What You Need to Know: Alcohol and Breast Cancer Risk

From the temperance movement that led to Prohibition to “Mommy Wine Culture,” women and alcohol have a complicated relationship, and now with the increasing availability of evidence connecting alcohol consumption and breast cancer, it’s becoming more complex. Here’s a breakdown of some of the latest research on how alcohol can increase the risk of breast cancer so you can make the best decision for yourself and how you want to live your life.

To be honest, it is difficult to wade into the space of how behavioral or “moral” factors increase breast cancer risk, so let’s start with: No One Deserves Cancer. The stigma of smoking and lung cancer is harmful to those who are facing that disease and has been difficult to combat, and we don’t want something similar to happen with alcohol and breast cancer. However, we also have an obligation to discuss additional information as it comes out and to try and understand what it means for breast cancer risk. A future blog is planned on some of the social history and health impact of the relationship between women and alcohol, so keep an eye out for that. For now, let’s talk about the science of alcohol and breast cancer.

Alcohol could increase the risk of breast cancer in a few different ways, and it’s not clear which mechanism has the most impact on developing the disease. The American Cancer Society explains potential cell and DNA damage caused by alcohol, the repair of which could trigger cancer growth or affect the absorption of nutrients. We also know that excess weight can increase the risk of breast cancer, and the empty calories in alcohol can lead to extra pounds. Alcohol also increases the estrogen in the body, which can increase the risk for the development of hormone-receptor-positive breast cancer, the most common type of the disease. 

There have also been different studies on the timing of alcohol consumption and breast cancer risk like perhaps the alcohol consumed before a woman’s first pregnancy (college and young adult years, for example) might have more of an effect than later drinking habits. Or, perhaps it could be routine drinking of any kind as opposed to social/occasional drinking. Whatever the mechanism, it is estimated that alcohol is a factor in at least 4% of all breast cancer diagnoses.

How much does drinking alcohol increase breast cancer risk? Well, it depends. If a woman’s average risk of developing breast cancer is represented as 1.00, a woman who is a light drinker (usually defined as 3-7 drinks per week) has a risk of breast cancer of 1.04-1.13. This is called relative risk. For comparison, the relative risk of dense breasts and developing breast cancer is 1.2 (for extremely dense, it is 2.1), and the relative risk for obesity post-menopause has been found to be between 1.16-1.58. For any alcohol consumption beyond one drink per day (that is regularly consumed), breast cancer risk goes up an additional 10%. So, how much someone drinks and how often has different effects. 

Also, the breast cancer risk may depend on how our bodies break down alcohol into acetaldehyde, the toxic substance that is responsible for the hangover feeling. We all know that people “handle their liquor” differently, and that can affect alcohol-related cancer risk as well. And no, being able to “handle” more alcohol is not a good sign, but neither is being a “lightweight” when it comes to alcohol. Someone who has a higher tolerance might end up drinking more, increasing cancer risk, but their bodies might also produce less of the harmful chemical, leading to decreased effect. People who react strongly to alcohol might, in turn, drink less, limiting their risk, but this feeling can also be overcome, and their bodies are less equipped to deal with the acetaldehyde. One thing that doesn’t matter is what type of alcohol you drink. Wine, beer, and liquor all contain the same type of alcohol which is ethanol.

So what do you do with this information? Whatever you want to. There is no safe amount of alcohol to drink. It is better for our health, in general, to limit alcohol consumption to 2 drinks per week, if we decide to drink at all. Some women who have a higher risk of breast cancer overall might decide not to drink alcohol in order to decrease the risk factors within their control. Some organizations, like the American Cancer Society, have decided to recommend that people do not drink alcohol at all. For some women, a drink at the end of the day is an important part of their lifestyle. 

For example, my grandmother has a gin and bitter lemon every day at 5 pm. She is also a breast cancer survivor. Would she have decided to forgo her afternoon drink even if she knew for a fact it was what caused her breast cancer? Not likely. But there are some women who would make a different choice, and that is why this information is important. Being our own health advocates means that we learn the facts and make the individual choices best for our circumstances and situation – Knowledge is Power. 

Photo by Kelsey Chance on Unsplash