Natural food science based novel approach toward prevention and treatment of obesity and type 2 diabetes: recent studies on brown rice and γ-oryzanol

Obes Res Clin Pract. May-Jun 2013;7(3):e165-72. doi: 10.1016/j.orcp.2013.02.003.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / prevention & control*
  • Diet, High-Fat
  • Endoplasmic Reticulum Stress*
  • Epigenomics
  • Female
  • Food Preferences*
  • Humans
  • Insulin / metabolism
  • Insulin Secretion
  • Insulin-Secreting Cells / metabolism
  • Japan / epidemiology
  • Male
  • Nutritional Sciences / trends
  • Obesity / diet therapy*
  • Obesity / epidemiology
  • Obesity / prevention & control*
  • Oryza* / metabolism
  • Phenylpropionates / administration & dosage*
  • Prevalence


  • Insulin
  • Phenylpropionates
  • gamma-oryzanol