Influence of some dietary constituents on aluminum absorption and retention in rats

Eight groups of female Sprague-Dawley rats were treated with 281 mg Al(OH)3/kg/day by gastric intubation five times a week for five weeks. Concurrently, animals in seven groups received ascorbic acid (56.3 mg/kg/day), citric acid (62 mg/kg/day), gluconic acid (62.7 mg/kg/day), lactic acid (28.8 mg/kg/day), malic acid (42.9 mg/kg/day), oxalic acid (28.8 mg/kg/day), and tartaric acid (48 mg/kg/day) in the drinking water. The eighth group did not receive any dietary constituent in the water and was designated as the control group. Animals were placed in plastic metabolic cages and urine was collected during the treatment period. The liver, spleen, kidney, brain and bone aluminum levels of each rat were measured, as well as the total amount of aluminum excreted into urine. All the dietary constituents significantly increased the aluminum concentrations in most of the tissues, with ascorbic and citric acids showing the highest rate of aluminum accumulation. In contrast, no significant differences between control and treated rats were observed in the concentrations of aluminum excreted into urine. In view of these results, we suggest that the effects of the simultaneous ingestion of aluminum hydroxide and those dietary constituents in uremic animals should be evaluated. Meanwhile, the diet of uremic patients should be carefully monitored.