Manganese is an essential trace mineral present in a variety of foods and dietary supplements. It's the 5th most abundant naturally occurring mineral in the Earth's crust and almost all life forms require it to function properly.
It's important because it's a cofactor for enzymes like manganese superoxide dismutase, arginase, and pyruvate carboxylase [2]. Through these enzymes, it's involved in bone formation, blood clotting, inflammation reduction, immune response, and the metabolism of carbohydrates, amino acids, and cholesterol.
Since the human body doesn't make manganese on its own, we need to intake small amounts of it through our diet. The body can store extra manganese in the liver, pancreas, bones, kidneys, and brain for later use.
Involved in bone health
Manganese is a co-factor for glycosyltransferase enzymes, which are enzymes involved in bone formation.
Glycosyltransferases enzymes help synthesize compounds needed to form healthy cartilage and bone [3]. In a study measuring bone mineral density in postmenopausal women, blood plasma manganese levels were positively associated with bone mineral density and negatively associated with bone fracture rates [2].
There are many other studies showing supplementing with a combination of vitamin D, calcium, and trace minerals copper, zinc, and manganese may improve bone mass, overall bone health and help prevent spinal bone loss.
However, other studies show supplementing with just vitamin D and calcium has similar effects. Consistent findings of the association between circulating manganese and bone mineral density/osteoporosis are required to further back up these claims.
Helps blood clotting
Manganese and vitamin K aid the formation of blood clots. Forming a blood clot is the first step to healing an injury. If proper clotting doesn't occur, blood loss or abnormally large bruising may occur. Manganese is important in the blood clotting process and later on in the wound healing process by increasing collagen synthesis.
Wound healing
When a wound is repairing itself, increased amounts of collagen are required. Manganese activates prolidase, an enzyme that provides the amino acid proline for collagen formation [3]. Prolidase deficiency, a genetic disorder that leads to abnormal wound healing, is caused by abnormal manganese metabolism.
Thus, manganese is essential for healthy wound healing in both clotting and tissue repair aspects.
Metabolism of nutrients
Manganese is involved in glucose, carbohydrate, lipid, and amino acid metabolism. It activates enzymes responsible for breaking down macronutrients into compounds our bodies use.
It also helps the body use vitamins C, vitamin E, choline, and thiamine.
Synthesizes neurotransmitters
In the brain, there is a manganese-activated enzyme called glutamine synthetase. This enzyme converts the amino acid glutamate into glutamine, which is then used for energy production and protein synthesis.
Glutamate, a neurotransmitter involved in memory and learning, is also a precursor to another neurotransmitter, GABA. GABA controls impulses between nerve cells and is associated with fear, anxiety, and stress management.
Without manganese, the cascade of reactions that converts glutamate into glutamine and GABA is affected.
Detoxifies ammonia
During amino acid metabolism, ammonia is produced as an unwanted byproduct. Arginase, another manganese-containing enzyme, is used by the liver to detoxify this ammonia.
Essential for thyroid gland health
Manganese helps form thyroxine, the main type of thyroid hormone. Low manganese results in poor thyroid gland function.
Also, the manganese superoxide dismutase helps protect the thyroid gland from cellular damage [7].
Can help diabetes mellitus
Manganese may help regulate blood sugar levels.
Since manganese is associated with carbohydrate metabolism, it may be involved in the glucose intolerance observed in diabetes mellitus patients. Studies have shown strong correlations between diabetes and too much manganese. However, it's unknown if diabetes causes manganese levels to drop or if low manganese contributes to diabetes.
In animal studies, manganese supplementation improves glucose tolerance, a key factor in treating diabetes [2].
Manganese is also involved in insulin production in the pancreas. Insulin is responsible for regulating blood sugar by removing sugar from the blood.
Studies have found that "dietary manganese deficiency can result in impaired insulin secretion producing impaired carbohydrate metabolism" [4]. This may mean without adequate manganese, not enough insulin is released into the bloodstream which causes dysfunctional glucose uptake.
Has strong antioxidant properties
Manganese superoxide dismutase (MnSOD) is a strong antioxidant enzyme in the mitochondria.
The manganese superoxide dismutase starts the conversion of superoxide radicals, dangerous free radicals that cause oxidative stress, into hydrogen peroxide, which are then reduced to water by other antioxidant enzymes.
Thus, manganese is important in reducing cellular damage caused by oxidative stress, especially in the mitochondria.
Improves arthritis
People with arthritis usually have lower levels of SOD, or superoxide dismutase, the antioxidant that helps protect the joints from damage during inflammation.
Some studies have shown manganese increases superoxide dismutase levels, which is why is may be helpful in treating arthritis. However, there is no proof that it specifically targets arthritis.
Clinical studies involving patients with rheumatoid and osteoarthritis suggest that manganese taken along with glucosamine and chondroitin can reduce pain [5].
Helps seizure disorders
Some researchers report a deficiency in glutamine synthetase in the hippocampus is a potential cause of seizures. Since glutamine synthetase requires manganese for activation, the correlation between the two has not gone unnoticed.
A older study showed patients with epilepsy had lower blood manganese concentrations than patients without epilepsy. Deficiencies in magnesium, zinc, and copper were also noted.
One study found blood manganese concentrations of individuals with epilepsy of unknown origin were lower than those of individuals whose epilepsy was induced by trauma or disease, suggesting a possible genetic relationship between epilepsy and abnormal manganese metabolism.
Too much manganese is most likely not the cause of epilepsy in humans, but the relationship between manganese metabolism and epilepsy should be researched further [3].
Improves immune response
Recent epidemiological and animal studies have shown that manganese increases the immune response in the human body. Manganese appears to increase the inflammatory response of the immune system, affect T-cell signaling, which can lead to the elimination of pathogens.
Manganese also increases myeloid cell and NK (natural killer) cell activity. Myeloid cells are blood cells that help out at the site of tissue damage and natural killer cells help inhibit the spread of infection or tumor growth [6].
All of these actions strengthen the response of the immune system and boosts the bodies' defense against infection.
Deficiency
A manganese deficiency is rare.
When it occurs though, it can cause serious problems. In experimental animal studies, dietary manganese deficiency leads to "biochemical and structural" abnormalities like lowered glucose tolerance, impaired carbohydrate and fat metabolism, impaired oxidant defense, fertility problems, and issues with growth factor metabolism [1].
Toxicity
Manganese toxicity is more common than a deficiency.
Though this may take years, an accumulation of manganese can damage the nervous system, lungs, liver, and kidneys. Damage to the nervous system, or neurotoxicity, can cause Parkinson's-like symptoms: tremors, slow movement, and poor balance.
Manganism
This toxicity condition is known as manganism and is the result of very high amounts of manganese being consumed, either from inhalation (in jobs like welding or mining) or with too high of supplementation.
Due to this, it's important to consult with health professionals before adding a supplement to your diet and/or to get a blood test done to figure out what vitamins and minerals your body needs.
Dietary manganese intake
There adequate intake level for manganese is 2.3 mg/day for male adults and 1.8 mg/day for female adults. The tolerable upper intake level, or the highest level you can safely consume, is 11 mg/day.
Food sources
Manganese is present in many foods like whole grains, clams, oysters, mussels, nuts, soybeans, legumes, rice, leafy green vegetables, coffee, tea, and spices.
Drinking water also contains small amounts of manganese, however too much manganese in drinking water can be toxic.
Manganese absorption
Manganese is absorbed through the small intestine, with only 1%-5% of dietary manganese being absorbed and 90% being excreted out. Absorption efficacy increases with low manganese intake and decreases with high intake, meaning your body absorbs more manganese when you're consuming low amounts of it and lowers absorption when you're consuming high amounts of it.
Iron, calcium, and phosphorous have been shown to decrease the absorption of manganese.
Key takeaways
Manganese deficiency is rare, with most people getting adequate amounts through the food they eat everyday. A manganese supplement is usually recommended after blood tests have shown low levels of it.
Manganese is an essential trace mineral that facilitates many reactions in our bodies
It activates enzymes involved in bone formation, antioxidant response, collagen formation, and nutrient breakdown and utilization.
The benefits of manganese are: improve weak bones, improve antioxidant function, regulate blood sugar and production of insulin, and improve cognitive function by assisting neurotransmitter synthesis.
It may help treat specific nervous disorders like epilepsy and inflammatory conditions like arthritis.
The antioxidant enzyme superoxide dismutase is activated by manganese and helps fight oxidation in the body, one of the main health benefits of manganese.
Sources
CL, K., & JL, E. (1999). Nutritional aspects of manganese from experimental studies.Europe PMC. Retrieved June 15, 2022, from https://europepmc.org/article/med/10385885
National Institute of Health. (2021). Manganese. NIH Office of Dietary Supplements. Retrieved June 15, 2022, from https://ods.od.nih.gov/factsheets/Manganese-HealthProfessional/
Hidden , J. (2001). Manganese . Manganese. Retrieved June 15, 2022, from https://lpi.oregonstate.edu/book/export/html/261
Bally, D., Curry, D., & Keen, C. (1984). Effect of manganese deficiency on insulin secretion. Research Gate. Retrieved June 15, 2022, from https://www.researchgate.net/publication/16817427_Effect_of_Manganese_Deficiency_on_Insulin_Secretion_and_Carbohydrate_Homeostasis_in_Rats
Manganese. Mount Sinai Health System. (2017). Retrieved June 15, 2022, from https://www.mountsinai.org/health-library/supplement/manganese
Wu, Q., Mu, Q., Xia, Z., Min, J., & Wang, F. (2021, January 5). Manganese homeostasis at the host-pathogen interface and in the host immune system. Seminars in Cell & Developmental Biology. Retrieved June 15, 2022, from https://www.sciencedirect.com/science/article/pii/S1084952120302007
Balchem. (2021, February 25). The role of minerals in supporting Thyroid Health. Human Nutrition & Health. Retrieved June 15, 2022, from https://balchem.com/human-nutrition-health/blog/the-role-of-minerals-in-supporting-thyroid-health/