Most of the confusion surrounding soy stems from its role in preventing or causing hormone-dependent cancers, like breast and prostate cancer. To better understand this relationship, we need to take a closer look at soy’s isoflavones.
Yet, Asian women tend to eat a lot of soy and are actually less likely to develop breast cancer than women in other countries where soy consumption is low. Moreover, human studies show that eating moderate amounts of soy don’t increase a woman’s risk of cancer death or recurrence. Likewise for men, research on soy and prostate cancer show that soy reduces levels of PSA, a protein that typically increases as prostate cancer grows.
So, where did this fear of eating soy come from?
Some–but not all–animal studies showed that soy’s primary isoflavone, genistein, increased growth of breast cancer cells in rodents. The media had a field day with this information and scared the beejeebers out of most us to the point that many continue to avoid soy without even remembering why. What we weren’t told is that a rodent’s metabolism is very different from a human’s metabolism and therefore these findings aren’t all that applicable to you and me.
The bottom line, at least according to the American Cancer Society, is that “moderate consumption of soy foods appears safe for both breast cancer survivors and the general population, and may even lower breast cancer risk.”
This is great news because soy is an excellent source of protein, vitamins, minerals, fiber, and phytochemicals, which have anti-inflammatory and anti-oxidant properties. Soy consumption has been shown to decrease LDL (lousy) cholesterol and increase HDL (good) cholesterol and reduce blood pressure. Plus, soy foods are typically inexpensive, safe for people with a lactose intolerance or milk allergy, and a great substitute for animal protein.
When choosing soy products, be sure to choose whole or minimally processed forms, like tofu, tempeh, edamame, soynuts, soymilk and miso. Keep in mind that most soybeans in the United States are genetically modified so I recommend that you buy organic.