Liu Ruying, Wu Yue, Wang Jinqiu
National Engineering Research Center of Rice and Byproduct Deep Processing, Food Science and Engineering College, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China.
Biol Trace Elem Res. 2024 Sep 24. doi: 10.1007/s12011-024-04390-3.
The actual exposure, bioavailability, and body burden of dietary cadmium (Cd) vary with the food matrix. Here, we evaluated the health hazards of 45-day long-term exposure of growing Sprague-Dawley (SD) female rats to a natural and endogenous Cd-contaminated brown and white cooked rice dietary model. Cd was found mainly in the duodenum, kidney, and liver; the cecum and colon also contained substantial amounts of Cd in rats fed Cd-contaminated cooked white rice (cWR-test) but not Cd-contaminated cooked brown rice (cBR-test). Damage due to Cd exposure was reflected in liver dysfunction, altered estradiol levels, and distinctive pathologies in organ systems, although urinary Cd (U-Cd) excretion and blood Cd (B-Cd) were not detectable, suggesting that these are not the most accurate or appropriate biomarkers for evaluating dietary Cd exposure. Brown rice, despite being higher in Cd, can reduce Cd absorption and distribution in organs and increase the volume of Cd-containing feces, even achieving slightly higher excretion and lower apparent absorption rates of Cd than white rice, thereby reducing Cd damage to the body. The beneficial components of brown rice such as more dietary fiber, rice bran oil and polyphenol were speculated therefore to confer a degree of protection or repair. Nevertheless, the high apparent absorption levels observed here (> 5%) and signs of significant physical damage indicate that more stringent Cd intake guidelines and measures are needed to minimize Cd levels in rice.
膳食镉（Cd）的实际暴露量、生物利用度和体内负荷会因食物基质的不同而有所差异。在此，我们评估了生长中的斯普拉格-道利（SD）雌性大鼠长期（45天）暴露于天然且内源性镉污染的糙米和精米饮食模型的健康危害。镉主要存在于十二指肠、肾脏和肝脏中；在喂食镉污染精米（cWR-试验）的大鼠中，盲肠和结肠也含有大量镉，但喂食镉污染糙米（cBR-试验）的大鼠则不然。尽管未检测到尿镉（U-Cd）排泄和血镉（B-Cd），但镉暴露造成的损害体现在肝功能障碍、雌二醇水平改变以及器官系统的明显病变上，这表明这些并非评估膳食镉暴露最准确或合适的生物标志物。糙米尽管镉含量较高，但能减少镉在器官中的吸收和分布，并增加含镉粪便的量，甚至其镉排泄量略高于精米，表观吸收率低于精米，从而减少镉对身体的损害。因此推测糙米中的有益成分，如更多的膳食纤维、米糠油和多酚，具有一定程度的保护或修复作用。然而，此处观察到的较高表观吸收率（>5%）和明显的身体损伤迹象表明，需要更严格的镉摄入指导方针和措施，以尽量降低大米中的镉含量。
