Aluminium: gastrointestinal absorption and renal excretion.

Aluminium is the most abundant metal and constitutes 8% of the earth’s crust. It is a normal constituent of vegetable and animal tissues and is present in raw untreated water. In domestic tap-water supplies, aluminium may be present in high concentrations either from its presence in raw water or, more commonly, as a result of its use during the water-purification process. Aluminium in the metallic form is widely used for both industrial and domestic purposes, and a variety of aluminium salts are used in foods, fluids, cosmetics and medications. The toxicity of aluminium in patients with renal failure is now well documented, and dialysis encephalopathy, osteomalacia and anaemia are recognized hazards in such patients if aluminium is not excluded from dialysis fluids and medications. The safe levels of aluminium in food, water, medications and infusion fluids for subjects with normal renal function are unknown, but aluminium has been implicated as causative agent in a number of dementia diseases, including Alzheimer’s disease. There are a number of recent reviews of aluminium toxicity [l-51. In contrast to these, in the present review, we concentrate on the mechanisms of absorption and excretion of aluminium, rather than the consequences of aluminium deposition in the body. The normal dietary source of aluminium is food and water to which aluminium has been added or in which there is naturally a high content [6,7]. The normal daily intake of aluminium is estimated to be approximately 9 mg/day in teenage and adult females and 12-14 mg/day in teenage and adult males [7]. However, it has been stated that “the inappropriate choice of foods, methods of food preparation and non-prescription drugs can readily increase the daily intake of aluminium to several thousand mg each day” [8]. Such high aluminium intakes are particularly likely in