Soy. That little three-letter word that strikes fear into the stomachs of so many. Why are we so afraid of soy? Well, I bet you’re asking…
What’s So Great About Soy?
In 2009, results from a study of over 5,000 Chinese breast cancer survivors stated that women who consumed three cups of soy milk per day were less likely to have a recurrence or to die of breast cancer than women who only drank ½ cup a day!
Soy also contains phytoestrogens (aka plant estrogens), which are pretty similar to the estrogen formed naturally in your body. Soy has a high level of phytoestrogens, but still only has a teeny-weeny bit of the power of human estrogen – just two percent! Phytoestrogens will bind to your cells’ estrogen receptors, but oddly enough, at the
And most people don’t realize that soy is not the only plant to contain phytoestrogens. Believe it or not, over 300 plants contain them, including flax, sesame, wheat, oats, barley, beans, yams, apples, carrots and pomegranates.
Can I Eat Soy If I Have Breast Cancer?
Soy can seem kinda scary if you have breast cancer that is estrogen-receptor positive (ER+). But scientists are starting to unlock this mystery of how soy works in the body with breast cancer. What they have found is that many cells in the body have estrogen receptors. Think of these receptors like little locks that need estrogen to act as the key to open them.
So estrogen unlocks these doors and lets breast cancer cells grow and multiply. But phytoestrogens fit into these same locks but cannot open the doors so they wind up competing with your natural estrogen and blocking it from working!
On top of that, phytoestrogens help to prevent cancer cells from talking to
Now, if you have what is called human epidermal growth factor receptor 2 (HER-2) positive breast cancer and are on a drug called trastuzumab (Herceptin), soy may actually help trastuzumab work better. Late breaking news: Breast cancer cells treated with genistein along with trastuzumab significantly slowed breast cancer cell growth more than using just the drug alone![i] On top of that, genistein has been shown to suppress HER-2 activity!
If you are on the drug tamoxifen, then soy may help you, too. Many people on tamoxifen are told by their docs to avoid soy because tamoxifen’s job is to block those estrogen receptors, and the thinking is that tamoxifen might bind to the phytoestrogen in soy instead.
But, back in 2007, researchers in Israel found that genistein may actually sensitize ER+ and HER-2+- breast cancer cells to tamoxifen and help it work better.
What If I’m A Breast Cancer Survivor?
First of all, congrats for making it through a long and difficult journey! And to reward you, you can add soy to your diet, too! In 2009, results from a study of over 5,000 Chinese breast cancer survivors stated that women who consumed three cups of soy milk per day were less likely to have a recurrence or to die of breast cancer than women who only drank ½ cup a day![iii]
And last month, researchers found that the risk of recurrence for postmenopausal breast cancer survivors was 33 percent lower for Chinese women who ate more than 42 mg/day of isoflavones – that’s only ¼ cup tofu a day! And they found this was especially true for women with ER+ breast cancer and who were taking anastrozole (Arimidex).[iv] Okay, yes, these were all Chinese women who
What Kinds Of Soy Should I Eat?
Definitely choose organically grown soy, which by definition means that it will also be what is called “non-GMO” (non-genetically modified organism). Genetically modified (GM) soy is scary! Over 90 percent of soy grown in the United States is modified genetically to be resistant to herbicides sprayed on fields to kill off weeds. As a result, GM soy is now contained in up to 70 percent of all food products including cereals, pasta, breads and even meat since animals are fed GM soy as part of their feed to help them grow faster. GM soy has been linked to allergies, birth defects, infertility and cell mutations in the liver and pancreas. Yikes!