Recent advances in the nutritional biochemistry of trivalent chromium.
The nutritional biochemistry of trivalent Cr has been a poorly understood field of study; investigations of the biochemistry of the other essential transition metals have not proven as problematic. Despite over four decades of endeavour, only recently has a picture of the role of Cr potentially started to be defined. The biologically-relevant form is the trivalent ion. Cr3+ appears to be required for proper carbohydrate and lipid metabolism in mammals, although fortunately Cr deficiency is difficult to achieve. Conditions that increase circulating glucose and insulin concentrations increase urinary Cr output. Cr is probably excreted in the form of the oligopeptide chromodulin. Chromodulin may be the key to understanding the role of Cr at a molecular level, as the molecule has been found to bind to activated insulin receptor, stimulating its kinase activity. A mechanism for the action of chromodulin has recently been proposed; this mechanism can serve as a potential framework for further studies to test the role of Cr in metabolism. An examination of the nutritional supplement chromium picolinate illustrates some of the difficulties associated with these biochemical studies.
Vincent
John B
JB
Department of Chemistry and Coalition for Biomolecular Products, The University of Alabama, Tuscaloosa, AL 35487-0336, USA. jvincent@bama.ua.edu
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002352:Carrier Proteins / Q000652:urine; D002857:Chromium / Q000008:administration & dosage / Q000737:chemistry / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2; D004032:Diet; D019587:Dietary Supplements; D006801:Humans; D007328:Insulin / Q000097:blood; D009747:Nutritional Physiological Phenomena; D009751:Nutritional Requirements; D010848:Picolinic Acids / Q000008:administration & dosage; D011972:Receptor, Insulin / Q000378:metabolism
D001786:Blood Glucose; D002352:Carrier Proteins; D007328:Insulin; D010848:Picolinic Acids; C485789:chromodulin protein, human; C406742:chromodulin protein, mouse; D002857:Chromium; D011972:Receptor, Insulin; C030614:picolinic acid