(See also Overview of Dietary Supplements.)
Chromium, a trace mineral, potentiates the action of insulin. Nutritional sources that contain sufficient amounts include carrots, potatoes, broccoli, whole grains, and molasses. Picolinate, a by-product of tryptophan that is paired with chromium in supplements, is said to help the body absorb chromium more efficiently. Chromium dinicocysteinate is a newer supplement complex of trivalent chromium with L-cysteine and niacin.
Chromium picolinate is said to promote weight loss, build muscle, reduce body fat, lower cholesterol and triglyceride levels, and enhance insulin function. Although chromium deficiency impairs insulin function, there is little evidence that supplementation helps patients with diabetes, nor is there evidence that it benefits body composition or lipid levels.
The role of supplemental chromium is controversial, and the clinical data conflict. A 2002 meta-analysis evaluated 20 randomized clinical trials and concluded that the data indicated no effect of chromium on glucose or insulin levels in nondiabetic patients; results were inconclusive in diabetic patients (1). However, a 2013 meta-analysis of data from a separate group of 20 randomized clinical trials indicated that supplementation in overweight or obese people resulted in statistically significant reductions in body weight (2). The authors speculate that the effect is small and they are unsure of the clinical relevance, suggesting further long-term studies are warranted.
Randomized, controlled, clinical trials are needed to determine whether chromium can influence diabetes, lipid metabolism, or weight loss. These studies should control or adjust for baseline chromium status and the form of chromium used and be done in well-defined at-risk populations in whom food intake is monitored.
Several studies have demonstrated that daily doses up to 1000 mcg of chromium are safe. Some in vitro evidence suggests that chromium picolinate damages chromosomes and may cause cancer. However, no clinical studies have shown an association. Some forms of chromium may contribute to GI irritation and ulcers. Isolated cases of impaired kidney and liver function have been reported; thus, people with pre-existing kidney or liver disorders should avoid supplementation. Chromium supplements interfere with iron absorption.
Althuis MD, Jordan NE, Ludington EA, et al. Glucose and insulin responses to dietary chromium supplements: a meta-analysis. Am J Clin Nutr 76(1):148-155, 2002.
Onakpoya I, Posadzki P, Ernst E. Chromium supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials. Obes Rev 14(6):496-507, 2013.