Submitted to: The American Journal of Clinical Nutrition
Publication Type: Review Article
Publication Acceptance Date: 5/24/2002
Publication Date: N/A
Technical Abstract: Evidence is emerging that dietary phytoestrogens have a beneficial role in obesity and diabetes. This is based on nutritional intervention studies performed in animals and humans suggesting that ingestion of soy protein associated with isoflavones, and flaxseed rich in lignans, improves glucose tolerance and insulin resistance. In animal models of obesity and diabetes, soy protein and flaxseed have been shown to reduce serum insulin and insulin resistance. In studies of human subjects with or without diabetes, soy protein also appear to moderate hyperglycemia and reduce body weight, hyperlipidemia, and hyperinsulinemia supporting their beneficial effects in obesity and diabetes. However, most of these clinical trials were of relatively short duration and involved a small number of patients. Furthermore, it is not clear whether the beneficial effects of soy protein and flaxseed are due to the isoflavones (daidzein and genistein) and lignans (matairesinol and secoisolariciresinol) or some other component. Isoflavones and lignans appear to act through various mechanisms that either modulate pancreatic insulin secretion or through anti-oxidative actions. 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 in a variety of chronic diseases. Further investigations are needed to evaluate their long-term effects on obesity and diabetes mellitus and their associated possible complications.