A broad survey of studies on isoflavones, the soy ingredient to which numerous health improvements have been attributed, has found that the best-known beneficial effect of isoflavones is on reduction of cholesterol levels, lowering the risk of heart disease.

"The addition of even small amounts of isoflavone-containing foods to the western diet may reduce the risk of heart disease ... ," a new report published in the July-August issue of the journal Menopause said..

The survey looked primarily at isoflavone effects on menopause, but the report considered numerous other possible applications of isoflavones and soy foods on illness and disease.

" ... There is a growing database of information suggesting that isoflavones exhibit a wide range of diverse physiologic actions in humans," the new report said, recommending that additional studies are needed to determine effects on menopausal problems.

"Specific controlled clinical trials are needed before definitive recommendations can be made about increasing the consumption of isoflavones in large populations of women approaching menopause and beyond," the journal article said.

Considering studies of a lengthy list of illnesses and disease, the survey found that:
  • Isoflavones have been shown to ease menopausal problems, but "more research is needed."

  • On blood pressure, recent animal studies demonstrated that soy lowers high blood pressure, and a test of 5l women showed a significant decrease in diastolic blood pressure when a soy protein supplement was given twice daily.

  • On oxidation, the survey said isoflavones seem to protect LDL cholesterol (so-called bad cholesterol) from oxidation. "These antioxidant effects were observed with relatively low levels of isoflavones," the article reported.

  • On cancer, high concentrations of the isoflavone genistein have inhibited "most types of cancer cells." Soy has been shown to prevent cancer in some breast cancer models. The survey called for further evaluations "before making specific recommendations that western women increase their intake of isoflavones as a preventive measure against breast cancer."
The article reported on isoflavone intake amounts and said:

"Increasing consumption of soy, soy products and plant-based foods in general is supported by current recommendations to increase intake of fiber and antioxidants while lowering intake of saturated fat and cholesterol."

Optimal cholesterol reduction, for example, "seems to require approximately 50 milligrams daily of isoflavones; this amount would be found in approximately 25 grams a day of soy protein, which corresponds to the health claim allowed by the FDA."

The article referred to a decision last year by the U.S. Food and Drug Administration permitting soy food products to be sold with health information noting that soy can be useful in reducing cholesterol and helping prevent heart disease.

The journal article was based on findings by the North American Menopause Society, a scientific organization promoting understanding of menopause and aging.