The Benefits, Risks, and Uncertainties of Soy for Lower Blood Cholesterol

Soy, a type of legume, can be found in many products. On the grocery store shelves, you will see soy milk, tofu, protein bars, veggie burgers, and many other options. If you are interested in adding soy to your diet and wondering if there health benefits, then read on to find out if soy is a good option for you.

Soy and Cholesterol Levels

Some studies have found that substituting soy protein for high-fat meats and other foods may slightly reduce LDL (bad) cholesterol levels. Since high cholesterol puts you at an increased risk of developing heart disease, the United States Food and Drug Administration (FDA) allows a "heart healthy" label on foods that contain 6.25 grams (g) of soy protein. But, researchers do not know the exact components of soy that may lead to these benefits. And some experts are debating if this label is deserved at all.

Soy Safety Issues

While soy is considered safe for most people, there may be some health concerns if you have certain conditions, such as:

  • Problems with absorbing certain nutrients—Soy could reduce how well your body absorbs zinc, iron, and calcium.
  • Impaired thyroid function—Soy may affect the thyroid gland, but research has produced conflicting results. In general, if you have problems with your thyroid gland, you may want to avoid eating large amounts of soy.
  • Lower testosterone levels—One study found that soy may decrease testosterone levels in men. This could potentially cause problems with infertility or erectile dysfunction.

If you are concerned about any of these safety issues, talk to your doctor before adding soy to your diet.

Ways to Get More Soy Into Your Diet

Here are some tips on substituting soy protein for meats and other protein sources in your diet:

  • Include it in other dishes:
    • Mash a cake of tofu and use it in place of ricotta cheese in your lasagna, soups, or stews.
    • Mix textured vegetable protein into hamburgers and seasoned meat dishes like tacos, chili, and casseroles.
    • Add cubes of fried, seasoned tofu to salads.
  • Try Asian cuisine—Japanese, Chinese, Thai, and Vietnamese foods often contain flavorful soy options, including tofu, tempeh, and edamame (green soy beans). Edamame is eaten cold and salted. Tofu and tempeh can be stir-fried, steamed, or added to soups.
  • Use supplements and soy protein powders—Try mixing soy protein powders into smoothies or mashed potatoes.
  • Soy nuts, flavored with salt and spices, make a delicious snack.
  • Use soymilk in cereal.

Major Food Sources

Soy Food Serving size Soy content (grams) Isoflavones (milligrams)
Soybeans, cooked ½ cup 9-11 40-50
Soy milk (regular) 1 cup 7 10
Soy milk (fortified) 1 cup 10 43
Textured soy protein ¼ cup 11 33
Isolated soy protein ½ ounce 11 27
Tofu ½ cup 10 25
Meat alternatives (soy crumbles) ½ cup 11 8.5


American Heart Association
National Heart, Lung, and Blood Institute


Dietitians of Canada
Health Canada


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Last reviewed May 2016 by Michael Woods, MD
Last Updated: 6/11/2014

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