The effect of chromium on inflammatory markers, 1st and 2nd phase insulin secretion in type 2 diabetes.

OBJECTIVE: Impaired insulin sensitivity (SI) and β-cell function are the two main causes of type 2 diabetes (T2D) and are related to low-grade inflammation status. Trivalent chromium has shown to improve SI in our previous study. This might be due to the ability of decreasing interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) shown in animal studies. In the current study, we measured SI, β-cell function, and plasma levels of IL-6 and TNF-α after treatment of chromium chloride (GaCr) in T2D.

RESEARCH DESIGN AND METHODS: Sixty-six patients were randomly assigned to the 20 g of GaCr milk powder studying group or the milk powder placebo group. Oral glucose tolerance test was performed before and after the treatment. The SI and the β-cell function were measured as well.

RESULTS: The SI was significantly improved. At the same time, the static insulin responsivity index (Φs) was significantly higher after the treatment (p = 0.003). On the other hand, the dynamic insulin responsivity index (Φd) remained unchanged. Interestingly, a significant decrease in the IL-6 level after the treatment (p = 0.015) was noted. Although there was a trend of decreasing in TNF-α, it was not statistically significant. Finally, there was no significant correlation between the δ-IL-6, SI, and Φd after GaCr treatment.

CONCLUSIONS: In conclusion, other than the improvement of SI, GaCr could also improve the second phase of insulin responsivity (Φs) and IL-6. However, δ-IL-6 was correlated with neither δ-SI nor δ-Φs which indicated that the improvement of SI and Φs might involve mechanisms other than lower inflammatory effect.