Absorption of isoflavones in humans: effects of food matrix and processing

Abstract

If soy isoflavones are to be effective in preventing or treating a range of diseases, they must be bioavailable, and thus understanding factors which may alter their bioavailability needs to be elucidated. However, to date there is little information on whether the pharmacokinetic profile following ingestion of a defined dose is influenced by the food matrix in which the isoflavone is given or by the processing method used. Three different foods (cookies, chocolate bars and juice) were prepared, and their isoflavone contents were determined. We compared the urinary and serum concentrations of daidzein, genistein and equol following the consumption of three different foods, each of which contained 50 mg of isoflavones. After the technological processing of the different test foods, differences in aglycone levels were observed. The plasma levels of the isoflavone precursor daidzein were not altered by food matrix. Urinary daidzein recovery was similar for all three foods ingested with total urinary output of 33-34% of ingested dose. Peak genistein concentrations were attained in serum earlier following consumption of a liquid matrix rather than a solid matrix, although there was a lower total urinary recovery of genistein following ingestion of juice than that of the two other foods.

Tempeh flour as a substitute for soybean flour in coconut cookies

“…Isoflavones are present in soy as glucosides, which are biologically inactive, or as aglycones, which are biologically active. After ingestion, the isoflavone glycosides (daidzin and genistin), are converted by the action of hydrochloric acid (HCl β-Glycosidases) present in the stomach and the bacteria present in the intestine into aglycones, which are their most active forms (TERESA et al, 2006). Isoflavones are involved in physiological processes that help reduce the risk of chronic degenerative and non-transmissible diseases, menopausal symptoms, osteoporosis, some cancers, and cardiovascular diseases, and these effects are associated with the consumption of soy (MCCUE;SHETTY, 2004).…”

Excreción Urinaria De Isoflavonas en Adultos Mayores De 65 Años Que Consumen Un Alimento Funcional

“…Esta alta intervariabilidad se atribuye a que en el metabolismo de los fitoestrógenos la microflora intestinal tiene un papel crucial, la que depende de múltiples factores (12,(14)(15)(16), sumado a efectos del tiempo de tránsito intestinal, pH y estado redox del intestino (21), todo lo cual se encuentra a su vez bajo la influencia de la dieta, posible uso previo de fármacos, situación inmunitaria, así como la matriz alimentaria que contiene las isoflavonas, entre otros (24)(25)(26)33). …”

Enhanced Bioavailability of Soy Isoflavones by Complexation with β-Cyclodextrin in Rats

“…3,4) Most isoflavone products sold on the market are either extracts from soybean or soybean products, and contain a number of isoflavone glycoside forms. 5) Isoflavones play an important role in the prevention of menopausal symptoms, 6,7) osteoporosis, 8) breast cancer, 9) and prostate cancer. 10) Moreover, papers about new physiological effects of isoflavone are steadily being published.…”