Manganese

Manganese is one of the most common elements in the earth's crust. All animal and plant tissues, as well as all fresh and sea water, rain water, and atmospheric dust, contain manganese. Human tissue has not yet been found that doesn't contain some manganese. Manganese is considered an essential trace mineral because it is an essential cofactor in several vital enzyme systems. Manganese functions in the synthesis of protein, DNA and RNA, and cartilage.  Manganese also plays a role in the utilization of insulin, and it may be essential to metabolism of fats as well. There are reports of a preparation of alfalfa, high in manganese, being used in African folk medicine as a treatment for diabetes.

A deficiency of manganese causes impairment of growth, reproduction, glucose tolerance, egg shell formation, blood clotting, and skeletal deformities and loss of muscular coordination. Manganese deficiency has also been found to lower the immune response in animals. Manganese deficiency has been found to be responsible for certain birth defects in animals, once thought to be caused by genetic mutations. Supplying manganese supplements to pregnant animals erased the effects in offspring.

In humans, the symptoms of a manganese deficiency were discovered by accident when manganese was mistakenly left out of a test diet. The volunteer experienced weight loss, dermatitis, nausea, slow growth of hair and beard with color changes, and uncommonly low blood levels of cholesterol.

Schizophrenia patients, especially those with tardive dyskinesia have been found to have abnormally low blood levels of manganese. Manganese supplementation (fifteen to sixty mg. per day) was found to either prevent or alleviate tardive dyskinesia in most people suffering this side effect of psychiatric medications.

Where is it found ?

The best natural sources of manganese include whole grains, wheat germ and bran, peas, beet tops, pineapple, tea, ginger, and sage. Wine, nuts, leafy vegetables, and fruits are fair sources. Manganese is sometimes included in multimineral supplements.

Who is likely to be deficient ?

Many people consume less than the 2.5-5mg of manganese currently considered safe and adequate. Nonetheless, clear deficiencies are rare. Individuals with osteoporosis sometimes have low blood levels of manganese, suggestive of deficiency.

How much to take

Whether most people would benefit from manganese supplementation remains unclear. The 5-15 mg often found in a high-potency multivitamin/mineral supplement is generally considered to be a reasonable level for those wishing to supplement manganese.

Side effects

Amounts found in supplements (5-20 mg) have not been linked with any toxicity. Excessive intake of manganese can lead to the rare side effects of dementia and psychiatric symptoms. Preliminary research suggests that individuals with cirrhosis may not be able to properly excrete manganese; until more is known, these people should not supplement manganese.

Several minerals such as calcium and iron, and possibly zinc reduce the absorption of manganese. Zinc and copper work together with manganese to activate superoxide dismutase.

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