Trivalent chromium (Cr(III) or Cr3+) occurs in trace amounts in foods and waters, and appears to be benign. In contrast, hexavalent chromium (Cr(VI) or Cr6+) is very toxic and mutagenic when inhaled. Cr(VI) has not been established as a carcinogen when in solution, although it may cause allergic contact dermatitis (ACD).
Chromium deficiency, involving a lack of Cr(III) in the body, or perhaps some complex of it, such as glucose tolerance factor is controversial, or is at least extremely rare. Chromium has no verified biological role and has been classified by some as not essential for mammals. However, other reviews have regarded it as an essential trace element in humans.
Chromium deficiency has been attributed to only three people on long-term parenteral nutrition, which is when a patient is fed a liquid diet through intravenous drips for long periods of time.
Although no biological role for chromium has ever been demonstrated, dietary supplements for chromium include chromium(III) picolinate, chromium(III) polynicotinate, and related materials. The benefit of those supplements is questioned by some studies. The use of chromium-containing dietary supplements is controversial, owing to the absence of any verified biological role, the expense of these supplements, and the complex effects of their use. The popular dietary supplement chromium picolinate complex generates chromosome damage in hamster cells (due to the picolinate ligand). In the United States the dietary guidelines for daily chromium uptake were lowered in 2001 from 50–200 µg for an adult to 35 µg (adult male) and to 25 µg (adult female).
Read more about this topic: Cromium
Other articles related to "biological role, biological, role":
... Tungsten has been studied as a biological copper metabolic antagonist, in a role similar to the action of molybdenum ... It has been found that tetrathiotungstates may be used as biological copper chelation chemicals, similar to the tetrathiomolybdates ...
Famous quotes containing the words role and/or biological:
“Given that external reality is a fiction, the writers role is almost superfluous. He does not need to invent the fiction because it is already there.”
—J.G. (James Graham)
“I am fifty-two years of age. I am a bishop in the Anglican Church, and a few people might be constrained to say that I was reasonably responsible. In the land of my birth I cannot vote, whereas a young person of eighteen can vote. And why? Because he or she possesses that wonderful biological attributea white skin.”
—Desmond Tutu (b. 1931)