Few foods can stir up as strong of opinions as the humble soybean. Everyone and their dog has a take on whether or not you should include soy in a healthy diet, despite the fact that soy products have been consumed all over the world for centuries.
Of course, as with all foods, there’s a big difference between the natural form (the bean) and the ultra-processed variations, or even supplements of the plant compounds found in soy.
Minimally processed forms of soy—such as edamame, tofu, tempeh, miso paste, and soy milk—are all safe and healthy. In fact, soy products are recommended as part of a healthy diet by such groups as the American Cancer Society, Physicians Committee for Responsible Medicine, Academy of Nutrition and Dietetics, American Heart Association, and the American Diabetes Association (and we can go on).
So if you’ve been shunning soy at the grocery store or at your favorite neighborhood Japanese restaurant, here’s why you need to forget the myths you’ve heard about soy and embrace the bean.
1. Soy’s got the nutritional goods.
Like other beans, soy comes loaded with nourishing vitamins, minerals, and protein. A half-cup serving of edamame, for example, supplies over 20 percent of your daily value of protein, fiber, vitamin K, and manganese, according to the American Institute of Cancer Research. It also has 10 percent of your DV of magnesium, copper, iron, and folate.
Another key nutrient in soy is potassium. Edamame contains 10 percent of your DV of this crucial nutrient, which can help counter the effects of sodium on the body and may lower blood pressure. (Check out these other natural ways to lower blood pressure.) While the recommended daily intake is 4,700 milligrams, the average intake among Americans is just 2,640 milligrams a day, according to a study by the U.S. Department of Agriculture. Here are other sources of potassium to add to your diet.
Soy is also a “complete” protein, which means that it contains all the essential amino acids. It’s one of the few plant proteins to carry that honor. (That said, don’t feel obligated to seek out complete proteins for your diet: “Your body will make its own complete proteins if a variety of foods and enough calories are eating during the day,” according to the Academy of Nutrition and Dietetics, or AND.)
2. Soy can help keep your heart happy.
Nearly one third of deaths in the United States each year are caused by heart disease and stroke, and at least 200,000 of them are preventable, according to the Centers for Disease Control and Prevention. That’s because heart disease is primarily caused by lifestyle factors, such as smoking, a sedentary lifestyle, and a poor diet. Learn more about other factors for heart disease.)
A heart-healthy diet is one low in saturated fat, trans fat, and sodium, and rich in whole grains, fresh fruits and vegetables, and lean proteins. Choosing beans (like soy) instead of red meat can reduce the amount of saturated fat in your meals, which in turn may help lower your LDL, or “bad,” cholesterol. (Learn more about what your cholesterol numbers mean.)
3. Soy may lower your risk of certain cancers.
And here’s where the main controversy over soy lies: Soy contains phytoestrogens (phyto- meaning “plant”), and some people worry the influx in estrogens could increase your risk of breast cancer. That’s because one risk factor for breast cancer is prolonged exposure to increased levels of estrogen in the breast tissue.
But it turns out that the opposite effect may be true. Several studies of large populations of women who regularly included soy in their diets found that soy had either no association with breast cancer risk, or it actually lowered breast cancer risk, according to the American Cancer Society.
In fact, a study of 5,042 women who had previously been diagnosed with breast cancer found that those who consumed soy regularly had a 32 percent lower risk of breast cancer recurrence and a 29 percent lower chance of mortality from cancer, compared to women who did not.
Other studies have found that eating soy (especially in place of other high-fat proteins) may also lower your risk of endometrial, ovarian, colorectal, and prostate cancers. For this reason, the American Institute for Cancer Research lists soy as a cancer-fighting food.
An important caveat: The possible protection against cancer is linked to eating whole and minimally processed forms of soy, not soy supplements, including soy isoflavone supplements. The safety or benefits of this more concentrated form of soy for any health purpose has not been established, according to the National Center for Complementary and Integrative Health. As with all foods, the natural form of soy contains a variety of nutrients that work synergistically in the body; a single concentrated part of the food may not provide the benefits you’re looking for.
4. Soy may boost your bone health.
Regular consumption of soy products, as part of an overall healthy diet, may help reduce your bone fracture risk, according to the International Osteoporosis Foundation.
It’s not yet clear why soy seems to result in stronger bone health. One theory is that phytoestrogens may have a beneficial effect on the bone. Another theory is simply that swapping animal protein for soy (and other plant proteins) may lower your saturated fat intake and provide more micronutrients that are important to bone health (like magnesium and vitamin K), according to a 2011 study in Therapeutic Advances in Musculoskeletal Disease.
5. Soy may be good for your kidneys.
Diseases of the kidneys are becoming increasingly more common, mostly due to an increased incidence of diabetes. Your kidneys are responsible for filtering waste out of your blood (which you eliminate when you pee). Soy protein may place less stress on kidney function than animal protein does, which could help reduce the risk of kidney diseases.
The best way to prevent kidney disease to is to prevent or manage the diseases that are linked to kidney disease: diabetes, high blood pressure, and heart disease, according to the National Institute of Diabetes and Digestive and Kidney Diseases. A diet low in saturated fats, trans fats, cholesterol, salt, and added sugars may help prevent those chronic diseases and the development of chronic kidney disease.