Effect Of Dietary Chromium Supplementation Research Articles

The Effects of Dietary Chromium Supplementation along with Discontinuing a High-Fat Diet on the Microbial Enzymatic Activity and the Production of SCFAs in the Faeces of Rats.

The present study assessed the changes in faecal microbial activity in obese Wistar rats fed high-fat or low-fat diets supplemented with various forms of chromium (picolinate or nanoparticles). The 18-week study was divided into two phases: an introductory period (9 weeks; obesity status induction via a high-fat diet) and an experimental period (9 weeks; maintained on a high-fat diet or switched to a low-fat diet and Cr supplementation). During the experimental period (10-18 weeks of feeding), samples of fresh faeces were collected on chosen days. The bacterial enzymatic activity and short-chain fatty acids (SCFAs) concentration were assessed to characterise the dynamism of the changes in faecal microbial metabolic activity under the applied dietary treatments. The results indicated that faecal microbial metabolic activity displayed several adaptation mechanisms in response to modifications in dietary conditions, and a beneficial outcome resulted from a pro-healthy dietary habit change, that is, switching from a high-fat to a low-fat diet. Dietary supplementation with chromium nanoparticles further modulated the aforementioned microbial activity, i.e., diminished the extracellular and total enzymatic activities, while the effect of chromium picolinate addition was negligible. Both the high-fat diet and the addition of chromium nanoparticles reduced SCFA concentrations and increased the faecal pH values.

Apparent nutrient digestibility of carbohydrate (corn) in Cirrhinus mrigala under the influence of chromium chloride hexahydrate.

A feeding trial was carried out to assess the effect of dietary chromium supplementation on apparent nutrient digestibility coefficient (%) of gelatinized and non-gelatinized corn in Cirrhinus mrigala fingerlings for 90 days. Using various levels of chromium chloride hexahydrate six test diets designated as T1 (G/0.0 Cr2Cl3.6H2O mg Kg-1), T2 (NG/0.0 Cr2Cl3.6H2O mg Kg-1), T3 (G/0.2 Cr2Cl3.6H2O mg Kg-1), T4 (NG/0.2 Cr2Cl3.6H2O mg Kg-1), T5 (G/0.4 Cr2Cl3.6H2O mg Kg-1) and T6 (NG/0.4 Cr2Cl3.6H2O mg Kg-1) were prepared. Results showed highest apparent digestibility coefficient (ADC) of nutrients dry matter, crude lipid and gross energy in test diet T5 that was gelatinized and supplemented with chromium 0.4 mg/Kg while, for crude protein higher value of nutrient digestibility was recorded in T3 test diet (G/0.2 Cr2Cl3.6H2O mg/Kg). It was concluded that chromium supplementation with gelatinized corn in fish (Cirrhinus mrigala) diet can improve the nutrients digestibility more efficiently.

Chromium supplementation modulates glucose metabolism in heat-stressed Girolando dairy cows

The objective of this study was to evaluate the effects of dietary chromium supplementation on hepatic gene expression of lactating Girolando (Holstein x Gyr) cows under heat stress conditions in climatic chamber. Thirty-six ¾ Holstein x Gyr lactating cows were used, based on a 2x3 factorial scheme, to evaluate the effects of two diets (0 vs 0.50 mg of organic chromium kg-1 dry matter) and three environmental conditions (ECs): heat stress conditions in climatic chamber with ad libitum feeding (HS), a thermoneutral environment with ad libitum feeding (TN), and a pair-fed group in a thermoneutral environment (PF). Under HS group, the expression levels of glucose transporter 2 (GLUT2), glucose-6-phosphatase (G6Pase), and growth hormone receptor (rGH) were downregulated (P < 0.05) in chromium-supplemented cows compared to those in cows fed the control diet. GLUT2 expression was upregulated (P = 0.02) in the HS group and insulin-like growth factor 1 (IGF1) was downregulated (P < 0.01) in the PF group in cows fed the control diet compared to the expression in the TN group. No differences were observed between the ECs in terms of relative abundances of GLUT2, phosphoenolpyruvate carboxykinase (PEPCK), G6Pase, rGH, and IGF1 transcripts among the chromium-supplemented cows (P > 0.05). Heat stress caused changes in the expression of genes related to glucose metabolism, and organic chromium could modulate glucose metabolism in animals under heat stress conditions to some extent.

Effects of dietary chromium supplementation on calf performance, metabolic hormones, oxidative status, and susceptibility to diarrhea and pneumonia

The objective of this study was to determine the effect of chromium (Cr) supplementation on the health status, blood attributes, and insulin sensitivity in dairy calves reared under hot summer conditions. Twenty-four newborn Holstein calves were assigned randomly to a control group (Cr-) and a group (Cr+) receiving 0.05 mg Cr-methionine per kg BW0.75. The starter feed contained 0.95 mg Cr/kg dry matter. Dietary level of Cr was within the ranges (0.08 to 1 mg Cr/kg body mass daily or more) reported to affect metabolism). Supplemental Cr was included in colostrum and milk before weaning (d 1 to 63), and in the starter feed from d 64 to 91. Dry matter intake and average daily gain increased but respiration rate was lower in Cr + calves. Cr supplementation decreased the number of days with pneumonia and medication days during the post-weaning period; however, Cr did not affect diarrhea frequency or the number of days with diarrhea. Supplementing Cr increased blood serum concentration of total proteins. Furthermore, blood serum concentration of globulins tended to increase in Cr + calves during the pre-weaning and overall periods. Cr supplementation increased catalase activity during the post-weaning period. Glucose disappearance rate tended to increase in Cr + calves. Overall, supplementary feeding of Cr may benefit growth performance and health status without a major effect on blood metabolites, antioxidant status, and insulin sensitivity in dairy calves under high ambient temperature summer conditions.

Effect of dietary chromium supplementation on meat nutritional quality and antioxidant status from broilers fed with Camelina-meal-supplemented diets

Poultry meat is a valuable source of nutrients and the enrichment with health-promoting substances such as polyunsaturated fatty acids (n-3 PUFA) is an important factor for consumers’ choice. Camelina meal (Camelina sativa) is an animal feedstuff used to achieve this goal, but the administration of n-3 PUFA-enriched diets in broiler nutrition can accelerate the oxidative processes in meat leading to a decreased quality of final product. The aim of this study was to investigate the effect of the organic Cr as chromium picolinate (CrPic) on meat quality, fatty acid profile of fat and oxidative stability of meat from broilers fed supplemented dietary Camelina meal. An experiment was conducted on 240 Ross 308 broiler chicken aged 14 days which were assigned to 6 dietary treatments in a randomized complete block design with a 2 × 3 factorial arrangement. Within the treatment arrangement two concentrations of Camelina meal (0% and 3%) and three concentrations of Cr3+ (0, 200 and 400 μg/kg) were used. Dietary treatments were: (1) Control diet (C) containing a corn–soybean diet with no added Camelina meal or Cr3+; (2) a C diet containing an additional 200 μg/kg of Cr3+ as CrPic; (3) a C diet containing an additional 400 μg/kg of Cr3+ as CrPic; (4) a C diet containing an additional 3% Camelina meal; (5) diet 2 containing an additional 3% Camelina meal; (6) diet 3 containing an additional 3% Camelina meal. Chromium supplementation significantly (P<0.05) increased the CP concentrations and significantly (P<0.05) decreased the crude fat concentrations in breast samples. The Camelina meal groups presented higher values of unsaturated fatty acids, particularly n-3 fatty acids (P<0.05). In CrPic groups, increased retention of Zn and Fe (P < 0.05) was observed in breast samples, compared to control group, and thiobarbituric acid reactive substances values were significantly (P<0.05) smaller. Myoglobin fraction (metmyoglobin and oximyoglobin) concentrations differ significantly (P<0.05) from the control group, under the influence of Cr3+ supplements. This study found that broilers fed with CrPic supplements showed improved mineral composition and oxidative stability of breast meat, proving an effective protection of lipid molecules from oxidation in PUFA-enriched meat.

Effects of dietary chromium supplementation on muscle and bone mineral interaction in broiler chicken

The study was conducted to ascertain the effects of dietary chromium chloride (CrCl3·6H2O) supplementation on mineral interaction in blood serum, leg muscles and bones of broilers at 35th day of age. For this purpose, ninety male broiler chicks were divided into three groups. One served as control (group I) while, the other two groups were supplemented with CrCl3 (group II-12.5mg/Kg feed; group III–25mg/Kg feed) from 12 to 28days of age. In serum, Cr concentration remained non-significant however, Zn, and K concentrations decreased (P<0.05) with both levels of Cr-supplementation. Furthermore, in muscles Cr, Cu, Ca and Na levels remained non-significant but concentrations of Zn and K decreased (P<0.05) with feed Cr enrichment. Chromium had a substantial effect on femur and fibula Zn retention with 25mg/Kg feed supplementation while, Cr deposition decreased (P<0.05) in fibula. Femur Ca (P<0.002), Na (P<0.001) and K (P<0.05) retention was inversely proportional to both Cr concentrations in feed. In tibia, Cu and Na concentration decreased (P<0.002) with high dietary Cr supplementation. Fibular Ca and Na concentrations remained significantly (P<0.001) lower in Cr supplemented groups. Bone robusticity index was non-significant but ash to weight ratio of femur, tibia and fibula decreased (P<0.05) in group III. Chromium supplementation has a major effect on serum or muscle Zn and K deposition while bone mineral interaction shows a major thrust on Zn, Ca and Na levels.

The Effect of Dietary Chromium Supplementation on Blood Biochemical Parameters of Broiler Chicks

This study investigated the effect of dietary supplementation of chromium from chromium picolinate source on the blood biochemical parameters of broilers. A three hundred sixty- one day old commercial male broiler were randomly allocated to one of 24 floor pens in a completely randomized design with six treatments and four replicate groups and fifteen chicks per each pen. Dietary treatments consisted of zero (control), 400, 800, 1200, 1600 and 2000 µg kg -1 Cr of basal diets. At 42 days of age, two birds from each pen were selected and blood samples were collected from wing vein. Concentrations of high density lipoprotein (HDL), low density lipoprotein (LDL), glucose, cholesterol, triglyceride, total protein and insulin were measured. There were not significant effects of supplementary Cr on HDL and glucose concentrations. But favourably cholesterol (P = 0.0002), triglyceride (P = 0.0004), total protein (P = 0.0003), insulin (P = 0.0004) and LDL (P = 0.058) significantly affected by Cr supplementation. Birds receiving Cr supplementation had lower LDL, cholesterol, triglyceride and higher total protein and insulin concentrations. It can be concluded that under conditions of this experiment Cr addition to broiler diets have an effect on lipid metabolism in broilers.

Assessment of Chromium Content of Feedstuffs, Their Estimated Requirement, and Effects of Dietary Chromium Supplementation on Nutrient Utilization, Growth Performance, and Mineral Balance in Summer-Exposed Buffalo Calves (Bubalus bubalis)

This study was conducted to determine the chromium content of different feedstuffs, their estimated requirement, and effect of dietary Cr supplementation on nutrient intake, nutrient utilization, growth performance, and mineral balance in buffalo calves during summer season. Levels of Cr was higher in cultivated fodder, moderate in cakes and cereal grains, while straw, grasses, and non-conventional feeds were poor in Cr content. To test the effect of Cr supplementation in buffalo calves, 0, 0.5, 1.0, and 1.5 ppm of inorganic Cr were fed to 24 buffalo calves. Buffalo calves were randomly assigned to four treatments (n = 6) and raised for 120 days. A metabolic trial for a period of 7 days was conducted after 3 months of dietary treatments. Blood samples were collected at fortnight interval for plasma mineral estimation. The results suggested that dietary Cr supplementation in summer did not have any affects (P > 0.05) on feed consumption, growth performance, nitrogen balance, and physiological variables. However, dietary Cr supplementation had significant effect (P < 0.05) on balance and plasma Cr (ppb) levels without affecting (P > 0.05) balance and plasma levels of other trace minerals. The estimated Cr requirement of buffalo calves during summer season was calculated to be 0.044 mg/kg body mass and 10.37 ppm per day. In conclusion, dietary Cr supplementation has regardless effect on feed consumption, mass gain, and nutrient utilization in buffalo calves reared under heat stress conditions. However, supplementation of Cr had positive effect on its balance and plasma concentration without interacting with other trace minerals.

Lack of Effect of Dietary Chromium Supplementation on Growth Performance and Serum Insulin, Glucose, and Lipoprotein Levels in Broilers Reared Under Heat Stress Condition

This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcass traits, and some serum parameters of broilers under a heat stress (23.9 to 37°C cycling) condition. A total of 150 1-day-old broiler chicks (Cobb 500) according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Treatments were supplemented with 0 (control), 600, and 1,200μgkg(-1) Cr in the form of Cr chloride (CrCl3) and Cr L-methionine from 1 to 49days of age. Blood samples were collected from two birds in each replicate to determine serum parameters at 35 and 49days of age. The body mass, feed intake, and conversion ratio were not influenced by dietary Cr (P > 0.05). Dietary supplementation of Cr from either CrCl3 or Cr L-methionine caused increased serum concentrations of Cr (P < 0.05), but had no effect on serum insulin and glucose concentrations at both sampling times (P > 0.05). Serum triglycerides, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were also not significantly affected (P > 0.05) by dietary treatments, whereas total cholesterol concentration decreased in chicks fed Cr L-methionine compared to the control (P < 0.05).

Effect of Dietary Chromium Supplementation on Growth Performance, Rumen Fermentation Characteristics and Some Blood Serum Units of Fattening Dairy Calves under Heat Stress

Effect of Dietary Chromium Supplementation on Growth Performance, Rumen Fermentation Characteristics and Some Blood Serum Units of Fattening Dairy Calves under Heat Stress

Effect of Dietary Chromium Supplementation on Performance and Carcass Traits of Broiler Chicks

This study investigated the effect of dietary supplementation of chromium from chromium picolinate source on the performance, carcass traits of broilers. Three hundred sixty one day old commercial male broilers (Ross 308) were randomly allocated to one of 24 floor pens in a completely randomized design with six treatment and four replicate groups and fifteen chicks per each pen. Dietary treatments consisted of 0 (control), 400, 800, 1200, 1600 and 2000 μg Cr per kg of basal diet. Feed intake, body weight gain and feed conversion ratio were measured during 1 to 21, 21 to 42 and 1 to 42 days of age. At 42 days of age two birds from each pen were selected and after weighing slaughtered and dissected manually. Carcass yield, liver, abdominal fat, pancreas, thighs and breast weight declared as percentage of live body weight. The results showed that performance of broilers was not affected by dietary supplemental chromium. Also supplementation of broiler diet didn't influence carcass traits. Nevertheless there is a non significant increase in liver and pancreas weight while increasing the Cr content of the diet. It can be concluded that chromium content of the basal starter and finisher diet and drinking water is adequate to normal requirement of broilers under such experimental conditions and supplementing of Cr may not be essential.

Effects of dietary chromium supplementation on performance, carcass characteristics, and meat quality of growing-finishing swine: A meta-analysis1

Dietary Cr supplementation has potential to decrease fat and increase lean in carcasses of growing-finishing swine. However, effects of Cr supplementation on performance and economically important carcass and meat quality characteristics varied considerably among studies. Therefore, a meta-analysis was designed to quantitatively describe effects obtained in several independent studies. To accommodate differences in methodology among studies, standardized effect sizes (Hedges's g) were calculated for results from 31 studies, in which Cr was supplemented as complexes of Cr Met chelate, Cr nanocomposite, Cr nicotinate, Cr propionate, Cr tripicolinate, or Cr yeast in diets for growing-finishing swine. Summary statistics were calculated by frequentist fixed and random effects, and hierarchical Bayesian models. With characteristics related to carcass quality, observed heterogeneity (P < 0.10) could not adequately be explained in a meta-regression by differences in initial BW and amount of Cr supplemented. Random effects and Bayesian models to summarize effect sizes for these characteristics showed similar results. According to random effects models, dietary Cr supplementation decreased (P < 0.05) 10th-rib fat thickness (mean effect size = -0.479; 95% confidence intervals = -0.680 to -0.279; 24 studies; 59 comparisons), whereas percentage carcass lean (mean effect size = 0.614; 95% confidence intervals = 0.366 to 0.863; 22 studies; 52 comparisons) and LM area (mean effect size = 0.571; 95% confidence intervals = 0.364 to 0.778; 29 studies; 72 comparisons) increased. Average daily gain and G:F, which did not present heterogeneity, were improved by Cr supplementation, whereas no effects were detected in characteristics (CIE color, drip loss, cook loss, shear force) related to meat quality. Some publication, or other small-study bias, was evident in results on growth and feed efficiency. However, directions of mean effect sizes were not changed by application of the trim-and-fill method to correct for bias.

Effect of dietary chromium supplementation on productive and reproductive performance of early lactating dairy cows under heat stress

One hundred and twenty early lactating Holstein dairy cows were assigned to investigate the effect of dietary chromium (Cr) supplementation (0 or 6 mg Cr/head/day from organic preparation) on the productive and reproductive performance as well as on some blood serum parameters under heat stress (35-40 degrees C). Cows received treatment from 3 weeks pre-partum through 12 weeks post-partum. Chromium supplemented diet had lower body weight loss and improved dry matter intake with consequent reduction in the energy balance deficits during the first period after calving when compared with the control group. Chromium supplementation increased (p < 0.05) milk yield by 6.7%, 12.3% and 16.5% at 4, 8 and 12 weeks post-partum, respectively, whereas milk composition and milk to feed ratio were unaffected (p > 0.05) when compared with the control. Moreover, dietary Cr supplementation had no effect (p > 0.05) on blood serum glucose, calcium and phosphorus concentrations. A reduction (p < 0.05) of non-esterified fatty acids at 1 week pre-partum, 2 and 4 weeks post-partum was also observed. Serum insulin concentration increased whereas cortisol concentration decreased, when compared with the control group, throughout the whole experimental period. Also Cr supplementation showed a trend towards improving reproductive performance as indicated by increased percentage of pregnant cows in the first 28 days of breeding. It could be concluded that dietary Cr supplementation at level of 6 mg/head/day may offer a potential protective management practice to lessen the effect of heat stress in dairy cattle.

Effects of dietary chromium supplementation on glucose tolerance and primary antibody response against peste des petits ruminants in dwarf Bengal goats (Capra hircus)

An experiment was conducted to exploit the immune-modulation effect of trivalent chromium (Cr) for augmenting immunity against peste des petits ruminants (PPR) in dwarf black Bengal goats (Capra hircus). The goats (n = 6 per treatment group) either received a basal diet devoid of supplemental Cr (control) or were supplemented with 0.5 mg Cr as chromic chloride (+Cr) for 60 days. Live weight gain and feed conversion efficiency improved (P < 0.05) in the +Cr dietary group. Supplemental Cr did not affect the total number of monocytes, eosinophils and basophils (P > 0.1) although total leukocytes increased (P < 0.05) and the ratio of neutrophils to lymphocytes narrowed down (P < 0.05) in the +Cr dietary group. The effect of Cr supplementation on variables of the intravenous glucose tolerance test (IVGTT) was inconclusive. Compared to the control group, the basal concentration of glucose (P < 0.05) and insulin (P < 0.001) was higher, clearance rate was slower (P < 0.05) and serum half-life was greater (P < 0.05) in the +Cr dietary group during the IVGTT. Over the duration of the experiment, serum concentration of insulin increased (P < 0.001) and that of cortisol decreased (P < 0.01) in the +Cr group, which also showed a relatively higher primary antibody (Ab) response against PPR on days 10 (P < 0.01) and 20 (P < 0.05) post-vaccination. In conclusion, the experiment indicated that supplementation of Cr as CrCl3, in the diet of non-stressed goats, may improve primary Ab response against PPR and help confer an augmented immunity to the disease besides promoting growth and feed conversion.

Effects of Dietary Chromium Supplementation on the Performance and Some Serum Parameters in Bovans-type Chicks

Effects of Dietary Chromium Supplementation on the Performance and Some Serum Parameters in Bovans-type Chicks

Effects of Dietary Chromium Supplementation on Performance, Carcass Traits, Serum Metabolites, and Tissue Chromium Levels of Japanese Quails

This study was conducted to investigate the effects of various levels of dietary chromium supplementation on performance, carcass traits, blood chemistry, and tissue distribution of chromium (Cr3+) in quails. Two hundred forty 1-d-old Japanese quails were divided into five groups with four replicates and were fed a basal diet or the basal diet supplemented with 20, 40, 80, or 100 mg/kg Cr (CrCl3.6H2O) until 38 d of age. Chromium supplementation decreased carcass fat percentage, serum low-density lipoprotein (LDL), and glucose and increased serum magnesium (Mg) and Cr content of kidney, liver, and muscle. In conclusion, 20, 40, 80, or 100 mg/kg Cr supplementation to quail diet had no effect on performance, chemical composition of carcass except fat percentage, serum protein, calcium (Ca), and inorganic phosphorus (Pi) levels, but reduced serum glucose, LDL and fat percentage of carcass. Chromium is accumulated mainly in the kidneys and liver.

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 0ppb (control), 150ppb, 300ppb, or 600ppb 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 (300ppb only), were significantly lower after the trial in cats supplemented with 300ppb and 600ppb 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 600ppb 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.

The effects of dietary chromium supplementation on some blood parameters in sheep.

The effects of dietary inorganic chromium on some biochemical parameters were determined in lambs fed either a control diet or a 200-ppb or 400-ppb chromium-supplemented diet. The live weight of the animals were measured and jugular blood samples were collected prior to supplementation (d 0) and on d 20, 40, and 55. On d 55, three animals from each group were slaughtered to measure subcutaneous fat. Sera were analyzed for glucose, triglyceride, total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, total protein, albumin, ALT, AST, and GGT levels. Chromium supplementation had no significant effect on live weight, but subcutaneous fat was reduced significantly in both chromium groups. There was a slight decrease in glucose concentrations in the 200-ppb chromium group, although only the differences on d 55 were significant. Triglyceride levels in both chromium groups were lower than the control group with marked differences in the 400-ppb chromium group. HDL cholesterol levels increased in both treatment groups compare to control, although the differences in the 400-ppb chromium group on d 40 were significant. Serum Cr concentrations slightly but not significantly increased in both chromium groups. No significant differences were found in total and LDL cholesterol, total protein, albumin, ALT, AST, and GGT levels. In conclusion, chromium supplementation may affect carbohydrate and lipid metabolisms and lipid deposition in lambs.

Lack of effect of dietary chromium supplementation on glucose tolerance, plasma insulin and lipoprotein levels in patients with type 2 diabetes.

Chromium is essential for the regulation of insulin action, thereby influencing carbohydrate and lipid metabolism. An uncontrolled pilot study was designed to measure the habitual daily intake of chromium in a group of healthy individuals with type 2 diabetes and to monitor the effect of daily supplementation with high chromium yeast on glucose tolerance, plasma insulin and lipoproteins. Twelve free-living adults with type 2 diabetes underwent a glucose tolerance test (GTT) on recruitment, at 4 weeks (after a 7-d duplicate diet collection) and at 12 weeks (following 8 weeks daily supplementation with 100 micrograms of chromium). Urine samples were collected on the day before and the day of each GTT. Blood samples were taken at half hourly intervals for 3 hours during the GTT and the plasma glucose, cholesterol, triglyceride, HDL, LDL and insulin concentration measured. The chromium content of diets and urine samples was determined. Fasting glucose concentrations and glucose area under the curve profiles did not alter significantly post supplementation with the chromium rich yeast. No significant changes in insulin and lipoprotein concentrations were observed. The results of this study do not support the hypothesis that individuals with type 2 diabetes benefit from yeast-based chromium supplements (100 micrograms/day).

Effects of dietary chromium supplementation on cardiac mass, metabolic enzymes, and contractile proteins

Chromium, a popular but controversial micronutrient, can increase skeletal muscle growth when provided in supplemented quantities, presumably because of its suspected insulin like action. Whether chromium similarly affects cardiac muscle is an important issue because inappropriate cardiac growth can suggest decrements in cardiac performance. Therefore, the purpose of this study was to determine if chromium supplementation impacted contractile and metabolic properties of the heart. Male Sprague-Dawley rats received a semi-purified basal diet supplemented with 300 PPB chromium picolinate (CONTR), or supplemented with 1500 PPB chromium picolinate (SUPPLEM). After 12 weeks on the respective diets, animals were killed, and the left ventricles removed and analyzed for differences in cardiac metabolic and contractile proteins. Chromium supplementation failed to alter body weights, left ventricular mass, total protein content, and myofibrillar protein content, citrate synthase, or hexokinase activity. The amount of the high ATPase myosin isoform, V1 was diminished by 11% in the SUPPLEM group (p ≤ 0.05). These findings demonstrate that the adaptive response of the heart to dietary chromium supplementation is limited to changes in the myosin isoform. These changes may provide the heart with a more economical contractile apparatus without compromising cardiac performance.