Quitting smoking, limit alcohol use, exercise, more fruits and veggies. We all know these risk factors for breast cancer.
Or at least I hope you know these factors and more. If you need a little refresher, feel free to check out prior blog posts on breast cancer prevention by clicking here.
Some risk factors are a little less obvious. Exposure to toxic chemicals like BPA in plastic water bottles, cooking in Teflon and phthalates from vinyls all increase your risk of breast cancer. Stress plays a role. Vitamin D plays a role.
But the gut?
Or, more specifically, the bacteria in your gut.
To understand the relationship of the bacteria in your gut to breast cancer risk, you have to better understand the way the human body breaks down estrogen. The 3 main estrogens in the body are estriol, estradiol and estrone.
Estrogens in the human body are broken down through several mechanisms. The breakdown occurs through several pathways which can be either safe or damaging and this pathway is called hyrodylation. Hydroxylation can occur down several pathways that produce different end-products. The 2 pathway is generally considered the friendly pathway. On the other hand, the 16-alpha pathway creates an estrogen that damages DNA and increases the risk of hormone related cancers like breast and uterine.
Dietary choices like broccoli and cauliflower will help your body breakdown estrogen into the safer 2 pathway. That’s why you should eat more cruciferous vegetables to lower your risk of breast cancer (never saw a poster proclaiming this during any of the Susan Komen 3-days).
But there’s another really important factor that helps to determine what pathway your body will take when breaking down estrogens, which brings us back to the gut.
The bacteria in your gut play a very large role in how estrogens get broken down. And since most of the estrogens that your body is trying to get rid of are dumped into the bile and then into the gastrointestinal and out the body from there. This means that the estrogens have a very heavy exposure to the bacteria in the gut.
In this particular study, researchers looked at how much the bacteria in the gut played a role in the breakdown of estrogens. Specifically, they looked at estrone and estradiol levels (called the parent estrogens) and compared them to the hydroxylated estrogens.
Without going into details of the study, the take home message is that the more diversity there was in the bacteria of the gut, the better the ratio between the parent estrogens and the estrogen byproducts.
So what does this mean? Anything that destroys bacterial diversity in the gut is likely to increase your risk of breast cancer.
Highest on the list for destroying the good bacteria in your gut? Antibiotics. And not just in the past week. As in EVER.
Even 2 years after a course of antibiotics bacterial diversity still has not recovered. There really hasn’t been any studies looking at how long it takes to recover diversity, but I would guess it takes decades when left alone.
You can probably shorten this time by using probiotics and eating foods that support the growth of bacteria in the gut. This includes foods like beans, whole grains and fruits. These foods contain soluble fiber that the bacteria feeds on.
Remember this info the next time your primary care or urgent care offers you a prescription for your upper respiratory viral infection.