Nutrigenomic Effects of White Rice and Brown Rice on the Pathogenesis of Metabolic Disorders in a Fruit Fly Model

Consumption of white rice (WR) has been shown to predispose individuals to metabolic disorders. However, brown rice (BR), which is relatively richer in bioactive compounds, possesses anti-glycaemic and antioxidant effects. In this study, fifteen cultivars of paddy rice that are predominantly consumed in North West Nigeria were analysed for their nutritional composition, bioactive contents and effects on metabolic outcomes in a fruit fly model. Gene expression analyses were conducted on the whole fly, targeting dPEPCK, dIRS, and dACC. The protein, carbohydrate, and fibre contents and bioactives of all BR cultivars were significantly different (p < 0.05) from the WR cultivars. Moreover, it was demonstrated that the glucose and trehalose levels were significantly higher (p < 0.05), while glycogen was significantly lower (p < 0.05) in the WR groups compared to the BR groups. Similarly, the expression of dACC and dPEPCK was upregulated, while that of dIRS was downregulated in the WR groups compared to the BR groups. Sex differences (p < 0.05) were observed in the WR groups in relation to the nutrigenomic effects. Our findings confirm metabolic perturbations in fruit flies following consumption of WR via distortion of insulin signalling and activation of glycogenolysis and gluconeogenesis. BR prevented these metabolic changes possibly due to its richer nutritional composition.

Automated summary

By analyzing fifteen cultivars of paddy rice consumed in North West Nigeria, it was found that brown rice differed significantly from white rice in terms of nutritional composition and bioactive content, and possessed anti-diabetic and antioxidant effects. The study further showed that fruit flies fed with white rice exhibited higher glucose and trehalose levels and lower glycogen levels compared to those fed with brown rice, accompanied by increased expression of dACC and dPEPCK and decreased expression of dIRS. Sex differences were also observed in the nutrigenomic effects of white rice. These findings confirm that white rice consumption can disrupt fruit fly metabolism through insulin signaling distortion, glycogenolysis, and gluconeogenesis, while brown rice can prevent these metabolic changes possibly due to its richer nutritional composition.