Chromium(III) picolinate

Chromium(III) picolinate is a chemical compound sold as a nutritional supplement to prevent or treat chromium deficiency. Another is chromium polynicotinate, and six forms of chromium are sold for this purpose. This bright-red coordination compound is derived from chromium(III) and picolinic acid. Small quantities of chromium are needed for glucose utilization by insulin in normal health, but deficiency is extremely rare and has only been observed in hospital patients on long-term defined diets. No biochemical basis for the human body's need for chromium has been identified. Chromium(III) picolinate has been described as a "poor choice as a nutritional supplement".

Health claims and debates
A pilot trial of 15 patients suggested that chromium picolinate might have antidepressant effects in atypical depression. A larger follow-up trial failed to reproduce this effect, but indicated that the use of chromium picolinate could help to reduce carbohydrate cravings and regulate appetite in these patients. A post-hoc analysis of a subpopulation of patients in this study that experienced high carbohydrate cravings suggested that patients treated with chromium picolinate experienced significant improvements in their depression (as measured by the 29-item Hamilton Depression Rating Scale) compared to those treated with a placebo. A more recent study focused on the effects of chromium picolinate supplementation on food intake and satiety. It indicated that chromium supplementation led to reduced cravings for fat, not carbohydrates.

Some commercial organizations promote chromium picolinate as an aid to body development for athletes and as a means of losing weight. But a number of studies have failed to demonstrate an effect of chromium picolinate on either muscle growth or fat loss.

There are claims that the picolinate form of chromium supplementation aids in reducing insulin resistance, particularly in diabetics, but a meta-analysis of chromium supplementation studies showed no association between chromium and glucose or insulin concentrations for non-diabetics, and inconclusive results for diabetics. This study has been challenged on the grounds that it excluded significant results. Subsequent trials gave mixed results, with one finding no effect in people with impaired glucose tolerance, but another seeing a small improvement in glucose resistance. A further study on obese adults with metabolic syndrome was published in 2009, this found no significant effect on insulin sensitivity, but increased short-term levels of insulin. The study also observed no effect on weight or serum lipids.

In a review of these trials it was again concluded that chromium supplements had no effect on healthy people, but that there might be an improvement in glucose metabolism in diabetics, although the authors stated that the evidence for this effect remains weak. However, opinions differ on this conclusion, a review published in 2006 argued that these data instead supported the clinical efficacy of chromium picolinate for the treatment of diabetes. In 2006, the U.S. Food and Drug Administration stated that the "relationship between chromium picolinate intake and insulin resistance is highly uncertain".

Initial concerns were raised that chromium picolinate is more likely to cause DNA damage and mutation than other forms of trivalent chromium, but these results are also debated. These concerns were based, in part, on studies in fruit flies, where chromium(III) picolinate supplementation generates chromosomal aberrations, impedes progeny development, and causes sterility and lethal mutations. However, other studies indicate that chromium picolinate is safe even at very high doses. In mice, one study observed that chromium(III) picolinate supplementation caused skeletal defects in their offspring. However, a two-year study of the long-term effects of this supplement in rats and mice found no effects on overall survival, or on the animal's body weight and food consumption, the authors of this review also found no toxicity beyond an increase in preputial gland adenoma which was tentatively considered equivocal.

Regulation of chromium III picolinate
In 2004, the UK Food Standards Agency advised consumers to use other forms of trivalent chromium in preference to chromium picolinate until specialist advice was received from the Committee on Mutagenicity. This was due to concerns raised by the Expert Group on Vitamins and Minerals that chromium picolinate might cause cancer (its genotoxicity). The committee also noted two case reports of renal failure that might have been caused by this supplement and called for further research into its safety. In December 2004, the Committee on Mutagenicity published its findings, which concluded that "overall it can be concluded that the balance of the data suggest that chromium picolinate should be regarded as not being mutagenic in vitro" and that "the available in-vivo tests in mammals with chromium picolinate are negative.". Following these findings, the UK Food Standards Agency withdrew its advice to avoid chromium picolinate, though it plans to keep its advice about chromium supplements under review.

In 2010, chromium picolinate was approved by Health Canada to be used in dietary supplements. The monograph includes use in capsules, chewables (e.g. gummies, tablets), liquids, powders, strips or tablets. Approved labeling statements include: a factor in the maintenance of good health, provides support for healthy glucose metabolism, helps the body to metabolize carbohydrates and helps the body to metabolize fats.