We thank David Mark for his comments (1) about our study (2) in which subjects with type 2 diabetes, who were given 1,000 μg chromium in the form of chromium picolinate (CrPic) in combination with 5 mg glipizide, were compared with subjects receiving glipizide plus placebo. Mark suggests that the attenuation in weight gain reported in our study may be indicative of a drug-supplement interaction and suggests that all of the reported differences in body weight gain at the end of the study were caused by an acute weight loss, which occurred within the 1st week after CrPic was started. He implies that given the SEs, it was possible that some of the subjects lost as much as 3.0 kg in 1 week. Further, he questions whether diarrhea, anorexia, or some other symptom was responsible for the acute weight loss. First and foremost, the weight reported was not the value after only 1 week but was the recorded weight after 1 month of intervention. At that time, the difference in mean weight between placebo and chromium groups was 0.9 kg. Six months after randomization, the weight difference ranged 1.3–1.5 kg, suggesting a gradual, yet consistent, attenuation in weight gain between the two treatment groups. We also noted that the chromium group was found to have a lower percentage of body fat, less visceral fat, and more fat free mass as determined by dual-energy X-ray absorptiometry and computed tomography scans. While the increase in fat free mass lacks an explanation at this time, one would have expected loss of muscle mass and adipose tissue if there was an acute adverse effect. Also, while the mechanism for the weight difference is not known at this time, we are pursuing studies evaluating both dietary intake and energy expenditure with chromium supplementation.
In addition, the question of adverse gastrointestinal events from initiation of CrPic were suggested. As with any double-blinded, placebo-controlled clinical study, adverse events were recorded at each visit. Although it was not specified in our article, there was no increase in gastrointestinal symptoms (i.e., nausea, vomiting, or diarrhea) for the CrPic group, nor was there an increase in symptoms between groups over the course of study. Thus, we feel the aforementioned clarification is evidence against a suggested “drug-supplement” interaction.
Mark also states that our study provides data in contrast to other reported studies using 800–1,000 μg CrPic (3–6). However, one of the studies cited, i.e., Guntun et al. (5), did not use similar doses of elemental chromium and had intakes of ∼100 μg/day chromium, which was much less than the reported study. Of the other cited studies (3,4,6), there are clear differences as outlined in our original discussion, but the major difference is that our study is one of the only reported studies to use body weight, dual-energy X-ray absorptiometry, and computed tomography scans to evaluate body weight in a population being randomized to chromium and one in which weight gain with a specific pharmacologic agent, i.e., sulfonylurea, was expected (7).
