Genistein and Bone Health: Risks and Benefits

Genistein, a type of photoestrogen, is used to treat osteoporosis in post-menopausal women.  Some, but not all studies have found that genistein can improve bone mineral density in this demographic.1,2,3,4  It is often used as an alternative to hormone replacement therapy (HRT) which has been found to increase the risk of endometrial and breast cancer.   

Phytoestrogens can be found in over 300 food sources such as fruits, grains and herbs.  Isoflavones are one of the main types of dietary phytoestrogens, and they are found primarily in soybeans, soy products, chickpeas and other legumes.  Soy is the most common source of isoflavones, and genistein is the isoflavone that is most abundant in soy.  Genistein has gained a lot of attention because it was observed that those who consume Asian diets, which are high in soy, have a lower incidence of post-menopausal osteoporosis, among other diseases, than those who consume the typical “western” diet. 

Although genistein seems to have some promising effects on preventing and treating osteoporosis, it may be too early to start recommending it as a supplement.  More research is needed to determine the optimum dosage and whether the benefits pertain to those with severe osteoporosis, since most studies have been done on those with mild to moderate levels of this disease.  There are also some questions as to the safety of taking soy isoflavones in certain populations.  Some studies have found that soy-based diets may have potential anti-cancer benefits, making genistein a good alternative to hormone replacement therapy.  However, other studies have found that genistein may have some cancer-promoting effects.5,6  Currently, the National Institutes of Health (NIH) is undergoing several studies to clarify the risks and benefits of taking these supplements.  At this point in time, it would be best to talk to your doctor before taking a genistein supplement.

1. Yamaguchi, M. Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis. Yakugaku zasshi. 2006; 126:1117-1137.

2. Marini H, Minutoli L, Poilito F, et al. Effects of the phytoestrogen genistein on bone metabolism in osteopenic postmenopausal women.  Ann Intern Med. 2007; 146:839-847.

3. Morabito N, Crisaffuli A, Gaudio A, et al. Effects of genistein and hormone-replacement therapy on bone loss in early postmenopausal women: a randomized double-blind placebo-controlled study. J Bone Miner Res. 2002; 17: 1904-1912.

4. Zhang G, Qin L, Shi Y. Epimedium-derived phytoestrogen flavonoids exert beneficial effect on preventing bone loss in late postmenopausal women: a 24-month randomized, double-blind and placebo-controlled trial. J Bone Miner Res.  2007;22:1027-1079.

5. Bouker KB, Hilakivi-Clarke L.  Genistein: does it prevent or promote breast cancer? Environmental Health Perspectives. 2000;108:8.

6. Allred CD, Allred KF, Ju YH, et al. Dietary genistein results in larger MNU-induced, estrogen-dependent mammary tumors following ovariectomy of Sprague-Dawley rats. Carcinogenesis. 2004; 25:211-218.