Isoflavones are a type of naturally occurring isoflavonoids, Isoflavones occur in many plant species, but are especially high in soybeans. Some studies indicate that isoflavone supplementation may help lower the risk of hormone-related cancers.
Substituted isoflavone derivatives are related to the parent by the replacement of two or three hydrogen atoms with hydroxyl groups. green bean (Phaseolus vulgaris L.), alfalfa sprout (Medicago sativa L.), mung bean sprout (Vigna radiata L.), cowpea (Vigna unguiculata L.), kudzu root (Pueraria lobata L.), and red clover blossom and red clover sprout (Trifolium pratense L.) have been studied for their estrogenic activity. Highly processed foods made from legumes, such as tofu, retain most of their isoflavone content, and fermented miso, which has increased levels.
Other dietary sources of isoflavones include chick pea (biochanin A), alfalfa (formononetin), and peanut (genistein). Isoflavones are also found in foods of animal origin such as dairy products, meat, eggs and seafood, but the overall contribution to total intake is low. In countries using the chorleywood bread process, such as in the UK, bread is a source of isoflavones from soy.
In plant tissue, they most often occur as glycosides or their respective malonates or acetyl conjugates,
Research
The consumption of isoflavones-rich food or dietary supplements is under preliminary research for its potential association with lower rates of postmenopausal cancer and osteoporosis in women. Use of soy isoflavone dietary supplements may be associated with reduction of hot flashes in postmenopausal women.
Despite the frequent use of isoflavone supplements, there are insufficient data on safety and adverse effects. In a risk assessment of isoflavone supplements for post-menopausal women, the European Food Safety Authority found no adverse effects with intakes up to 150 mg/d, although it criticized the lack of data.
See also
- Equol
- Glycitein
- Isoflavonoid
- Phytochemical
- Rotenoids