Beneficial role of dietary phytoestrogens in obesity and diabetes

Abstract

Evidence is emerging that dietary phytoestrogens play a beneficial role in obesity and diabetes. Nutritional intervention studies performed in animals and humans suggest that the ingestion of soy protein associated with isoflavones and flaxseed rich in lignans improves glucose control and insulin resistance. In animal models of obesity and diabetes, soy protein has been shown to reduce serum insulin and insulin resistance. In studies of human subjects with or without diabetes, soy protein also appears to moderate hyperglycemia and reduce body weight, hyperlipidemia, and hyperinsulinemia, supporting its beneficial effects on obesity and diabetes. However, most of these clinical trials were relatively short and involved a small number of patients. Furthermore, it is not clear whether the beneficial effects of soy protein and flaxseed are due to isoflavones (daidzein and genistein), lignans (matairesinol and secoisolariciresinol), or some other component. Isoflavones and lignans appear to act through various mechanisms that modulate pancreatic insulin secretion or through antioxidative actions. They may also act via estrogen receptor-mediated mechanisms. Some of these actions have been shown in vitro, but the relevance of these studies to in vivo disease is not known. The diversity of cellular actions of isoflavones and lignans supports their possible beneficial effects on various chronic diseases. Further investigations are needed to evaluate the long-term effects of phytoestrogens on obesity and diabetes mellitus and their associated possible complications.

The effect of equol injection in ovo on lipid metabolism and hepatic lipogenic gene expression in broilers

“…Several studies have also reported that soy protein rich in isoflavones reduces fat-pad mass in rats, accompanied by decreased serum TG concentrations and cholesterol levels (Akahoshi et al, 2004;Torres et al, 2006). It has been suggested that isoflavones are the principal physiologically active components responsible for the lipid-lowering effects of soy (Bhathena and Velasquez, 2002). The results of the present study showed that serum TG concentrations in broilers decreased following in ovo Eq injection during the early embryonic period, without changes in BW or fat deposition.…”

“…Numerous studies have demonstrated that isoflavones have beneficial effects on lowering serum lipids and decreasing body fat deposition (Bhathena and Velasquez, 2002). Cederroth et al (2007) reported that male CD-1 mice fed from conception to adulthood a high soy-containing diet significantly increased energy expenditure and decreased adiposity (Cederroth et al, 2007).…”

“…Numerous studies have demonstrated that isoflavones have beneficial effects on lowering serum lipids and decreasing body fat deposition (Bhathena and Velasquez, 2002). Supplementation of the soy protein diet with isoflavone in rats has been reported to dose-dependently decrease serum TG concentration (Takahashi et al, 2009).…”

“…Phytoestrogens include isoflavonoids, lignans, coumestanes, stilbenes and flavonoids (Price and Fenwick, 1985). Numerous studies in humans and rodents have suggested that, like estrogens, -E-mail: niyingdong@njau.edu.cn dietary phytoestrogens and their metabolites play a beneficial role in reducing obesity and body mass index (Bhathena and Velasquez, 2002). In contrast, however, other studies have reported no beneficial effects of these chemicals on fat mass and serum lipid profiles (Yeung and Yu, 2003;Anderson et al, 2007).…”

Urinary phytoestrogen concentrations in the U.S. population (1999–2000)

“…Many studies have associated phytoestrogen consumption and/or excretion with reduced risk for hormone-dependent cancers, as well as for coronary heart disease, symptoms of menopause and osteoporosis (Adlercreutz et al, 1992;Adlercreutz 1995;Gambacciani et al, 1997;Anderson et al, 1999;Cassidy and Griffin, 1999;Adlercreutz 2002;Bhathena and Velasquez, 2002;Clarkson, 2002;de Kleijn et al, 2002). For example, soy ingestion in rodents has been associated with a decrease in the growth of breast cancer tumors (Barnes et al, 1990), and flaxseed ingestion protects against both breast and colon cancers in rodents Thompson, 1991, 1992).…”