Manganese is an essential trace mineral needed for healthy skin, bone, and cartilage
formation, as well as glucose tolerance. It also helps activate superoxide dismutase
(SOD)—an important antioxidant
enzyme.
Where is it found?
Nuts and seeds, wheat germ, wheat bran, leafy green vegetables, beet tops, tea, and
pineapple are all good sources of manganese.
Manganese has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Who is likely to be deficient?
Many people consume less than the 2–5 mg of manganese currently considered safe and
adequate. Nonetheless, clear deficiencies are rare. People with osteoporosis sometimes have low blood levels of
manganese, suggestive of deficiency.1
How much is usually taken?
Whether most people would benefit from manganese supplementation remains unclear. While
there is no recommended dietary allowance, the National Research Council’s
“estimated safe and adequate daily dietary intake” is 2–5 mg.2
The Institute of Medicine recommends that intake of manganese from food, water and dietary
supplements should not exceed the tolerable daily upper limit of 11 mg per day. In contrast,
the 5–15 mg often found in high-potency
multivitamin-mineral supplements is generally considered to be a reasonable level by many
doctors, though many manufacturers are likely to reformulate their products to contain no more
than 11 mg per daily amount.
Are there any side effects or interactions?
Amounts found in supplements (5–20 mg) have not been linked with any toxicity.
Excessive intake of manganese rarely lead to psychiatric symptoms. However, most reports of
manganese toxicity in otherwise healthy people have been in those people who chronically
inhaled manganese dust at their jobs e.g., miners or alloy plant workers. Other sources of
manganese intoxication are now recognized, including total parenteral nutrition (TPN) in
patients who are being fed intravenously3 4 5 and pesticides
containing manganese in agricultural workers who have been exposed.6
Preliminary research suggests that people with
cirrhosis7 or cholestasis (blocked bile flow from the gall bladder)8
may not be able to properly excrete manganese. Until more is known, these people should not
supplement manganese. Manganese supplementation (3–5 mg per day) has caused severe hypoglycemia (low blood sugar) in a person with
insulin-dependent diabetes.9 People with diabetes who want to
take manganese should consult their doctor.
Several minerals, such as calcium and iron, and possibly zinc, reduce the absorption of manganese.10
Of these interactions, the link to iron may be the most important. In one study, women with
high iron status had relatively poor absorption of manganese.11 In another report
of manganese/iron interactions in women, increased intake of “non-heme
iron”—the kind of iron found in most supplements—decreased manganese
status.12 These interactions suggest that taking multi-minerals that include
manganese may protect against manganese deficiencies that might otherwise be triggered by
taking isolated mineral supplements, particularly iron.
Are there any drug
interactions?
Certain medicines may interact with manganese. Refer to drug interactions for a list of those medicines.
References
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1. Raloff J. Reasons for boning up on manganese. Science
1986;130:199 [review].
2. National Research Council. Recommended Dietary Allowances.
10th ed. Washington, DC: National Academy Press, 1989.
3. Nagatomo S, Umehara F, Hanada K, et al. Manganese intoxication during
total parenteral nutrition: report of two cases and review of the literature. J Neurol
Sci 1999;162:102–5.
4. Ejima A, Imamura T, Nakamura S, et al. Manganese intoxication during
total parenteral nutrition. Lancet 1992;339:426 [letter].
5. Fell JM, Reynolds AP, Meadows N, et al. Manganese toxicity in children
receiving long-term parenteral nutrition. Lancet 1996;347:1218–21.
6. Ferraz HB, Bertolucci PH, Pereira JS, et al. Chronic exposure to the
fungicide maneb may produce symptoms and signs of CNS manganese intoxication.
Neurology 1988;38:550–3.
7. Krieger D, Krieger S, Jansen O, et al. Manganese and chronic hepatic
encephalopathy. Lancet 1995;346:270–4.
8. Staunton M, Phelan DM. Manganese toxicity in a patient with
cholestasis receiving total parenteral nutrition. Anaesthesia 1995;50:665.
9. Rubenstein AH, Levin NW, Elliott GA. Hypoglycaemia induced by
manganese. Nature (London) 1962;194:188–9.
10. Freeland-Graves JH. Manganese: an essential nutrient for humans.
Nutr Today 1989;23:13–9 [review].
11. Finley JW. Manganese absorption and retention by young women is
associated with serum ferritin concentration. Am J Clin Nutr 1999;70:37–43.
12. Davis CD, Malecki EA, Gerger JL. Interactions among dietary
manganese, heme iron, and nonheme iron in women. Am J Clin Nutr
1992;56:926–32.
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The information presented in Aisle7 is for informational purposes only.
It is based on scientific studies (human, animal, or in vitro), clinical experience,
or traditional usage as cited in each article. The results reported may not necessarily occur
in all individuals. For many of the conditions discussed, treatment with prescription or over
the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist
for any health problem and before using any supplements or before making any changes in
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