Rice bran is a key structure affecting high nutrition and low toxicity of indica hybrid rice (Oryza sativa L.)

Rice is a staple for over half of the world's population. However, it presents toxicity risks. In this study, 23 indica rice varieties were selected; the concentration and accumulation of 18 elements in husk, bran, and milled rice were measured. The correlations between elements differ, with specific correlation networks in each grain layer, with the bran layer being the most complex. Cd and As in the bran layer accounted for 16.6% and 39.7% of the total accumulation in brown rice, respectively. Removal of the bran layer significantly reduced Fe by 35.2% and Zn by 30.2%. With the goals of high nutrition and low toxicity, the CY6709 and LLY7810 brown rice varieties were suitable without modification, whereas JY781 is best milled to reduce the risk of heavy-metal poisoning. Overall, the bran layer was enriched with both toxic and nutrient elements. To ensure greater nutrient intake, we encourage more brown rice consumption. Moreover, rice varieties should be milled according to their distributions of toxic elements to reduce safety concerns.