title: Natural food science based novel approach toward prevention and treatment of obesity and type 2 diabetes: recent studies on brown rice and γ-oryzanol.
abstract: The prevalences of obesity and type 2 diabetes mellitus are dramatically increasing, and there is a strong need for more effective and safer therapies. However, some of drugs show limited efficacy and considerable adverse effects. Furthermore, artificial energy-dense foods and non-caloric foods may promote overeating and weight gain. In this context, a natural food-based approach may represent a valuable means of tackling the obesity-diabetes syndrome. Although recent studies have shown that brown rice improves glucose intolerance and prevents obesity and type 2 diabetes in humans, the underlying molecular mechanisms remain unclear. We found that one of the major components of brown rice, γ-oryzanol (Orz), plays an important role in the metabolically beneficial effects of brown rice. Orz acts as a chemical chaperone and decreases high fat diet (HFD)-induced endoplasmic reticulum (ER) stress in the hypothalamus, thereby leading to a significant shift in preference from fatty to healthy foods. Orz also decreases HFD-induced ER stress in pancreatic β-cells and improves β-cell function. Notably, Orz directly acts on pancreatic islets and enhances glucose-stimulated insulin secretion (GSIS). This evidence highlights food preference as a promising therapeutic target in obesity-diabetes syndrome and suggests that brown rice and Orz may have potential for the treatment of obesity and type 2 diabetes in humans.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
authors.forename: Chisayo
authors.initials: C
authors.lastname: Kozuka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Yabiku
authors.forename: Chitoshi
authors.initials: C
authors.lastname: Takayama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsushita
authors.forename: Michio
authors.initials: M
authors.lastname: Shimabukuro
mesh_terms: D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy* / Q000453:epidemiology / Q000517:prevention & control*; D059305:Diet, High-Fat; D059865:Endoplasmic Reticulum Stress; D057890:Epigenomics; D005260:Female; D005518:Food Preferences; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007564:Japan / Q000453:epidemiology; D008297:Male; D052756:Nutritional Sciences / Q000639:trends; D009765:Obesity / Q000178:diet therapy* / Q000453:epidemiology / Q000517:prevention & control*; D012275:Oryza / Q000378:metabolism; D010666:Phenylpropionates / Q000008:administration & dosage*; D015995:Prevalence
chemical_list: D007328:Insulin; D010666:Phenylpropionates; C013172:gamma-oryzanol