Cancer and Food: Does Soy Increase Risk?

Soy Products

If you’re in the market for nutritional info, Ohio State dietitian Candice Schreiber is here to help, serving up details about the sometimes complicated relationship between food and cancer.

On today’s menu: Does eating soy increase cancer risk?

“This is the number one question I get from our breast cancer patients but also from patients with other types of cancer,” says Schreiber, RD, CSO, LD, a JamesCare for Life outpatient clinical dietitian. “The evidence shows soy foods do not increase cancer or recurrence – there are even possible health benefits for patients.

The myth: soy increases cancer risk

The misconception that soy can increase the risk of cancer comes from earlier studies in mice, where phytoestrogens found in soy and flaxseed promoted the growth of breast cancer. Newer and larger studies have shown that this does not translate to humans, according to Schreiber.

Because of the myth’s persistence, however, many of The James patients that Schreiber and her colleagues talk to are either shocked to learn, or reluctant to believe, they can eat soy.

“Some patients are thrilled and tell me that being able to eat tofu and edamame again has changed their lives,” Schreiber says. “Some patients are still anxious about it, and I tell them if it makes them anxious and causes stress, despite the research, they should avoid it.”

The truth: soy could have anti-cancer benefits

According to the National Cancer Institute, “Soy isoflavones have been shown to reduce tumor cell proliferation and induce tumor cell apoptosis (death), as well as to be able to regulate hormone balance and reduce the risks of breast cancer, heart disease and osteoporosis.”

Some preliminary studies have also shown that soy isoflavones may reduce the risk of prostate cancer. Soy products are also rich in fiber and protein, low in saturated fat, free of cholesterol and lactose and good sources of omega-3 fatty acids and antioxidants.

Some soy suggestions

Schreiber recommends as many as three servings of soy a day. A serving is equal to three ounces of tofu, a cup of soy milk or a half-cup of edamame.

“We recommend whole food soy products rather than soy supplements,” she says, while advising particular caution with bars, cereals and veggie burgers that contain added soy, as these are often highly-processed foods with lots of added sugar.

“I like to use tofu as a substitute for recipes that call for ground beef, such as tacos or in a meat sauce for pasta,” Schreiber says. “First, before I cook tofu, I wrap it in a paper towel and then a dish towel and press it to get out a lot of the moisture. Then you can sauté it or roast it or chop it up and cook it like you’d cook ground beef.”

Schreiber also suggests adding soy milk or uncooked tofu to smoothies for a creamier texture and added protein, and popping pods of edamame for some healthy flavor at meal and snack times.

“I love edamame and add it to salads and pasta dishes or just eat it plain.”