Genistein is an aglycone and part of the family of plant isoflavones. While it occurs naturally in soya beans, it can also be prepared in a purer, synthetic form. Isoflavones have similar chemical structures to human estrogen. Over the past few decades, evidence has emerged that genistein intake may have health benefits that span heart disease, reduced onset levels for breast and prostate cancer, and bone health.
Genistein is thought to benefit heart health through maintaining normal arterial elasticity and hence helping prevent hypertension. More specifically, genistein may help prevent cardiac hypertrophy. This condition involves abnormal enlargement and thickening of the heart muscle often a result of high blood pressure (hypertension) or valvular disease. A recent study (1) has shown genistein is able to reduce cardiac hypertrophy in vivo. The authors suggest the underlying mechanisms of genistein activity may be associated with blocking the JNK1/2 signalling pathways. Additionally, a new paper (2) suggests that genistein can provide protection against the risk of ischaemic stroke. The authors suggest the mechanism is through the reduction of oxidative stress, promotion of growth factor signalling, and immune suppression in endothelial, glial and neuronal cells.
Research suggests that genistein intake can reduce levels of 8-Epiprostaglandin and 5 Hydroxymethyl 2-desoxyuridine in the blood. These markers are associated with a reduced risk of the onset of prostate cancer (3). It is believed genistein can reduce oxidative DNA damage, which lead to elevated levels of these markers. Further, genistein intake is associated with raised levels of blood enzymes that are able to help clear toxic metabolites e.g. Glutathion-S-transferase, Quinone reductase and UDP-glucuronosyl transferase. In addition, it is suggested genistein may have a beneficial effect in providing protection against the onset of breast cancer. Genistein alone is able to induce apoptosis (cell death) in some breast cancer cells, but this can be enhanced if equol, a bioactive metabolite of daidzein (another isoflavone), is present (4).
Genistein is believed to be beneficial for bone health though maintenance of bone mineral density. Specifically, it is thought to downregulate the resorption marker desoxypyridinoline while upregulating the bone synthesis markers IGF-I protein and bone alkaline phosphatase.
Estrogen deficiency is a major contributor to the development of osteoporosis in older women. Genistein is able to bind to estrogen receptors. However, to date, the results of human intervention studies have been mixed and further work is required (5).
A recent pre-clinical study (6) has demonstrated that genistein may play a neuroprotective role in Alzheimer's disease through regulating CAMK4 (calcium/calmodulin dependent protein kinase IV) and thus reducing the hyperphosphorylation of tau protein. It is the excessive phosphorylation of tau protein that causes production of neurofibrillary tangles, which is one of the main pathological characteristics of Alzheimer's disease.
Current research demonstrates that genistein is a safe, potent, bioactive molecule with an increasing range of beneficial effects in serious non-communicable diseases.
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