Trace minerals

As the name indicated trace minerals are required in very small quantities but play an important role in human metabolism. The list of trace minerals with known functions has grown longer over the years.

Currently the following trace elements have been recognized as being important biologically-Iron, Iodine, Zinc, Copper, Selenium, Manganese, Molybdenum, Chromium, Cobalt and Fluoride.

Iron: Iron is essential for formation of hemoglobin the substance in the red blood cells which carries oxygen to all the tissues. An adult body contains about 3-4 G of iron of which about 60-70 percent is in blood as hemoglobin. The rest is stored in the body. Each gram of hemoglobin contains roughly 3.3 mg of iron. It is also a component of several enzymes.

Sources: There are 2 forms dietary iron-heme iron and non heme iron. Heme iron is contained in liver, meat and fish. Non heme iron is present in green leafy vegetables, nuts, jaggary and dried fruits.

Iron in breast milk is better absorbed than that in cow’s milk.

Iron deficiency causes anemia, irritability and decreased resistance to infections.

Iodine: Iodine is absolutely essential for the synthesis of thyroid hormones-thyroxine and triiodothyronine which are vital for normal growth and development of children and normal metabolism.

Adult human body contains about 50mg of iodine. Sea foods are the richest sources of iodine (eg. sea fish and salt). Small amounts are present in milk, meat, vegetables and cereals. Water contains very small quantity of iodine.

In areas where diet does not contain adequate iodine salt is fortified with iodine. Use of such iodized salt has greatly reduced the incidence of iodine deficiency disorders.

The spectrum of Iodine deficiency disorder includes. Goitre (enlargement of thyroid gland), hypothyroidism, subnormal intelligence and other nervous system disorders.

Fluorine: Fluorine is necessary for proper mineralization of bones and formation of enamel of teeth. About 96 percent of fluoride in the body in found to bones and teeth.

Sources: The major source of fluoride is drinking water. Some foods such as sea fish, cheese and tea also contain fluoride.

While deficiency of fluoride predisposes to dental caries excess of fluoride causes a condition called fluorosis. Fluorosis causes mottling of enamel of teeth and bony deformity.

Zinc: An adult body contains about 1.5 to 2 grams of zinc. It is present is small quantities in almost all tissues. Zinc is an essential component of several enzymes. It is also required for synthesis of insulin by pancreas and for optimal functioning of the immune system.

Zinc is widely distributed in food stuffs, meat, milk and fish, vegetables and fruits. Zinc deficiency can cause growth failure, delayed wound healing and loss of taste sensation.

Copper: An adult body contains about 100-150mg of copper. About 30 percent of this is found in skeletal muscles. Another 30 percent is found in brain and liver. The remaining is distributed in other tissues.Copper is widely distributed in nature. Deficiency of copper is rare.

Cobalt: This is a component of vitamin B12. Deficiency of cobalt is not known.

Chromium: This is supposed to play a role in regulation of glucose level in blood. It is a component of glucose tolerance factor which is necessary for binding of insulin to cells.

Selenium: This trace mineral is an important anti-oxidant. It protects the cell membrane against oxidative damage and complements the action of vitamin E. It is also necessary for the proper functioning of the immune system.

Isolated selenium deficiency is rare. Deficiency can occur as part of general malnutrition and in patients receiving intravenous nutrition without getting selenium supplements. It is found in cereals, milk, nuts, garlic, eggs and liver.

Manganese: This is a co enzyme for many enzymes. An adult body contains about 10 to 20 milligrams of manganese. It is important for growth of bones and connective tissue. Its deficiency has not been documented.

Molybdenum: This is an important constituent of the enzymes involved in the metabolism of nucleotides which are the building blocks of DNA and RNA. Its deficiency has not been reported.

Page last reviewed on 13th November 2009

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