How It Works

While scientists are still working on a better understanding of exactly how alcohol increases the risk of breast cancer, we do know a lot about some of the most likely ways it happens. Here are 3 of those ways.

1. Alcohol messes with your estrogen levels.

Drinking alcohol actually increases your levels of estrogen, a hormone important to a woman’s reproductive system. Women who regularly drink alcohol show higher levels of estrogen in their bodies compared to women who don’t drink. Estrogen can encourage breast cells to grow and multiply, which can lead to increases in breast density, and higher breast density is known to increase the risk of developing breast cancer.

Read a review of how this works.

2. Alcohol messes with your folate levels.

Alcohol reduces your levels of folate. Folate is a B vitamin found in many foods, like beans and leafy green vegetables. When you drink alcohol, it makes it harder for your body to absorb folate and other nutrients. Folate is important in how DNA is made and maintained. If the way DNA is made and maintained is disrupted, it means a cell’s DNA can become damaged which in turn makes it more likely that the cell will become cancerous.

If you want to read more about this, here is a good systematic review and meta-analysis (translation: a study that got data from a bunch of other studies and analyzed all the data together).

3. Alcohol breaks down into acetaldehyde, a carcinogen.

When you drink alcohol, your body breaks it down into a chemical called acetaldehyde. Acetaldehyde is a carcinogen (cancer-causing agent) that damages your DNA and keeps your body from repairing the damage. When a cell’s DNA is damaged, it’s more likely to start growing out of control and become cancerous.

Another good review of what we know about the carcinogenic effects of acetaldehyde. Or get an overview of how this works.

Check the facts.