Lind Y, Engman J, Jorhem L, Glynn A W
Swedish National Food Administration, Uppsala, Sweden.
Br J Nutr. 1998 Aug;80(2):205-11.
The gastrointestinal absorption and organ distribution of Cd after exposure for 9 weeks to three fibre-rich foodstuffs (wheat bran, sugar-beet fibre and carrots) were determined in mice. Groups of eight mice were given a diet containing 0.05 mg Cd/kg from wheat bran, sugar-beet fibre, carrots or CdCl2 mixed in a semi-synthetic, low-Cd (< 0.007 mg/kg) feed. A control group was fed on the low-Cd semi-synthetic feed. The water consumption, food consumption and the weight of the animals were monitored throughout the study. The feed was changed once weekly and Cd was analysed in the feed at each change. myo-Inositol phosphates (hexa-, penta-, tetra- and tri-) and Zn, Cu, Fe and Ca were also analysed in the diets. After 9 weeks, the mice were killed and liver and kidneys were sampled and analysed for Cd. The group receiving the wheat-bran diet had significantly lower fractional Cd accumulation (% total Cd intake) in the liver and kidneys than the other groups, indicating a lower fractional absorption of Cd. The wheat-bran diet had markedly higher levels of inositol hexa- and pentaphosphates (phytates) and a Zn level that was twice as high as those in the other diets. The higher levels of myo-inositol hexa- and pentaphosphates in the wheat-bran diet most probably contributed more to the lower fractional absorption of Cd than the elevated Zn level, due to the formation of insoluble Cd-phytate complexes. Compared with the wheat-bran diet, the sugar-beet-fibre and carrot diets contained very low levels of myo-inositol penta- and hexaphosphates, and consequently the fractional Cd absorption from these diets was higher.
在小鼠中测定了连续9周暴露于三种富含纤维的食物（麦麸、甜菜纤维和胡萝卜）后镉的胃肠道吸收及器官分布情况。将八只小鼠分为一组，分别给予含有0.05 mg镉/千克的麦麸、甜菜纤维、胡萝卜饮食，或在半合成低镉（<0.007 mg/千克）饲料中混入氯化镉的饮食。对照组喂食低镉半合成饲料。在整个研究过程中监测动物的饮水量、食物摄入量和体重。每周更换一次饲料，每次更换时分析饲料中的镉含量。还分析了饲料中的肌醇磷酸酯（六磷酸、五磷酸、四磷酸和三磷酸）以及锌、铜、铁和钙的含量。9周后，处死小鼠，采集肝脏和肾脏样本并分析镉含量。接受麦麸饮食的组肝脏和肾脏中镉的累积分数（占总镉摄入量的百分比）显著低于其他组，表明镉的吸收分数较低。麦麸饮食中肌醇六磷酸和五磷酸（植酸盐）的含量明显更高，锌含量是其他饮食的两倍。麦麸饮食中较高水平的肌醇六磷酸和五磷酸很可能比升高的锌水平对镉吸收分数降低的贡献更大，这是由于形成了不溶性的镉 - 植酸盐复合物。与麦麸饮食相比，甜菜纤维和胡萝卜饮食中肌醇五磷酸和六磷酸的含量非常低，因此从这些饮食中吸收的镉分数更高。
