Background: A trace element is a dietary mineral that is needed in very minute quantities for the proper growth, maintaining and recovering the health status of the organism. Based on nutritional significance 19 trace elements have been indentified (WHO classification): 1- Essential elements such as copper etc. 2- Probable essential elements such as manganese etc. 3- Potentially toxic elements such as lead, & etc.

Materials and Methods: For this review article links such as http://www.britannica.com/EBchecked/topic/601406/trace-element http://www.tree.com/health/supplements-trace-elements.aspx were used.

Results: Essential trace elements are required by man in amounts ranging from 50 ug to 18 mg per day. They act as catalyzers or are structural components of larger molecules. The 6 essential trace elements are Chromium, Copper, Zinc, Molybdenum, Selenium, and Iodine. Very little is known about the probable essential elements and they are thought unlikely to have a beneficial function in the life process of humans. They include manganese, silicon, nickel, boron, and vanadium. Potentially toxic elements, if present in excessive concentrations may be hazardous to health. However, there may be some possibility with essential functions for these elements. In this category fluoride, lead, cadmium, lithium, aluminum, arsenic, tin and mercury are included.

Conclusion: The role of small amounts of certain elements alone or in compound on living organisms has long been known. Although the principal elements regarded as essential for organisms are comparatively few, most are recognized poisonous. Further investigations are essential to complete important gaps in our knowledge on trace elements role in health and controlling diseases.