Chromium supplements for glycemic control in type 2 diabetes: limited evidence of effectiveness

Abstract

Some adults with type 2 diabetes mellitus (T2DM) believe that chromium-containing supplements will help control their disease, but the evidence is mixed. This narrative review examines the efficacy of chromium supplements for improving glycemic control as measured by decreases in fasting plasma glucose (FPG) or hemoglobin A1c (HbA1c). Using systematic search criteria, 20 randomized controlled trials of chromium supplementation in T2DM patients were identified. Clinically meaningful treatment goals were defined as an FPG of 7.2 mmol/dL, a decline in HbA1c to 7%, or a decrease of 0.5% in HbA1c. In only a few randomized controlled trials did FPG (5 of 20), HbA1c (3 of 14), or both (1 of 14) reach the treatment goals with chromium supplementation. HbA1c declined by 0.5% in 5 of 14 studies. On the basis of the low strength of existing evidence, chromium supplements have limited effectiveness, and there is little rationale to recommend their use for glycemic control in patients with existing T2DM. Future meta-analyses should include only high-quality studies with similar forms of chromium and comparable inclusion/exclusion criteria to provide scientifically sound recommendations for clinicians.

Environmental Metals and Cardiovascular Disease in Adults: A Systematic Review Beyond Lead and Cadmium

“…Chromium and its salts are used in metallurgical, refractory and chemical industries. The essentiality of Cr(III) and the use of it as supplement for glycemic control in type 2 diabetes is controversial [83]. Several clinical trials have evaluated the effect of chromium supplementation on glycemic control, with inconsistent findings [84–87].…”

Inverse Association of Plasma Chromium Levels with Newly Diagnosed Type 2 Diabetes: A Case-Control Study

“…However, clinical trials evaluating chromium supplementation on glucose control have yielded conflicting results [9,10,11]. As a result, the routine use of chromium supplementation for glycemic control in patients with T2DM was not recommended due to insufficient evidence of effectiveness [12,13,14]. …”

Effects of Chromium on Glucose Tolerance in Infants Receiving Parenteral Nutrition Therapy

“…[5][6][7] On the contrary, a systematic review of clinical trials examining efficacy of chromium supplementation on glycemic control in healthy adults with type 2 diabetes failed to detect any consistent benefits. 29 Likewise, Nur et al 11 conducted a randomized, blinded prospective study that examined the effects of supplemental chromium (0.2 mcg/kg/d) in 75 preterm and full-term newborns receiving PN for longer than 2 weeks and failed to demonstrate any carbohydrate tolerance benefits. The authors did not define the extent of prematurity, and the intervention occurred after the period of highest risk for glucose intolerance, 17 so the negative findings may have resulted from older gestational age of the infants and later timing of therapy.…”