Comparison of bioaccessibility and relative bioavailability of arsenic in rice bran: The in vitro with PBET/SHIME and in vivo with mice model.

Rice bran, a super food or health food supplement, contains high arsenic (As) levels. However, the evaluation of relative bioavailability (RBA) or bioaccessibility (BA) is limited in the rice bran. In this study, the As-RBA in rice bran was determined based on mice model and compared to As-BA using in vitro methods. The As-BA from rice bran-amended feed in the gastric, small intestinal, and colon phases were 33.1-56.4%, 50.5-75.6%, and 35.5-71.4%, respectively. The As-BA was adversely associated with bioaccessible Ca and Fe concentrations in the gastrointestinal phases. Similarly, the As-RBA was significant negative relative with Ca, Fe, and Zn concentrations. The As-RBA values were 37.9-65.5%, 41.5-75.6% and 38.7-71.5% based on liver, kidneys, and combined endpoint (liver plus kidneys), respectively. The in vitro-in vivo correlations (IVIVCs) in the gastric (R = 0.392) and colon (R = 0.362) phases were weak. While the IVIVC (R = 0.544) in the small intestinal phase was stronger than those of the gastric and colon phases. In addition, there was no significant difference in As speciation between colonic residual solids and faeces (p > 0.05). This work provides a better view of human health risk evaluation on rice bran As consumption in humans.