Apparent bioavailability of isoflavones in urinary excretions of postmenopausal Malay women consuming tempeh compared with milk

Abstract

Quantitation of isoflavones in humans is important to establish the benefits of these compounds to the populations. Urinary isoflavones are frequently used as a biomarker of isoflavone bioavailability from food or supplement since urine contains 100-fold higher concentrations of isoflavones. The objective of the present study was to determine and compare the urinary excretions of daidzein (DA), genistein (GE) and equol (EQ) in postmenopausal Malay women following the consumption of tempeh and milk in a calcium absorption study and to test the hypothesis that the excretion of isoflavones following consumption of tempeh maybe higher compared with milk. The amounts of DA (47.06 ± 4.18 μmol/h), GE (33.27 ± 3.71 μmol/h) and EQ (24.35 ± 4.34 μmol/h) excreted in urine following tempeh consumption were significantly higher (P < 0.05) compared with those in milk (3.51 ± 0.62 μmol/h DA, 2.79 ± 0.35 μmol/h GE and 0 μmol/h EQ). Almost all studied postmenopausal Malay women were able to excrete EQ following consumption of 240 g tempeh but only one subject can be classified as an equol producer. We concluded that most postmenopausal Malay women excreted DA, GE and EQ in their urine following tempeh consumption and the amount of the excreted isoflavones were higher compared with those in milk. However, further studies are needed to determine whether longer periods of time are required to capture EQ producers.

Germination conditions influence the physical characteristics, isoflavones, and vitamin C of soybean sprouts

“…Soybean isoflavones are bioactive compounds that benefit human health and are divided into four groups: β-glycosides (daidzin, genistin, and glycitin); 6''-O-acetylglycosides (acetyldaidzin, acetylgenistin, and acetylglycitin); 6''-O-malonylglycosides (malonyldaidzin, malonylgenistin, and malonylglycitin; and aglycones (daidzein, genistein, and glycitein) (Falcão et al, 2018). Soybean isoflavones have also been extensively investigated because of their positive effects, including antioxidant and hypocholesterolemic activity, prevention of menopausal symptoms, and cardiovascular diseases; besides, such isoflavones protect against bone loss in postmenopausal symptoms, in women, and against the development of breast and prostate cancers (Haron et al, 2011;Dong et al, 2013;Wada et al, 2013;Liu et al, 2017;Ramdath et al, 2017).…”

The Soy Isoflavone Equol May Increase Cancer Malignancy via Up-regulation of Eukaryotic Protein Synthesis Initiation Factor eIF4G

“…This concentration of equol has been found in the urine of humans after consumption of soy foods (51).…”

Efectos de la inclusión de dietas ricas en flavonoides en la calidad de la leche bovina

“…Se reitera que el tipo de efecto producido por los flavonoides es concentración dependiente y varía de acuerdo con el receptor sobre el que actúe, de manera que dicho efecto no se puede considerar completamente adverso o benéfico. Entonces, el efecto puede ser estrogéni-co, y por ello la presencia de flavonoides en los alimentos ayuda a disminuir las alteraciones propias de la menopausia y aquellas relacionadas con la falta de estrógenos (acción estrogénica moderada), o bien disminuir los tumores mediados por estrógenos (acción antiestrogénica) y solo en casos de sobredosis produce alteraciones reproductivas consideradas como indeseables (47,48).…”