Update on regulations of aluminium intake -biochemical and toxicological assessment

摘要

For aluminium (Al), the European Food Safety Authority (EFSA) has recently established a Tolerable Weekly Intake (TWI) of 1 mg Al/kg bw/week due to its neurotoxicity, embryotoxicity and adverse effects on the development of the nervous system. The TWI took the place of the Provisional Tolerable Weekly Intake (PTWI) of 0 - 7 mg Al/kg bw/week issued by FAO/WHO in 1989. The considerable reduction in the TWI for Al intake means a conflicting situation because a significant part of the European population exceeds the TWI value. Al absorption is a complex network of biochemical reactions which are influenced by several parameters and can vary up to 50-fold, depending on the chemical form of Al only. Al absorption is increased by low pH, high solubility of Al species, organic acids and their salts, a low Fe status and uremia, whereas it is decreased by phosphates or phosphate-rich compounds and silicates. The presence of citrate increases Al absorption also from Al compounds with low solubility. This outcome is very important regarding the fact that the human diet contains considerable amounts of citric acid which is reported to average 4 g (as citrate) in the daily diet. Elevated exposure of Al may produce accumulation of systemic Al and cause toxicity of the respiratory, central nervous, skeletal and hematopoietic systems. In this way, Al may induce lung fibrosis, the dialysis encephalopathy syndrome, a low bone turnover osteodystrophy and an erythro-poietin-resistant microcytic anaemia. Due to the new regulation of the EFSA for reduced Al intake it is suggested to reconsider the allowance and use of Al-containing food additives being a main Al source in some foods. Furthermore, the contamination of Al in Ca compounds used as fortifiers in infant foods should be reduced to the lowest possible limit because infants are particularly susceptible to Al.