Marco Vinceti, Margherita Ferrante, Tommaso Filippini, Teresa Urbano
8th FESTEM Symposium, Madrid, September 28-October 1, 2022
Abstract
Both the nutritional and the toxicological properties of selenium are of considerable interest with reference to the risk of neurological disorders in humans. There is evidence that inadequate availability of selenoproteins could have deleterious effects on the neurological function, for instance following mutations of selenoenzymes-encoding genes, and that brain needs an adequate and constant supply of selenoproteins. Conversely, excess selenium exposure has been linked to a broad range of adverse effects on the central nervous system. Such effects range from specific toxicity on motor neurons following chronic overexposure to reversible leukoencephalopathy and cortical blindness in case of acute intoxication. Abnormalities of the peripheral nervous system have also been described in individuals living in seleniferous areas. Little evidence of any effect on Alzheimer’s dementia has been recently provided by a large selenium trial, SELECT, while the results of observational studies on the relation between selenium status and cognition are conflicting, with the only cohort study suggesting an adverse effect of inorganic hexavalent selenium. Overall, the actual effects of too high and too low selenium intake on the central nervous system in the human are still to be adequately characterized, also due to the methodological limitations of observational studies. Such limitations include unmeasured confounding and exposure misclassification, with particular reference to lack of speciation analyses, of biomarkers of selenium exposure in the central nervous system, and of longitudinal studies. Further research in this field is clearly warranted.