Nutrition and breast cancer myth-busting
Up until the spring of 2022, I was the clinical dietitian at a breast cancer center here in New York for about 6.5 years. Since it’s breast cancer awareness month, I thought I’d share a few nutrition misconceptions and myths I’ve busted (and continue to bust - I do work with breast cancer patients in my practice) most frequently.
Taking X supplement will treat or cure breast cancer
Claims like this can cause harm (and I’ve seen it first hand, many times). Now, I know Western medicine and specifically the U.S. healthcare system is far from perfect. But, advances in medicine and meaningful research is lifesaving, especially when it comes to breast cancer (there are more breast cancer survivors than any other cancer!). On the other hand, there is zero research existing in the world suggesting any vitamin or herbal supplement should be used as a treatment for breast cancer. What’s more, many of them can interact with medications and treatments that do work, like chemotherapy, and essentially make them less effective. Dietary supplements are also not regulated by the FDA, meaning there is no one monitoring what goes into supplements before we ingest them, unless they are third party certified. There’s also no one monitoring claims on supplement packaging, the claims made by various internet persons or alternative practitioners, even though their advice can directly cause harm. How this is legal is beyond me. If you’re thinking of taking any kind of dietary supplement and you have breast cancer, make sure you run it by your oncologist or RD.
Soy causes breast cancer
The majority of breast cancers are hormone sensitive, which means that breast cancer cells need the hormones estrogen and/or progesterone to grow, and women naturally produce both. However, contrary to a lot of misinformation on the internet, no food contains estrogen like the estrogen we make in our bodies. That means you can’t eat a certain food and increase the amount of estrogen circulating in your body. However, there are some foods that have a plant-based form of estrogen, called a phytoestrogen. These foods include soy and flaxseeds. Phytoestrogens have been extensively studied in relation to breast cancer because early on there was a concern about whether they did cause estrogen-like activity in the body, and in women with breast cancer, bind to estrogen receptors on a breast cancer cell and promote growth. All of the research to date points to soy and other phytoestrogen containing foods not to be harmful in women with or at risk for breast cancer. If anything, they may be protective against breast cancer. So if you like tofu, tempeh, soy milk, etc., enjoy at them as part of a varied diet.
Sugar feeds cancer
I cannot tell you how many times I’ve had women diagnosed with breast cancer come to me terrified to eat sugar or carbohydrates because of this myth. It is literally everywhere. Here’s the truth: all of our cells, including cancer cells, need sugar, or glucose, for energy. There is no way around that. But, cancer cells are not taking all of the sugar we eat away from our other cells and they will not grow faster if we eat more sugar. When it comes to breast cancer, there is no sufficient research showing that restricting sugar and carbohydrates slows tumor cell growth and I do not advocate for either. I will always encourage a plant-forward diet for women with breast cancer, but this can (and should!) include carbohydrates with every meal and foods that contain sugar from time to time.
Fasting or juice cleanses are helpful during chemotherapy
100% no. Both from a research perspective and from a “being healthy during treatment” perspective. This one can get tricky especially because fasting is so popular right now, in general and in some instances related to cancer. There has been recent preliminary research showing fasting the day before, day of and the day after chemotherapy may help reduce side effects. Whether it helped reduce the likelihood of a recurrence is unknown, and that would take much longer to examine. The problem here is all of the downsides to fasting around treatment days for a possible positive outcome. In general, we know a nourished body handles treatment best. We also know that weight loss and malnourishment are associated with poorer outcomes, in which fasting can increase risk for. Because of how treatment-related side effects work, some patients may feel their best appetite-wise right before their next treatment, the day of and day after, before the chemo-related side effects kick in again. Taking nutrition away on the days when patients actually want to eat can result in the negative consequences I mentioned above. When it come to juice cleanses, in short, there is zero research on any benefit, whether it’s related to cancer, chemotherapy or otherwise. Basically, just say no to juice cleanses.
Hope this was helpful! I’m due to schedule my annual mammogram, so here is your push if you are too.
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