Get acquainted with your nutrients - Manganese

Manganese (Mn) is a vital micro-nutrient which comes mainly from food and water. Manganese is absorbed through the gastrointestinal tract and then transported to organs. Manganese is involved in the synthesis and activation of several enzymes that are required for proper functioning of immune system, regulation of blood sugar and cellular energy, reproduction, digestion, bone growth, blood coagulation, and hemostasis and defense against reactive oxygen species.

Foods that provide manganese

Good sources of manganese are

1. Whole grain cereals
2. Fruits and vegetables
3. Legumes
4. Nuts
5. Tea and leafy vegetables.

Manganese content in fruits and vegetables is dependent on the soil content of manganese. Animal foods, in general, are poor sources of manganese.

Recommendations for manganese intake

The adequate intake (AI) for manganese is 1.8 and 2.3 mg respectively for adult women and men daily. During pregnancy and lactation the adequate intake increases to 2.0 and 2.6 mg daily. In children, the adequate intake values vary with age.

Summary of Manganese adequate intake (ages 0 through 18 years)

Source: Institute of Medicine’s Dietary Reference Intake for Mn

Only a small percentage of these amounts are absorbed from the intestine, since the gut tightly controls body manganese load and the mineral is efficiently excreted via bile as long as there is no hepatic disease issues. Fiber, phytate, oxalate and excess calcium, phosphorous, iron can decrease manganese absorption.

Functions of manganese

Manganese is involved in many functions in the cells.

Firstly manganese can interact with certain enzymes to increase their activity. Manganese activated enzymes are involved in reactions in protein digestion, making glucose from certain amino acids and lactate (gluconeogenesis).

Secondly manganese is a component of several enzymes which are involved in several activities including urea formation, glucose formation and anti-oxidation.

Manganese although a co-factor for many enzymes, its action as co-factor is most of the time nonspecific that is other minerals can also perform the same role. Pyruvate carboxylase and manganese superoxide dismutase are metalloenzymes and contain manganese as a constituent. Pyruvate carboxylase is a regulatory enzyme involved gluconeogenesis. Manganese superoxide dismutase has protective property towards cells against damage by superoxide free radicals.

Manganese may also be involved in the activity of some hormones. Manganese is found mostly in bones, the liver, kidneys, and pancreas.

Manganese deficiency

Manganese deficiency and intoxication are both related with negative metabolic and neuropsychiatric effects. Manganese deficiency is not seen much in human beings, it is a very rare occurrence.

Signs and symptoms that may be associated with manganese deficiency are

1. Nausea
2. Dermatitis
3. hair and nail growth are affected
4. glucose tolerance is affected
5. bone formation is affected
6. reduced fertility
7. birth defects
8. may cause altered lipid and carbohydrate metabolism

Manganese toxicity has not been reported as far as diet is concerned. Manganese toxicity is also very rare.