Isoflavone Levels in Soy Foods Consumed by Multiethnic Populations in Singapore and Hawaii
ABSTRACT Concentrations and glucosidic conjugation patterns of isoflavones were determined in soy foods consumed by multiethnic populations in Singapore and Hawaii. Six raw and 11 cooked food groups traditionally consumed in Singapore and 8 food groups consumed in Hawaii were analyzed by reversed-phase high-pressure liquid chromatography with diode array detection. Mean total isoflavone levels varied between 35 and 7500 ppm, with the lowest values found in soy milk and burgers and the highest levels observed in soybean and its seeds and in supplements. Total isoflavone levels and conjugation patterns varied as a function of soybean variety, storage conditions, and food processing. A large contribution to the differences in total isoflavone content between food groups was due to the water content in foods and to leaching of polar analytes into the water phase during boiling. Soy protein drinks and traditional soy foods were found to possess very similar isoflavone amounts considering usual serving sizes. Keywords: Isoflavones; genistein; daidzein; glycitein; isoflavone conjugates; soy foods; supplements; high-pressure liquid chromatography; diode array detection
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ABSTRACT: Recent studies have suggested that natural agents such as isoflavones, resveratrol, and anthocyanin have beneficial effects on metabolic syndrome-related disorders. The objective of this study was to evaluate dietary isoflavone intake, urinary isoflavone level, and their relationship with the risk of metabolic syndrome (MetS) among Korean postmenopausal women. The subjects included 46 MetS and 60 controls. The MetS risk score was determined by adding the number of risk factors such as waist circumference, blood pressure (BP) and levels of triglyceride (TG), HDL-cholesterol, and glucose. Dietary isoflavone intake was not significantly different between the MetS and control groups; however, the urinary daidzein level was significantly higher in the MetS subjects compared to that of the controls. Subjects with high TG had higher urinary daidzein and isoflavone (daidzein + genistein) levels than those without such abnormalities. But, the MetS risk score showed no significant correlation with urinary daidzein, genistein, and isoflavone excretions.Clinical nutrition research. 01/2013; 2(1):59-66.
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ABSTRACT: The total isoflavones in tempeh and selected local soy products was determined. Raw tempeh contained 26 ± 6 mg daidzein (Da) and 28 ± 11 mg genestein (Ge) while fried tempeh contained 35 ± 11 mg Da and 31 ± 11 mg Ge in 100 g (wet basis). Total isoflavone content in 100 g of raw tempeh, based on a dry weight, was 205 ± 56 mg and significantly reduced to 113 ± 41 mg in 100 g of fried tempeh. Tempeh in batter was deep-fried for 30 min which reduced 45% of the total isoflavone content compared to the raw one. Raw tempeh contained the highest total content of isoflavone among the studied local soy products. Total isoflavone content in processed soy foods like egg tofu and home made soybean drink were significantly lower than other soy products studied.
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ABSTRACT: We conducted a double-blind, randomized, placebo-controlled trial to evaluate the effects of soy-derived isoflavone on blood glucose, lipid profiles, and sex hormones related to cardiovascular disease in Korean postmenopausal women. One hundred thirteen postmenopausal women were recruited from the Seoul metropolitan area. To confirm postmenopausal and gynecologic status, the subjects were clinically examined by a gynecologist using ultra sound and X-ray. Finally, 85 postmenopausal women whose follicle-stimulating hormone (FSH) levels were higher than 40 IU/ml were enrolled. Subjects received either 70 mg isoflavone or placebo capsules daily for 12 weeks. As a result, the values of fasting glucose, insulin and HOMA-IR, as well as those of TC, LDL-C, HDL-C and FFA, were not different between the groups after supplementation. However, triglyceride (TG) levels in the treatment group decreased significantly compared with those of the placebo group (p = 0.0215). The levels of luteinizing hormone (LH) significantly decreased in the treatment group (p = 0.027); however, the levels of FSH, estrone and estradiol were not changed after intervention. In conclusion, isoflavone supplement of 70 mg/day for 12 weeks decreased blood levels of TG and LH in Korean postmenopausal women.Archives of Pharmacal Research 03/2013; · 1.54 Impact Factor