Glucose and insulin responses to dietary chromium supplements: a meta-analysis.



Authors: Althuis MD, Jordan NE, Ludington EA, Wittes JT.

BACKGROUND: Several authors, mostly on the basis of nonrandomized studies, have
suggested dietary trivalent chromium supplementation as an attractive option for
the management of type 2 diabetes and for glycemic control in persons at high
risk of type 2 diabetes.

OBJECTIVE: The study aimed to determine the effect of chromium on glucose and
insulin responses in healthy subjects and in individuals with glucose intolerance
or type 2 diabetes.

DESIGN: The study design was a systematic review and meta-analysis of randomized
clinical trials (RCTs).

RESULTS: The authors identified 20 reports of RCTs assessing the effect of
chromium on glucose, insulin, or glycated hemoglobin (Hb A(1c)). This review
summarizes data on 618 participants from the 15 trials that reported adequate
data: 193 participants had type 2 diabetes and 425 were in good health or had
impaired glucose tolerance. The meta-analysis showed no association between
chromium and glucose or insulin concentrations among nondiabetic subjects. A
study of 155 diabetic subjects in China showed that chromium reduced glucose and
insulin concentrations; the combined data from the 38 diabetic subjects in the
other studies did not. Three trials reported data on Hb A(1c): one study each of
persons with type 2 diabetes, persons with impaired glucose tolerance, and
healthy subjects. The study of diabetic subjects in China was the only one to
report that chromium significantly reduced Hb A(1c).
CONCLUSIONS: Data from RCTs show no effect of chromium on glucose or insulin
concentrations in nondiabetic subjects. The data for persons with diabetes are
inconclusive. RCTs in well-characterized, at-risk populations are necessary to
determine the effects of chromium on glucose, insulin, and Hb A(1c).

Am J Clin Nutr. 2002 Jul;76(1):148-55.