If you like tofu, or opt for soy milk over dairy, concerns about the health effects of soy may have piqued your interest.
However, 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. 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. 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 contains phytoestrogens, or plant-based estrogens. These are mainly two isoflavones, genistein and daidzein, that 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.
Most studies linking soy consumption to an increased risk for 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, according to the American Cancer Society (ACS).
Further, studies looking at the effects of soy on humans haven’t shown the potential for harm.
The ACS states 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.
An early study conducted in Japan suggests that hormone fluctuations in men who consume soy products daily could protect against prostate cancer. A 2013 study found that consuming soy in conjunction with probiotics could reduce the risk for breast cancer in rats.
The bottom line: There isn’t substantial evidence that soy definitively increases or decreases cancer risk.
Many studies have investigated the effect that soy may have on thyroid health. Currently, soy isn’t 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. According to the Mayo Clinic, avoiding soy at least 4 hours after taking your medication is recommended.
Menopause occurs when women experience a reduction in estrogen levels.
Because soy isoflavones act similarly to estrogen within the body, they’re sometimes credited with easing the symptoms of menopause. However, the American Heart Association states that this effect is somewhat unlikely.
Early evidence showed that soy could even reduce the risk for 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.
Researchers conclude that their findings indicate that postmenopausal women and other people with low bone density could benefit from consuming soy.
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.