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Mini Review

The effects of soy isoflavones on obesity

Anne rgaard ¹ and Lotte Jensen ^1*

¹ University of Copenhagen

^* To whom correspondence should be addressed. E-mail: lottejen{at}gmail.com.

	Abstract

Over the last decades, the prevalence of obesity and related diseases has increased rapidly in the Western world. Obesity is a disorder of energy balance and is associated with hyperinsulinemia, insulin resistance, and abnormalities in lipid metabolism, and it is one of the most important risk factors in the development of type 2 diabetes, cardiovascular disease, atherosclerosis, and certain cancers. Due to the lower frequency of these diseases in Asian countries, attention has been turned toward the Asian diet which is highly consistent of soy and soy-based products. The health benefits associated with soy consumption have been linked to the content of isoflavones, the main class of the phytoestrogens. As a result of their structural similarities to endogenous estrogens, isoflavones elicit weak estrogenic effects by competing with 17-estradiol (E2) for binding to the intranuclear estrogen receptors (ERs) and exert estrogenic or antiestrogenic effects in various tissues. The estrogenic activities of soy isoflavones are thought to play an important role in their health-enhancing properties. Additionally, the isoflavones have also been proven to exert non-ER mediated effects through numerous other pathways. Genistein, daidzein, and glycitein are the principal isoflavones in soy. Genistein is the most thoroughly examined of these, because it is the most prevalent isoflavone in soy and also the most active of these compounds, due to its higher binding affinity for the estrogen receptor. Genistein and daidzein can be obtained in high levels in humans under certain nutritional conditions, and epidemiological and laboratory data suggest that these compounds could have human health benefits on obesity. The focus of this review will be on the latest results from research on isoflavones and their effect on obesity in cell cultures, rodents, and humans.

Key Words: isoflavones, obesity, metabolic syndrome