Manganese is a mineral found in large quantities in both plant and animal matter. Only trace amounts of this element can be found in human tissue, however. Manganese is predominantly stored in the bones, liver, kidney, and pancreas. It aids in the formation of connective tissue, bones, blood-clotting factors, and sex hormones and plays a role in fat and carbohydrate metabolism, calcium absorption, and blood sugar regulation. Manganese is also necessary for normal brain and nerve function.

Manganese is a component of the antioxidant enzyme manganese superoxide dismutase (MnSOD). Antioxidants scavenge damaging particles in the body known as free radicals. These particles occur naturally in the body but can damage cell membranes, interact with genetic material, and possibly contribute to the aging process as well as the development of a number of health conditions. Antioxidants such as MnSOD can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

Low levels of manganese in the body can contribute to infertility, bone malformation, weakness, and seizures. Manganese deficiencies are considered rare, however, since it is relatively easy to obtain adequate amounts of manganese through the diet. Interestingly, though, some experts estimate that as many as 37% of Americans do not get the recommended daily amounts of manganese in their diet. This may be due to the fact that whole grains are a major source of dietary manganese, and many Americans consume refined grains more often than whole grains. Refined grains provide half the amount of manganese as whole grains.

Manganese may be of some benefit for the following illnesses when used in conjunction with conventional medical care:

Arthritis
People with rheumatoid arthritis tend to have low levels of MnSOD (an antioxidant that helps protect the joints from damage during inflammation). Manganese supplementation is thought to increase MnSOD activity. In addition, a few studies of people with osteoarthritis suggest that the combination of manganese supplementation taken along with glucosamine and chondroitin can reduce pain associated with the condition.

Osteoporosis
Manganese and other trace elements are necessary for bone health. Therefore, many experts feel that appropriate balance and intake of manganese and these other nutrients may play a role in preserving bone density and preventing osteoporosis.

Diabetes
Although results have been conflicting, some research suggests that people with diabetes have significantly lower levels of manganese in their bodies than people without diabetes. It is not clear, however, whether this is a cause or effect of the condition. In other words, researchers have yet to determine whether diabetes causes levels of manganese to drop or if deficiencies in this trace element actually contribute to the development of the metabolic disorder. In addition, one study found that diabetics with higher blood levels of manganese were more protected from oxidation of LDL ("bad") cholesterol than those with lower levels of manganese. (LDL oxidation contributes to the development of plaque in the arteries which can lead to heart attack and stroke.) Further studies are needed to determine whether supplementation with manganese helps prevent and/or treat diabetes and its associated complications.

Premenstrual Syndrome (PMS)
In at least one study, women who ate small amounts of manganese (levels below the recommended daily amount) experienced greater mood swings and cramping pain just prior to their periods than women who ate normal to high amounts of manganese. These results suggest that a manganese-rich diet may help reduce symptoms of PMS.

Epilepsy
Several studies suggest that manganese levels may be lower in people with seizure disorders. It is not known, however, whether seizures reduce manganese levels or if low manganese levels make a person more susceptible to convulsions. It is also unclear at this time whether manganese supplements would help reduce the number of seizures in people with epilepsy. In fact, at least one animal study suggests that manganese supplementation does not alter the severity or frequency of seizures in rats.

Other
Low levels of manganese have also been associated with muscle disorders that involve lack of coordination, irregular menstrual cycles, tinnitus (ringing in the ears), hearing loss (even in infants), and poor milk production in lactating women.

Rich dietary sources of manganese include nuts and seeds, wheat germ and whole grains (including unrefined cereals, buckwheat, bulgur wheat, and oats), legumes, and pineapples.

Manganese is available in a wide variety of forms including manganese salts (sulfate and gluconate) and manganese chelates (aspartate, picolinate, fumarate, malate, succinate, citrate, and amino acid chelate). Manganese supplements can be taken as tablets or capsules, usually along with other vitamins and minerals.

The estimated safe and adequate daily intakes for dietary manganese established by the Food and Nutrition Board of the National Research Council are listed below.

In the case of epilepsy and joint inflammation, the recommended dose may be increased under the direction of a healthcare professional. Supplements and dietary intake of manganese together should not exceed 11 milligrams per day because of the risk of neurological side effects. Supplementation from non-food sources, particularly for children, should only be undertaken with direction from a healthcare provider.

Pediatric

• Infants birth to 6 months: 0.3 mg
• Infants 7 to 12 months: 0.6 mg
• Children 1 to 3 years: 1.2 mg
• Children 4 to 8 years: 1.5 mg
• Males 9 to 13 years: 1.9 mg
• Males 14 to 18 years: 2.2 mg
• Females 9 to 18 years: 1.6 mg

Adult

• Males 19 years and older: 2.3 mg
• Females 19 years and older: 1.8 mg
• Pregnant females: 2 mg
• Breastfeeding females: 2.6 mg

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable healthcare provider. The amount of manganese ingested in one day (from foods and/or supplements) should not exceed 11 milligrams.

Calcium, phosphorous, and manganese work closely together in the body. For this reason, dietary requirements of manganese may increase as calcium and phosphorous consumption increases.

Manganese rarely causes side effects when taken orally. It is possible, however, for manganese toxicity to occur in those who regularly inhale manganese vapors, such as industrial workers in steel mills and mines. Potential symptoms of such toxicity include loss of appetite, headaches, leg cramps, muscle rigidity, tremors, convulsions, extreme irritability, acts of violence, and hallucinations. Manganese toxicity has also been seen in individuals who received very high amounts of intravenous nutrition (containing manganese) administered over long periods of time.

If you are currently being treated with any of the following medications, you should not use manganese supplements without first talking to your healthcare provider.

Haloperidol and other Antipsychotics
There has been at least one report of an interaction between haloperidol and manganese that resulted in hallucinations and behavioral changes in a person with liver disease. In addition, some experts believe that medications for schizophrenia and other forms of psychosis may worsen side effects from manganese supplements. Therefore, individuals taking haloperidol or other antipsychotic medications (particularly a class called phenothiazines which includes chlorpromazine, mesoridazine, perphenazine, prochlorperazine, thioridazine, and trifluoperazine) should use manganese only under the careful supervision of a qualified health professional.

Reserpine
Reserpine, a medication used to treat high blood pressure, may decrease manganese levels in the body.

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