Soy Protein and Cholesterol

Medically Reviewed by Arefa Cassoobhoy, MD, MPH on May 16, 2014
3 min read

Adding tofu to your stir-fry, soy milk to your morning bowl of oatmeal, or edamame as a snack can be a good move if you're working on improving your cholesterol level.

Some studies suggest that soy protein may help, says cardiologist James Beckerman, MD, of Portland, OR. But the evidence isn’t strong, so you'll definitely want to make other changes to your diet to help your cholesterol, too.

Eating soy foods may help lower your LDL ("bad") cholesterol by about 3%. That's very little, but when you're trying to take advantage of everything you can do for your cholesterol, it's worth considering.

Soy is also a good source of protein, fiber, and heart-healthy omega-3s (though not the same kind that you get in salmon or tuna). Plus, soy is naturally cholesterol-free and low in saturated fat.

The best way to benefit is to swap soy products for foods you usually eat that are high in animal fats. Here’s how:

  • Instead of chicken, try a soy substitute like firm tofu.
  • Instead of ground beef, try soy protein.
  • Instead of a regular hot dog, choose a soy dog.
  • Instead of beef chili, cook chili with soybeans.
  • Instead of drinking cow’s milk, experiment with soy milk. Check the label to make sure it's fortified with calcium and vitamin D, and not too high in sugar.
  • Instead of butter, use soy nut butter.
  • Instead of high-fat cheese, try soy cheese.
  • Instead of processed snack foods, enjoy a cup of edamame.

There’s one exception: soy supplements. There’s no proven benefit to adding soy isoflavone supplements to your diet. Stick with whole soy foods instead.

Three other things to remember:

  1. Soy sauce and soybean oil don’t contain soy protein, even though "soy" is part of their name.
  2. Read the label. Make sure the soy products you buy are also low in saturated fat, cholesterol, salt, and added sugar.
  3. If you see "soya" on a packaged food, that's another word for soy.

If you’re new to eating soy, add it to your diet a little bit at a time. Substitute soy protein for animal protein foods a few times a week. That’s the best way to cut saturated fat and lower your overall risk of disease.

A little goes a long way. Your best diet is one that has a variety of foods, like fruits, vegetables, nuts, seeds, whole grains, and beans. That’s better than a diet that’s too heavy in soy products.

Eating soy in moderation should be fine. But ease into it and see how you do. It's rare, but some people have digestion problems (like stomach pain, loose stools, or diarrhea) when they eat soy. Others are allergic to soy.

Also, "some people have concerns that too much soy can have negative hormonal effects, particularly on men,” Beckerman says. There is some controversy about this. Talk with your doctor or a nutritionist about how much soy you should include in your diet.