Manganese

Manganese is a metal that occurs widely in plant and animal tissues. It is called a trace element because it is found in very small quantities in the human body. Our bodies store approximatley 20 milligrams of manganese, mostly in the bones. Manganese aids in forming connective tissue, fats and cholesterol, bones, blood-clotting factors, and proteins. It is also necessary for normal brain function. Manganese is a component of manganese superoxide dismutase (MnSOD), an antioxidant that protects the body from toxic substances. It is easy to obtain adequate amounts of manganese from the diet.

Uses

The following illnesses may be affected by manganese.

• Diabetes. People who have diabetes sometimes have significantly less manganese than healthy people. Manganese decreases blood sugar levels in some people with diabetes.
• Rheumatoid arthritis. People with rheumatoid arthritis (inflammation of the joints) can have low levels of MnSOD, which helps protect the joints from damage during inflammation. Manganese supplementation increases MnSOD activity.
• Epilepsy. An important study in the early 1960s demonstrated that manganese-deficient rats were more susceptible to seizures and had electroencephalograms (EEGs) consistent with seizure activity.
• Schizophrenia. People who have schizophrenia may also respond well to manganese supplementation.
• Osteoporosis. Bone loss occurs more rapidly after menopause and can lead to osteoporosis (brittle, thin, bones). Manganese, and other trace elements, increase bone density in postmenopausal women.
• Other conditions. Manganese is also used to treat hardening of the arteries (atherosclerosis), high cholesterol (hypercholesterolemia), tinnitus, and hearing loss.

Dietary Sources

• Nuts (especially pecans and almonds)
• Wheat germ and whole grains
• Unrefined cereals
• Leafy vegetables
• Liver
• Kidney
• Legumes (peanuts, beans)
• Dried fruits

Refined grains, meats, and dairy products contain very small amounts of manganese. Unrefined foods, such as whole grain breads and cereals, are higher in manganese.

Other Forms

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). It is available in tablets or capsules, usually along with other vitamins and minerals.

How to Take It

There is no recommended dietary allowance (RDA) for manganese. Dietary recommendations are based on typical dietary intake and are intended to prevent deficiency symptoms. The average intake of manganese ranges from 2 mg to 9 mg per day. In some cases, people may require more manganese (10 mg per day) than is indicated below.

The estimated safe and adequate daily intakes for manganese are 2 to 5 mg for adults, 1 to 3 mg for children and adolescents, and 0.3 to 1 mg for infants.

Precautions

Excessive intake of manganese can produce toxic effects. You should not regularly exceed the estimated safe and adequate daily intakes for manganese listed above.

Possible Interactions

Reserpine, a medication used to treat high blood pressure, may diminish manganese levels.

Supporting Research

Davis CD, Greger JL. Longitudinal changes of manganese-dependent superoxide dismutase and other indexes of manganese and iron status in women. Am J Clin Nutr. 1992;55:747–752.

el-Yazigi A, Hannan N, Raines DA. Urinary excretion of chromium, copper, and manganese in diabetes mellitus and associated disorders. Diabetes Res. 1991;18:129–134.

Fell JM, Reynolds AP, Meadows N, et al. Manganese toxicity in children receiving long-term parenteral nutrition. Lancet. 1996;347:1218–1221.

Finley JW, Davis CD. Manganese deficiency and toxicity: are high or low dietary amounts of manganese cause for concern? Biofactors. 1999;10(1):15-24.

Friedman E, ed. Biochemistry of the Essential Ultratrace Elements. New York, NY: Plenum Press; 1984.

Goering PL, Haassen CD. Mechanism of manganese-induced tolerance to cadmium lethality and hepatotoxicity. Biochem. Pharmacol. 1985;34:1371-1379.

Ingersoll RT, Montgomery EB Jr, Aposhian HV. Central nervous system toxicity of manganese. II: Cocaine or reserpine inhibit manganese concentration in the rat brain. Neurotoxicol. 1999; 20(2-3):467-476.

Itokawa Y. Trace elements in long-term total parenteral nutrition [in Japanese]. Nippon Rinsho. 1996;54:172–178.

Johnson MA, Smith MM, Edmonds JT. Copper, iron, zinc, and manganese in dietary supplements, infant formulas, and ready-to-eat breakfast cereals. Am J Clin Nutr. 1998;67(suppl):1035S–1040S.

Krause, MV., & Mahan, L.K. Food, Nutrition, and Diet Therapy. 7th ed. Philadelphia, Pa: WB Saunders Co., 1984.

Orten JM., Neuhaus OW, eds. Human Biochemistry. 10th ed. St. Louis, MO: The C.V. Mosby Co; 1982.

Pasquier C, Mach PS, Raichvarg D, Sarfati G, Amor B, Delbarre F. Manganese-containing superoxide-dismutase deficiency in polymorphonuclear leukocytes of adults with rheumatoid arthritis. Inflammation. 1984;8:27–32.

Saltman PD, Strause LG. The role of trace minerals in osteoporosis. J Am Coll Nutr. 1993;12:384–389.

Shils ME, Olsen JA, Shike M, eds. Modern Nutrition in Health and Disease. 8th ed. Media, Pa: Williams and Wilkins Co; 1994:1.

Shvets NV, Kramarenko LD, Vydyborets SV, Gaidukova SN. Disordered trace element content of the erythrocytes in diabetes mellitus [in Russian]. Lik Sprava. 1994;1:52–55.

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