Research Project Abstracts

A Pilot Study of Chromium Supplementation Influences on Insulin Resistance and Glycemic Control in Type 2 Diabetes Mellitus

Principal Investigator: Joel Edman, DSc. (EdmanNutrition@aol.com)

Grant Period: 2002-2004

Objective:
Research has shown that the trace mineral chromium may improve glucose tolerance and lipid parameters, and therefore may be helpful for Type 2 Diabetes Mellitus (T2DM).  However, there are many aspects of this relationship that remain unknown including necessary chromium doses, duration of treatment, specific mechanisms involved, reliable chromium status measures, and the specific T2DM patient characteristics which may indicate who will benefit most from added chromium supplementation.  This study was therefore conducted to add to data available on chromium supplementation and its effects on Type 2 Diabetes.

Methodology:
A double-blind, placebo-controlled pilot study was conducted and included 11 subjects (7 females and 4 males) who had stable T2DM and were not on insulin therapy.  Their mean age was 58.4 (range 44 to 67) and they had a diagnosis of T2DM for an average of 5.9 years (range 1-17 years).  Their initial hemoglobin A1C ranged from 6.2 to 7.6, and they were on an average of 1.7 oral diabetic medications (range 0-3). 

Subjects were randomly assigned to take 600 mcg per day of chromium picolinate (200 mcg with each meal) or a placebo for 4 weeks.  Baseline and 4 weeks visits included: assessment of weight; vital signs; fasting lipid profile; a 2-hour glucose tolerance test (GTT) and insulin tolerance test (ITT) in which blood samples were drawn at time 0, 30, and 120 minutes; and a 3-hour urinary sample collection for assessment of chromium content.

Results:
Results showed that there was a significant decrease in the area under the glucose tolerance curve between the baseline and 4 week GTT for the chromium subjects in comparison to placebo subjects (p=0.04).  In addition there was a decrease in the area under the insulin tolerance curve between the baseline and 4 week ITT for the chromium subjects compared to placebo subjects.  Although this difference was not statistically significant, it may be clinically significant and it may have been statistically significant if there was a larger sample size.  There was also a significant increase in the urinary chromium level in the chromium-supplemented subjects in comparison to those taking placebo (p=.003).  No statistically significant differences were observed between groups for weight, lipid profiles, or insulin sensitivity (QUICKI model).

Discussion:
An estimated 15 million Americans have T2DM and the problem is expected to worsen in the near future.  The disease-associated morbidity, mortality and health-care costs are a serious public health problem.  It is therefore important to examine all potentially beneficial therapies to prevent and control T2DM.  Although there is no clear evidence that low chromium causes T2DM, low chromium levels have been associated with T2DM in prior studies.  A large clinical trial conducted in China found that chromium was helpful for those with diabetes, but their chromium levels were not evaluated.  One major obstacle is that chromium deficiency is difficult to diagnose.  This study contributes to existing data on both the effect of chromium supplementation in T2DM and urinary measurements of chromium status.

Conclusions:
Our data suggest that chromium picolinate may improve glycemic parameters in patients with stable non-insulin dependent T2DM.  However, further research in larger subject populations followed for longer periods of time is required to establish more definitively the role that chromium picolinate may have in the treatment of T2DM.

Presentation:
This topic was presented as a poster at the 14th Annual Meeting of the American Association of Clinical Endocrinology, Washington DC, May 18-22, 2005.