Chromium

  • Earlier studies indicated that chromium (III) compounds improved insulin efficiency in people with impaired glucose tolerance (1,2). Chromium supplementation was shown to improve glucose metabolism and decrease the total cholesterol/HDL cholesterol regardless of the status of glucose tolerance. Glucose tolerance is a term that defines the ability of muscle and liver cells to remove glucose from the blood stream. As you age the glucose tolerance decreases.
  • Results from earlier studies have also suggested that the so-called 'glucose tolerance factor' (GTF), which appears to improve the impaired glucose tolerance in animals comprises a mixture of chromium-containing organic complexes (3-5). In one of these studies it was shown that the GTF activity was due to chromium complexed to amino acid/peptide-like molecules and these substances caused increased glycolysis in yeast as well as increased glycolysis and fatty acid synthesis in adipocytes in culture (4). In addition, a low molecular weight chromium-binding protein isolated from bovine liver was shown to activate phosphotyrosine phosphatase from adipocyte membrane (6). However, the results of these studies were later questioned as no chromium-containing GTF has been fully characterized, the purpose of low molecular weight chromium-binding protein is not well defined and no direct interaction between chromium and insulin has been demonstrated (7).
  • Health benefits: Despite claims that chromium supplementation may be beneficial for the management of type 2 diabetes several randomized clinical trials failed to show an effect of chromium on glucose or insulin concentrations in nondiabetic subjects while the results with diabetic subjects were inconclusive (8).
  • Best food sources: Meat and whole grains products, brewer's yeast.


References
1. Wallach, S. (1985) J.Am.Coll.Nutr. 4(1) 107-120. Clinical and biochemical aspects of chromium
    deficiency.
2. Mertz, W. (1993) J.Nutr. 123(4) 626-633. Chromium in human nutrition: a review.
3. Haylock, S.J. et al. (1983) J.Inorg.Biochem. 18(3) 195-211. Separation of biologically active chromium-
    containing complexes from yeast extracts and other sources of glucose tolerance factor (GTF) activity.
4. Davies, D.M. et al. (1985) Biochem.Med. 33(3) 297-311. The isolation of glucose tolerance factors from
    brewer's yeast and their relationship to chromium.
5. Simonoff, M. et al. (1992) Biol. Trace Elem.Res. 32, 25-38. The isolation of glucose tolerance factors
    from brewer's yeast and their relation to chromium.
6. Davis, C.M. et al. (1996) Biochemistry 35(39) 12963-12969. A biologically active form of chromium
    may activate a membrane phosphotyrosine phosphatase.
7. Stearns, D.M. (2000) Biofactors 11(3) 149-162. Is chromium a trace essential element?
8. Althuis, M.D. et al. (2002) Am.J.Clin.Nutr. 76(1) 148-155. Glucose and insulin responses to dietary
    chromium supplements: a meta-analysis.