Manganese

Why manganese is good for you

Manganese is a trace mineral, which means the body only needs a very small amount of it to be healthy.

Manganese plays an important role in a number of physiological processes as a constituent of some enzymes and an activator of other enzymes. Manganese-activated enzymes play important roles in the metabolism of carbohydrates, amino acids, and cholesterol.

Manganese enables the body to utilize vitamin C, Vitamin B1 (thiamin) , vitamin H (biotin) as well as choline. It is used in the manufacture of fat, sex hormones and breast milk in females.

Manganese is also necessary for healthy bone and cartilage development as well as wound healing.

Manganese is thought to also help neutralise free radicals as well as being of assistance in preventing diabetes and it is also needed for normal nerve function.

Important manganese facts

• Manganese is lost in milling and its absorption is decreased in the presence of large amounts of calcium, phosphorous, zinc, cobalt and soy protein.
• Manganese is depleted in the soil by extensive use of chemical fertilizers or too much lime, and food grown in such soil will have a low manganese content
• Manganese works with Vitamin K to promote blood clotting

Groups at risk of manganese deficiency

• Pregnant or breastfeeding mothers – much of the nutrients eaten are passed onto the child and extra may be needed each day to top up supplies of manganese

People in these groups at risk of deficiency should talk to a medical professional about manganese supplements before taking them.

Symptoms of manganese deficiency

Manganese is not easily absorbed but since very small amounts are needed, deficiency is rare.

Deficiencies symptoms include:

• poor bone growth
• birth defects and reduced fertility
• problems with blood glucose levels

Serious deficiency in children can result in paralysis, deafness and blindness.

Manganese and health

• Osteoporosis – women with osteoporosis have been found to have decreased blood levels of manganese. A 2-year study of healthy postmenopausal women found that a supplement containing manganese, copper and zinc, in combination with calcium, was more effective than just a calcium supplement alone in preventing spinal bone loss over a period of 2 years. More research needs to be undertaken in this area to determine how effective manganese is for osteoporosis
• Diabetes – manganese deficiency resulted in glucose intolerance similar to diabetes in some studies. Although manganese appears to play a role in glucose metabolism, there is little evidence in studies conducted so far, that manganese supplementation improves glucose tolerance in diabetic or non-diabetic individuals
• Epilepsy – certain subgroups of people with epilepsy have been found to have lower blood manganese levels than non-epileptic people. One study found blood manganese levels of individuals with epilepsy of unknown origin to be lower than those of individuals whose epilepsy was induced by trauma (e.g., head injury) or disease, suggesting a possible relationship between epilepsy and abnormal manganese metabolism. Further research needs to be undertaken to determine the role manganese plays in epilepsy

People who wish to take a manganese supplement should talk to a medical professional before taking it.

Manganese in food

Manganese recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

* The tolerable upper limit for manganese for infants aged 0-12 months has not yet been determined due to a lack of data about the adverse effects in this age group. The only source of manganese intake should be from food (breast milk and/or baby formula).

Manganese works best with

• Vitamin H (Biotin)
• Vitamin B1 (Thiamin)
• Vitamin C
• Vitamin K
• Copper
• Iron
• Zinc
• Glucosamine

Acute manganese toxicity

Toxicity of manganese by diet is rare. Miners who are exposed to high levels of manganese (which they may inhale), can get “manganese madness”.

Acute toxicity from taking too many manganese supplements – over 1000mg can cause the following symptoms:

• Breathing problems *
• Impotence
• Muscle fatigue
• Weight loss

* People who experience the highlighted symptoms should seek immediate emergency treatment.

Chronic manganese toxicity

Chronic toxicity of manganese from taking higher than the therapeutic dose of supplements for a long time can cause the following symptoms:

• Anaemia (lowered iron levels)
• Confusion
• Delusions
• Dementia
• Depression
• Hallucinations
• Headaches
• High blood pressure
• Impotence
• Inflammation of the kidneys
• Insomnia
• Liver cirrhosis
• Memory problems
• Muscle fatigue
• Parkinson’s disease (Parkinson-like symptoms) *
• Slurred speech
• Tremors

People who experience any of the above toxicity symptoms should discontinue their manganese supplements and see their doctor for advice.

Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of manganese is highly unlikely to cause overdosage.

* Parkinson’s disease is a health condition in which high levels of manganese (as well as other minerals) could be an underlying component in its development.

Precautions

There are some individuals who have increased susceptibility to manganese toxicity:

• People with chronic liver disease – manganese is eliminated from the body mainly in bile. Impaired liver function may lead to decreased manganese excretion. Manganese accumulation in people with cirrhosis or liver failure may contribute to neurological problems and Parkinson’s disease-like symptoms.
• Newborns – the newborn brain may be more susceptible to manganese toxicity due the developing nerve cells and the immaturity of the liver’s bile elimination system. Do not use manganese supplements for newborns.

Manganese interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with manganese supplements:

• Calcium
  Calcium, either from foods rich in calcium or supplements may decrease the absorption of any manganese supplements taken at the same time, especially if the calcium is taken in larger doses.
• Iron
  Manganese supplements, especially if they are very high levels, seem to interfere with iron absorption and can lead to iron-deficiency anaemia, irrespective of whether the iron is from food or supplements.
• Magnesium
  Magnesium, either from foods rich in magnesium or supplements may decrease the absorption of any manganese supplements taken at the same time, especially if the magnesium is taken in larger doses.
• Phosphorus
  Phosphorus, either from foods rich in phosphorus or supplements may decrease the absorption of any manganese supplements taken at the same time, especially if the phosphorus is taken in larger doses.
• Oral contraceptives
  The oral contraceptive decreases blood manganese levels, even if manganese supplements (at recommended levels) are used.

Other interactions with manganese

There are none reported.

Manganese’s effect on lab tests

Manganese can have the following effect on lab tests:

• Serum iron levels

Excess manganese intake may decrease serum iron levels.

References

• USDA National Nutrient Database – provides nutrient values for foods (accessed 5 January 2005)
• Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
• Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002

Last updated: 6 May 2024