August 25, 2020

A systematic review and meta-analysis published on July 27, 2020 in Pharmacological Research found reductions in fasting plasma glucose, insulin, hemoglobin A1c (HbA1c, a marker of long term glucose control) and insulin resistance in men and women with type 2 diabetes who supplemented with the mineral chromium.

For their analysis, Omid Asbaghi of Lorestan University of Medical Sciences and colleagues selected 23 randomized, controlled trials that evaluated the effects of supplementing with chromium on various glycemic control indexes. Doses used in the studies ranged between 50 micrograms (mcg) and 1,000 mcg per day consumed from four to 25 weeks. Eleven of the trials evaluated a chromium dosage within a 400 to 600 mcg range.

Analysis of 22 trials that reported fasting plasma glucose levels concluded that chromium supplementation was associated with an average reduction of 19.0 milligrams per deciliter (mg/dL) in comparison with the placebo. Trials of at least 12 weeks duration were associated with a far greater average decrease of 58.74 mg/dL in association with chromium.

Of the 14 trials that reported insulin levels, levels declined by an average of 1.7784 µIU/mL among subjects who received chromium compared to the placebo, with trials that lasted 12 weeks or longer associated with a decrease of 3.47 µIU/mL.

For the 22 trials that reported HbA1c, supplementation with chromium was associated with an average decrease of 0.71%, which improved to a significant 1.70% reduction when trials of 12 weeks duration or more were examined. Homeostatic model assessment for insulin resistance (HOMA-IR) also decreased significantly among participants who received chromium.

The authors observed that chromium plays a role in carbohydrate and lipid metabolism and may enhance insulin sensitivity. Other nutrients that have been associated with a lower risk of type 2 diabetes include vitamins A, C, D and E, beta-carotene, calcium, magnesium, potassium and zinc.

“Present systematic review and meta-analysis of all available published randomized trials up to 2020 found a significant reduction in all glycemic control indices such as fasting plasma glucose, insulin, HbA1c and HOMA-IR levels after chromium supplementation,” they wrote. “Furthermore, long term intervention contributed to greater reduction of all mentioned indices.”

“The results of the current meta‐analysis study might support the use of chromium supplementation for the improvement of glycemic control indices in T2DM patients,” they concluded.