Manganese hypermineralosis is a real possibility with most of the multivitamin supplements on the market today.

Manganese deficiency even in people eating the horrid standard American diet is extremely rare; most people get more than the two mg daily they need for optimal functioning. Dietary sources can be found in brown rice, pineapples, pecans, almonds, beans, spinach, and sweet potatoes.¹ Also, if you drink well or even tap water, manganese is concentrated in most water sources and can add to your total daily intake of the mineral.²

Adequate intake is essential for the body; it is used for the production of manganese superoxide dismutase a principal mitochondrial antioxidant. Manganese is used by the body for proper metabolism, bone development, and wound healing.^{3 4}

Manganese is important for the production of many crucial enzymes in the body. The mineral is used to produce the enzyme phosphoenolpyruvate carboxykinase (PEPCK) which is vital for proper gluconeogenesis. The mineral is also essential for reducing glutamate excitability in the brain through the production of the enzyme glutamine synthetase that converts it into safer glutamine. Finally, it is required for the activation of prolidase, an enzyme that provides proline for proper collagen formation.⁵

What Issues Can Come from Ingesting Too Much Manganese?

Manganese in large doses, on the other hand, is harmful and is a potent neurotoxin. Manganese poisoning causes many neurologic and physical problems that resemble diseases including Parkinson’s disease and schizophrenia. A study from Greece concluded that people who ingested water with natural levels as low as 2.3 mg a liter might show adverse neurological symptoms. Another study showed that children who ingested water that contained elevated amounts of the mineral experienced cognitive and behavioral deficits. The EPA even limits concentrations in drinking water to 0.05 mg/liter.^{6 7 8 9}

Toxicity from inhaling manganese dust (known as manganism) can be an occupational hazard, and cause a more rapid onset of neurological symptoms including tremors, irritability, aggressiveness, hallucinations difficulty walking, and facial muscle spasms.^{10 11}

People who have chronic liver disease (the mineral is excreted through bile), newborns, children, if you are female, or people who are iron deficient are at greater risks for manganese toxicity. ^{10 11}

My recommended daily supplementation limit of manganese is two milligrams. Even though I support the use of most of Thorne Research multivitamins, they usually have too much manganese in their vitamins, and I suggest reducing the dosage till it is at or around two milligrams.

If you believe that you are suffering for manganese hyperminerlosis supplementing with magnesium (at least 200 mg) and calcium citrate (500 mg) may help increase its excretion or blunt its absorption leading to decreased bioavailability.¹⁴