Recent growing interest in health and the diet has led to an increased focus on soy foods and their functional components,
e.g., isoflavones. The labeling and isoflavone content of 20 commercially available health foods were assessed. The isoflavone content (aglycone equivalents) in one serving of soymilk was in the range of 20-29 mg, these values being almost the same as those reported on the labels of these foods. However, one soft drink had an isoflavone content 1/3 of the value reported on its label. Some powdered foods,
e.g., kinako, contained 6-18 mg of isoflavones in one serving; the isoflavone content reported on the labels of these foods was almost equivalent to the actual isoflavone content of the foods. The isoflavone content of such solid foods as tablets, dried soybean, and soy snacks was in the range of 3-46 mg. One tablet contained only 2/3 of the isoflavone content reported on its label. Based on the presence of 12 isoflavone components, a wide variety of isoflavone components and contents was noted, and the foods were classified into three types: soymilk, soy extract preparation, and soybean. Differences in the isoflavone components of the health foods would vary the absorption rate and effect of the foods. Furthermore, differences in the age, sex, and individual characteristics of consumers also need to be considered when assessing the effectiveness and safety of isoflavone-containing health foods.
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