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

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.

Oral chromium picolinate improves carbohydrate and lipid metabolism and enhances skeletal muscle Glut-4 translocation in obese, hyperinsulinemic (JCR-LA corpulent) rats

Human studies suggest that chromium picolinate (CrPic) decreases insulin levels and improves glucose disposal in obese and type 2 diabetic populations. To evaluate whether CrPic may aid in treatment of the insulin resistance syndrome, we assessed its effects in JCR:LA-corpulent rats, a model of this syndrome. Male lean and obese hyperinsulinemic rats were randomly assigned to receive oral CrPic [80 microg/(kg. d); n = 5 or 6, respectively) in water or to control conditions (water, n = 5). After 3 mo, a 120-min intraperitoneal glucose tolerance test (IPGTT) and a 30-min insulin tolerance test were performed. Obese rats administered CrPic had significantly lower fasting insulin levels (1848 +/- 102 vs. 2688 +/- 234 pmol/L; P < 0.001; mean +/- SEM) and significantly improved glucose disappearance (P < 0.001) compared with obese controls. Glucose and insulin areas under the curve for IPGTT were significantly less for obese CrPic-treated rats than in obese controls (P < 0.001). Obese CrPic-treated rats had lower plasma total cholesterol (3.57 +/- 0.28 vs. 4.11 +/- 0.47 mmol/L, P < 0.05) and higher HDL cholesterol levels (1.92 +/- 0.09 vs. 1.37 +/- 0.36 mmol/L, P < 0.01) than obese controls. CrPic did not alter plasma glucose or cholesterol levels in lean rats. Total skeletal muscle glucose transporter (Glut)-4 did not differ among groups; however, CrPic significantly enhanced membrane-associated Glut-4 in obese rats after insulin stimulation. Thus, CrPic supplementation enhances insulin sensitivity and glucose disappearance, and improves lipids in male obese hyperinsulinemic JCR:LA-corpulent rats.

Beneficial effects of hormonal replacement therapy on chromium status and glucose and lipid metabolism in postmenopausal women

OBJECTIVES

Postmenopausal women exhibit an increased incidence of cardiovascular diseases, and type 2 diabetes mellitus compared with younger women. However, women receiving hormonal replacement therapy (HRT) seem to be protected. Since chromium (Cr) functions in glucose, lipid and corticosteroid metabolism and these variables, as well as Cr status, decline with age, Cr status may be a contributing factor in the effects of hormone replacement therapy. Therefore, the objective of this study was to determine the effects of hormonal replacement therapy (HRT) on serum and urinary Cr, plasma lipids, glucose, fructosamine and the related hormonal variables, estradiol, insulin, leptin, cortisol, and DHEA-sulfate.

METHODS

Forty-four healthy postmenopausal women 50-60 years old participated in the study. Eighteen were treated by combined oral hormonal replacement therapy (estradiol 2 mg per day during days 1-25 and 10 mg of dydrogesterone on days 10-25) for at least 2 years, and 26 were untreated.

RESULTS

Serum Cr concentrations were significantly lower in untreated postmenopausal women than in women receiving HRT (0.070+/-0.008 vs. 0.100+/-0.008 ng/ml) whereas urinary Cr excretion was increased (0.14+/-0.02 vs. 0.07+/-0.01 ng of Cr/mg creatinine). The urinary losses of Cr were inversely correlated with plasma estradiol. Median value of urinary Cr was higher in postmenopausal women exhibiting endogenous estradiol levels below 250 pmol/l, whereas women with estradiol levels >250 pmol/l, exhibited lower Cr values. Plasma fructosamine, total and LDL cholesterol and TC/HDL ratio, which are all decreased by improved Cr nutrition, were also improved in the women receiving HRT. There were also nonsignificant decreasing trends in DHEA-sulfate (P<0.06) and cortisol (0.07).

CONCLUSIONS

Chromium status, based upon blood and urinary analyses, and glucose, insulin and lipid variables were improved in postmenopausal women receiving HRT. Additional studies are needed to determine if improved Cr status due to supplemental Cr can elicit effects consistent with those of hormone replacement therapy.

Dietary chromium tripicolinate supplementation reduces glucose concentrations and improves glucose tolerance in normal-weight cats

The effect of dietary chromium supplementation on glucose and insulin metabolism in healthy, non-obese cats was evaluated. Thirty-two cats were randomly divided into four groups and fed experimental diets consisting of a standard diet with 0 ppb (control), 150 ppb, 300 ppb, or 600 ppb added chromium as chromium tripicolinate. Intravenous glucose tolerance, insulin tolerance and insulin sensitivity tests with minimal model analysis were performed before and after 6 weeks of feeding the test diets. During the glucose tolerance test, glucose concentrations, area under the glucose concentration-time curve, and glucose half-life (300 ppb only), were significantly lower after the trial in cats supplemented with 300 ppb and 600 ppb chromium, compared with values before the trial. Fasting glucose concentrations measured on a different day in the biochemistry profile were also significantly lower after supplementation with 600 ppb chromium. There were no significant differences in insulin concentrations or indices in either the glucose or insulin tolerance tests following chromium supplementation, nor were there any differences between groups before or after the dietary trial.Importantly, this study has shown a small but significant, dose-dependent improvement in glucose tolerance in healthy, non-obese cats supplemented with dietary chromium. Further long-term studies are warranted to determine if the addition of chromium to feline diets is advantageous. Cats most likely to benefit are those with glucose intolerance and insulin resistance from lack of exercise, obesity and old age. Healthy cats at risk of glucose intolerance and diabetes from underlying low insulin sensitivity or genetic factors may also benefit from long-term chromium supplementation.

Blood chromium determination in assessing reference values in an unexposed Mediterranean population

Plasma chromium levels were determined in 243 healthy subjects. The study group consisted of 134 men and 109 women, ages 19-71 yr, all residing in Barcelona in northeastern Spain. The study was designed to assess the reference levels for plasma chromium and to investigate its relationships to age and sex. The assays were performed by means of a graphite-furnace atomic absorption spectrometer. The mean plasma chromium concentration was 3.01 +/- 1.45 nmol/L, ranging from 0.6 to 6 nmol/L. The upper reference values in the 0.95 percentile for this population was 5 nmol/L. No significant differences were observed with respect to the subjects' sex.

Chromium research from a distance: from 1959 to 1980

More than 50 years of work have led to the recognition of trivalent chromium as an essential element. Shortly after its identification as an essential element in 1959, its interaction with insulin in vitro and in vivo was established, and the site of action identified as the insulin-sensitive cell membrane. Despite other early clinical successes with chromium supplementation, four major problems have influenced the rate of progress since then: 1) chromium analysis; 2) interaction of chromium with other dietary factors; 3) diagnosis of chromium status; and 4) other controversies, such as the carcinogenic potential of chromium (since disproved) and the lack of an effect on glucose tolerance even in chromium deficient organisms (now explained). These controversies have mostly dissipated as new knowledge integrated seemingly irreconcilable facts and opinions. It is now known that chromium may potentiate the action of insulin either by an effect on insulin dependent functions, or by maintaining these functions with less insulin, or by a combination of both. Despite much progress in the last 30 years, major challenges in chromium research remain, such as the development of practical methods for diagnosing chromium deficiency. Of several approaches for solving this problem, the most feasible might be to standardize the urinary chromium response following an insulinogenic challenge, such as an oral load of glucose or of glucose plus fructose (for maximal stimulation) with urine collection before and during the 2-hour test.

Chromium update: examining recent literature 1997-1998

Trivalent chromium is an essential nutrient required for sugar and fat metabolism. The majority of people eating typical Western diets consume less than the upper limit of the estimated safe and adequate daily dietary intake, which is set at 50-200 micrograms per day. Insufficient chromium intake is associated with signs and symptoms similar to those seen in diabetes and cardiovascular diseases. The efficacy of chromium in the general population relates to its prevention of deficiency or a reduction in the risk of chronic diseases. It is possible that doses above the estimated safe and adequate daily dietary intake are necessary for the treatment of certain chronic disease states. In a study performed in China, the use of 1000 micrograms of chromium per day (five times above the upper limit of the estimated safe and adequate daily dietary intake) was highly effective in relieving many of the symptomatic manifestations of type 2 diabetes mellitus, including a return of the HbA1C levels into the normal range. Most recent evidence strongly supports the conclusion that there is little fear of toxic reactions from chromium consumption. In addition to type 2 diabetes mellitus, chromium supplementation may be useful to direct overall weight decrements specifically towards fat loss with the retention of lean body mass and to ameliorate many manifestations of aging.