The Manganese (Mn) content in the adult human is 12 to 20 mg. About 25% is stored in the skeleton. Within each cell, Manganese is concentrated in the mitochondria. Bone, liver and pancreas tend to have the highest concentrations.
Deficiency symptoms are unclear. There may be blood clotting defects, hypocholesterolemia, elevated serum calcium, phosphorus and alkaline phosphatase. There may be loss of muscle tone, diabetes and heart disease. Mn is an important part of the anti-oxidant enzyme super oxidase dismutase.
Functions of Mn include synthesis of skeletal and connective tissue, fatty acids, cholesterol, DNA, RNA, and urea. It mobilizes fats from the liver and releases energy. Mn deficiency has also been indicated in development of hip abnormalities, joint disease and congenital malformations. Increased levels are found following industrial exposure (miners, foundry workers, ceramics, glass, varnish, food additives), in acute hepatitis, myocardial infarction and rheumatoid arthritis.
Good sources of Mn are rice and wheat bran, whole grain cereals, green vegetables, nuts, dried legumes, tea, ginger and cloves.
The RDA is about 2 to 3 mg/day.