woman’s risk of developing breast cancer both in early as well as later years in life, regardless of cumulative intake.

Because the carcinogenic effects of alcohol have been shown to accumulate over time, increase with alcohol dose, and have a particular affinity for breast tissue, especially during the developmental years, the widespread use of alcohol coupled with low-risk awareness raises significant clinical and public health concerns. 

Despite the large body of compelling evidence linking alcohol to breast cancer and numerous public health warnings, there is a disturbing lack of national awareness surrounding this risk-relationship, healthcare providers included. Low levels of awareness surrounding other key modifiable risk factors such as obesity and physical inactivity which have been shown to potentiate the carcinogenic effects of alcohol have also been observed.

Even women who associate poor lifestyle choices with breast cancer are generally unaware of what those specific risk factors may be. In fact, research done on women’s adherence to breast cancer prevention guidelines has in part been inspired by the prevalence of generally poor awareness of risk.The condition of awareness is a necessary first step toward change, a critical precursory condition if you will.

Studies have repeatedly shown women to be more open to engaging in health seeking and preventive behaviors when they believe their actions will reduce their personal risk of developing breast cancer. Lack of knowledge and consequent lack of attention given to alcohol-related breast cancer has largely contributed to the number of missed, preventable breast cancer cases.

So, why is it that are we not talking about such a prevalent and serious issue? Especially when alcohol intake is a 100% modifiable risk factor among the many risk factors for breast cancer that cannot be altered. Most women and their providers (nearly 90%) are aware of the importance of family history and identify it as a major risk factor for breast cancer, but only about 20% of women, including young adults identify alcohol as a key risk factor.

So, it may surprise you to learn that Eighty-five percent of breast cancers occur in the absence of family history, implicating mainly behavioral and environmental causes (Breastcancer.org, 2023). Emerging evidence points to cancer as a systemic, metabolic disease rather than a local, genetically driven wave of bad luck. Genetics as a primary driver of cancer has been called into question and is a theory many believe to be a misguided and myopic way of thinking.  

What does this mean for you?

Learning that alcohol poses a considerable risk for developing breast cancer may come as an unwelcomed bit of information. But the good news is that breast cancer is a largely preventable disease, and you may have much more control over your risk then you have been led to believe. Multiple reports suggest that a substantial proportion of breast cancer cases are preventable through mitigation of behavioral risks, of which alcohol drinking is one.

Most newly diagnosed cases of breast cancer have known modifiable risk factors while less than 10% can be attributed primarily to genetic factors. We know that breast cancer is the culmination of the complex interplay between an individual’s environment and genetics that develops at the cellular level for years, likely decades prior to receiving a diagnosis.

Therefore, risk reduction involves the alteration of controllable environmental influences that continuously interact with uncontrollable genetic determinants, and risk reduction should begin early in life. The ball is in your court to embark upon a truly proactive approach to prevention. 

Secondly, the news of alcohol as a major risk does not mean that you must to submit to lifelong abstinence from drinking to avoid a breast cancer diagnosis. It does mean that you need to pay close attention to your intake and assess your personal level of risk based on your total number of risk factors; both modifiable and nonmodifiable.

Another way to say this is that you should take a personal inventory of the combination of genetic and reproductive factors in addition to environmental and behavioral exposures that may be putting you at risk and then determine which of the modifiable risk factors you can and are willing to reduce or eliminate. You should also consider each risk factor’s degree of influence to get the most accurate assessment of your total risk profile and the most important steps you can take to minimize it.

This approach to risk assessment and reduction is important because various combinations of multiple risk factors have a combined, cumulative, and synergistic impact, especially on alcohol-related cancers. Be assured that no one else is checking. When is last time your doctor inquired about your alcohol intake, looked a food journal, or had a serious discussion with you about a long-term weight loss or exercise regimen as it relates to your risk of breast cancer?

Furthermore, most risk calculators exclude lifestyle factors which you now know to carry 90% of the risk weight. These tools use primarily family history, genetics, and some reproductive factors to estimate risk based on population statistics (not your personal risk). Therefore, they provide only a partial picture and are not helpful in guiding fully informed health related decisions.

Several nonmodifiable risk factors play a role in breast carcinogenesis, making it critical for women to understand the impact of those lifestyle factors which they can control and the degree to which each of these factors plays a role in their personal risk profile. For instance, one major study showed that a third of postmenopausal breast cancers are preventable by losing weight, decreasing alcohol intake, increasing physical activity, and eliminating hormone replacement therapy.

In this study, alcohol alone was responsible for 6.5% of cases. But every woman is unique from this perspective. Yes, you are special, and you need to know your own personal risk to help guide the proper behavioral modifications and lifestyle choices that will work the strongest in your favor. 

Here is a list of well-known risk factors for breast cancer:

• Female Gender
• Age – Risk increases greatly over the age of 55
• Family History – breast cancer, ovarian cancer, or other hereditary breast and ovarian syndrome- associated cancer (e.g. prostate cancer, pancreatic cancer)
• Genetics – known deleterious gene mutation.
• Personal history of breast cancer 
• Radiation to the chest or face before age 30 
• Certain benign breast conditions
• Ethnicity – Caucasian females are at a slightly higher risk than African American and Hispanic females and Ashkenazi Jewish women have increased risk of BRCA mutation
• Being Overweight
• Prolonged interval between menarche and first pregnancy – women who had their first child after age 30 are at greater risk compared to women who gave birth before age 30 
• Nulliparity – Never had a full term pregnancy
• Early Menarche – Women who started menstruating before age 12
• Late menopause – Women who go through menopause after age 55 are at higher risk
• Not Breastfeeding
• Using Hormone replacement Therapy (HRT) – Estrogen and Progesterone, oral contraceptives
• Drinking Alcohol, no matter the type
• Dense Breasts
• Lack of exercise – Less than 4-7 hours of moderate exercise a week has been shown to increase risk 
• Smoking

Other breast cancer risk factors:

• Low Vitamin D Levels
• Nutrient deficiencies (Low Magnesium Levels, Zinc and Folate Deficiency)
• Diabetes and Insulin Resistance
• Light Exposure at Night (shift work)
• DES (Diethylstilbesterol) Exposure (In utero)
• Eating Unhealthy Food – Poor diet is thought to be responsible for 30-40% of all cancers 
• Certain Medications
• Exposure to Chemicals and Endocrine Disruptors in:
  • Cosmetics
  • Food
  • Lawn and Garden treatments (herbicides, pesticides) 
  • Plastic
  • Sunscreen
  • Water
  • Grilled and Cured Food

A word about Estrogen 

Some estrogens are produced naturally in the body, some can be taken intentionally from outside sources such as HRT and oral contraceptives. These are the estrogens with which you are likely familiar. Then there are environmental estrogens to which we are exposed inadvertently through pesticides, fuels, plastics, Styrofoam, and hormones in our food supply.

We refer to these as “exogenous” because they come from outside the body but unlike natural hormone replacements used for medicinal purposes these exogenous estrogens are synthetic chemical versions that have more of a mimicking effect and are usually much more potent.

They are bad actors and can significantly disrupt your endocrine function. Unfortunately, they have become quite ubiquitous in the environment, and we cannot discount them when considering our overall estrogen load.

But the point here is that whether you take or make it, you must get rid of it! Your body has a natural means of doing so through its own built-in detoxification system. But if this system is faulty and/or you have an excess of estrogen in your body it can increase your risk of hormone driven cancers, particularly breast cancer of which 85% are hormone positive.

Alcohol can interfere significantly with your body’s ability to detoxify estrogen since this process occurs primarily through the liver and gut. It can also throw off the balance of “good and bad” estrogens in the body. The topic of good vs bad estrogen is one for another day but just know that when estrogen is broken down, the body requires a delicate balance of its metabolites to avoid negative effects and this balance can be negatively influenced by alcohol and other chemical exposures.

High levels of circulating estrogen of any kind, but particularly the DNA damaging kind, is one of the mechanisms through which alcohol increases breast cancer risk. The best screening test to evaluate your risk of hormone driven breast cancer is the DUTCH (Dried Urine Test for Comprehensive Hormones) which is an advanced hormone test that you can read about here (link to labs or DUTCH page). Stay tuned for the blog on estrogen metabolites and the DUTCH test!

Ideally, you want to work with your provider to establish a targeted and personalized plan of care that involves specific recommendations for alcohol intake based on your personal and comprehensive risk profile. 

Although leading agencies such as the World Cancer Research Fund (WCRF) have established that there is no safe lower limit for intake when it comes to breast cancer risk, it is unrealistic, and quite frankly naive to think that everyone who is warned of alcohol’s deleterious effects and encouraged to abstain from drinking altogether would be willing to comply with such an order, nor should all women be expected to do so.

Some women are at much greater risk than others and may need to abstain, whereas the majority may be prescribed a plan that allows for either low or moderate exposure that includes dosage and frequency. This prescription should be coupled with routine checkups that include blood and hormone testing to continuously assess risk and “stay on top of it” so to speak.

This proactive and personalized approach is the best way to minimize your risk of breast cancer while at the same time comfortably maintaining a potentially important social aspect of your life for which the benefits need to be weighed carefully against the risks associated with alcohol intake.  

Breast Cancer Prevention Lifestyle Guidelines

The WCRF/AICR as well as the American Cancer Society (ACS) has established a set of breast cancer prevention lifestyle guidelines to help women understand the risk associated with certain behaviors and how to minimize their risk through recommendation adherence. These recommendations can serve as guide toward better breast health and cancer prevention.

But Keep in mind that these are generic guidelines designed for the public and not the necessarily recommendations of The Path CIFM or Dr. Krail-javier, DNP. While some align with our philosophy, some may not, or in some cases clarification is warranted. However, the point to make here is that studies have analyzed the effectiveness of recommendation adherence to these lifestyle-related factors and have consistently shown a significant reduction in breast cancer risk that is proportional to the degree of adherence.

One study showed women meeting six or seven WCRF/AICR lifestyle recommendations, had a 51% decrease in risk of breast cancer compared to women meeting zero to two recommendations. Each additional recommendation met came with an 11% decrease in overall risk. Many similar studies have been done and the collective evidence suggests that over half of all breast cancers are potentially avoidable through behavior modification that leads to the removal of harmful environmental exposures, especially alcohol.

Alcohol has been shown in most studies to be a heavily weighted risk factor in the combined effects of multiple exposures. Meaning, the more risk factors you have (modifiable or not) the more detrimental alcohol drinking can be on your risk.

Altogether, this line of research has called into question the degree of influence lifestyle-related factors may have over a woman’s genetic predisposition and to what extent these factors may abate the impact of the genetic forces considered to be driving breast cancer development. 

What about genetics?

Although to a lesser degree, adherence to established lifestyle recommendations has also been shown to substantially benefit women with preexisting nonmodifiable and genetic risk factors such as nulliparity and family history, respectively with removal of alcohol having the greatest positive influence on risk reduction in high-risk women.

So, if you have a strong family history of breast cancer or genetic predisposition toward the disease, drinking alcohol, living a sedentary lifestyle, being overweight, and eating the standard American diet, just to name a few, can individually and collectively be the modifying factors for the development breast cancer.

While the role of genetics is supported as a contributing factor, study data point to alcohol as a highly influential exogenous mediator suggesting that without exposure, disease may not be expressed. In other words, some high-risk women according to genetic predisposition may only develop breast cancer if exposed to alcohol. Some studies have shown alcohol to increase risk only in women with a family history of breast cancer demonstrating its potential to impact gene expression.

Continued research unequivocally implicates the complex interaction between genetic and environmental influences. 

So, what about genetics!?? LOL!

Genetic drivers of breast cancer are an import consideration of which to be aware, but they are unworthy of the grand attention afforded to them by the current social and medical landscape. This super attention also appears to come with consequence. Because genetics is not something perceivably controllable, the belief that family history or faulty genes is the primary driver of breast cancer can be misleading.

An ambivalent or noncommittal attitude toward changing destructive behaviors such as alcohol drinking is not uncommon due to such a belief as well as the many other misconceptions surrounding breast cancer development and prevention. Many women may be under the assumption that that behavior modification will have little impact on their already established genetic risk.

But the truth is, if you have a family history or a faulty BRCA gene your fate is FAR from sealed! Only 3-5% of cancers can be attributable to altered BRCA genes (if that). If you learned nothing else from reading this article, hopefully it is this; the overemphasis placed on genetics shadows the great importance of lifestyle over which you preside. But with power comes responsibility.

You are in control but also responsible for your health and must take that responsibility. National breast cancer screening guidelines ignore nearly everything outside of imaging for the detection of existing disease. But there are ways to screen for your risk of alcohol and lifestyle driven cancers and there are certainly ways to prevent it!

If you want to learn more about how to assess your risk and how to be truly proactive about breast cancer prevention, please reach out to The Path CIFM. We would love to work with you!

Dr. Krail-Javier completed her Doctor of Nursing Practice (DNP) project and PhD thesis on alcohol-mediated breast cancer. She is experienced in comprehensive breast cancer risk assessment and has a toolkit for prevention customized for each patient according to their unique needs.

She also works with patients who have been diagnosed or have survived a diagnosis of breast cancer. She has years of experience applying DUTCH test results to your prevention or care plan which is unique to her approach.  

How does alcohol Increase the Risk of Breast Cancer? Calling all fellow nerds 😉 

Several different mechanisms have been suggested to underpin the ability of alcohol to drive tumor development in breast tissue. 

• Alcohol itself as a sole compound appears to be carcinogenic (cancer causing), aside from the several other potentially problematic substances contained in alcoholic beverages. How exactly it exerts its actions is unclear, but we know that risk increases regardless of the type of beverage consumed. 
• Oxidative stress from alcohol also plays a role in breast carcinogenesis with the production of a highly reactive oxygen species, alpha-hydroxyethyl radical.
• Acetaldehyde, a known carcinogen classified as such by the IARC, is produced as a by-product of alcohol metabolism. Breast tissue not only participates in the conversion but may concentrate the acetaldehyde in mammary cells, even after a single exposure. Acetaldehyde can cause DNA damage directly and through oxidation. It can cause overexpression of cancer-causing genes and negatively affect DNA methylation patterns, thus hindering the DNA repair process.
• Alcohol may increase cell proliferation, including that of breast tissue.
• A more commonly understood and familiar mechanism includes alcohol’s effects on hormones, namely estrogen. Just 15-30 grams of alcohol per day can increase blood and urine estrogen levels. Increased estrogen contributes to the development of hormone positive cancers, cell proliferation through alpha estrogen receptor activity, and DNA methylation. Certain pathogenic estrogen metabolites can directly damage DNA strands and cause mutations while an imbalance of certain metabolites is also associated with substantial risk.
• Alcohol dinking can cause essential nutrient deficiencies. B vitamins and magnesium are common deficiencies. Alcohol interferes directly with folate metabolism and absorption further disrupting methylation pathways and increasing susceptibility to risk. One study showed alcohol to increase risk only in women with a family history of breast cancer and low folate status combined while neither modified risk individually. 
• Other possible and emerging mechanisms include a dysregulated oral and gut microbiome and effects on metastasis, angiogenesis (tumor blood supply) and cancer stem cells affecting development as well as pathogenic progression of cancer cells.

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