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Chromium
Description:
Chromium is an essential trace mineral that helps the body maintain normal blood sugar levels.
Properties & Uses:
Chromium is mainly used to stabilize blood sugar. The major role for chromium in weight loss is to correct insulin resistance caused by chromium deficiency. However, assessing chromium deficiency is difficult since normal blood levels are of such a low concentration that they can escape detection by even the most sensitive instruments. Hair and toenail levels can be evaluated, but are not routinely done.
Known causes of chromium deficiency include malnutrition, TPN (total parenteral nutrition), alcoholism, and strenuous exercise, which can cause what is called “chromium dumping.”
Recommended Dietary Allowances:
Chromium, primarily in a form called chromium picolinate, has been studied for its potential role in altering body composition. One group of researchers has reported significant reductions in body fat in double-blind trials using 200 to 400 mcg per day of chromium for six to twelve weeks in middle-aged adults,1 2 but the methods used in these studies have been criticized.
Food Sources:
The best source of chromium is true brewer’s yeast. Nutritional yeast and torula yeast do not contain significant amounts of chromium and are not suitable substitutes for brewer’s yeast. Chromium is also found in grains and cereals, though much of it is lost when these foods are refined. Some brands of beer contain significant amounts of chromium.
Side Effects & Interactions:
In supplemental amounts (typically 50–300 mcg per day), chromium has not been found to cause toxicity in humans. While there are a few reports of people developing medical problems while taking chromium, a cause-effect relationship was not proven. One study suggested that chromium in very high concentrations in a test tube could cause chromosomal mutations in ovarian cells of hamsters.4 5 Chromium picolinate can be altered by antioxidants or hydrogen peroxide in the body to a form that could itself create free radical damage.6 In theory, these changes could increase the risk of cancer, but so far, chromium intake has not been linked to increased incidence of cancer in humans.7
Chromium supplementation may enhance the effects of drugs for diabetes (e.g., insulin, blood sugar-lowering agents) and possibly lead to hypoglycemia. Therefore, people with diabetes taking these medications should supplement with chromium only under the supervision of a doctor.
One report of severe illness (including liver and kidney damage) occurring in a person who was taking 1,000 mcg of chromium per day has been reported.8 However, chromium supplementation was not proven to be the cause of these problems. Another source claimed that there have been reports of mild heart rhythm abnormalities with excessive chromium ingestion.9 However, no published evidence supports this assertion.
Three single, unrelated cases of toxicity have been reported from use of chromium picolinate. A case of kidney failure appeared after taking 600 mcg per day for six weeks.10 A case of anemia, liver dysfunction, and other problems appeared after four to five months of 1,200–2,400 mcg per day.11 A case of a muscle disease known as rhabdomyolysis appeared in a body builder who took 1200 mcg over 48 hours.12 Whether these problems were caused by chromium picolinate or, if so, whether other forms of chromium might have the same effects at these high amounts remains unclear. No one should take more than 300 mcg per day of chromium without the supervision of a doctor.
Preliminary research has found that vitamin C increases the absorption of chromium.
References:
1. Kaats GR, Blum K, Fisher JA, Adelman JA. Effects of chromium picolinate supplementation on body composition: a randomized, double-masked, placebo-controlled study. Curr Ther Res 1996;57:747–56.
2. Kaats GR, Blum K, Pullin D, et al. A randomized, double-masked, placebo-controlled study of the effects of chromium picolinate supplementation on body composition: a replication and extension of a previous study. Curr Ther Res 1998;59:379–88.
3. Vincent J. The potential value and toxicity of chromium picolinate as a nutritional supplement, weight loss agent and muscle development agent. Sports Med 2003;33:213–30 [review].
4. Sterns DM, Belbruno JJ, Wetterhahn KE. A prediction of chromium (III) accumulation in humans from chromium dietary supplements. FASEB J 1995;9:1650–7.
5. Sterns DM, Wise JP, Patierno SR, Wetterhahn KE. Chromium (III) picolinate produces chromosome damage in Chinese hamster ovary cells. FASEB J 1995;9:1643–9.
6. Speetjens JK, Collins RA, Vincent JB, Woski SA. The nutritional supplement chromium (III) tris(picolinate) cleaves DNA. Chem Res Toxicol 1999;12:483–7.
7. Garland M, Morris JS, Colditz GA, et al. Toenail trace element levels and breast cancer. Am J Epidemiol 1996;144:653–60.
8. Cerulli J, Grabe DW, Guathier I, et al. Chromium picolinate toxicity. Ann Pharmacother 1998;32:428–31.
9. Shannon M. Alternative medicines toxicology: a review of selected agents. J Clin Toxicol 1999;37:709–13.
10. Wasser WG, Feldman NS. Chronic renal failure after ingestion of over-the-counter chromium picolinate. Ann Intern Med 1997;126:410 [letter].
11. Cerulli J, Grabe DW, Gauthier I, et al. Chromium picolinate toxicity. Ann Pharmacother 1998;32:428–31.
12. Martin WR, Fuller RE. Suspected chromium picolinate-induced rhabdomyolysis. Pharmacotherapy 1998;18:860–2.
13. Offenbacher EG. Promotion of chromium absorption by ascorbic acid. Trace Elements Electrolytes 1994;11:178–81.