Soy the Subject of Serious Research

Once A Day For Life | April Is Soyfoods Month

WASHINGTON, D.C. - Familiar products, improved taste, colorful packaging, increased visibility and reasonable price all contribute to a new popularity for soyfoods in the United States. This surge toward soy can also be traced to positive publicity surrounding serious research into these unique beans.

Medical and scientific interest centers around substances found in soy called phytoestrogens. Phytoestrogens are a natural plant estrogen. According to John J.B. Anderson, Ph.D., and Sanford C. Garner, Ph.D. in the 1997 November/December issue of Nutrition Today, phytoestrogens can be taken up by any cell in the body. Reproductive tissues are particularly responsive to phytoestrogens because they contain the greatest number of estrogen receptors. Unfolding research has revealed important advances in understanding the effects of phytoestrogens on the cells of these tissues.

Of special interest are the soy-derived phytoestrogens, primarily the isoflavones genistein and daidzein. Researchers are discovering the potential health benefits a diet rich in isoflavones might confer. Isoflavones are widely distributed in the plant kingdom, with highest concentrations found in legumes, particularly in soybeans.

Soy and Menopause

Hot flashes almost reduced by half. Recent findings suggest soy's estrogenic properties may decrease hot flashes and reduce bone loss in menopausal women. A study at the University of Bologna, Italy, published in the January 1998 issue of Obstetrics and Gvnecolo_~v/, found that "soy was significantly superior to a placebo in reducing the mean number of hot flashes per 24 hours after 4, 8 and 12 weeks of treatment." By the end of the study period, women taking soy had a 45 percent reduction in the number of hot flashes they experienced daily compared to a 30 percent reduction in the placebo-treated women.

An 18-week study at the Bowman Gray School of Medicine in North Carolina found that when women who were experiencing hot flashes added 20 grams of powdered soy protein to their daily breakfast for six weeks, their hot flashes significantly lessened in severity (though they occurred as often). The soy was also linked to an average 10 percent drop in total blood cholesterol and a 12 percent drop in the "bad" LDL cholesterol. In addition, soy supplementation doesn't appear to create ~he negative symptoms sometimes associated with more traditional hormone replacement therapies.

Soy and Heart Disease

A large body of evidence suggests that consumption of soy protein provides health benefits including reduced risk of cardiovascular disease. Plus, epidemiological evidence suggests that people consuming soyfoods in fairly high amounts are less likely to die of heart disease.

Soy reduces the "bad" LDL cholesterol and increases the "good" cholesterol. James W. Anderson, M.D., professor of medicine and clinical nutrition at the University of Kentucky, found that soy protein intake was accompanied by a significant 9.3 percent reduction in serum cholesterol, a significant 12.9 percent reduction in the "bad" LDL cholesterol, a significant 10 percent reduction in serum triglycerides, and a 2.4 percent increase in the "good" HDL cholesterol. For general prevention of atherosclerotic cardiovascular disease, Anderson recommends seven servings of soy protein a week providing an average of about 8 to 10 grams of soy protein daily. This amount can be obtained from 8 oz. of soy beverage daily, two soy muffins daily or 1 tablespo6n (14 g.) of isolated soy protein stirred into a beverage daily.

It has long been recognized that diets rich in soy protein reduce cholesterol, and the fiber, isoflavones and antioxidants in soy have beneficial effects on the cardiovascular system. However, the exact mechanisms for these properties are unclear. A recent study has discovered that the isoflavone genistein appears to be responsible for much of soy's cardiovascular benefits.

To enjoy the potential benefits of soy, everyone can begin by adding soyfoods once a day for life.

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The Soyfoods Association of North America is a nonprofit trade organization that has been promoting consumption of soyfoods in the American diet since 1978

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