General Description
Manganese is a metallic trace mineral essential to human nutrition.
The average human body contains 10 to 20 mg of manganese, most of
which is found in the liver, bones, kidneys, and pancreas. Manganese
acts as a cofactor in many enzymatic processes throughout the body,
and plays important roles in bone, cartilage, and skin formation,
glucose and cholesterol metabolism, and thyroid and pancreatic function.
It also contributes to the body's antioxidant defense mechanisms.1
Supplemental forms of manganese include manganese salts (sulfate
or chloride) and chelates such as picolinate and gluconate. Supplemental
manganese is usually found in multi-vitamin/mineral formulas rather
than as an individual supplement.
Food sources
Manganese is found in a wide variety of foods, but concentrations
vary in relation to soil manganese levels. Good sources of manganese
include whole grains, nuts, seeds, and green leafy vegetables.
Health applications
Deficiency symptoms
Because manganese is only needed in miniscule amounts and is plentiful
in foods, overt manganese deficiency is rare. However, a four
year study by the Food and Drug Administration indicates most
Americans consume diets low in manganese.2
Manganese depletion may cause dermatitis in humans,3
and in animal models has been linked to impaired insulin production,
altered cholesterol metabolism, skeletal abnormalties and impaired
antioxidant defense systems.4
Dosage/toxicity
The Reference Daily Intake (RDI) for manganese is 2 mg per day.
As much as 20 mg (as found in some high potency supplements) appears
to be safe. Manganese toxicity is generally confined to populations
such as miners and metal workers with chronic exposure to manganese
pollution. Manganese intoxication can cause neurological damage,
impaired memory, tremors, and mood disturbances.5-7
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