Biochemical Mechanisms of Aluminum Toxicity

Abstract

In considering Al1 toxicity, one is struck by the normally successful exclusion of this ubiquitous element from animal tissues. Al is the third most prevalent element in the world, naturally present in air, soil, and water. In addition, Al enjoys a GRAS (Generally Regarded As Safe) rating by the FDA, allowing unregulated addition not only to most municipal water supplies, but to many processed foods and medications. Even with such wide exposure, tissue Al levels are normally very low. Under the unusual conditions where tissue Al levels start to rise, several distinct lesions, including an encephalopathy, osteodystrophy, and anemia are seen to occur. Some tissues accumulate Al more readily than others. Whether Al has one dominant effect, with organ selectivity of lesions accounted for by the uneven Al accumulation, or several organ-specific effects on cellular biochemistry, is yet to be determined. Several reviews on Al toxicity focus on bioavailability (e.g., DE VOto and YOkel 1994; VAn DEr VOet 1992b), but few focus on biochemical mechanisms of toxicity (EXley and BIrchall 1992; ABreo and GLass 1993).