Dietary sources of isoflavones

Soybeans (Glycine max) are protein-rich legumes widely grown around the world as a food crop. They are the major dietary source of isoflavones, which are broken down in the intestine into the phytoestrogens genis-... 

The anticancer effect of soy, the only relevant dietary source of isoflavones and the main candidate foodstuff responsible for the cancer protection conferred by Asian diets, has been tested in a number of animal studies. Messina et al. [204] reviewed 26 such studies published up to 1994 (gastrointestinal and non gastrointestinal). Seventeen of them (65%) reported a protective effect and none found a potentiation of carcinogenesis. One study has examined the effect of feeding a soy protein diet in a genetic... 

Y (1999) Dietary intake and sources of isoflavones among Japanese. iVnlr Cancer. 33 (2) 139 5. 

Isoflavones are a class of phytoestrogens with estrogenic activity. They are related to isoflavonoids. Isoflavones are produced almost exclusively by members of the Fabaceae (Leguminosae) family. Soy products and soybeans are the richest sources of isoflavones that humans consiune [43]. Recent surveys suggest that the average dietary isoflavone intake in Asian countries ranges from 25-50 mg/day [44]. Dietary isoflavone intakes are considerably lower in Western countries, where on average intake is as low as 2 mg/day. Soy products that are... 

Dietary isoflavones come from traditional soy foods (SF), modem soy products (a new source of isoflavones in Western populations, e g., soy buigers, soy yoghurts), and commonly consumed foodstuffs which contain soy flour or soy protein isolates (SPI). The isoflavone content of traditional SF, e g., miso, soy milk, tofu, and modem soy products vary... 

Wakai, K., Egami, I., Kato, K., Kawamura, T., Tamakoshi, A., Lin, Y., Nakayama, T., Wada, M., and Ohno, Y. 1999. Dietary intake and sources of isoflavones among Japanese. Nutr Cancer... 

Component biomarkers are found more easily than food biomarkers, because food markers are included within component biomarkers. For example, plasma isofla-vones are measured as a marker of the exposure to isoflavones, although as they have an almost unique dietary source, soybean products and their derivatives. 

Aside from possible exposure through drinking water sources, dietary exposure to EDCs results from components of diet known as bioflavanoids, phytohormones, or phytoestrogens. These natural plant hormones are less potent than the estrogens found in mammals and in terms of a mass balance approach it has been suggested that the action of such weak or antiestrogens may work to combat the action of elevated environmental estrogen exposure. Some flavones and isoflavones may play an important role in cancer prevention as they are found in plants that are associated with reduced cancer rates. 

Flavonoids are also important antioxidants in many food sources. Flavonoids are divided into anthocyanins, flavanols/flavans, flavanones, flavones, flavonols, and isoflavones/isoflavonoids [15]. The sum of individual flavonoids (SIF) can be a simple indicator of flavonoid levels in dietary food sources which provides useful information for their potential benefits in human health. 

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