The skinny on soy

By Karen Collins, R.D.

How can you get more soy in your diet? How much does it take to lower blood pressure? How healthy are soynuts? Nutritionist Karen Collins serves up answers on eating soy products.

Q: I’d like to try including soy foods in my diet, but I’m not sure how to start.

A: Soy milk can be used just as you would cow’s milk — for drinking, with cereal or in cooking. (If this means your use of dairy products is limited, be sure to choose soy milk that is fortified with calcium and vitamin B-12.) If you are trying to cut back on the amount of meat you eat, several soy foods could work as meat substitutes in dishes like casseroles and stir-fries, and would provide protein and minerals.

Firm tofu, tempeh or a variety of soy-based meat substitutes (check the freezer or boxed entrée sections of the grocery store) fill in very nicely. Soft and silken types of tofu can replace ricotta cheese in pasta dishes and cream or sour cream in sauces and dressings.

If you’re trying to cut back on crunchy snack foods, soynuts make a nutritious substitute. Edamame (pronounced “aid-a-MOM-eh” and sometimes marketed as “sweet beans”) are found in the frozen vegetable section and can serve as a snack or side dish. Soy foods do not magically transform an unhealthy diet into a healthy one, but they have a lot to offer as part of a balanced, plant-based diet.

Q: I read that eating 25 grams of soy protein a day will lower blood cholesterol. How much soy does it take to do that?

A: Soy foods differ in their concentration of soy protein.

A 1-cup serving of green soybeans, or edamame, has slightly over 25 grams of soy protein all on its own. Snacking on a quarter-cup of soynuts gives you 15 grams of soy protein.

Tempeh, which can be used as a meat substitute in a casserole or stir-fry, for example, contains about 17 grams per half-cup.

A half-cup of tofu provides about 10 grams, and each cup of soy milk contains 6 to 10 grams.

Just two or three concentrated sources of soy could bring you to the 25 gram mark. On the other hand, some cereals, meat alternatives, grain products and other foods offer soy protein in such small amounts that it could take four to 12 servings to reach that target. Although the 25 gram goal is supported for cholesterol reduction by several studies, a recent Journal of the American Dietetic Association study found that adding soy to a diet already low in saturated fat did not produce any additional cholesterol reduction. Soy may be helpful in lowering risk of some cancers, but the question is still under study. If soy does help lower cancer risk, some researchers believe about 20 grams of soy protein a day would provide benefits, but others think that having soy foods even a few times a week might help.

Q: How do soynuts compare to peanuts in nutritional benefits?

A: Both are good sources of protein, but soynuts are lower in fat and calories. In a standard quarter-cup serving, soynuts contain 190 to 200 calories and 9 to 11 grams of fat, while peanuts provide 210 to 215 calories and about 18 grams of fat. (There is only a 1 gram difference in saturated fat between them.) In addition to containing more protein and carbohydrate than peanuts, soynuts provide phytoestrogens, natural plant substances that scientists are studying for possible benefits in reducing the risk of some cancers and heart disease, and in relieving symptoms of menopause. Whichever of these healthy choices you prefer, watch your portion size — calories can add up quickly.

(Nutrition Notes is provided by the American Institute for Cancer Research in Washington, D.C.)