I wish to thank you for this opportunity to respond to the letter by Juturu and Komo 1 rowski [1,2]. Their statement that chromium (Cr) is ''known'' to be an essential element is not true, although I wish the data were so clear-cut. The data are strongly suggestive that Cr is a nutrient but not definitive; an accurate statement would be that the element generally is accepted as essential. Strong debate exists in the field as to whether Cr is essential. For example, as early as 1996, Holm et al., in a seminal review of bioinorganic chemistry, indicated that Cr was not a ''biological metal '' [3]. Stearns in 2000 [4] detailed both sides of the issue and concluded Cr was not essential; Levina and coworkers have also recently questioned the role of Cr [5]. Thus, my conclusion that ''Cr is probably an essential element'' is an accurate reflection of the current literature. The recent preliminary report of an association between toenail Cr and diabetes-related coronary heart disease [6] does not provide any information as to cause and effect. These diseases alter the transport and storage of several metal ions. Cr appears to be transported from the bloodstream to the tissues by the iron transport protein transferrin [7]; thus, changes in Cr content could simply reflect changes in iron metabolism in these diseases.
Juturu and Komorowski also criticize me for not providing all the data on chromium picolinate, Cr(pic) 3 . My article in the Journal is a brief review of several topics related to Cr biochemistry and nutrition, stemming from my plenary lecture at the VIth Conference of the International Society for Trace Elements Research in Humans (ISTERH). The article was not meant to be a comprehensive review of all areas of Cr biochemistry and nutrition. A review article I authored specifically on Cr(pic) 3 was published in 2003 [8]; I cited this article as a source for more information. In the summary to the toxicology of Cr(pic) 3 presented in this article, I indicated that ''potentially deleterious effects from Cr(pic) 3 supplementation must be taken seriously. Further investigation into the effects of Cr(pic) 3 on humans consuming 200 lg or greater, as the supplement, daily for prolonged periods of time is urgently needed '' [8]. This position, the same position as in my current article [2], reflects well the subsequent determinations by the Institute of Medicine (IOM) and Food Standards Agency (vide infra). Other investigators have also recently concluded that additional studies are required on Cr(pic) 3 [9]. Juturu and Komorowski also suggest I did not indicate all the evidence from human supplementation studies, John Vincent has a potential conflict of interest because he is the inventor or co-inventor of 4 patents on the use of Cr oligopeptides or synthetic compounds as nutritional supplements or therapeutic agents.