Can Soy Cause Breast Cancer?

 research involves small animals, the findings are a little bit different.

Rodents exposed to high doses of isoflavones can show an increased risk of breast cancer, according to studies. “Issues have come up in animal models,” says Dr. Onger.

It’s important to note the same results haven’t come up in human studies. But when studies suggest any possible correlation between food and cancer, misinformation and worry can spread quickly.

High soy diets and cancer rates

While soy-based foods may be trending in the United States, the plant has long served as a dietary staple in other areas of the world (particularly in Asia).

So, why bring that up? Breast cancer rates have historically been much lower in Asian countries than in the U.S., which suggests there isn’t a high correlation between consumption of soy and the disease.

Those countries also typically feature an overall lower-fat diet and differences in birthrates, both of which affect cancer rates.

So, is it safe to eat soy?

There’s no need to clear soy milk, tofu, edamame or other soy-based items out of your kitchen. The food is safe. If you enjoy it, keep eating it.

But it’s best to eat soy in moderation within a balanced diet, agree Dr. Roesch and Dr. Onger. Federal recommendations show health benefits when eating 25 grams of soy protein per day. (That’s equal to about 1 1/4 cups of tofu or 1 to 2 cups of soymilk.)

What about soy supplements?

As a general rule, you’re better off getting your nutrition through food sources rather than through soy supplements or isoflavone extracts.

“Doses of isoflavones from a vitamin store can be several hundred times higher than what you would ingest from eating tofu or drinking soy milk — and that could be a potential problem,” warns Dr. Roesch.

It’s always best to talk to your healthcare provider before beginning a supplement.

Bottom line on breast cancer risk

Known breast cancer risk factors such as having obesity, smoking at an early age, a sedentary lifestyle or high saturated fat intake all qualify as much bigger concerns than consuming soy-based foods.