WHAT IS MANGANESE?
Manganese (Mn) is a trace mineral, a chemical element, that has the atomic number 25. Our bodies have about 10 mg of manganese stored in the kidneys and in the liver. Manganese is an essential mineral when it is ingested with food or as a supplement but when manganese dust, in industrial settings for instance, is inhaled it is toxic and is linked to motor skill and cognitive impairment.
WHAT DOES MANGANESE DO FOR US?
Manganese plays a role as both a member of many enzymes and as an activator of other enzymes.
There is a principal antioxidant enzyme in the mitochondria and it is called ‘manganese superoxide dismutase or MnSOD.
Mitochondria are especially vulnerable to the ravaging effects of free oxygen molecules This is called oxidative stress. When the mitochondria create ATP (adenine triphosphate) they produce superoxides. Superoxides are two oxygen atoms that share two electrons but one atom has a missing electron and the other consequently has an unbonded electron. This means that the oxygen molecule needs to find a partner for the unbonded electron.
It does so by attacking other atoms and molecules in the cells and consequently destroys the molecular structure of the cell. It is therefore necessary for the superoxide to be dissolved or as they say in biology dismutased so that it will not be destructive.
This is where the manganese superoxide dismutase (MnSOD) comes in. The MnSOD sets in motion a process that converts the superoxide radicals into hydrogen peroxide from which they are reduced to water by other antioxidants.
1. Gluconeogenesis is the production of glucose from non-carbohydrates such as pyruvate, lactate, glycerol and glucose friendly amino acids.
Gluconeogenesis is important in maintaining blood glucose levels when carbohydrates are missing from our diets. Two manganese containing enzymes are used in gluconeogenesis.
2. The process of detoxifying the liver is done by the urea cycle. The urea cycle detoxifies ammonia that is created when amino acids are being metabolized. The manganese containing enzyme called arginase is required by the urea cycle for this detoxification.
3. The glutamate is an important neurotransmitter in the central nervous system. The manganese activated enzyme glutamine synthase is responsible for converting glutamate to glutamine which is part of the glutamate-glutamine cycle that maintains a proper supply of glutamate for our nervous system.
Bone and Cartilage Development
Manganese is preferred as a cofactor for glycosyltransferases. Glycosyltransferases are needed to create proteoglycans that are needed to form healthy cartilage and bone.
Collagen is an important factor in wound healing which needs collagen in increased amounts. The enzyme prolidase provides the amino acid proline that forms collagen in human skin cells. Manganese is needed to activate prolidase.
WHAT HAPPENS WHEN WE DON’T GET ENOUGH MANGANESE?
The signs of ‘some animal’ species getting too little manganese in their diets show problems leading to growth impairment, reproductive problems, skeletal abnormalities, problems with glucose tolerance leading to diabetes, and problems with metabolizing carbohydrates and lipids.
Manganese deficiency in humans is uncommon and its effects are unclear. Manganese is not thought to cause some diseases but may contribute to them.
- Because manganese plays a role in glucose tolerance levels and in gluconeogenisis (producing glucose from non carbohydrate sources) there is some evidence that it affects diabetes in certain circumstances but supplementation has no affect on glucose tolerance.
- There is a possibility that inherited epilepsy is somehow associated with abnormal manganese metabolism.
- Iron absorption in the small intestines and transport pathways throughout the body is thought to compete with manganese absorption and transport pathways although these systems are not fully understood for manganese. What has been discovered is that MnSOD activity is reduced in white blood cells when iron levels are high. Conversely when iron levels are low manganese absorption through the intestines is increased and the risk of manganese accumulation in the brain increases.
WHAT HAPPENS WHEN WE GET TOO MUCH MANGANESE?
Getting too much manganese from non supplemental dietary sources is not found to be toxic but high levels of manganese in the water supply can lead to toxicity. It is thought that the bioavailability of manganese may be different when ingested with water than with food. This is one of the reasons that it is important for municipalities to test the drinking water regularly.
Even though vegetarian diets can provide high levels of manganese per day (up to 20 mg) there have been no cases of manganese toxicity that are diet related. The only cases that have been reported are from excessive supplementation.
WHERE DO WE GET MANGANESE?