Functions: Manganese is involved in many enzyme systems-that is, it helps to catalyze many biochemical reactions. These and its other functions, shown to be essential in animals, are still under investigation for humans, but we are finding out that manganese also has some very important roles in the human body. There are some biochemical suggestions that manganese is closer to magnesium in more than just name. It is possible that magnesium can substitute for manganese in certain conditions when manganese is deficient.

Manganese activates the enzymes necessary for the body to use biotin, thiamine (B1), vitamin C, and choline. It is important for the digestion and utilization of food, especially proteins, through peptidase activity, and it is needed for the synthesis of cholesterol and fatty acids and in glucose metabolism. As a cofactor in glycolysis, manganese aids glucose metabolism. By activating the arginase enzyme, manganese helps form urea, the end product of protein and ammonia breakdown cleared by the kidneys. Manganese may also be important in the growth and development of normal bone structure and in the formation of mucopolysaccharides, which are needed for healthy joint membranes.

Manganese may function as a protective antioxidant, especially in its +2 valence state. Divalent manganese, commonly found in the brain and other tissues as part of the enzyme superoxide dismutase (SOD), can bind oxygen free radicals, thus protecting the cell membranes and tissues from degeneration and disruption. Those areas in danger of oxidative damage are the cell membranes, nerve coverings (myelin), and tissue linings, and these are mainly protected by the antioxidant nutrients and enzymes. The manganese present in SOD is found in the "energy factories," the mitochondria, within the cells, and this enzyme protects the mitochondrial membrane from destruction, especially from superoxide free radicals. Trivalent (+3) manganese may be a prooxidant, meaning that it may generate oxidation and unstable molecules. This role as well as manganese's antioxidant functions are still being researched.

Also still under study is manganese's role in the production of thyroxine, essential for thyroid function; its role in normal lactation, in bone health, and in glucose metabolism; and its importance in reproduction. Since manganese seems to be needed in cholesterol synthesis, which is important to sex hormone formation, it may be essential in normal sexuality and reproduction. The idea that manganese is important to some enzymes that seem to stimulate maternal instincts is vague and difficult to research, and there is currently no proof to support this contention.

Uses: Manganese has been used as a therapeutic nutrient, but other than preventing problems of manganese deficiency, its influence on certain disease states seems only anecdotal to date; further research will provide us with more evidence. The superoxide dismutase enzymes, only one of which contains manganese (others utilize zinc or copper), have an anti-inflammatory effect in the body, and this function may be relevant to many of the possible uses suggested here.

Manganese has been helpful in some cases of fatigue (possibly by enhancing certain enzymes), poor memory (by protecting brain tissue and helping oxygenation), and nervousness, irritability, or dizziness. In his book Mental and Elemental Nutrients, Carl Pfeiffer, M.D., suggests that manganese along with zinc will help decrease copper levels by both decreasing absorption and increasing urinary losses. He feels that copper in higher than normal amounts can cause psychological problems and even some forms of schizophrenia (see the earlier section on Copper). Also, by some unknown mechanism, manganese may help reduce some of the parkinsonian symptoms, such as muscle rigidity and twitching, secondary to phenothiazine drug use. Manganese supplementation may also help in some cases of epilepsy.