Manganese is a naturally occurring element found in rock, soil, water, and food. In humans and animals, manganese is an essential nutrient that plays a role in bone mineralization, protein and energy metabolism, metabolic regulation, cellular protection from damaging free radical species, and formation of glycosaminoglycans. Manganese acts as both a constituent of metalloenzymes and an enzyme activator. Enzymes that contain manganese include arginase, pyruvate carboxylase, and manganese-superoxide dismutase.
Mild or unnoticeable effects may be caused by low, but physiologically excessive, amounts of manganese, and these effects appear to increase in severity as the exposure level or duration of exposure increases. It is clear that chronic exposure to manganese at very high levels results in permanent neurological damage, as is seen in former manganese miners and smelters. Chronic exposure to much lower levels of manganese (as with occupational exposures) has been linked to deficits in the ability to perform rapid hand movements and some loss of coordination and balance, along with an increase in reporting mild symptoms such as forgetfulness, anxiety, or insomnia.1
- Toxicological Profile for Manganese. Williams M, Todd GD, Roney N, et al.