Is chromium a trace essential metal?
If chromium is an essential metal it must have a specific role in an enzyme or cofactor, and a deficiency should produce a disease or impairment of function. To date, no chromium-containing glucose tolerance factor has been characterized, the purpose of the low-molecular-weight chromium-binding protein is questionable, and no direct interaction between chromium and insulin has been found. Furthermore, chromium3+ is treated like the toxic metals arsenic, cadmium, lead and mercury in animals. Chromium3+ may be involved in chromium6+-induced cancers because chromium6+ is converted to chromium3+ in vivo, and chromium3+ is genotoxic and mutagenic. Although there is no direct evidence of chromium deficiencies in humans, dietary supplements exist to provide supraphysiological doses of absorbable chromium3+. Chromium3+ may act clinically by interfering with iron absorption, decreasing the high iron stores that are linked to diabetes and heart disease. If so, this would make chromium3+ a pharmacological agent, not an essential metal.
Stearns
D M
DM
Northern Arizona University, Department of Chemistry, Flagstaff 86011-5698, USA. Diane.Stearns@nau.edu
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002273:Carcinogens; D002857:Chromium / Q000172:deficiency / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007501:Iron / Q000378:metabolism; D009747:Nutritional Physiological Phenomena; D014131:Trace Elements / Q000378:metabolism
D002273:Carcinogens; D014131:Trace Elements; D002857:Chromium; D007501:Iron