MANGANESE

Manganese (Mn) is a transition element and can assume 11 different oxidation states. An adult man weighing 70 kg is estimated to contain 10-20 mg of the metal, with 25% of the total body stores in the skeleton. Relatively high amounts of the minerals are also present in the liver, pancreas, and intestine.

Why is Manganese essential for the human body?

Manganese is a cofactor for many enzymes. Through the action of these enzymes, it helps in the metabolism of:

–     amino acid

–     cholesterol

–     glucose

–     carbohydrate

It also plays a crucial role in bone formation, reproduction, and immune response. Manganese also plays a vital role in blood clotting and haemostasis in conjunction with vitamin K.

What are the signs and symptoms of Manganese deficiency?

There is little evidence of Manganese deficiency in humans as this mineral is widely distributed in a variety of foods. However, limited studies have reported symptoms of its deficiency after consuming experimental diets deficient in the mineral. These include dermatitis, depressed growth of hair and nail, low cholesterol, and weight loss.

Evidence is accumulating that Mn deficiency may be present in patients on long-term parenteral nutrition when the solutions are low in Mn content. Also, in cases where a high frequency of iron supplementation is given, there is a possibility of Fe- supplementation-induced reduction in Manganese status.

Manganese deprivation has been associated with osteoporosis, diabetes, epilepsy, atherosclerosis, and impaired wound healing.

What is the daily requirement of Manganese?

There is no RDA (Recommended Dietary Allowance) for Manganese. Instead, there is an average intake (AI) value established by the US Food and Nutrition Board:

What are the food sources of manganese?

Dietary iron intakes and iron status (measured by serum ferritin concentration) appear to be inversely associated with manganese absorption. In addition, men appear to absorb dietary manganese less efficiently than women, possibly because men usually have higher iron status.

Some of the good sources of Manganese are:

• Whole grains
• Nuts
• Green leafy vegetables
• Tea
• Chickpeas
• Pineapple
• Lentils

Can a high intake of manganese lead to toxicity?

Manganese is considered the least toxic of the trace minerals through oral intake. However, some people may be at a risk to develop toxicity. For example, individuals with liver disease are more susceptible, as dietary manganese is cleared by the liver. Similarly, patients on total parenteral nutrition (TPN) are at risk.

However, manganese toxicity occurs primarily in industrial workers exposed to excess airborne Mn such as in the case of industries manufacturing steel, alloys, and iron products. 

Mn toxicity is a serious health hazard; in its severe form, it results in serious psychiatric symptoms such as hyperirritability, violent acts, hallucinations, and poor coordination. Several abnormalities occur in the central nervous system, the morphological lesions being like Parkinson’s disease.