Cancer Awareness Month: Debunked Myth #2
By Corinne Glazer, RDN
Clinical Outpatient Registered Dietitian Nutritionist
Soy products increase the risk of cancer. MYTH.
Soy-based foods are a popular alternative for those who want to reduce
or eliminate meat from their diet. The ongoing hot topic is whether soy-containing
foods can increase the risk of developing cancer. In order to understand
why this is false, it is important to first understand what soy is. Soy
is a plant-based protein packed full of fiber, calcium, iron, and other
vitamins/minerals. Common soy-based foods include tofu, tempeh, edamame,
miso, and soy milk. Several observational studies have shown that a lifelong
diet of soy consumption (one to two servings per day) has been associated
with a decrease in risk for developing breast cancer.
Where did this theory originate from and what’s the truth? High levels
of estrogen has been linked to an increased risk for breast cancer. The
confusion arises from the fact that soy contains isoflavones, which are
plant estrogens, and their chemical structure is similar to that of human
estrogen. However, it’s important to note that plant estrogens bind
to the body’s estrogen receptors differently and function differently.
In isolated cell studies, isoflavones have actually been shown to stimulate
genes that slow the growth of cancer cells and even promote destruction.
Isoflavones have been identified in numerous studies to protect against
cancer by supporting the body’s antioxidant defenses and DNA repair.
Keep in mind, if you have a history of breast cancer or thyroid problems,
it is recommend to avoid soy or isoflavone supplements as they contain
higher concentrations of isoflavones.
It is recommended to consume fewer processed soy foods like soy nuggets,
bacon, and sausage, available in many grocery stores. In other words,
if you want to add soy to your diet it is recommended to choose the whole
food sources. If possible, buying non-genetically modified soy is optimal
since about 93% of planted soy in the United States is genetically modified
in some way. Avoiding processed foods in general is one way to decrease
the risk of developing cancer.
A moderate amount of whole soy foods is one to two daily servings. Examples
of a single serving include:
- 1 cup of soy milk
- 1/2 cup cooked soy beans
- 1/2 cup of edamame
- 1 ounce of soy nuts
- 1/3 cup of tofu or tempeh
Interested in learning more about the latest evidence-based research on
cancer and nutrition?
Call Torrance Memorial Specialty Center regarding our
Cancer and Nutrition Series or theNEW (Nutrition Education and Wellness) Program, (310) 891-6707.