Manganese absorption

Manganese is a trace mineral essential to all forms of life. It is required for the normal development, growth, and function of our bodies. Manganese is a cofactor for many enzymes, including manganese superoxide dismutase, arginase, and pyruvate carboxylase. The best whole food sources for manganese are brown rice, rice bran, wheat bran, wheat germ, molasses, beans, nuts, and tea.

Manganese is absorbed in the small intestine through an active transport system and, possibly, through diffusion when intakes are high. Uptake is regulated so that when dietary manganese intake is high, gastrointestinal absorption is reduced.

After absorption, some manganese remains free, but most is bound to transferrin, albumin, and plasma alpha-2-macroglobulin. Manganese is taken up by the liver and other tissues, but the mechanism of this process is not well understood.

Manganese is generally considered a poorly absorbed mineral. Fiber, phosphorus, oxylates, and iron can all reduce absorption of manganese. Alkalinity can also decrease manganese uptake. Manganese is also rapidly cleared from the blood in the liver via biliary excretion. Only a small fraction (less than 5 percent) of ingested manganese is normally absorbed by adults.

A number of manganese-activated enzymes play important roles in the metabolism of carbohydrates, amino acids, and cholesterol.
Manganese absorption