In experimental animals, dietary manganese deficiency can result in numerou
s biochemical and structural abnormalities. Deficient animals can be charac
terized by impaired insulin production, alterations in lipoprotein metaboli
sm, an impaired oxidant defense system, and perturbations in growth factor
metabolism. if the deficiency occurs during early development there can be
pronounced skeletal abnormalities and an irreversible ataxia. Several lines
of evidence suggest that manganese deficiency may be a problem in some hum
an populations. Manganese toxicity can also pose a significant health risk.
In experimental animals, acute manganese toxicity can result in numerous b
iochemical pathologies. However, the above occurs typically when the mangan
ese is given via injection; most animals show considerable resistance to di
etary manganese toxicosis. Similarly, confirmed cases of manganese toxicity
in humans are currently restricted to cases of exposure to high levels of
airborne manganese, and to cases when manganese excretory pathways are comp
romised. (C) 1999 Inter Press, Inc.