Optimal dietary concentration of chromium for alleviating the effect of heat stress on growth,carcass qualities,and some serum metabolites of broiler chickens

This study was conducted to determine the effects of chromium (chromium picolinate, CrPic) supplementation at various levels (0, 200, 400, 800, or 1200 microg/kg of diet) on performance, carcass characteristics, and some serum metabolites of broiler chickens (Ross) reared under heat stress (32.8 degrees C). One hundred fifty old male broilers were randomly assigned to 5 treatment groups, 3 replicates of 10 birds each. The birds were fed either a control diet or the control diet supplemented with either 200, 400, 800, or 1200 microg Cr/kg of diet. Increased supplemental chromium resulted in an increase in body weight (p = 0.01, linear), feed intake (p < or = 0.05, linear), and carcass characteristics (p < or = 0.05, linear) and improved feed efficiency (p = 0.01, linear). Increased supplemental chromium decreased serum corticosterone concentration (p = 0.01, linear), whereas it increased serum insulin and T3 and T4 concentrations (p = 0.01). Serum glucose and cholesterol concentrations decreased (p = 0.01), whereas protein concentrations increased linearly (p = 0.001) with higher dietary chromium supplementation. Results of the present study conclude that a supplementation of diet with chromium at 1200 ppb can alleviate the detrimental effects of heat stress in broiler.     

Chromium supplementation in non-obese non-diabetic subjects is associated with a decline in insulin sensitivity

The use of chromium supplements is widespread for the prevention and treatment of diabetes mellitus but there are conflicting reports on efficacy, possibly reflecting discrepant effects across different populations. In the present studies, we test the hypothesis that chromium supplementation raises serum chromium levels and correspondingly improves insulin sensitivity. A double blind placebo-controlled randomized trial was conducted on 31 non-obese, normoglycemic subjects. After baseline studies, the subjects were randomized to placebo or chromium picolinate 500 μg twice a day. The primary endpoint was change in insulin sensitivity as measured by euglycemic hyperinsulinemic clamp. Pre-specified secondary endpoints included fasting lipids, blood pressure, weight, body composition measured by DXA scan. After 16 weeks of chromium picolinate therapy there was no significant change in insulin sensitivity between groups (p=0.83). There was, however, a strong association between serum chromium and change in insulin resistance (β = -0.83, p=0.01), where subjects with the highest serum chromium had a worsening of insulin sensitivity. This effect could not be explained by changes in physiological parameters such as body weight, truncal fat and serum lipids with chromium therapy. Chromium therapy did not improve insulin sensitivity in non-obese normoglycemic individuals. Further, subjects who have high serum chromium levels paradoxically had a decline in insulin sensitivity. Caution therefore should be exercised in recommending the use of this supplement. The study was registered on the NIH registry (clinicaltrials.gov) and the identifier is NCT00846248     

A pilot study of the effects of chromium picolinate supplementation on serum fetuin-A,metabolic and inflammatory factors in patients with nonalcoholic fatty liver disease: A double-blind,placebo-controlled trial

BackgroundEvaluating the impact of chromium picolinate supplementation on glycemic status, lipid profile, inflammatory markers and fetuin-A in patients with non-alcoholic fatty liver disease (NAFLD).MethodsIn present research, participants (N = 46) were randomized to (400 mcg/day, n = 23) chromium picolinate and placebo (n = 23) for 3 months.ResultsGlucose indices, and lipid profiles, inflammatory biomarker and fetuin-A were measured before and after the intervention. Chromium reduced triglyceride (TG), atherogenic index of plasma (AIP), very-low-density lipoprotein (VLDL), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), high-sensitivity C-reactive protein (hs-CRP), interleukin (IL) -6, tumor necrosis factor-alpha (TNF-α) and fetuin-A significantly compared to placebo group (p < 0.05). Furthermore, chromium significantly increased the quantitative insulin sensitivity check index (QUICKI). There were no significant differences in total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), fasting blood sugar (FBS), Hemoglobin A1c (HbA1C), interleukin (IL)-17 between the two groups (p < 0.05).ConclusionChromium picolinate significantly decreased TG, insulin, HOMA-IR, fetuin-A, the number of inflammatory factors, and increased QUICKI without changing FBS, HbA1C, TC, LDL, HDL, IL-17 levels and liver steatosis intensity in patients with NAFLD. Further studies by examining the effect of different doses of chromium and mechanisms of cellular action, would help further clarify the subject.     

Chromium Chloride Administration Causes a Substantial Reduction of Coronary Lipid Deposits,Aortic Lipid Deposits,and Serum Cholesterol Concentration in Rabbits

This experiment was carried out to test the null hypothesis that intramuscular trivalent chromium administration would not remove lipids from the heart and ascending aorta of the hyoercholesterolemic rabbits and would not lower their serum cholesterol levels. A novel computer-based method, previously described, was used to assess the sizes of the intracardiac and aortic lesions. Clinical chemistry and histopathology were performed through routine methods. The sizes of the lipid deposits in the coronary vasculature of the hypercholesterolemic rabbits were greatly reduced as a result of the intramuscular chromium chloride injections. Lipid deposits in the ascending aorta were similarly reduced, as well as the serum cholesterol concentrations. The terminal serum chromium concentrations in the chromium-treated group were in the range of 3,258–4,513 μg/L, whereas, in the untreated animals, the concentrations were 3.2 to 6.3 μg/L. The general condition of the chromium-treated animals was good and they were continuing to gain weight up to the time they were killed. However, it was found that their liver function tests had become abnormal even though there was no evidence of hepatic histopathological lesions specifically affecting the chromium-treated group. The kidney function tests and histopathology were normal. These findings suggest that a more aggressive approach than those tried hitherto might be useful in treating atherosclerotic human patients with chromium.     

Studies of LDL oxidation following alpha-, gamma-, or delta-tocotrienyl acetate supplementation of hypercholesterolemic humans

In vitro tocotrienols (T3s) have potent vitamin E antioxidant activity, but unlike tocopherols can inhibit cholesterol synthesis by suppressing 3-hydroxy-3-methyl-glutarylCoA (HMG-CoA) reductase. Because hypercholesterolemia is a major risk factor for coronary artery disease and oxidative modification of low-density lipoprotein (LDL) may be involved in atherogenesis, we investigated whether daily supplements of placebo, or alpha-, gamma-, or delta- (alpha-, gamma-, or delta-) tocotrienyl acetates would alter serum cholesterol or LDL oxidative resistance in hypercholesterolemics in a double-blind placebo controlled study. Subjects were randomly assigned to receive placebo (n = 13), alpha- (n = 13), gamma- (n = 12), or delta- (n = 13) tocotrienyl acetate supplements (250 mg/d). All subjects followed a low-fat diet for 4 weeks, then took supplements with dinner for the following 8 weeks while still continuing diet restrictions. Plasma alpha- and gamma-tocopherols were unchanged by supplementation. Plasma T3s were undetectable initially and always in the placebo group. Following supplementation in the respective groups plasma concentrations were: alpha-T3 0.98 +/- 0.80 micromol/l, gamma-T3 0.54 +/- 0.45 micromol/l, and delta-T3 0.09 +/- 0.07 micromol/l. Alpha-T3 increased in vitro LDL oxidative resistance (+22%, p <.001) and decreased its rate of oxidation (p <. 01). Neither serum or LDL cholesterol nor apolipoprotein B were significantly decreased by tocotrienyl acetate supplements. This study demonstrates that: (i) tocotrienyl acetate supplements are hydrolyzed, absorbed, and detectable in human plasma; (ii) tocotrienyl acetate supplements do not lower cholesterol in hypercholesterolemic subjects on low-fat diets; and (iii) alpha-T3 may be potent in decreasing LDL oxidizability.     

Effects of dietary chromium and zinc on egg production, egg quality, and some blood metabolites of laying hens reared under low ambient temperature

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, CrPic) and zinc (ZnSO₄·H₂O) on egg production, egg quality, and serum insulin, corticosterone, glucose, cholesterol, and total protein concentrations of laying hens reared under a low ambient temperature (6.8°C). One hundred twenty laying hens (Hy-Line; 32 wk old) were divided into 4 groups, 30 hens per group. The laying hens were fed the control diet (T1) or the control diet supplemented with either 400 μg of Cr/kg of diet (T2), 30 mg of Zn/kg of diet (T3), or 400 μg of Cr plus 30 mg of Zn/kg of diet (T4). Although the dry matter intake (DMI) was similar (p>0.05) for all treatment groups, supplemental chromium and zinc either individually or together increased live-weight change, egg production, and improved feed efficiency (p<0.05). However, no significant differences were observed between T4 and T2 or T3. Compared to T1, supplemental chromium and zinc increased egg weight, eggshell weight, eggshell thickness, egg specific gravity, and Haugh unit (p<0.05) in T2, T3, and T4 groups, among which there was no significant difference. Serum insulin concentration increased (p<0.05) and corticosterone concentration decreased (p<0.05) with dietary chromium and zinc supplementation. Serum glucose and cholesterol concentrations decreased (p<0.05) and protein concentrations increased (p<0.001) with dietary chromium and zinc supplementation in all treatment groups. The results of this study indicated that either supplemental dietary chromium or zinc increased plasma insulin and decreased corticosterone concentrations and that had a positive effect on performance of laying hens under low ambient temperature.     

Gliclazide mainly affects insulin secretion in second phase of type 2 diabetes mellitus.

We studied the effect of the acute administration of gliclazide at 160 mg on insulin release during hyperglycaemic clamps in 12 type 2 diabetes patients, age 50 +/- 9.0 years, diabetes duration 5.5 +/- 4.8 years, fasting blood glucose 9.6 +/- 2.1 mmol/L (means +/- SD). After a 210 min of hyperinsulinaemic euglycaemic clamp (blood glucose 4.6 +/- 0.14mmol/L), gliclazide or placebo (randomised, double-blind, cross-over) was administered; 60 minutes later, a hyperglycaemic clamp (4hr) at 8mmol/L was started. Plasma C-peptide levels increased significantly after the administration of gliclazide (increment 0.17 +/- 0.15 vs. 0.04 +/- 0.07 nmol/L, p = 0.024) before the clamp. After the start of the hyperglycaemic clamp, the areas under the curve (AUC) for insulin and C-peptide did not differ from 0-10 min (first phase) with gliclazide. However, second-phase insulin release (30-240 min) was markedly enhanced by gliclazide. AUC plasma insulin (30 to 240 min) was statistically significantly higher after gliclazide (12.3 +/- 13.9 vs. -0.56 +/- 9.4 nmol/L x 210 min, p = 0.022); similarly, AUC plasma C-peptide (30 to 240 min) was also higher: 128 +/- 62 vs. 63 +/- 50 nmol/L x 210 min, p = 0.002). In conclusion, in long-standing type 2 diabetes the acute administration of gliclazide significantly enhances second phase insulin release at a moderately elevated blood glucose level. In contrast to previous findings in mildly diabetic subjects, these 12 type 2 diabetes patients who had an inconsiderable first phase insulin release on the placebo day, only showed an insignificant increase in first phase with gliclazide.     

The Influences of Chromium Supplementation on Glycemic Control,Markers of Cardio-Metabolic Risk,and Oxidative Stress in Infertile Polycystic ovary Syndrome Women Candidate for In vitro Fertilization: a Randomized,Double-Blind,Placebo-Controlled Trial

This study was carried out to investigate the effects of chromium intake on glycemic control, markers of cardio-metabolic risk, and oxidative stress in infertile polycystic ovary syndrome (PCOS) women candidate for in vitro fertilization (IVF). This randomized double-blind, placebo-controlled trial was done among 40 subjects with infertile PCOS candidate for IVF, aged 18–40 years old. Individuals were randomly allocated into two groups to take either 200 μg/day of chromium (n?=?20) or placebo (n?=?20) for 8 weeks. Biochemical parameters were assessed at baseline and at end-of-trial. Compared with the placebo, taking chromium supplements led to significant reductions in fasting plasma glucose (??2.3?±?5.7 vs. +?0.9?±?3.1 mg/dL, P?=?0.03), insulin levels (??1.4?±?2.1 vs. +?0.4?±?1.7 μIU/mL, P?=?0.004), homeostatic model of assessment for insulin resistance (??0.3?±?0.5 vs. +?0.1?±?0.4, P?=?0.005), and a significant increase in quantitative insulin sensitivity check index (+?0.004?±?0.008 vs. ??0.001?±?0.008, P?=?0.03). In addition, chromium supplementation significantly decreased serum triglycerides (??19.2?±?33.8 vs. +?8.3?±?21.7 mg/dL, P?=?0.004), VLDL- (??3.8?±?6.8 vs. +?1.7?±?4.3 mg/dL, P?=?0.004) and total cholesterol concentrations (??15.3?±?26.2 vs. ??0.6?±?15.9 mg/dL, P?=?0.03) compared with the placebo. Additionally, taking chromium supplements was associated with a significant increase in plasma total antioxidant capacity (+?153.9?±?46.1 vs. ??7.8?±?43.9 mmol/L, P?<?0.001) and a significant reduction in malondialdehyde values (?0.3?±?0.3 vs. +?0.1?±?0.2 μmol/L, P?=?0.001) compared with the placebo. Overall, our study supported that chromium administration for 8 weeks to infertile PCOS women candidate for IVF had beneficial impacts on glycemic control, few variables of cardio-metabolic risk, and oxidative stress.     

The Vitamin D Dose Response in Obesity

ObjectiveThe prevalence of vitamin D inadequacy is high in obese individuals. Determining the response of serum 25-hydroxyvitamin D (25[OH]D) to vitamin D₃ supplementation in obese and nonobese individuals may lead to concurrent recommendations for optimal vitamin D intake in these populations. The objective of this study was to determine the dose response of vitamin D₃ in subjects with a body mass index ≥ 35 kg/m².MethodsRandomized, double-blind, placebo-controlled study. This study is an extension of our previous study of vitamin D dosing in healthy adults. After an assessment of baseline 25(OH)D levels, participants were randomized to a vitamin D supplementation arm (100 μg daily if baseline 25[OH]D was < 50 nmol/L, or 50 μg daily if baseline 25[OH]D was ≥ 50 nmol/L) or placebo arm. Subjects with baseline 25(OH)D level ≥ 80 nmol/L were excluded from the study. Two months following randomization, a repeat 25(OH)D measurement was done.ResultsFinal analysis included 25 subjects (14 placebo, 11 active). At 2 months, serum 25(OH)D concentration increased to a mean of 75 nmol/L in the active group. Mean slope (i.e., vitamin D₃ response), defined as 25(OH) D change/baseline dose, was 0.398 nmol/L/μg/day.ConclusionThe dose response of vitamin D₃ (slope) in obese subjects was significantly lower (P < .03) at 0.398 nmol/L/μg/day compared to the slope in the previous study of healthy subjects (0.66 nmol/L/μg/day). These results suggest that obese individuals may require 40% higher vitamin D intake than nonobese individuals to attain the same serum 25(OH)D concentration. (Endocr Pract. 2014;20:1258-1264)     

Impact of Vitamin D Replacement on Markers of Glucose Metabolism and Cardio-Metabolic Risk in Women with Former Gestational Diabetes—A Double-Blind,Randomized Controlled Trial

Gestational Diabetes Mellitus (GDM) and vitamin D deficiency are related to insulin resistance and impaired beta cell function, with heightened risk for future development of diabetes. We evaluated the impact of vitamin D supplementation on markers of glucose metabolism and cardio metabolic risk in Asian women with former GDM and hypovitaminosis D. In this double blind, randomized controlled trial, 26 participants were randomized to receive either daily 4000 IU vitamin D3 or placebo capsules. 75g Oral Glucose Tolerance Test (OGTT) and biochemistry profiles were performed at baseline and 6 month visits. Mathematical models, using serial glucose, insulin and C peptide measurements from OGTT, were employed to calculate insulin sensitivity and beta cell function. Thirty three (76%) women with former GDM screened had vitamin D level of <50 nmol/L at baseline. Supplementation, when compared with placebo, resulted in increased vitamin D level (+51.1 nmol/L vs 0.2 nmol/L, p<0.001) and increased fasting insulin (+20% vs 18%, p = 0.034). The vitamin D group also demonstrated a 30% improvement in disposition index and an absolute 0.2% (2 mmol/mol) reduction in HbA_1c. There was no clear change in insulin sensitivity or markers of cardio metabolic risk. This study highlighted high prevalence of vitamin D deficiency among Asian women with former GDM. Six months supplementation with 4000 IU of vitamin D3 safely restored the vitamin D level, improved basal pancreatic beta-cell function and ameliorated the metabolic state. There was no effect on markers of cardio metabolic risk. Further mechanistic studies exploring the role of vitamin D supplementation on glucose homeostasis among different ethnicities may be needed to better inform future recommendations for these women with former GDM at high risk of both hypovitaminosis D and future diabetes.     

Effect of Chromium-Enriched Yeast on Fasting Plasma Glucose, Glycated Haemoglobin and Serum Lipid Levels in Patients with Type 2 Diabetes Mellitus Treated with Insulin

Chromium is required for a normal insulin function, and low levels have been linked with insulin resistance. The aim of this study was to follow the effect of chromium supplementation on fasting plasma glucose (FPG), glycated haemoglobin (HbA_1c) and serum lipids in patients with type 2 diabetes mellitus (DM2) on insulin therapy. Eleven randomly selected patients with DM2 on insulin therapy were supplemented with a daily dose of 100 μg chromium yeast for the first supplementation period of 2 weeks. In the second supplementation period, the chromium dose was doubled and continued for the next 6 weeks. The third phase was a 6-week washout period. After each period, the levels of FPG and HbA_1c were compared with the corresponding values at the end of the previous period. Serum triglycerides, total HDL and LDL cholesterol values after supplementation were compared with the baseline values. FPG decreased significantly after the first period of chromium supplementation (p?<?0.001), and a tendency to a further reduction was observed after the second supplementation period. Similarly, HbA_1c decreased significantly in both periods (p?<?0.02 and p?<?0.002, respectively). Eight weeks after withdrawal of chromium supplementation, both FPG and HbA_1c levels returned to their pre-intervention values. The serum lipid concentrations were not significantly influenced by chromium supplementation. Chromium supplementation could be beneficial in patients with DM2 treated with insulin, most likely due to lowered insulin resistance leading to improved glucose tolerance. This finding needs to be confirmed in a larger study.     

Effect of chromium nicotinic acid supplementation on selected cardiovascular disease risk factors

The effects of daily supplemental chromium (200 μg) complexed with 1.8 mg nicotinic acid on plasma glucose and lipids, including total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides, were assessed in 14 healthy adults and 5 adults with noninsulin-dependent diabetes mellitus (NIDDM) using a double-blind crossover study with 8-wk experimental periods. Eight of the 14 healthy subjects and all 5 subjects with NIDDM also underwent an oral glucose tolerance test with assessment of 90 min postprandial plasma glucose and insulin concentrations. No statistically significant effects of chromium nicotinic acid supplementation were found on plasma insulin, glucose, or lipid concentrations, although chromium nicotinic acid supplementation slightly lowered fasting plasma total and LDL cholesterol, triglycerides, and glucose concentrations, and 90-min postprandial glucose concentrations in individuals with NIDDM.     

Chromium picolinate and conjugated linoleic acid do not synergistically influence diet- and exercise-induced changes in body composition and health indexes in overweight women

This study assessed the effects of combined chromium picolinate (CP) and conjugated linoleic acid (CLA) supplementation on energy restriction and exercise-induced changes in body composition, glucose metabolism, lipid lipoprotein profile and blood pressure in overweight, premenopausal women. For 12 weeks, 35 women [age 36+/-1 years (mean+/-S.E.M.); BMI 28.0+/-0.5 kg/m2] were counseled to consume a 2092 kJ/day (500 kcal/day) energy deficit diet and performed 30 min of moderate-intensity walking or jogging 5 days/week. The women were randomly assigned to ingest either CP-CLA [400 mug chromium (Cr), 1.8 g CLA in 2.4 g tonalin oil, n=19] or placebo (<0.1 microg Cr, 2.4 g canola oil, n=16). Compared to baseline, urinary Cr excretion increased 22-fold, plasma CLA isomer 18:2 (c9,t11) content increased 79% and plasma CLA isomer 18:2 (t10,c12) became detectable in CP-CLA and were unchanged in Placebo. Over time, body weight decreased 3.5+/-0.5% (CP-CLA -2.6+/-0.5; placebo -2.5+/-0.5 kg) and fat mass decreased 8.9+/-1.3% (CP-CLA -2.7+/-0.5, placebo -2.4+/-0.5 kg), with no differences in responses between groups. Fasting blood hemoglobin A1c, plasma glucose and insulin, a homeostatic assessment of insulin resistance, serum total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol, triacylglycerol (TG), CHOL/HDL ratio, TG/HDL ratio and sitting systolic and diastolic blood pressures were not changed over time or influenced by CP-CLA. The use of a combined CP and CLA supplement for 3 months does not affect diet- and exercise-induced changes in weight and body composition or improve indexes of metabolic and cardiovascular health in young overweight women.     

Effect of supplementation with organic selenium on mercury status as measured by mercury in pubic hair.

The purpose of this study was to evaluate the effect of four months of yeast-based selenium supplementation on selenium and mercury status in subjects with low serum selenium. The study was carried out in Rakvere, Estonia. Pubic hair mercury, serum selenium and blood selenium concentrations in 23 subjects (serum selenium < 90 micrograms/l) were investigated before and after selenium supplementation. Thirteen subjects were randomized into the selenium supplementation group and ten into the placebo group. The selenium supplementation group received daily 100 micrograms of selenomethionine. Selenium supplementation reduced pubic hair mercury level by 34% (p = 0.005) and elevated serum selenium by 73% and blood selenium by 59% in the supplemented group (p < 0.001 for both). The study indicates that mercury accumulation in pubic hair can be reduced by dietary supplementation with small daily amounts of organic selenium in a short range of time.     

Effects of chromium supplementation on lipid profile in patients with type 2 diabetes: A systematic review and dose-response meta-analysis of randomized controlled trials

BackgroundThe purpose of this study was to determine the influence of chromium supplementation on lipid profile in patients with type 2 diabetes mellitus (T2DM).MethodsA systematic search was performed in Scopus, Embase, Web of Science, the Cochrane library and PubMed databases to find randomized controlled trials (RCTs) related to the effect of chromium supplementation on lipid profile in patients with T2DM, up to June 2020. Meta-analyses were performed using the random-effects model, and I² index was used to evaluate heterogeneity.ResultsThe primary search yielded 725 publications. 24 RCTs (with 28 effect size) were eligible. Our meta-analysis indicated that chromium supplementation resulted in a significant decrease in serum levels of triglyceride (TG) (MD: -6.54 mg/dl, 95 % CI: -13.08 to -0.00, P = 0.050) and total cholesterol (TC) (WMD: -7.77 mg/dl, 95 % CI: -11.35 to -4.18, P < 0.001). Furthermore, chromium significantly increases high-density lipoprotein (HDL) (WMD: 2.23 mg/dl, 95 % CI: 0.07–4.40, P = 0.043) level. However, chromium supplementation did not have significant effects on low-density lipoprotein (LDL) (WMD: -8.54 mg/dl, 95 % CI: -19.58 to 2.49, P = 0.129) level.ConclusionChromium supplementation may significantly improve lipid profile in patients with T2DM by decreasing TG and TC and increasing HDL. However, based on our analysis, chromium failed to affect LDL. It should be noted that the lipid-lowering properties of chromium supplementation were small and may not reach clinical importance.     

Effects of short-term chromium supplementation on insulin sensitivity and body composition in overweight children: randomized, double-blind, placebo-controlled study

Excessive body weight is inversely associated with insulin sensitivity in children and adults. Chromium supplementation produces modest improvement in insulin sensitivity in adults. The aim of this study was to examine the beneficial effects of chromium supplementation on insulin sensitivity and body composition in overweight children simultaneously modifying lifestyle. Twenty-five overweight children aged 9–12 years were randomized to receive either 400 μg of chromium chloride or placebo in double-blind fashion, during a 6-week lifestyle modification regimen that included nutritional education and 3×90 min of aerobic physical activity weekly. Insulin sensitivity was demonstrated using homeostasis model assessment-insulin resistance and quantitative insulin sensitivity check index (QUICKI). Changes in body mass index (BMI; kg/m²), BMI Z-score, waist circumference, body composition and fasting plasma glucose were measured. Although no significant benefit of chromium supplementation over placebo was evident for BMI, BMI Z-score and fasting insulin level, children who received chromium chloride demonstrated more positive changes versus the placebo group in HOMA (−1.84±1.07 vs. 0.05±0.42, P=.05), QUICKI (0.02±0.01 vs. −0.002±0.01, P=.05), lean body mass (2.43±0.68kg vs. 1.36±1.61kg, P=.02) and percentage body fat (−3.32±1.29% vs. 0.65±1.05%, P=.04). The desirable effects of chromium supplementation on insulin sensitivity and body composition were more apparent in pre-pubertal children. These results suggest that short-term chromium supplementation can improve insulin sensitivity and body composition in overweight children.     

Supplemental selenium and coenzyme Q10 reduce glycation along with cardiovascular mortality in an elderly population with low selenium status – A four-year,prospective, randomised,double-blind placebo-controlled trial

BackgroundA low intake of selenium has been shown to increase the risk of cardiovascular mortality, and supplementation of selenium and coenzyme Q10 influences this. The mechanism behind is unclear although effects on inflammation, oxidative stress and microRNA expression have been reported.Fructosamine, a marker of long-term glycaemic control, is also a marker of increased risk of heart disease and death, even in non-diabetics.ObjectiveTo analyse the impact of selenium and coenzyme Q10 supplementation on the concentration of fructosamine. Also, the relation between pre-intervention serum selenium concentration and the effect on fructosamine of the intervention was studied.MethodsFructosamine plasma concentration was determined in 219 participants after six and 42 months of intervention with selenium yeast (200 μg/day) and coenzyme Q10 (200 mg/ day) (n = 118 of which 20 had diabetes at inclusion), or placebo (n = 101 of which 18 had diabetes at inclusion). Pre-intervention, the serum selenium levels were 67 μg/L (active treatment group: 66.6 μg/L; placebo group: 67.4 μg/L), corresponding to an estimated intake of 35 μg/day. Changes in concentrations of fructosamine following intervention were assessed by the use of T-tests, repeated measures of variance, and ANCOVA analyses.ResultsPost-intervention selenium concentrations were 210 μg/L in the active group and 72 μg/L in the placebo group. A lower concentration of fructosamine could be seen as a result of the intervention in the total population (P = 0.001) in both the males (P = 0.04) and in the females (P = 0.01) in the non-diabetic population (P = 0.002), and in both the younger (<76 years) (P = 0.01) and the older (≥76 years) participants (P = 0.03). No difference could be demonstrated in fructosamine concentration in the diabetic patients, but the total sample was small (n = 38). In subjects with a low pre-intervention level of serum selenium the intervention gave a more pronounced decrease in fructosamine compared with those with a higher baseline selenium level.ConclusionA significantly lower concentration of fructosamine was observed in the elderly community-living participants supplemented with selenium and coenzyme Q10 for 42 months compared to those on the placebo. As oxidative mechanisms are involved in the glycation of proteins, less glycoxidation could be a result of the supplementation of selenium and coenzyme Q10, which could have contributed to lower cardiac mortality and less inflammation, as has earlier been reported.This study was registered at Clinicaltrials.gov, and has the identifier NCT01443780.     

The Importance of Body Weight for the Dose Response Relationship of Oral Vitamin D Supplementation and Serum 25-Hydroxyvitamin D in Healthy Volunteers

Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body''s vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OH)D from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OH)D and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OH)D followed an exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OH)D. Relative to normal weight subjects, obese and overweight participants had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (P<0.001). We did not observe any increase in the risk for hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OH)D targets.     

Effects of Combined Calcium and Vitamin D Supplementation on Insulin Secretion,Insulin Sensitivity and β-Cell Function in Multi-Ethnic Vitamin D-Deficient Adults at Risk for Type 2 Diabetes: A Pilot Randomized,Placebo-Controlled Trial

Objectives

To examine whether combined vitamin D and calcium supplementation improves insulin sensitivity, insulin secretion, β-cell function, inflammation and metabolic markers.

Design

6-month randomized, placebo-controlled trial.

Participants

Ninety-five adults with serum 25-hydroxyvitamin D [25(OH)D] ≤55 nmol/L at risk of type 2 diabetes (with prediabetes or an AUSDRISK score ≥15) were randomized. Analyses included participants who completed the baseline and final visits (treatment n = 35; placebo n = 45).

Intervention

Daily calcium carbonate (1,200 mg) and cholecalciferol [2,000–6,000 IU to target 25(OH)D >75 nmol/L] or matching placebos for 6 months.

Measurements

Insulin sensitivity (HOMA2%S, Matsuda index), insulin secretion (insulinogenic index, area under the curve (AUC) for C-peptide) and β-cell function (Matsuda index x AUC for C-peptide) derived from a 75 g 2-h OGTT; anthropometry; blood pressure; lipid profile; hs-CRP; TNF-α; IL-6; adiponectin; total and undercarboxylated osteocalcin.

Results

Participants were middle-aged adults (mean age 54 years; 69% Europid) at risk of type 2 diabetes (48% with prediabetes). Compliance was >80% for calcium and vitamin D. Mean serum 25(OH)D concentration increased from 48 to 95 nmol/L in the treatment group (91% achieved >75 nmol/L), but remained unchanged in controls. There were no significant changes in insulin sensitivity, insulin secretion and β-cell function, or in inflammatory and metabolic markers between or within the groups, before or after adjustment for potential confounders including waist circumference and season of recruitment. In a post hoc analysis restricted to participants with prediabetes, a significant beneficial effect of vitamin D and calcium supplementation on insulin sensitivity (HOMA%S and Matsuda) was observed.

Conclusions

Daily vitamin D and calcium supplementation for 6 months may not change OGTT-derived measures of insulin sensitivity, insulin secretion and β-cell function in multi-ethnic adults with low vitamin D status at risk of type 2 diabetes. However, in participants with prediabetes, supplementation with vitamin D and calcium may improve insulin sensitivity.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12609000043235     

The influence of chromium chloride consumption on lipid peroxidation and activity of the antioxidant defense in rat tissues

The effect of food supplementation with chromium (CrCl₃ · 6H₂O) on intensity of peroxide processes and activity of antioxidant enzymes has been investigated in some rat tissues. Food supplementation with 200 μg/kg CrCl₃ · 6H₂O for 30 days resulted in the increase of tissue chromium. The tissue chromium content of chromium-treated rats decreased in the following order: spleen, heart, kidney, lung, brain, liver, skeletal muscles. All organs and tissues (except skeletal muscles) of chromium-treated rats were characterized by decreased content of lipid peroxidation (LPO) products: hydroperoxides and thiobarbituric acid reactive substances (TBARS). The maximal reduction in LPO products was observed in spleen, kidney, liver, and lung. Treatment with chromium also caused an increase in the activity of glutathione peroxidase, glutathione reductase, and calatase in all tissues and organs studied. In the brain and kidney an increase in the content of reduced glutathione was observed. Superoxide dismutase activity was higher in myocardium and skeletal muscles, basically equal in lung and liver, while in other organs (brain, kidney, spleen) of experimental animals it was lower than in control animals. Results of this study suggest that chromium exhibits tissue/organ-specific regulatory effects on enzymes of the antioxidant defense