If you like tofu, or opt for soy milk over dairy, concerns about the health effects of soy may have piqued your interest. But there seem to be more questions than answers about the role soy plays in women’s bodies, especially when it comes to menopause and breast cancer. And there are also many misunderstandings.
The soy in our food supply is a processed product of the soybean. Tofu is one of the most common sources, but you’ll increasingly find it in dairy substitutes like soy milk and soy cheese, as well as foods made specifically for vegetarians, like soy burgers and other meat substitutes.
Soy is a phytoestrogen, or a plant based estrogen. It contains two isoflavones, genistein and daidzein, which act like estrogen (the female sex hormone) within the body. Because estrogen plays a role in everything from breast cancer to sexual reproduction, this is where most of the soy controversy stems.
No Proven Link to Cancer
Most studies linking soy consumption to an increased risk of breast and other forms of cancer are done in laboratory animals. But because humans metabolize soy differently than rodents, these findings might not apply to people, says the American Cancer Society (ACS).
Further, studies looking at the effects of soy on humans have not shown the potential for harm.
The ACS says that because research on the link between soy and cancer is still evolving, much more analysis is needed. As it stands, soy doesn’t appear to pose any cancer risk.
In fact, some studies actually show that soy reduces cancer risk. One study from Japan suggests that hormone fluctuations in men who consume soy products daily could protect against prostate cancer. Another found consuming soy in conjunction with probiotics could reduce the risk of breast cancer.
The bottom line: There isn’t substantial evidence that soy definitively increases or decreases cancer risk.
Cautions with Soy
There is research underway to determine the effect that soy may have on thyroid health. At this time, soy is not thought to cause thyroid disease. However, for those on thyroid medications for hypothyroidism, managing soy intake may be helpful. Soy may interfere with the medication’s function. Avoiding soy at least four hours after taking your medication is recommended.
Possible Benefits of Soy
Menopause occurs when women stop producing estrogen. Because soy acts similarly to estrogen within the body, it’s sometimes credited with easing the symptoms of menopause. However, the American Heart Association says that this effect is somewhat unlikely.
Early evidence showed that soy could even reduce the risk of heart disease. While those claims were somewhat exaggerated, research does show that a diet that substitutes soy for animal protein can reduce LDL, or “bad” cholesterol.
Finally, a 2011 study revealed that soy could help prevent and even reduce bone loss associated with osteoporosis. Researchers say their findings indicate that postmenopausal women and other people with low bone density could benefit from consuming soy much in the same way they consume dairy products for bone health.
Research on the potential health benefits and risks of soy is ongoing. As it continues, what we do know about this plant-based food will evolve. For now, it looks like soy’s benefits outweigh the cons.