Chromium was discovered by Louis-Nicholas Vauquelin at 1797 in France. Origin of name: from the Greek word "chroma" meaning "colour", named for the many coloured compounds known for chromium.Chromium is an essential trace element for humans because it helps us to use glucose. We take in about 1 milligram a day; foods such as brewer’s yeast, wheat germ and kidney are rich in chromium. However it is poisonous in excess.
The biological function of chromium is not fully known yet. It is postulated that chromium interacts with the thyroid metabolism in humans.
Binding of Cr (III) with nucleic acids has been found to stimulate the DNA-dependant RNA synthesis .
The third inter-action of Cr (III) is with the hormone insulin and its receptors. This suggests that Cr (III) acts with insulin on the first step in the metabolism of sugar entry into the cell, and facilitates the interaction of insulin with its receptor on the cell surface.
The principal route by which trivalent chromium enters the body is the digestive system. Chromium in foods is present both in the inorganic form and as organic complexes. Intestinal absorption of chromium is low (0.5-2%), and the mechanism has not yet been fully elucidated.
Absorbed chromium circulates as free Cr3+, as Cr3+ bound to transferrin or other plasma proteins, or as complexes, such as glucose tolerance factor (GTF)-Cr.
Circulating trivalent chromium can be taken up by tissues, and its distribution in the body depends on the species, age, and chemical form. It is excreted primarily in the urine by glomerular filtration or bound to a low-mol-wt organic transporter. Chromium metabolism is still imperfectly understood.