Chromium can exist with a valence of +3 or a valence of +6. Trivalent chromium (Cr3+) is an essential trace element that is known to enhance the action of insulin, presumably by increasing the kinase activity of insulin receptor β. Cr6+, on the other hand, can cause damage to tissue as it is a strong oxidizer and mutagenic agent. In biological systems, Cr6+ will be rapidly reduced to Cr3+ by contact with proteins or food.
Chromium is present in the environment naturally and as a result of industrial products. It is released by incineration facilities, in cement dust, road dust from catalytic converter erosion, tobacco smoke, and topsoil, for example. Good sources of chromium in the diet include meats, green beans, broccoli, beer (brewer's yeast), and whole grains. The highest occupational exposure occurs in the metallurgy and tanning industries.
Outside of its role in insulin signaling, little is known about chromium's biological roles in the human body. However, deficiencies of chromium appear to lead to adverse health findings.
Absorption and Transport:
The gut usually absorbs less than 2.5% of ingested chromium. In plasma, chromium is found bound to transferrin. It tends to concentrate in the liver, spleen, and bone. Chromium is principally excreted in the urine.
