Estimated dietary isoflavone intake of Korean population based on National Nutrition Survey.

The dietary isoflavone intake of the Korean population was estimated based on data from the Korean National Nutrition Survey conducted in 1995, which included 3224 male and 3475 female subjects with a wide age range. Data on the isoflavone content of soybeans and their products were collected from a literature survey of Korean journals. This information was then screened based on the methodological validity, compared with values reported in international journals, and an average value adopted for each food. Thereafter, the total isoflavone intake per capita was estimated as 14.88 mg/d, which was attributed to genistein (7.32 mg), daidzein (5.81 mg), and glycitein (1.75 mg). Soybeans and three traditional soy foods (tofu, soybean paste, soybean sprouts) contributed to more than 94% of the total isoflavone intake of the Korean population. Slight differences in the isoflavone intake level and pattern were observed between the various residential areas. The rural and urban isoflavone intakes were estimated at 15.18 and 14.85 mg per capita, respectively. Rural residents were more dependent on soybeans than processed soy products for their isoflavone intake, while urban residents extracted more isoflavones from tofu, compared to their rural counterparts. The total isoflavone intake reported in this study may be underestimated, as other products containing soyflour and soy protein were not accounted for.