O R I G I N A L A R T I C L E
Chromium Treatment Has No Effect in Patients With Type 2 Diabetes in a Western Population
A randomized, double-blind, placebo-controlled trial
NANNE KLEEFSTRA, MD1,2 SEBASTIAAN T. HOUWELING, MD, PHD2 STEPHAN J.L. BAKKER, MD, PHD3 SIMON VERHOEVEN, MD, PHD2 RIJK O.B. GANS, MD, PHD3 BETTY MEYBOOM-DE JONG, MD, PHD4 HENK J.G. BILO,MD, PHD, FRCP1,3 chromomodulin) (7). This peptide has the ability to increase tyrosine kinase activity eightfold, depending on the chromium concentration (8), thus strengthening the idea that chromium plays an inﬂuential role in glucose metabolism (5). The largest study (n 180) to date investigating the effect of chromium in patients with type 2 diabetes was published by Anderson et al. (9). Theyfound that the A1C of Chinese patients treated with 1,000 g of chromium in the form of chromium picolinate decreased almost 2 percentage points compared with a placebo group after 4 months. However, two systematic reviews that addressed the effects of chromium on glycemic control concluded that, on the basis of the currently available data, the effects of chromium on glycemic control areinconclusive (10,11). Randomized studies with results on glucose, insulin, and/or A1C were collected by Althuis et al. (10) in their review. Reasons for the inconclusive ﬁndings are that too few trials in patients with diabetes have been conducted to allow conclusive ﬁndings (three trials with a total of 38 subjects). Furthermore, in recent years, the safety of chromium supplements has been called intoquestion because of mixed results in studies investigating the mutagenicity of chromium picolinate in vitro (12–14). Although toxic effects were reported in neither the systematic reviews (10,11) nor in the study of Anderson et al. (9), chromium picolinate was banned by the Food Standards Agency until December 2004 (15). This meant that investigations into the effects of chromium compounds on type 2diabetes had to involve compounds other than chromium picolinate. Some studies, in which the effects of chromium-enriched yeast in nondiabetic patients were investigated, showed mixed results (16 –19). Bahijri et al. (20) investigated the effects of different forms of chromium with a double-blind cross-over design and concluded that fasting glucose in patients with type 2 diabetes improved after 8weeks of daily diDIABETES CARE, VOLUME 30, NUMBER 5, MAY 2007
OBJECTIVE — Chromium treatment has been reported to improve glycemic control in patients with type 2 diabetes. However, concern exists about the possible toxic effects of chromium picolinate. The aim of this study was to determine the effect of chromium treatment in the form of chromium yeast on glycemic control in a Westernpopulation of patients with type 2 diabetes who were being treated with oral hypoglycemic agents. RESEARCH DESIGN AND METHODS — In this 6-month, double-blind study, patients with moderate glycemic control, being treated with oral hypoglycemic agents, were randomly assigned to receive either a placebo or treatment with 400 g of chromium daily in the form of chromium yeast. The primary efﬁcacy parameterwas a change in A1C. Secondary end points were changes in lipid proﬁle, BMI, blood pressure, body fat, and insulin resistance. RESULTS — No differences were found for the change in A1C between the intervention and placebo groups, nor were any differences found between the groups for the secondary end points. CONCLUSIONS — There is no evidence that chromium in the form of chromium yeast is effectivein improving glycemic control in Western patients with type 2 diabetes who are taking oral hypoglycemic agents. Diabetes Care 30:1092–1096, 2007
ype 2 diabetes is a chronic, progressive illness that causes considerable morbidity and premature mortality (1,2). The worldwide prevalence of type 2 diabetes is high and is increasing steadily (3). The majority of patients are insulin resistant (4)....