Effect of Brown Rice on Insulin Resistance and Insulin-Sensitive Glucose Transporters Expression in Adipose Tissue of Diet-Induced Obese Rats

Brown rice is rich in bioactive compounds like gamma-oryzanol that offer nutritional advantages over white rice. This study aimed to investigate the potential of brown rice to enhance insulin sensitivity by increasing the expression of insulin-sensitive glucose transporters 4 and 12 in the adipose tissue of rats with diet-induced obesity. Rats were induced to develop obesity by being fed a high-fat, high-fructose diet. These obese rats were then divided into five treatment groups: (i) high-fat, high-fructose diet only; (ii) high-fat, high-fructose diet with brown rice; (iii) white rice; (iv) white rice + gamma-oryzanol; and (v) gamma-oryzanol only. The treatment was administered for 12 weeks. Insulin resistance was evaluated using the glucose tolerance test and the homeostasis model assessment-insulin resistance calculation. The expression of glucose transporters 4 and 12 was assessed through immunofluorescence assays of adipose tissue. In obese rats, supplementation with brown rice or gamma-oryzanol in combination with the high-fat, high-fructose diet might improve fasting insulin and homeostasis model assessment-insulin resistance values. Brown rice additionally elevated the expression of not only glucose transporter-4 but also glucose transporter-12 in visceral adipose tissue (p < .05). Brown rice is preferable as a staple food alternative to white rice, particularly for obese individuals, because of its capacity to increase insulin sensitivity.