Glynn A W, Sparén A, Danielsson L G, Sundström B, Jorhem L
Swedish National Food Administration, Department of Environmental Toxicology, Uppsala University.
J Toxicol Environ Health A. 1999 Apr 9;56(7):501-12. doi: 10.1080/009841099157944.
The hypothesis was tested that the absorption of labile Al in rats will increase when the Al-binding capacity of food components in the stomach is saturated. Male rats were exposed to 0, 10, 50, or 500 mg labile Al/L in acidic drinking water (pH 3) for 9 wk. The results show that labile Al in drinking water is complexed by feed constituents in the stomach of the rat in vivo, thus causing a nondetectable absorption of Al at 10 mg Al/L. An increased absorption of Al at 50 and 500 mg Al/L was associated with a saturation of the Al-binding capacity of feed components in the lumen of the stomach, causing the appearance of labile Al. Thus, the presence of labile Al in drinking water does not necessarily result in a high Al absorption when the water is ingested, since the bioavailability of labile Al is dependent both on the amount and composition of Al-binding components present in the gastrointestinal tract at the time of ingestion of the water. It is thus not possible to predict the body burden of Al in humans just by measuring the Al concentrations in drinking water. Even a further refining of the exposure measurement to include speciation of Al in the water may not markedly improve the prediction of the Al body burden. Future epidemiological studies must therefore be based on actual measurements of Al concentration in tissues or fluids from the study subjects.
当胃中食物成分的铝结合能力饱和时，大鼠对不稳定铝的吸收将会增加。将雄性大鼠置于酸性饮用水（pH 3）中，分别暴露于含0、10、50或500 mg/L不稳定铝的环境中，为期9周。结果显示，饮用水中的不稳定铝在大鼠体内会与胃中的饲料成分络合，因此在铝含量为10 mg/L时铝的吸收无法检测到。在铝含量为50和500 mg/L时铝吸收增加，这与胃腔中饲料成分的铝结合能力饱和有关，导致不稳定铝出现。因此，饮用含有不稳定铝的水时，铝的吸收不一定会很高，因为不稳定铝的生物利用度既取决于饮水时胃肠道中铝结合成分的数量，也取决于其组成。因此，仅通过测量饮用水中的铝浓度，无法预测人体铝负荷。即使进一步完善暴露测量，将水中铝的形态也包括在内，也可能不会显著改善对铝身体负担的预测。因此，未来的流行病学研究必须基于对研究对象组织或体液中铝浓度的实际测量。
