Micronutrients | Functions of Other Trace Elements


The amount of magnesium is much smaller in the body as compared to that of calcium and phosphorus. Of the 20-35 g in the adult body, about 60% is present as phosphorus and carbonates chiefly at the surfaces of the bones. The rest is found within the cells.

Extra cellular fluids account for about 2% of the body’s magnesium. The normal concentration of magnesium in blood serum is 2 to 3 mg/dl about 80% of this being ionized, the remainder is bound to proteins.


Sulfur accounts for about 0.25% of body weight, or 175 mg in the adult male. It is present in all body cells, mainly as the sulfur – containing amino acids – methionine and cystein. Sulfur is a constituent of thiamine and biotin. Connective tissues, skin nails and hair are especially rich in sulfur.


The trace mineral, iodine is a vital component of hormones produced by the thyroid gland that are responsible for a number of important functions in our body. It including growth metabolism, reproduction, nerve and muscle function, regulation of body temperature and blood cell production. The thyroid gland produces two hormones:

  • Thyroxin
  • Tri-iodothyronine (T3)

These hormones are composed of two molecules of tyrosine combined with three or four atom of iodine. The thyroid hormones regulate the rate of oxidation within the cells and thus influence physical and mental growth, the functioning of the nervous and muscle tissues, circulatory activities and the metabolism of all nutrients.


About 2-3 g zinc is present in the adult body. It is distributed widely in all tissues but not evenly. High concentration are found in the eye, liver, bone, prostrate and in hair. Red blood cell and leukocytes also contain zinc.


Traces of copper are essential for the formation of hemoglobin. The body of a human adult contains about 100-150 mg copper. Traces of copper are found in all tissues, but higher concentrations are found in the liver, brain heart and kidneys. In the foetus and at birth, the levels are several times higher and they decrease during the first year.


Fluorine is potentially a toxic element. It occurs normally in the body as a calcium salt in the bones and teeth. Small amounts of fluoride bring about striking reduction in tooth decay as it makes the tooth enamel. It is more resistant to the action of acids produced in the mouth by bacteria.