Does Soy Cause Cancer?
A type of legume that has been a dietary mainstay in Asia for centuries, soy is rich in plant-based proteins and low in saturated fats. It is also chock-full of vitamins and amino acids, which provide essential support to many of the body’s vital functions. And it has plenty of fiber, which is known to reduce the risk of several types of cancer, including colorectal cancer. For all of those reasons and more, many people who want to eliminate or cut back on their consumption of meat view soy as a healthier alternative.
Despite the many claims touting the benefits of consuming soy, however, it is not without controversy. For instance, scientists have extensively explored the potential connection between soy consumption and the development of cancer.
A possible link between soy intake and estrogen-sensitive cancers
Soy contains a high concentration of isoflavones, a class of flavonoids that has many beneficial anticarcinogenic, antimicrobial, antioxidant and anti-inflammatory properties. More specifically, isoflavones are a type of plant estrogen known as phytoestrogen, which is structured similarly to human estrogen but has much weaker effects. Nevertheless, the similarities between phytoestrogen and estrogen have raised some concerns within the general medical community that soy intake could potentially increase the risk of certain estrogen-sensitive cancers, such as breast, endometrial and ovarian cancer.
However, studies performed to date have consistently confirmed that phytoestrogen is not identical to estrogen. Furthermore, after performing many clinical trials, researchers have been unable to establish any link between soy consumption and cancer. In fact, some data suggest a protective effect. For instance, although phytoestrogen may act like estrogen in some ways, it also contains anti-estrogen properties, which means it may prevent natural estrogen from binding to estrogen receptors in cancer cells.
Moderation is key
As with any other nutritional choice, most experts recommend consuming soy in moderation. For example, a moderate amount of natural soy would consist of one or two servings a day of whole-soy foods, such as tofu, edamame, soybeans and soy milk (high-dose supplements should be avoided). A balanced diet that is high in fruits and vegetables and low in saturated fats is the key to good health. Before making any nutritional changes, however, it’s always best to talk with a physician or dietitian.
At Moffitt Cancer Center, our research team is continually exploring possible links between nutrition and cancer, and we are learning more every day. If you have questions, we encourage you to rapidly connect with a specialist on our team by calling 1-888-663-3488 or completing our new patient registration form online to request an appointment. As Florida’s top cancer hospital, we are proactively changing the patient care model for the better.