MICROMINERAL
MANGANESE:
Manganese is an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes.
What does manganese do?
Manganese is important for several functions in your body.
Metabolism
Your body contains numerous proteins called enzymes. Enzymes help to speed up chemical reactions. Manganese is a necessary component of several important enzymes in your body that work to process carbohydrates, amino acids, and cholesterol.
Antioxidant properties
An antioxidant stops harmful free radicals from damaging your cells. A manganese-containing enzyme present in your cells is the main detoxifier of free radicals.
Bone health and development
Manganese is essential for enzymes that help form bone and cartilage.
Wound healing
Manganese is present in an enzyme that provides an amino acid called proline. Proline is necessary for the production of collagen in your skin cells. Collagen formation is essential to wound healing.
Nutrient interactions
Iron
Iron and manganese share common absorption and transport proteins, including the divalent metal transporter 1, the lactoferrin receptor, transferrin, and ferroportin . Absorption of manganese from a meal decreases as the meal's iron content increases.
Magnesium
Supplemental magnesium (200 mg/day) has been shown to slightly decrease manganese bioavailability in healthy adults, either by decreasing manganese absorption or by increasing its excretion.
Calcium
In one set of studies, supplemental calcium (500 mg/day) slightly decreased manganese bioavailability in healthy adults. As a source of calcium, milk had the least effect, while calcium carbonate and calcium phosphate had the greatest effect . Several other studies have found minimal effects of supplemental calcium on manganese metabolism.
Regulation:
Although manganese is a nutritionally essential mineral, it is potentially toxic; thus, it is important for the body to tightly regulate manganese homeostasis. While the exact mechanisms that govern manganese homeostasis are not completely understood, systemic regulation is achieved through intestinal control of manganese absorption and hepatic excretion of manganese. At the cellular level, influx of manganese into cells is regulated by several different transport proteins, including the transferrin receptor, the divalent metal transporter 1 (DMT 1), zinc-interacting proteins 8 and 14 (ZIP8 and ZIP14), as well as others. Efflux of manganese from cells is accomplished by various transporters, including SLC30A10; the sodium-calcium exchanger; and the iron transporter, ferroportin. Moreover, subcellular organelles (i.e., the nucleus, mitochondria, Golgi apparatus, lysosome, endosome) utilize various transporters for manganese trafficking within the cell, but the exact mechanisms of regulation are not fully understood.
What foods are rich in manganese?
Some examples of foods that are good sources of manganese include:
nuts, such as almonds and pecans
beans and legumes, such as lima and pinto beans
oatmeal and bran cereals
whole wheat bread
brown rice
leafy green vegetables, such as spinach
fruits, such as pineapple and acai
How much manganese do I need per day?
There is no Recommended Dietary Allowance (RDA) set for manganese. The daily Adequate Intakes (AIs) are listed below:
Side effects, toxicity, and interactions
If you take too much manganese as supplements, you could have side effects. These can include loss of appetite, slowed growth, and reproductive issues. It may also cause anemia. This is because manganese competes with iron for absorption.
People who receive total parenteral nutrition (TPN or intravenous feeding) can have serious side effects from oral manganese supplements. People with liver problems can, too. These effects include:
Headache and insomnia
Exaggerated tendon reflexes
Memory loss
Impaired motor skills
Psychiatric issues
Irreversible nerve damage that causes symptoms like Parkinson disease
Reproductive problems
People with liver issues shouldn’t take manganese supplements.
Manganese is toxic when you inhale manganese oxide from dust or fumes.
Well water can be contaminated with manganese.
Women who are pregnant or breastfeeding should talk to their healthcare providers before taking any supplements.
Manganese competes with iron for absorption. Its absorption can be decreased by fiber, phytates, oxalic acid, calcium, and phosphorus. It isn’t known if zinc and copper absorption is decreased by manganese.
What are the symptoms of a deficiency?
Since manganese is found in many foods within our daily diets, reports of manganese deficiency are rare.
A person that does have a deficiency in manganese could experience the following symptoms:
poor bone growth or skeletal defects
slow or impaired growth
low fertility
impaired glucose tolerance, a state between normal glucose maintenance and diabetes
abnormal metabolism of carbohydrate and fat
Common causes
Manganese deficiency could be caused by not having enough manganese in your diet. However, according to the Institute of Medicine’s review of dietary micronutrients, a clinical deficiency in manganese due to diet has not been observed in otherwise healthy people.
People with the following conditions could be at risk of lower-than-ideal manganese levels:
exocrine pancreatic insufficiency (an inability to digest food due to a deficiency of digestive enzymes produced by the pancreas)
people who are on hemodialysis
children with Perthes disease (a rare condition where blood flow to the thighbone is disrupted)
children with phenylketonuria (an inherited disorder in which blood levels of phenylalanine are elevated)
How it’s diagnosed
Manganese levels in your blood can be evaluated using a simple blood test. In order to perform the test, your doctor will need to obtain a blood sample from a vein in your arm.
How it’s treated
In manganese depletion studies, symptoms subsided when subjects were given manganese supplementation.
If you have a manganese deficiency, your doctor will likely prescribe manganese supplementation. They’ll also suggest that you try to include more manganese-rich foods in your diet.
What are the complications?
The effects of manganese deficiency have not been well studied in humans.
However, manganese deficiency in animals has been found to cause skeletal defects such as:
curved spine
shorter and thicker limbs
enlarged joints
Reference:
https://www.healthline.com/health/manganese-deficiency
https://lpi.oregonstate.edu/mic/minerals/manganese
https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=manganese
