title: Chromium is not an essential trace element for mammals: effects of a "low-chromium" diet.
abstract: Chromium was proposed to be an essential trace element over 50 years ago and has been accepted as an essential element for over 30 years. However, the studies on which chromium's status are based are methodologically flawed. Whether chromium is an essential element has been examined for the first time in carefully controlled metal-free conditions using a series of purified diets containing various chromium contents. Male Zucker lean rats were housed in specially designed metal-free cages for 6 months and fed the AIN-93G diet with no added chromium in the mineral mix component of the diet, the standard AIN-93G diet, the standard AIN-93G diet supplemented with 200 μg Cr/kg, or the standard AIN-93G diet supplemented with 1,000 μg Cr/kg. The chromium content of the diet had no effect on body mass or food intake. Similarly, the chromium content of the diet had no effect on glucose levels in glucose tolerance or insulin tolerance tests. However, a distinct trend toward lower insulin levels under the curve after a glucose challenge was observed with increasing chromium content in the diet; rats on the supplemented AIN-93G diets had significantly lower areas (P < 0.05) than rats on the low-chromium diet. The studies reveal that a diet with as little chromium as reasonably possible had no effect on body composition, glucose metabolism, or insulin sensitivity compared with a chromium-"sufficient" diet. Together with the results of other recent studies, these results clearly indicate that chromium can no longer be considered an essential element.
authors.affiliation: Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Kristin R
authors.initials: KR
authors.lastname: Di Bona
authors.forename: Sharifa
authors.initials: S
authors.lastname: Love
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Rhodes
authors.forename: DeAna
authors.initials: D
authors.lastname: McAdory
authors.forename: Sarmistha Halder
authors.initials: SH
authors.lastname: Sinha
authors.forename: Naomi
authors.initials: N
authors.lastname: Kern
authors.forename: Julia
authors.initials: J
authors.lastname: Kent
authors.forename: Jessyln
authors.initials: J
authors.lastname: Strickland
authors.forename: Austin
authors.initials: A
authors.lastname: Wilson
authors.forename: Janis
authors.initials: J
authors.lastname: Beaird
authors.forename: James
authors.initials: J
authors.lastname: Ramage
authors.forename: Jane F
authors.initials: JF
authors.lastname: Rasco
authors.forename: John B
authors.initials: JB
authors.lastname: Vincent
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002857:Chromium / Q000378:metabolism*; D005951:Glucose Tolerance Test; D007328:Insulin / Q000097:blood; D008297:Male; D051381:Rats; D011924:Rats, Zucker; D014131:Trace Elements / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014131:Trace Elements; D002857:Chromium