| Manganese | ||||||||
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- Why manganese is good for you
- Important manganese facts
- Groups at risk of manganese deficiency
- Symptoms of manganese deficiency
- Manganese and health
- Manganese in foods
- Manganese recommended daily intake (RDI)
- Manganese works best with
- Overdosage, toxicity and cautions for manganese
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 neutralize free radicals as well as being of assistance in preventing diabetes and it is also needed for normal nerve function.
- 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
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People in these groups at risk of deficiency should talk to a medical professional about manganese supplements BEFORE taking them.
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Symptoms of manganese deficiency
Manganese is not easily absorbed but since very small amounts are needed, deficiency is rare.
Deficiencies symptoms include:
Serious deficiency in children can result in paralysis, deafness and blindness. |
- 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.
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| FOOD | AMOUNT | Manganese (mg) |
|---|---|---|
| Raisin bran cereal | 1 cup | 1.88 |
| Pineapple, raw, diced | ½ cup | 1.28 |
| Pineapple juice | ½ cup | 1.24 |
| Instant oatmeal (made with water) | 1 packet | 1.20 |
| Pecans | 30g | 1.12 |
| Brown rice, cooked | ½ cup | 0.88 |
| Almonds | 30g | 0.74 |
| Whole wheat bread | 1 slice | 0.65 |
| Peanuts | 30g | 0.59 |
| Sweet potato, cooked | ½ cup | 0.55 |
| Navy beans, cooked | ½ cup | 0.51 |
| Pinto beans, cooked | ½ cup | 0.48 |
| Lima beans, cooked | ½ cup | 0.48 |
| Tea (green) | 1 cup | 0.41-1.58 |
| Tea (black) | 1 cup | 0.18-0.77 |
Manganese recommended daily intake (RDI)
| RDA | lifestage | age | amount |
|---|---|---|---|
| INFANTS | 0-6mths 7-12mths |
0.003mg 0.6mg |
|
| CHILDREN | 1-3yrs 4-8yrs |
1.2mg 1.5mg |
|
| CHILDREN - MALE | 9-13yrs 14-18yrs |
1.9mg 2.2mg |
|
| CHILDREN - FEMALE | 9-13yrs 14-18yrs |
1.6mg 1.6mg |
|
| ADULTS | male: 19-50yrs female: 19-50yrs |
2.3mg 1.8mg |
|
| SENIORS | male: 51+yrs female: 51+yrs |
2.3mg 1.8mg |
|
| PREGNANT | all ages | 2.0mg | |
| LACTATING | all ages | 2.6mg | |
| TOLERABLE UPPER LIMIT | lifestage | age | amounT |
| INFANTS | 0-12mths | n/a* | |
| CHILDREN | 1-3yrs 4-8yrs |
2mg 3mg |
|
| CHILDREN | 9-13yrs 14-18yrs |
6mg 9mg |
|
| ADULTS | 19-50yrs | 11mg | |
| SENIORS | 51+yrs |
11mg | |
| PREGNANT | <18yrs 19-50yrs |
9mg 11mg |
|
| LACTATING | <18yrs 19-50yrs |
9mg 11mg |
|
| Toxic Levels | >50mg (for long periods) | ||
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).
Overdosage, toxicity and cautions for manganese
Toxicity of manganese by diet is rare. Excess magnesium can reduce iron. Miners who are exposed to high levels of manganese (which they may inhale), can get "manganese madness".
Acute (>100mg) toxicity - anorexia, impotence, muscle fatigue.
Chronic toxicity - anaemia, liver cirrhosis, dementia, high blood pressure, headaches, impotence, insomnia, mental confusion, muscle fatigue, inflammation of the kidneys, poor memory, slurred speech, tremors.
CAUTION
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.
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
