|Johnson, Phyllis -|
Submitted to: Book Chapter
Publication Type: Review Article
Publication Acceptance Date: August 1, 1996
Publication Date: N/A
Technical Abstract: Manganese is nutritionally important because of both its essentiality, and toxic actions; laboratory rodents have been extensively utilized to study both aspects. Manganese deficiency is characterized by skeletal abnormalities, altered carbohydrate metabolism, and perhaps, altered lipid metabolism. Signs of deficiency are apparent when rodents are fed diets containing 3 mg of Mn/kg diet, but marked deficiency consequences can be best demonstrated by feeding diets containing only 1 mg of Mn/kg diet; this latter dietary intake may result in impaired reproduction. Feeding manganese-deficient diet through the F1 generation results in animals with extreme manganese deficiency. Manganese supposedly is one of the least toxic trace elements, however toxicity does occur, especially in human miners who breathe in manganese-laden dust. Manganese toxicity causes neurological problems, and can also adversely affect many organ systems. Manganese toxicity has been induced in laboratory rodents by feeding diets or providing drinking water high in manganese, and by gavage. Many dietary ingredients affect the bioavailability of manganese; most notable is iron, but other trace elements, phytate and protein source may also affect manganese bioavailability. Thus, toxicity of manganese can be affected by diet composition.