To eat soy or not to eat soy? Breast cancer and soy have had an “it’s complicated” type of relationship over the years, even though most minimally processed organic soy foods are considered safe and healthy to eat. Luckily, there’s growing research filled with great news! Today I’d like to walk you through it (and link you to it!) so you can take a look for yourself.
I want to unpack this research specifically for breast cancer thrivers—both current patients and anyone who is post-treatment—and then uncover what this means for breast cancer prevention too. If you’re curious about whether or not you should consume soy, then this is for you—knowledge is power, my friend!
Personally, I’ve made the choice to keep and enjoy organic soy in my diet. If you take a peek in my fridge, you’ll find a variety of whole and minimally-processed organic soy foods, such as edamame, tempeh, miso and tofu. These foods land on my plate 2-3 times per week. I made this choice because I’ve taken the time to understand the benefits of soy, I see they’re working for me, and my medical team has given me the green light. I’m also vegan and including organic, minimally processed soy in my diet (not the processed crap) provides more variety and protein options. There’s also just so many great dishes and recipes you can make that include healthy soy options!
Exploring the research and debunking common misconceptions can help you decide whether or not minimally-processed, organic soy is a good fit for you. As always, it’s important to follow your doctor’s advice. But if you’re wanting to include some soy in your world and your MD has given it the kibosh, you might want to alert your medical team to this soy and breast cancer research (check it out below!) Just because your doctor is a fabulous smarty pants, doesn’t always mean that he or she is up on all the nutrition studies. So let’s dig into these beautiful findings, thriving and prevention…
Breast Cancer Thriving and Soy
If you’re currently a breast cancer thriver, you may be feeling some confusion around soy. Many oncologists have been on the fence about whether or not women who have had breast cancer should consume soy foods. To play it safe, they’ve discouraged breast cancer thrivers from consuming soy.
The reason behind this is that soybeans contain weak estrogens, and these estrogen-like properties have raised concerns of potentially making the cancer grow in women with breast cancer. This is because in hormone receptor-positive cancer—the most common form of breast cancer—there are some worries that high estrogen levels help cancer cells grow and spread. But this remains very controversial. Oddly enough, most people are more fearful of soy than they are of dairy, which doesn’t have protective phytoestrogens and contains estrogen (with full-fat dairy products having the most estrogen).
In 2012, researchers took a look at the diets of nearly 10,000 breast cancer patients and what they found was worth noting—the women who consumed the most organic soy (at least ½ cup of edamame per day) had a 25 percent less chance of having a cancer recurrence compared to women who consumed little or no soy (study). But people and oncologists have still been on the fence….
Enter another study blessing soy for breast cancer thrivers
This study on soy and breast cancer (study abstract) included 6,235 American and Canadian breast cancer patients from the Breast Cancer Family Registry, a National Cancer Institute-funded program that has collected clinical and questionnaire data on participants since 1995. By looking at this diverse population of over 6,000 breast cancer patients, the researchers specifically analyzed their soy intake. And the results were pretty amazing. Here’s a summary of the top takeaways…
Higher Survival Rates
Eating foods rich in isoflavones (the specific phytoestrogens in soy foods) is associated with reduced all-cause mortality. More specifically, the researchers found a 21% decreased risk of death among women with the highest versus the lowest intake of soy foods. This was especially true in women with hormone-receptor-negative breast cancer (which is typically the more aggressive kind) and women not treated with hormone therapy.
Women in North America could benefit from increased organic soy consumption
Even though women living in North America had an overall low consumption of soy in their diet, they may still benefit from increasing their isoflavone intake to a higher level. This benefit may be for those thrivers who are not currently receiving hormone therapy, but there’s also no negative impact shown for those who are.
Increasing soy may increase survival rate after a cancer diagnosis
Here’s the absolute BEST news: recent diet is important! If you’ve been diagnosed with ER-negative breast cancer, soy may play a significant role in your survival, and may even matter more if you start eating it now than if you ate it way back when. So not only did this study find that soy wasn’t harmful for survival, but it actually may improve it. And while this study only found these specific perks for ER-negative survivors, previous research has found soy to be beneficial for ER-positive survivors and for both users and nonusers of hormone therapy (study). Happy dance!