Manganese (54,9 a.m.u.) – vital element for human, present in multiple metal ferments, acting also as non-specific enzyme activator. Manganese-dependent enzymes are superoxide dismutase (mitochondria), pyruvate carboxylase, arginase, glycosyltransferase. Mn2+ ions in activations of several enzymes could be replaced by Mg2+, Co2+ or other bivalent ions. This element is related to the processes of development of conjunctive tissues and bones, growth mechanisms, fertility, carbohydrates and lipids metabolism. In normal conditions only low amounts of manganese are being intaken by body with air, food and water. Most part of manganese intaken with food is not being absorbed, but the main passage of excretion is bilis.

Urine excretion of this element indicates low reaction to the fluctuations of manganese in diet. Manganese is transferred with blood together with proteins. In blood it is mostly linked with erythrocytes haemoglobin.

Long-lasting artificial nutrition with lack of manganese could cause signs of bones demineralization and growth damages, recovered in cases of intake of special supplements.

Experimental limitation of manganese in food led to the development of skin damages, decrease of cholesterol level. Rare genetic disease – pirrolidase deficit of children indicated with skin ulcers, mental retardation, increase of urine excretion of iminopeptides, by-pass infections with megalosplenia associated with damages of manganese metabolism (manganese is deposed in erythrocytes, arginase activity of erythrocytes loses half of its norm, but the content of manganese in serum is normal).

Decrease of manganese level was reported in some unlinked medical conditions: osteoporosis, insulin-resistant pancreatic diabetes, epilepsy, infertility, etc. Low level of manganese is peculiar to patients with disseminated sclerosis, vitiligo, pancreatic diabetes, allergic diseases and rheumatic disorders. Half of children suffering from bronchial asthma has decreased level of manganese in hair.

Overdoses of manganese causes neurotic syndromes, over-fatigue, rachitism, hypothyreosis. Toxic effects of manganese could be caused by the treatment of professional factors: inhalation of dust and vapours containing manganese, used to manufacture steel, dry batteries, construction materials, paints, ceramics, lead-free gasoline.

Throughout months and years of manganese exposition various neurologic symptoms are developing, peculiar to Parkinson disease, degenerative disorders of cerebrospinal system. Chronic intoxication with manganese are peculiar to foundry-men, welders, miners, workers of drugs manufacturing, ceramics, glass, varnish, food supplements.

Manganese toxicity was reported for some children with long-lasting parenteral feeding. Changes of manganese metabolism could make a contribution to the symptoms of developing encephalopathy, severe liver diseases due to damages of manganese excretion with bilis.