Role of chromium supplementation in Indians with type 2 diabetes mellitus

Type 2 diabetes mellitus is a complex metabolic disorder with adverse cardiovascular risk. The role of micronutrients has not yet been well clarified in this condition, especially in India. The objectives of this study were to: (1) evaluate chromium status in Indian subjects with type 2 diabetes mellitus, (2) assess the effect of chromium picolinate (200 μg trivalent chromium twice daily) administration on glycaemic control and lipid profile in these subjects and (3) comment on the possible mechanism of any beneficial effect noted above. Fifty subjects were studied in a double blind, placebo-controlled, crossover fashion, with each treatment arm (chromium/placebo) lasting 12 weeks and 4 weeks’ wash-off period in between. 50 healthy age- and sex-matched volunteers served as controls. Serum chromium level appeared to be higher in the general population in our country compared to western countries (36.5–59.5 nmol/L as compared to 2.3–40.3 nmol/L) However, the local diabetics were found to have a lower serum chromium level than the healthy controls (32.3 nmol/L against 44.7 nmol/L; p < 0.0001) and a mean increase of 3.5 nmol/L was noted after 12 weeks of chromium supplementation that was, expectedly, not seen in the placebo phase (p < 0.0001). Significant improvement in glycaemic control was noted in the chromium-treated group (ΔFasting serum glucose = 0.44 mmol/L, p < 0.001; ΔPost-prandial serum glucose = 1.97 mmol/L, p < 0.001; Δglycated hemoglobin = 0.01; p = 0.04, in comparison to placebo) This was accompanied by a significant greater fall in fasting serum insulin in the chromium-treated group, p < 0.05. The change in lipid parameters (total serum cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides) did not show significant difference between the chromium and placebo groups. Clinically significant hematological, renal or hepatic toxicity were excluded by routine hemogram, serum urea, creatinine, alanine amino transferase (ALT) and alkaline phosphatase estimations. In conclusion, chromium supplementation seems to improve glycaemic control in type 2 diabetic patients, which appears to be due to an increase in insulin action rather than stimulation of insulin secretion.