Estimated intakes of isoflavones and coumestrol in Korean population

Abstract

The dietary intakes and sources of isoflavones and coumestrol were estimated for each age group of Koreans based on data from the Korean Nutrition Survey conducted in 1998. For quantitative data on the levels of isoflavones and coumestrol, our previous study monitoring phytoestrogens in 220 Korean leguminous foodstuffs was employed and the median value for each food was adopted. The total isoflavones and coumestrol intake per capita was estimated as 23.3 mg/day, which constituted 14.2 mg daidzein, 6.7 mg genistein, 0.9 mg glycitein, 1.0 mg formononetin, 0.2 mg biochanin A, and 0.3 mg coumestrol. The top five foods arrowroot, soybean paste, tofu, soybean, and soybean sprout contributed to 88.2% of isoflavone intake, with the corresponding intake from each food being 8.3 mg/day, 4.9 mg/day, 2.6 mg/day, 2.5 mg/day, and 2.0 mg/day, respectively. Starting at age 3-6, the contributions of fermented soy products to the isoflavones intakes were around 30%. Soybean sprout was a major source of coumestrol intake in Koreans. Slight differences in the preference of these foods were observed among the various age groups. As regards the total isoflavone intakes, the highest value was 33.6 mg/day for people age 30-49, followed by age 50-64 (26.4 mg/day), 20-29 (21.0 mg/day), >or=65 (18.8 mg/day), 1-2 (14.5 mg/day), 7-12 (12.4 mg/day), 13-19 (10.1 mg/day), and 3-6 (8.9 mg/day). The intake levels are likely to be exceeded in groups who have preferably consumed high phytoestrogen-containing foods such as soy-protein-based infant formula and arrowroot.

Effect of dietary soy intake on breast cancer risk according to menopause and hormone receptor status

“…Finally, as the FFQ used in this study was not designed specifically for soy intakes, we may have missed some relevant information; however, the underestimation of soy intake would introduce random misclassification in both case and control groups nondifferentially and would likely move the effect estimates toward the null. However, the soy intake reported by this population was similar to the data from the Korea National Health and Nutrition Examination Survey conducted in 2007 (MIHWAF, 2007) and is estimated to cover B70% of isoflavone consumption in Koreans (Surh et al, 2006). Estimated isoflavone intake appears to be lower than the reports from Japan (425 mg per day), but comparable with intakes of other Asian countries (o20 mg per day) (Messina et al, 2006b).…”

Development of an Updated Phytoestrogen Database for Use With the SWAN Food Frequency Questionnaire: Intakes and Food Sources in a Community-Based, Multiethnic Cohort Study

“…Thus consumption of this class of phytoestrogen should be common in both diets, although estimated intakes are few and exact food sources are likely to differ (43, 47, 48, 54). Assessments of coumestan in the diet are similarly rare; because tofu is one source, one might expect higher relative intakes in Asian compared to non-Asian samples (46, 55–57). …”

Potential Health-modulating Effects of Isoflavones and Metabolites via Activation of PPAR and AhR

“…Hence, the isoflavone intake among Asians is about a factor of 100 higher than that of people in the Western world. The daily isoflavone intake among Southeast Asians ranges between 15 and 47 mg [10,11,12,13,14,15,16], while Western people consume only between 0.15 and 1.7 mg isoflavones per day [17,18,19,20,21]. …”