Health claims for soy abound

April 13, 1999

Health claims for soy seem too good to be true. How could one product, and a bean at that, be so good for you? Not only is soy a high-quality protein, it may help prevent or treat cardiovascular disease, cancer, osteoporosis and menopausal symptoms.

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The most well-documented health claim for soy is its cholesterol-lowering effect. In a 1995 analysis of 38 studies, researches showed that eating soy protein resulted in significant reductions (approximately 10 percent) in total cholesterol, LDL cholesterol and triglycerides, and slight increases (approximately 2 percent) in HDL cholesterol levels. Decreases were greater in people with high blood cholesterol levels than in those with normal levels.

The results have been enough for Protein Technology International of St. Louis to convince the Food and Drug Administration to allow health claims on certain soy-based products.

The rules regarding the claims are not yet out, but 6.25 grams of soy protein and 12.5 milligrams of total isoflavones (a phytochemical commonly referred to as phytoestrogens or estrogens) per serving are the minimum levels being proposed for a food to bear the health claim. Isoflavones have been highlighted as a possible way in which soy exerts its cholesterol-lowering effect. The exact mechanisms, however, are not well understood.


As for cancer prevention, while several anticarcinogens have been identified in soybeans, most research again has focused on isoflavones. To a mild degree, these plant chemicals imitate the human hormone estrogen. It is in this capacity, many researchers believe, that soy foods may have some benefit for those at increased risk for certain hormonally-related cancers, including breast and prostate cancer.

At this point, the cancer connection is weak. Research data on soy intake and cancer risk are inconsistent. Clinical trials on soy's role in reducing cancer risk are needed. It could take several years of research to fully examine the relationships between soy and cancer risk.

Soy foods also are being studied for their effects on bone health and postmenopausal symptoms. Again, isoflavones are being examined as the possible mechanism. In a recent study, 60 grams of isolated soy protein daily for three months reduced hot flashes by 45 percent in 104 postmenopausal women. More study is needed before recommendations can be made on soy as a potential substitute for hormone replacement therapy. On the other hand, women who choose not to use standard estrogen-replacement therapy might want to look for ways to increase soy foods in their diet.

Most soy products taste a little different when you first try them, but then so do most new foods. The key is to keep trying them and to try them in different ways. Because soy foods come in so many forms, they are one of the easiest, most adaptable foods to add to your diet. It just takes a little sense of adventure and experimentation to fit soy into a healthful diet.

Maryland Cooperative Extension programs are open to all citizens without regard to race, color, sex, disability, age, religion or national origin.

Fruit Smoothie

  • 1 10-ounce package of soft lite silken tofu
  • 1 medium banana
  • 2 cups unsweetened orange-pineapple juice, chilled
  • 1 8-ounce can unsweetened crushed pineapple, chilled

Combine all ingredients in electric blender; cover and process until smooth. Serve immediately.

Yield: 5 cups.

Serving size: 1 cup; 144 calories; 5.8 grams protein; 25.8 grams carbohydrates; 3.2 grams total fat; 0.5 grams saturated fat; 0 milligrams cholesterol; 6 milligrams sodium.

Strawberry-Banana Frosty

  • 3 cups plain or vanilla soy milk
  • 1 12-ounce box frozen sliced strawberries
  • 1 ripe banana

Blend in blender until smooth.

Yield: 4 servings.

Serving size: 1 cup; 167 calories; 5.7 grams protein; 31.9 grams carbohydrates; 4 grams total fat; 0.44 grams saturated fat; 0 milligrams cholesterol; 24 milligrams sodium.

Lynn F. Little is a family and consumer sciences extension educator for Maryland Cooperative Extension, Washington County - University of Maryland.

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