Genistin is an isoflavone. Isoflavones are derived from plants and are polyphenoic, which means that they have more than one phenol unit per molecule. Phenol is also known as carbolic acid. Many isoflavones act as phytoestrogens when ingested by mammals, which means that they bear a strong molecular resemblance to estradiol, the primary sex hormone in females. Phytoestrogens are able to either encourage or depress estrogen activity in the body.
The most common dietary source of genistin is the soybean, but it is also found in fava beans and coffee. This compound acts as a antioxidant, which means that it can slow or prevent the damage caused by free radicals in the body. Genistin also has functions as an anthelmintic. Anthelmintics are used to expel parasites, such as worms, from the body. Genistin is present in one of the traditional de-worming cures used by the Khasi tribes of India, which uses the Felmingia vestita plant. It contains high levels of genistin, which was identified in a 1997 study as its primary anthelmintic compound.
This compound has also shown some promise in fighting cancer. It and other isoflavones can prevent the formation of new blood vessels, giving them an antiangiogenic effect. It is thought that genistin may prevent the unrestrained growth of cancer cells by limiting their ability to both divide and survive. Multiple studies have demonstrated that this isoflavone has inhibitory properties on colon, brain, breast, and cervical cancers. This compound has also been used to treat post-menopausal women who lack estrogen, by utilizing its phytoestrogenic properties, but the extent of its effect is not well documented.
There have been several concerns raised about the consumption of isoflavones in large quantities by males. First, isoflavones such as genistin can act as phytoestrogens, mimicking estrogen in the body and causing an increase in female sex characteristics. Second, several studies have shown that at certain concentrations, isoflavones can cause the apoptosis, or pre-programmed cellular death, of testicular cells. This has raised concerns about the effect of these compounds on male fertility.
Consumption of genistin is far higher in some parts of the world than others. In Japan, the average daily intake of this compound is between seven and 12 milligrams (mg). North Americans and Europeans generally consume a far smaller amount. Genistin and other isoflavones are not considered nutrients, as they are not required for any essential bodily function, nor does a lack of any isoflavone produce symptoms.