phytoestrogen supplements should not be recommended, particularly for women at high risk of breast cancer.
We get phytoestrogen supplements traditionally from soy foods, soy-milk and isolated soy protein, during food processing or as beverage. This supplements are marketed in various forms. Consumers of phytoestrogen supplements tend to be peri- and postmenopausal women looking for an alternative to hormone therapy even though there are no approved health claims for phytoestrogen at this time, numerous claims are being made regarding benefits to heart, bone, breast and general menopausal health.
Estrogen is a hormone released in a woman's body that regulates her menstrual cycle. The body's endocrine system is responsible for producing this hormone. Phytoestrogens on the other hand are weak estrogen found concentrated in soybeans and other plants. Phytoestrogen imitate estrogen because their chemical structure is very similar to that of estrogen from the body. When phytoestrogen enters the human body, the body's estrogen receptors treat them as if they were estrogen. Phytoestrogens are endocrine disruptors because they are chemicals that disrupt normal hormonal function but does not bind to estrogen receptors as firmly as estrogen produced by the body, so their effects may be weaker.
The strongest data show that phytoestrogens reduce the number and intensity of hot flashes, although the reduction is a modest 10–20%. The studies showing cholesterol lowering have used soy protein rather than phytoestrogen extracts. The soy protein appears to be required for this effect, although phytoestrogen extracts may have other beneficial effects on the cardiovascular system. The data on bone metabolism are suggestive of possible benefits whereas the effects on the breast are the most poorly understood.
Studies show phytoestrogens may provide similar benefits to the synthetic estrogen used in hormone replacement therapy. However, this does not mean that they are safer than synthetic estrogen. They act in a similar way and may carry the same risks. These include increased risk of obesity, cancer, problems with reproduction and others.
The data supporting these claims are generally not strong but in the 2010 studies, it was found that high levels of soy in a woman's diet could affect how her ovaries' function. Although most animal studies have shown cancer-preventive effects, a few recent studies suggest that soy phytoestrogens may stimulate breast cancer cell growth under certain circumstances.
It is believed to be healthy to eat a plant-based diet, and many plant foods contain phytoestrogens. More research is needed to fully understand how phytoestrogens work, as it is not clear whether consuming them in high levels carries any health risks. Unless a person is taking phytoestrogen supplements, it is unlikely they could consume a harmful level, however.
Before recommendations regarding phytoestrogen supplements can be safely made, we must have more information on the effects of the extracts on bone, heart and breast health. Until safety with respect to breast cancer is established.
