Increased insulin resistance is associated with increased urinary excretion of chromium in non-diabetic, normotensive Saudi adults

The role of trivalent chromium in improving glucose tolerance is well documented. Increased urinary chromium has been reported in type 2 diabetes mellitus, but it was not clear whether this had preceded diabetes mellitus, or was caused by it. Aim was to investigate the relationship between urinary chromium and the degree of insulin resistance in non-diabetic normotensive Saudi adults. 357 healthy adults aged 18–50 years were recruited randomly in a cross-sectional study design. Anthropometric and demographic information were taken. Insulin, glucose and free fatty acids were measured in fasting blood samples. Fasting urinary chromium and creatinine were also determined. Using modified QUICKI, subjects were labeled as high insulin resistant, or low insulin resistant. High insulin resistant subjects were matched for age and sex to low insulin resistant subjects. High insulin resistant subjects had higher mean BMI (p<0.001), mean waist circumference (p<0.01), and median urinary chromium (p<0.001) compared to low insulin resistant subgroup. Higher urinary chromium in high insulin resistant subgroup indicates a renal lesion leading to chromium deficiency and possibly diabetes mellitus eventually. Chromium supplementation might help to protect against the development of diabetes mellitus in this group of high insulin resistant non-diabetic Saudi individuals.

Longitudinal hair chromium profiles of elderly subjects with normal glucose tolerance and type 2 diabetes mellitus

Longitudinal hair chromium (H-Cr) profiles in a group of patients with type 2 diabetes mellitus (n = 59; age, 62 +/- 9 years) and healthy elderly (control) subjects (n = 49; age, 59 +/- 10 years) matched by age and sex were measured by solid sampling electrothermal atomic absorption spectrometry, providing data on the magnitude of variation of Cr content along the hair length. H-Cr average (H-Cr(av)) and H-Cr proximal (H-Cr(pr))(.), relating to the average Cr content of the whole hair and the proximal 3-mm hair length, respectively, were also obtained. No significant difference between the healthy and diabetic group was found in mean H-Cr(av) or H-Cr(pr) contents (248 +/- 108 vs 247 +/- 143 and 233 +/- 98 vs 278 +/- 195 ng/g, respectively. However, women in the control group had significantly lower H-Cr values (P < .01) compared with men, but this difference was absent in the diabetic population. The distribution of log H-Cr(pr) values in the control population displayed a Gaussian shape, in contrast to the substantially wider distribution, skewed toward lower H-Cr(pr) values, observed in the diabetic group. The magnitude of variation in H-Cr content in the patient group over an interval of approximately 2 to 3 months (time of growth of the hair sampled) was found to be a factor of more than 2 larger than that in the control population (+/- 58% vs +/- 26%). A strong relationship (R = 0.656; P < .01) between log H-Cr(pr) and log fasting plasma Cr was observed in the diabetic group (n = 20). The mean fasting plasma Cr value of this group was 0.41 +/- 0.10 microg Cr per liter. No correlation between H-Cr(av.) and duration of diabetes was observed. A strong positive association was observed in the control population between H-Cr(pr) and fasting plasma insulin (n = 22; R = 0.6157; P < .01), and H-Cr(pr) and fasting plasma glucose (n = 24; R = 0.4118; P < .05), which is indicative of the interrelation of these parameters. In the control population, H-Cr(av) showed a slight decrease with age (n = 54; R = 0.2691; P < .05), which is assumed to be the result of increased insulin resistance caused by various age-associated factors including Cr deficiency. None of the above relationships was significant in the diabetic group. Evidence is presented that justifies the assumption that the longitudinal H-Cr profile resembles the variation in Cr metabolic rate over the time span of growing hair, which is not appreciably affected by external contamination. This suggests that glucose intolerance (type 2 diabetes mellitus) is an important factor that disturbs Cr metabolism.

Comparison of anti-hyperglycemic effect amongst vanadium, molybdenum and other metal maltol complexes

A wide variety of vanadium-containing complexes have been tested, both in vivo and in vitro, as possible therapeutic agents for the oral treatment of type 2 diabetes mellitus. None so far has surpassed bis(maltolato)oxovanadium(IV) (BMOV) for glucose- and lipid-lowering in an orally available formulation. Ligand choice is clearly an important factor in pharmacological efficacy of vanadium compounds as insulin enhancing agents. In this study, we kept the ligand and dose the same, varying instead the metal ion bound to the maltolato ligand in a series of binary complexes of neutral charge. A requirement for vanadyl ion as the metal ion of choice was apparent; no other metal ion tested served as a suitable substitute. Amongst [MoO(2)](2+), Co(II), Cu(II), Cr(III), and Zn(II), only [MoO(2)](2+) and Co(II) showed any hypoglycemic activity at the ED(50) dose for bis(maltolato)oxovanadium(IV), 0.6 mmolkg(-1) by oral gavage in streptozotocin (STZ)-diabetic rats within 72 h of administration of compound.

Role of chromium supplementation in Indians with type 2 diabetes mellitus

Type 2 diabetes mellitus is a complex metabolic disorder with adverse cardiovascular risk. The role of micronutrients has not yet been well clarified in this condition, especially in India.THE OBJECTIVES OF THIS STUDY WERE TO: (1) evaluate chromium status in Indian subjects with type 2 diabetes mellitus, (2) assess the effect of chromium picolinate (200 &mgr;g trivalent chromium twice daily) administration on glycaemic control and lipid profile in these subjects and (3) comment on the possible mechanism of any beneficial effect noted above.Fifty subjects were studied in a double blind, placebo-controlled, crossover fashion, with each treatment arm (chromium/placebo) lasting 12 weeks and 4 weeks' wash-off period in between. 50 healthy age- and sex-matched volunteers served as controls. Serum chromium level appeared to be higher in the general population in our country compared to western countries (36.5-59.5 nmol/L as compared to 2.3-40.3 nmol/L) However, the local diabetics were found to have a lower serum chromium level than the healthy controls (32.3 nmol/L against 44.7 nmol/L; p < 0.0001) and a mean increase of 3.5 nmol/L was noted after 12 weeks of chromium supplementation that was, expectedly, not seen in the placebo phase (p < 0.0001).Significant improvement in glycaemic control was noted in the chromium-treated group (DeltaFasting serum glucose = 0.44 mmol/L, p < 0.001; DeltaPost-prandial serum glucose = 1.97 mmol/L, p < 0.001; Deltaglycated hemoglobin = 0.01; p = 0.04, in comparison to placebo) This was accompanied by a significant greater fall in fasting serum insulin in the chromium-treated group, p < 0.05.The change in lipid parameters (total serum cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides) did not show significant difference between the chromium and placebo groups.Clinically significant hematological, renal or hepatic toxicity were excluded by routine hemogram, serum urea, creatinine, alanine amino transferase (ALT) and alkaline phosphatase estimations.In conclusion, chromium supplementation seems to improve glycaemic control in type 2 diabetic patients, which appears to be due to an increase in insulin action rather than stimulation of insulin secretion.

Community exposure and medical screening near chromium waste sites in New Jersey

Chromium waste slag containing potentially hazardous levels of hexavalent chromium was used as fill material at more than 160 residential, industrial, and recreational sites. Persons living or working in the vicinity of the sites may have been exposed through inhalation, ingestion, or skin contact with contaminated soils and dusts. In 1992-1993, the New Jersey Department of Health and Senior Services (NJDHSS) and the Environmental and Occupational Health Sciences Institute (EOHSI) conducted a screening project to assess exposure to chromium and to provide medical evaluations to people living in 14 residential areas or working in 78 workplaces near chromium waste sites. The screening included a physical examination for irritant or allergic effects and a urine chromium test for recent exposure. Participants were referred for follow-up medical evaluation if specific criteria were met. Of 800 residents and 938 workers receiving the screening physical examination, 32 adults were referred for follow-up evaluation. Of 806 residents and 934 workers submitting a urine specimen for chromium analysis, 158 adults and children had levels exceeding specified criteria and were referred for follow-up evaluation. The proportion of persons referred on the basis of the urine chromium test varied among screened groups. Multiple linear regression models showed that average urine chromium differences between residents and a comparison group, adjusting for potential confounders, were highest in children under 6 years of age. Most of the persons undergoing the follow-up medical examinations revealed no apparent clinical effects attributable to chromium exposure. The screening results indicated the need for expanded environmental evaluation in specific residential areas and workplaces.

Age-related decreases in chromium levels in 51,665 hair, sweat, and serum samples from 40,872 patients--implications for the prevention of cardiovascular disease and type II diabetes mellitus

This report shows, for the first time using modern analytical techniques, highly significant age-related decreases in chromium levels in 51,665 hair, sweat, and serum samples obtained from 40,872 patients referred by their physicians to an independent medical research clinic and laboratory (r = -.598 to -.762, P < .0001 for all correlations). Males were found to have significantly lower mean chromium levels than females (P < .05 to .0001). There was good correlation between chromium levels in hair, sweat, and serum (r = .536 to .729, P < .0001 for all correlations), indicating that hair and sweat chromium levels are valid additions to the serum levels in assessing chromium status. Chromium measurements in sweat, hair, and serum were performed using graphite furnace atomic absorption spectrophotometry. The influences that age-related decreases in chromium levels might have on increasing the risk to develop age-related impaired glucose metabolism, disordered lipid metabolism, coronary heart disease, arteriosclerosis, and type II diabetes mellitus are outlined, and the role that refined carbohydrates play in the development of compromised chromium status is presented.

Isolation and characterization of a biologically active chromium oligopeptide from bovine liver

Low-molecular-weight chromium-binding substance (LMWCr), the only known naturally occurring Cr-containing polypeptide from mammals and candidate for the biologically active form of chromium, has been isolated for the first time in yields sufficient for spectroscopic studies capable of providing structural and mechanistic data on a molecular level. The results of paramagnetic 1H NMR, electron paramagnetic resonance, and electronic spectroscopic studies indicate that the four chromic ions per polypeptide are probably arranged in an integer-spin tetranuclear assembly, although an alternate possibility, the presence of two dinuclear assemblies, could not be ruled out. This assembly (or assemblies) is bridged by anionic ligands and supported by carboxylates provided by the polypeptide.