Manganese

Figure 1. The crystal structure of Manganese.

Manganese is a chemical element with the symbol Mn and atomic number 25. Manganese is the 12th most abundant element in the Earth's crust.

Manganese is also an essential trace mineral. It is important as a coenzyme in macronutrient metabolism, bone formation, and free radical defense systems. Manganese is a critical component in dozens of proteins and enzymes, and the human body contains about 12mg-20mg of Manganese. Manganese is found mostly in the bones, but it can also be found in the liver, kidneys, and brain. In the human brain, Manganese is bound to Manganese metalloproteins, most notably glutamine synthetase in astrocytes.

Food sources

Manganese can be found in many food sources, including:

• Mussels
• Hazelnuts
• Pecans
• Brown rice
• Oysters
• Clams
• Chickpeas
• Spinach
• Pineapple
• Soybeans
• Bread
• Oatmeal
• Peanuts
• Black Tea
• Lentils
• Potato
• White rice
• Kidney beans
• Squash
• Blueberries
• Sesame seeds
• Kale
• Black pepper
• Asparagus
• Apple
• Lettuce
• Coffee
• Shrimp
• Tuna
• Chicken
• Ground beef
• Egg
• Milk
• Yogurt

Taken as a Dietary Supplement

In dietary supplements, manganese is present in many different forms, including amino acid chelates (e.g. manganese bisglycinate chelate, manganese glycinate chelate, and manganese aspartate). Other forms include manganese gluconate, manganese picolinate, manganese sulfate, manganese citrate, and manganese chloride.

Manganese supplements are commonly promoted for bone health, given that Manganese is a cofactor for several enzymes involved in bone formation. Manganese supplementation is taken to help increase both bone mineral density and bone formation, and is usually taken in combination with other minerals like Calcium, Zinc, and Copper.

As an enzyme cofactor, Manganese is also involved in glucose, carbohydrate, and lipid metabolism. Manganese deficiency, while rare, might affect carbohydrate metabolism and cause abnormalities in glucose tolerance. Manganese supplements are promoted to help with blood sugar related conditions such as diabetes.

Manganese also provide other health benefits, including as an antioxidant (Manganese is part of the antioxidant enzyme superoxide dismutase), helping to reduce inflammation in the joints (together with Glucosamine and Chondroitin), increasing blood flow to the brain (Manganese acts as a vasodilator), helping the body to utilise a number of compounds such as Choline, Thiamine, and Vitamin C and Vitamin E, ensuring proper liver function, ensuring proper thyroid function (Manganese plays a role in the production of thyroxine), and aiding wound healing (Manganese is needed to produce the amino acid proline, which is essential for Collagen formation).

Manganese deficiency is very rare in humans and may cause bone demineralization and poor growth in children; skin rashes, hair depigmentation, decreased serum cholesterol, and increased alkaline phosphatase activity in men; and altered mood and increased premenstrual pain in women. Manganese deficiency may also alter lipid and carbohydrate metabolism and cause abnormal glucose tolerance.

The adequate intake for Manganese is 1.8mg-2.3mg a day for adults. The tolerable upper intake level is 11mg for adults. Like zinc, copper, selenium and iron, manganese is considered a heavy metal, and consuming too much can be dangerous.

Side Effects

Abnormal and excessive Manganese exposure may lead to Manganese toxicity. Manganese toxicity mainly affects the central nervous system and can cause tremors, muscle spasms, tinnitus, hearing loss, and the feeling of being unsteady on one’s feet. Additional symptoms include mania, insomnia, depression, delusions, anorexia, headaches, irritability, lower extremity weakness, changes in mood and short-term memory, altered reaction times, and reduced hand-eye coordination. These signs and symptoms can progress to neuromotor impairments similar to those associated with Parkinson’s disease, including changes in gait and balance, tremor, and rigidity.