Published online Apr 15, 2014. doi: 10.4239/wjd.v5.i2.160
Revised: January 23, 2014
Accepted: March 13, 2014
Published online: April 15, 2014
Chromium is considered to have positive effects on insulin sensitivity and is marketed as an adjunctive therapy for inducing glucose tolerance in cases of insulin resistance (“the glucose tolerance factor”). Case reports on patients who received prolonged parenteral nutrition indeed showed that the absence of trivalent chromium caused insulin resistance and diabetes. However, whether patients with type 2 diabetes can develop a clinically relevant chromium deficiency is unclear. This review summarizes the available evidence regarding the potential effectiveness of chromium supplementation on glycemic control (Hemoglobin A1c levels) in patients with type 2 diabetes. No studies investigating the long-term safety of chromium in humans were found. All clinical trials that have been performed had a relative short follow-up period. None of the trials investigated whether the patients had risk factors for chromium deficiency. The evidence from randomized trials in patients with type 2 diabetes demonstrated that chromium supplementation does not effectively improve glycemic control. The meta-analyses showed that chromium supplementation did not improve fasting plasma glucose levels. Moreover, there were no clinically relevant chromium effects on body weight in individuals with or without diabetes. Future studies should focus on reliable methods to estimate chromium status to identify patients at risk for pathological alterations in their metabolism associated with chromium deficiency. Given the present data, there is no evidence that supports advising patients with type 2 diabetes to take chromium supplements.
Core tip: In some patients who received prolonged parenteral nutrition, absence of trivalent chromium caused insulin resistance and diabetes and supplementation with trivalent chromium “cleared” this metabolic disease. The question is, whether chromium deficiency is a relevant factor in the cause of type 2 diabetes in general and whether supplementation with trivalent chromium can have beneficial effects in type 2 diabetes. Unfortunately, no reliable methods to estimate chromium status exists and according to current evidence, chromium does not improve glycemic control in patients with type 2 diabetes and patients should be advised not to take chromium supplements.