 Soy has enjoyed a long-term reputation as a good meat alternative for vegetarians and an elite group of health enthusiasts, but recently the benefits of soy have been discovered by the general public. First, a number of clinical trials examining the dietary effects of soy on cardiovascular diseases, breast and prostate cancers, and osteoporosis—and showing possible statistical significance—began to penetrate the mainstream media. In response to public awareness of these encouraging reports, more foods containing soy began to appear in grocery stores. In October 1999, the Food and Drug Administration granted permission to food manufacturers to label products high in soy protein with a statement that these foods may help to lower heart-disease risk.
Also driving the increasing consumption of soy were rapid changes in our present-day society. Interest in longevity and good health was growing steadily in both baby boomers and seniors, who desired diets with less cholesterol and saturated fat. School- and college-age youth were choosing more plant-based foods due to perceived health reasons and compassion for animals. Double-digit growth in the United States in Asian populations for whom soy is a traditional food created a profitable demand in neighborhood stores and restaurants. For these reasons, soy products are now available everywhere and are being touted as excellent sources of dietary protein.
In her book The Complete Idiot's Guide to Being Vegetarian, Frankie Avalon Wolfe says that soybeans are one of the important foods that contain all of the essential amino acids and are, therefore, "complete proteins." She also believes that "it is almost impossible not to get enough protein in your diet, even as a strict vegetarian or vegan (those who don't eat dairy products or eggs)." For the unconvinced, she says, "just include a soy-based food in your diet every day, and you are ensured of a whole protein." To prove that vegetarian complete-protein meals can be simple and delicious, she offers the following examples: bean burritos (with or without cheese) with Spanish rice; tempeh burger with French fries; nut butter and jelly on whole wheat bread; stir-fry tofu and mixed vegetables, and brown rice; mixed green salad topped with a three-bean salad.
The advantage of including soy in the diet for the nonvegetarian is clear to nutritionist/professor Alice Lichtenstein of Tufts University. "If individuals begin to substitute soy products—for example, soy burgers—for foods high in saturated fat, such as hamburgers, there would be the added advantage of replacing saturated fat and cholesterol in the diet," she says. Whole soy foods are a good source of fiber, B vitamins, calcium, and omega-3 essential fatty acids.
The use of soy, however, is not without some controversy. "Soy by itself is not a magic food," says Christine Lewis of the Center for Food Safety and Applied Nutrition's Office of Nutritional Products, Labeling, and Dietary Supplements, "but rather it is an example of the different kinds of foods that together in a complete diet can have a positive effect on health."
Margo Woods at Tufts University, who holds a doctor of science degree in nutrition, advises, "The story is not all in yet." She is more comfortable recommending soy as a whole food; her concern centers mainly on isoflavone supplements. "There are probably hundreds of protective compounds in soy [foods]. It's just too big a leap to assume that a pill could do the same thing." Daidzein and genistein are common isoflavones offered over the counter in pills or powders to help women lessen menopausal symptoms such as hot flashes. Some studies suggest that high isoflavone levels might increase the risk of breast cancer. While not those studies are not conclusive, some researchers are urging caution with the use of isoflavones.
The evidence for the positive effects of soy protein in the diet is much clearer, and this is why the FDA limited the health claim to foods containing intact soy protein. A science-based agency, the FDA will continue to monitor the evidence as clinical trials continue. For example, trials are in progress at the National Cancer Institute and the National Heart, Lung, and Blood Institute that involve the use of soy and its derivatives in diets for a number of diseases.
For now, we who use soy as a part of a healthy low-fat diet need to learn how to read the labels when buying soy products. Look for foods containing 6.25 grams/serving or more of soy protein that was derived from whole soybeans, or foods that contain isolated soy protein, soy protein concentrate, soy flour, texturized soy protein, or texturized vegetable protein.
The FDA recommends 25 grams of soy per day to get the benefits to heart health. The numbers add up quickly when using the following typical soy foods. Four ounces of firm tofu contains 13 grams of soy protein; one soy burger includes 1012 grams; eight ounces of soy milk provides 10 grams; one-half cup of tempeh delivers 19.5 grams; and one-quarter cup of roasted soy nuts has 19 grams of soy protein.
The American Dietetic Association recommends introducing soy slowly into your new diet plan by mixing it into existing foods. Because the flavor is mild or even neutral, it's possible to add to favorite dishes such as stir fries and stew.
Andrea Dorey is a licensed vocational nurse, medical writer and former AARP president. Contact her at andid@cagreens.org.
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