Our bodies contain only a very small amount of manganese, but this metal is important as a constituent of many key enzymes. The chemical structure of these enzymes is interesting: large protein molecules cluster around a tiny atom of metal.
Manganese plays a particularly important role as part of the natural antioxidant enzyme superoxide dismutase (SOD), which helps fight damaging free radicals. It also helps energy metabolism, thyroid function, blood sugar control, and normal skeletal growth.
The official US recommendations for daily intake of manganese are as follows:
The absorption of manganese may be impaired by simultaneous intake of antacids or calcium or iron supplements.13-15
The best sources of dietary manganese are whole grains, legumes, avocados, grape juice, chocolate, seaweed, egg yolks, nuts, seeds, boysenberries, blueberries, pineapples, spinach, collard greens, peas, and green vegetables.
A typical dosage used in studies on manganese is 3 to 6 mg daily. It is sometimes recommended at a much higher dose of 50 to 200 mg daily for 2 weeks following a muscle sprain or strain, but this dosage exceeds recommended safe intake levels (see Safety Issues).
Because manganese plays a role in bone metabolism, it has been suggested as a treatment for osteoporosis, a condition in which bone mass deteriorates with age. However, we have no direct evidence that manganese is helpful, except perhaps in combination with other minerals.4
Manganese has also been suggested for the treatment of muscle strains and sprains, rheumatoid arthritis, and tardive dyskinesia,6 but there is no reliable evidence as yet to indicate that it actually helps.
People with epilepsy7 or diabetes8,9 have lower-than-normal levels of manganese in their blood. This suggests (but definitely doesn't prove) that manganese supplements might be useful for these conditions. Unfortunately, the studies that could prove or disprove this idea haven't been performed.
What Is the Scientific Evidence for Manganese?
Although manganese is known to play a role in bone metabolism, there is no direct evidence that manganese supplements can help prevent osteoporosis. However, one double-blind placebo-controlled study suggests that a combination of minerals including manganese may be helpful.10 Fifty-nine women took either placebo, calcium (1,000 mg daily), or calcium plus a daily mineral supplement consisting of 5 mg of manganese, 15 mg of zinc, and 2.5 mg of copper. After 2 years, the group receiving calcium plus minerals showed better bone density than the group receiving calcium alone. But this study doesn't tell us whether it was the manganese or the other minerals that made the difference.
Manganese is thought to be safe when taken by adults at a dose of 11 mg daily or less. The maximum safe dosage of manganese for pregnant or nursing women has also been established as 11 mg daily, or 9 mg if 18 years old or younger.12
Very high exposure to manganese (due either to environmental pollution or manganese mining) has resulted in a serious psychiatric disorder known as "manganese madness."
Interactions You Should Know About
If you are taking:
1. Freeland-Graves JH. Manganese: an essential nutrient for humans. Nutr Today. 1988;23:13-19.
2. Davidsson L, Cederblad A, Lonnerdal B, et al. The effect of individual dietary components on manganese absorption in humans. Am J Clin Nutr. 1991;54:1065-1070.
3. Freeland-Graves JH, Lin PH. Plasma uptake of manganese as affected by oral loads of manganese, calcium, milk, phosphorous, copper, and zinc. J Am Coll Nutr. 1991;10:38-43.
4. Strause L, Saltman P, Smith KT, et al. Spinal bone loss in postmenopausal women supplemented with calcium and trace minerals. J Nutr. 1994;124:1060-1064.
5. Penland JG, Johnson PE. Dietary calcium and manganese effects on menstrual cycle symptoms. Am J Obstet Gynecol. 1993;168:1417-1423.
6. Kunin RA. Manganese and niacin in the treatment of drug-induced tardive dyskinesias. In: Werbach MR. Nutritional Influences on Illness [book on CD-ROM] . 2nd ed. Tarzana, CA. 1996.
7. Akram M, Sullivan C, Mack G, et al. What is the clinical significance of reduced manganese and zinc levels in treated epileptic patients? Med J Aust. 1989;151:113.
8. Kosenko LG. The content of some trace elements in the blood of patients suffering from diabetes mellitus. Klin Med (Mosk). 1964;42:113-116. In: Werbach MR. Nutritional Influences on Illness: A Sourcebook of Clinical Research [book on CD-ROM]. Tarzana, CA: Third Line Press; 1998.
9. Kosenko LG. The content of some trace elements in the blood of patients suffering from diabetes mellitus [in Russian; English abstract]. Klin Med (Mosk). 1964;42:113-116.
10. Strause L, Saltman P, Smith KT, et al. Spinal bone loss in postmenopausal women supplemented with calcium and trace minerals. J Nutr. 1994;124:1060-1064.
11. Penland JG, Johnson PE. Dietary calcium and manganese effects on menstrual cycle symptoms. Am J Obstet Gynecol. 1993;168:1417-1423.
12. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. National Academies Press website. Available at: http://www.nap.edu. Accessed October 4, 2001.
13. Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington DC: National Academy of Sciences; 2001.
14. Davidsson L, Cederblad A, Lonnerdal B, et al. The effect of individual dietary components on manganese absorption in humans. Am J Clin Nutr. 1991;54:1065-1070.
15. Freeland-Graves JH, Lin PH. Plasma uptake of manganese as affected by oral loads of manganese, calcium, milk, phosphorous, copper, and zinc. J Am Coll Nutr. 1991;10:38-43.
Last reviewed December 2015 by EBSCO CAM Review Board
Last Updated: 12/15/2015
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