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Isoflavones - the Active Ingredients in Soybean

Soybean is becoming a popular food ingredient. More and more consumers are looking for products that contain soybean, and fortunately the grocery stores have many soy-based foods. Food manufacturers have been happy to find that alternatives to replace traditional meat and milk products using soy have been relatively easy to produce. Foods containing textured soy have the same taste and mouth feel as equivalent meat products. Soy beverages abound and, although the flavoured varieties are popular, the natural soy drinks have lost the bean flavour that initially turned many consumers off. Soy products include soy-meat paddies, soy cheese, soy ice cream soy yogurt - the list keeps growing.


Isoflvones are the active ingredients in soybeans. Interest in soy has grown because it has been shown that the isoflavones in soybean have weak estrogen-like properties. Women who question hormone replacement therapy and are looking for natural ways to reduce the effects of menopause have turned to soybean.

There are three major isoflavones in soybean - daidzein, genistein, and glycitein. Tofu, soybean sprouts, miso and tempeh all have high isoflavone levels. Soy sauce is a poor source of soy isoflavones.

Asians are known to consume high levels of soybean and, therefore, isoflavones. Typically Asians consume 20-80 mg of isoflavones per day. At the present time food labels do not contain information about isoflavone levels. But, as consumer interest grows, don’t be surprised to see daidzein, genistein, and glycitein levels quoted on product labels.

Chemical Structure of Daidzein, Genistein, and Glycitein

Isofafone R1 R2 R3
Daidzein:H H OH
Genistein:OH HOH
Glycitein:H OCH3 OH


USDA Database for the Isoflavone Content of Selected Foods
National Agricultural Library

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