MANGANESE and HEALTH*
Manganese (Mn) is a pinkish-grey, chemically active element. It is a hard metal and very brittle, difficult to melt and easily oxidised. It is reactive when pure, and as a powder it will burn in oxygen. It reacts with water (rusts like iron) and dissolves in dilute acids.
How can such a substance be relevant to health?
Manganese is very common, and can be found everywhere on earth. It is one of the most abundant metals in soils, where it occurs as oxides and hydroxides. It is one of three toxic essential trace elements needed for health. Manganese is not only necessary for humans to survive, but it is also toxic when too high concentrations are present in the human body. A deficiency of manganese in the body leads to a decrease in health. But when the intake/ uptake is too high, health problems will also occur.
The uptake of manganese by humans mainly takes place from food sources.
Manganese in the body is called a trace mineral or trace element. It participates in many enzymes systems in the body, and was first considered an essential nutrient in 1931.
The human body contains between 12 and 20 milligrams of manganese, found mainly in the bones. The rest is in the soft tissues, mostly concentrated in the liver and kidneys. It is also found in the brain.
The Function of Manganese
The two main functions of manganese are:
as an enzyme activator
as a component of metalloenzymes.
Manganese as an Enzyme Activator
Manganese activates the enzymes responsible for the utilisation of several key nutrients including biotin, thiamin, ascorbic acid and choline.
It is a catalyst in the synthesis of fatty acids and cholesterol. It also facilitates protein and carbohydrate metabolism and participates in the production of sex hormones.
In addition, manganese activates certain enzymes important in the formation of bone. It is also believed to be involved in the production of thyroxine by the thyroid gland, as well as maintaining the health of nerve tissue.
Manganese as a Component of Metalloenzymes.
A metalloenzyme is an enzyme that contains a metal ion in its structure.
The classes of enzymes that have manganese co-factors are very broad, and include oxidoreductases, transferases, hydrolases etc.
Manganese is a constituent of the following metalloenzymes:
- Arginase. This enzyme is in the liver, and is responsible for creating urea, excreted in the urine.
- Glutamine synthetase. This is an enzyme involved in the synthesis of glutamine. Glutamine is the most abundant amino acid (building block of protein) in the body. The body manufactures glutamine, it is not an essential amino acid (one which has to be obtained from food).
- Phosphoenolpyruvate decarboxylase. This is an enzyme that participates in the metabolism of blood glucose (sugar).
- Manganese-dependent superoxide dismutase (Mn-SOD). This is a very important enzyme because of its antioxidant activity, protecting tissues from the damaging effects of free radicals. This enzyme is found exclusively in the mitochondria (the oxygen-based factories inside most of our cells).
Symptoms of Manganese Deficiency
Poor dietary intake of manganese appears to be the most common cause of manganese deficiency. Excessive sweating may lead to deficiency of manganese which is excreted in significant amounts in sweat. Individuals with chronic liver disease may need more dietary manganese.
Because manganese plays a role in a variety of enzyme systems, dietary deficiency of this trace element can impact many physiological processes.
In experimental animals, manganese deficiency causes impaired growth, skeletal abnormalities, and defects in carbohydrate and fat metabolism.
In humans, manganese deficiency is associated with the following symptoms:
- Nausea and vomiting
- Glucose intolerance
- Skin problems such as rashes
- Calcium loss from bones, and skeletal disorders
- Changes in hair colour
- Lowered cholesterol levels
- Neurological disorders.
Health Conditions where Manganese Intake may be Relevant
The following conditions (listed simply in alphabetical order) may result from a deficiency of manganese (www.whfoods.org)
- Heart disease
- Learning disabilities
- Multiple sclerosis
- Myasthenia gravis
- Premenstrual syndrome
- Rheumatoid arthritis
- Sprains and strains.
Chronic manganese poisoning may result from prolonged inhalation of manganese dust, and can be a problem in industrial workers who are exposed to this dust. These workers develop nervous system problems similar to Parkinson's disease. There may also be emotional disturbances, recurring cramps, weakness and paralysis.
Symptoms of manganese toxicity do not typically appear even at high levels of dietary intake. Manganese toxicity is most likely to occur in people with chronic liver disease, as the liver plays an important role in eliminating excess manganese from the body.
Food Sources of Manganese
The majority of foods contain some manganese. Excellent food sources of manganese include:
- Greens such as kale, spinach, lettuce
- Grains, especially brown rice
- Soya beans
- Olive oil
- Herbs such as thyme, turmeric, cinnamon, black pepper, oregano
Diet is the best way to obtain this important mineral.
Most high-quality supplements of manganese are in a chelated form, where the manganese is joined onto an organic acid like gluconic acid or an amino acid like glycine or arginine. Capsules and tablets generally contain 10mg of manganese.
The 'Tolerable Upper Intake Level' for manganese as a supplement is about 10mg for adults. No supplemental manganese should be given to infants, and no more than 3-6mg to children, depending on their age.
Too little (deficiency) or too much (toxicity) manganese can result in clinical symptoms.
Manganese is readily obtainable from food sources, and this is the best way to obtain this important trace element.
Careful supplementation of manganese in the conditions outlined above is worth considering in the overall management of those disease states.
*Copyright 2013: The Huntly Centre.
Disclaimer: All material in the huntlycentre.com.au website is provided for informational or educational purposes only. Consult a health professional regarding the applicability of any opinions or recommendations expressed herein, with respect to your symptoms or medical condition.
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