Submitted to: Nutrition Reviews
Publication Type: Review Article
Publication Acceptance Date: January 1, 2004
Publication Date: April 1, 2004
Citation: Finley, J.W. 2004. Does environmental exposure to manganese pose a health risk to healthy adults? Nutrition Reviews. 62(4):148-153. Interpretive Summary: Manganese is an essential nutrient, but excessive exposure to manganese causes toxicity problems. Until recently there was no evidence that low level exposure to manganese caused problems. However, because manganese has been proposed to be added to gasoline as a replacement for lead, this area has received renewed research attention. A number of researchers that have used psychological evaluations have suggested that low level exposure to manganese contributes to decreased cognitive performance and increased violence. Although these studies are increasingly cited as evidence of the danger of even minor exposure to manganese, a complete search of the literature does not give a clear pattern of toxicity, and suggests researchers may be forcing data to support their own hypotheses.
Technical Abstract: Manganese is an essential nutrient that also may be toxic at high concentrations. Subjects chronically exposed to manganese-laden dust in industrial settings develop neuropsychological changes that resemble Parkinson's disease. Manganese has been proposed as an additive to gasoline (as a replacement for the catalytic properties of lead) and this has resulted in increased research interest in the possible deleterious effects of environmental exposure to manganese. Low level exposure to manganese has been implicated in neurological changes, decreased learning ability in school-aged children, and increased propensity for violence in adults. However, a thorough review of the literature shows very weak cause and effect relationships that do not justify concern about environmental exposure to manganese for most of the North American population.