The effects of tricentric chromium(III) propionate complex supplementation on pregnancy outcome and maternal and foetal mineral status in rat

Steviol Glycoside, L-Arginine, and Chromium(III) Supplementation Attenuates Abnormalities in Glucose Metabolism in Streptozotocin-Induced Mildly Diabetic Rats Fed a High-Fat Diet

Stevia rebaudiana Bertoni and its glycosides are believed to exhibit several health-promoting properties. Recently, the mechanisms of the anti-diabetic effects of steviol glycosides (SG) have been the subject of intense research. The following study aims to evaluate the results of SG (stevioside (ST) and rebaudioside A (RA)) combined with L-arginine (L-Arg) and chromium(III) (CrIII) supplementation in streptozotocin- (STZ) induced mild type 2 diabetic rats fed a high-fat diet (HFD), with particular emphasis on carbohydrate and lipid metabolisms. The experiment was carried out on 110 male Wistar rats, 100 of which were fed an HFD to induce insulin resistance, followed by an intraperitoneal injection of streptozotocin to induce mild type 2 diabetes. After confirmation of hyperglycemia, the rats were divided into groups. Three groups served as controls: diabetic untreated, diabetic treated with metformin (300 mg/kg BW), and healthy group. Eight groups were fed an HFD enriched with stevioside or rebaudioside A (2500 mg/kg BW) combined with L-arginine (2000 or 4000 mg/kg BW) and Cr(III) (1 or 5 mg/kg BW) for six weeks. The results showed that supplementation with SG (ST and RA) combined with L-arg and Cr(III) could improve blood glucose levels in rats with mild type 2 diabetes. Furthermore, ST was more effective in improving blood glucose levels, insulin resistance indices, and very low-density lipoprotein cholesterol (VLDL-C) concentrations than RA. Although L-arg and Cr(III) supplementation did not independently affect most blood carbohydrate and lipid indices, it further improved some biomarkers when combined, particularly with ST. Notably, the beneficial impact of ST on the homeostatic model assessment–insulin resistance (HOMA-IR) and on the quantitative insulin-sensitivity check index (QUICKI) was strengthened when mixed with a high dose of L-arg, while its impact on antioxidant status was improved when combined with a high dose of Cr(III) in rats with mild type 2 diabetes. In conclusion, these results suggest that supplementary stevioside combined with L-arginine and Cr(III) has therapeutic potential for mild type 2 diabetes. However, further studies are warranted to confirm these effects in other experimental models and humans.

Safety and efficacy of Availa®Cr (chromium chelate of DL-methionine) as a feed additive for dairy cows

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of Availa®Cr (active compound: chromium chelate of DL-methionine) as a feed additive for dairy cows. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) Panel was assigned to this mandate. The tolerance study did not show adverse effects with respect to body weight, milk yield, haematology and blood biochemistry up to the 10-fold overdose of chromium from Availa®Cr; however, owing to deficiencies in design and reporting of the study, it provided only supportive evidence on the safety of the additive. A safe level for dairy cows could be derived from a toxicological study with laboratory rodents. Taking all together, the FEEDAP Panel considers the maximum recommended use level (8 mg Cr from Availa®Cr/cow per day; about 0.4 mg Cr/kg complete feed) as safe. Chromium DL-Met shows a genotoxic activity in vitro that is not expressed in vivo after systemic exposure; although no data on genotoxicity at the site of contact are available, the Panel notes that chromium(III) is not carcinogenic and concludes that chromium DL-Met is unlikely to pose a carcinogenic risk at levels occurring in the diet. The use of Availa®Cr in feed of dairy cows up to the recommended supplementation level would not measurably increase consumer exposure to chromium(III), and therefore is safe for consumers. The additive poses a risk to users by inhalation, it is not an irritant to skin and eyes and should be considered a sensitiser. The use of the additive is not expected to pose a risk to the environment. Since only one study could be considered for the efficacy assessment, and three studies are required, the FEEDAP Panel cannot conclude on the efficacy of Availa®Cr for dairy cows.

The Combined Effects of Cr(III) Supplementation and Iron Deficiency on the Copper and Zinc Status in Wistar Rats

The aim of the study was to assess the combined effects of chromium(III) supplementation and iron deficiency on the copper (Cu) and zinc (Zn) status in female rats. The Cr, Fe, Cu and Zn dietary and tissular levels were measured by Atomic Absorption Spectrometry (AAS) method. The data show that chromium(III) supplementation compensated for the negative effects of Fe deficiency on the Cu content but it deepened the effect on Zn levels in the female rats. Detailed data on the status of trace elements and their interactions in healthy subjects and patients with metabolic disorders (e.g. anaemia, diabetes mellitus) are strongly required for effective nutritional and therapeutic strategies.

The combined effects of Cr(III) propionate complex supplementation and iron excess on copper and zinc status in rats

It is suggested that both iron overload and chromium(III) deficiency may be risk factors of diabetes. It seems that both Fe and Cr(III) metabolism as well as copper and zinc metabolism are interrelated. However, the direction of these changes may depend on mutual proportions of these elements in the diet and organism. The aim of the study was to evaluate the combined effects of Cr(III) supplementation with Fe excess on the Cu and Zn status in female rats. Thirty-six healthy rats were divided into 6 experimental groups with different Fe levels in the diet. Groups marked with C (control) contained Fe at the recommended level (45 mg kg^-1). The excess groups (E) contained Fe at 180 mg kg^-1. At the same time the animals were supplemented with Cr(III) of doses 1, 50 and 500 mg kg^-1 of diet. The Cr, Fe, Cu and Zn dietary and tissular contents were measured with the AAS method.The excess Fe in the diet significantly decreased the Cu content in the liver and kidneys, but it increased the spleen Cu level. The Cr(III) supplementary did not affect the tissular Cu levels, regardless of Fe supply with diet. The experimental factors did not have significant interactional effect on the Cu status parameters under study.The Fe excess in the diet reduced the renal and splenic Zn content, but increased the heart Zn content. The Cr(III) supplementation decreased the Zn content in the kidneys. The Zn content in the liver and spleen tended to decrease as the Cr(III) supply in the diet increased. There was no significant interactional effect of Cr(III) supplementation and the Fe excessive supply in diet on the parameters of Zn metabolism in Wistar rats. Iron oversupply disturbed the rat's Cu and Zn status. However, Cr(III) supplementation did not affect the tissular levels of these elements, except the kidney Zn content. Simultaneous supplementation with the Cr(III) propionate complex did not deepen changes in tissular Cu and Zn levels caused by the Fe excess in the diet.

The Combined Effects of Iron Excess in the Diet and Chromium(III) Supplementation on the Iron and Chromium Status in Female Rats

Inadequate iron supply has significant consequences to health. There are some relations between the metabolism of different trace elements, such as iron, zinc, copper and chromium. However, the direction of these interactions can be antagonistic or synergistic, and it depends on many factors. The aim of the study was to evaluate the combined effects of supplementary of chromium(III) propionate complex (Cr3) with iron excess on the Cr and Fe status in healthy female rats. The 36 healthy female Wistar rats were divided into six experimental groups (six animals in each) with different Fe levels-adequate (45 mg kg^-1-100% RDA) and high (excessive-180 mg kg^-1-400% RDA). At the same time, they were supplemented with Cr(III) at doses of 1, 50 and 500 mg kg^-1 of diet: C1-control (Fe 45 mg kg^-1, Cr 1 mg kg^-1); C50 (Fe 45 mg kg^-1, Cr 50 mg kg^-1); C500 (Fe 45 mg kg^-1, Cr 500 mg kg^-1); H1 (Fe 180 mg kg^-1, Cr 1 mg kg^-1); H50 (Fe 180 mg kg^-1, Cr 50 mg kg^-1); H500 (Fe 180 mg kg^-1, Cr 500 mg kg^-1). The serum iron level and total iron binding capacity (TIBC) were measured with colorimetric methods. The serum ferritin level was measured by means of electrochemiluminescence immunoassay. The serum transferrin level was measured with the ELISA method. Haematological measurements were made with an automated blood analyser. The Cr and Fe tissular levels were measured with the AAS method. The exposure to a high level of Fe(III) alone or in combination with Cr caused Fe accumulation in tissues, especially in the liver and kidneys, but there were no significant changes in the TIBC, transferrin, ferritin concentration in the serum and most haematological parameters. Moreover, the serum, hepatic and renal Cr concentrations decreased. The doses of supplementary Cr(III) given separately or in combination with high level of Fe(III) disturbed the Cr content in the liver and kidneys of healthy female rats. However, they did not change most of the parameters of Fe metabolism, except the Fe kidney concentration. Supplementary Cr3 decreased the renal Fe level in groups with adequate Fe content in the diet. However, the renal Fe levels increased along with a higher Cr level in the diet in groups with high Fe content. The findings proved a relationship between Fe(III) and Cr(III) metabolism in healthy female rats. However, the direction of change varied and depended on relative amounts of these elements in the diet.

The combined effect of supplementary Cr(III) propionate complex and iron deficiency on the chromium and iron status in female rats

The aim of the study was to evaluate the combined effect of supplementary chromium(III) and iron deficiency on the chromium and iron status in female rats. The study was carried out on female Wistar rats, which were divided into 6 experimental groups with different Fe levels (deficient 10% RDA and recommended (adequate) 100% RDA). Simultaneously, for six weeks their diets were supplemented with Cr(III) at doses of 1, 50 and 500mgkg^-1. The tissular chromium and iron levels were measured with the AAS method. The serum iron and TIBC were measured with colorimetric methods The serum ferritin level was measured by means of electrochemiluminescence immunoassay. The serum transferrin level was measured with the ELISA method. The haematology was measured with an automated blood analyser. Supplementary Cr3 increased the Cr content in the tissues. This effect was weaker in the Fe-deficient groups than in those with the recommended Fe level, but it did not affect the Fe status. Fe deficiency significantly reduced the Fe content in the tissues. Simultaneously, Cr3 supplementation mitigated the symptoms of Fe deficiency. Fe deficiency increased TIBC and transferrin levels but reduced ferritin and most haematological parameters. However, simultaneous addition of high doses of Cr3 did not deepen these adverse changes. Our results show that the trend of changes in the Fe-Cr interaction depends on the content of these elements in the body.

The Effects of Supplementary Cr3 (Chromium(III) Propionate Complex) on the Mineral Status in Healthy Female Rats

More and more people use food supplements for various reasons, e.g. to prevent mineral deficiency and diseases (e.g. osteoporosis, diabetes, anaemia). Supplements containing Cr(III) are purchased primarily for weight loss and antidiabetic effects. The aim of this study was to evaluate the effects of supplementary Cr3 {chromium(III) propionate complex, [Cr3O(O2CCH2CH3)6(H2O)3]NO3)} on the mineral status in female Wistar rats. The study was carried out on 30 female Wistar rats, divided into five groups (six animals in each): a control group and test groups fed Cr3 supplemented diets with 100, 200, 500 and 1000 mg Cr · kg-1 diet (equivalent to 10, 20, 50 and 100 mg Cr ·kg-1 body mass (b.m.) per day) given as Cr3 for 4 weeks. Supplementary Cr3 increased the Cr content in tissues in a dose-dependent manner. High dietary doses of Cr3, 20 and 100 mg Cr · kg-1 b.m., increased the Cu content in the liver and spleen as well as the Zn content in the kidneys but decreased the liver Ca content. Doses of 50-100 mg Cr ·kg-1 b.m. decreased the serum Fe concentration and the Fe content in the liver and kidneys. Supplementation with Cr3 at doses of 10 and 100 mg Cr ·kg-1 b.m. did not affect the Mg content in the rats' tissues. In conclusion, high dietary doses of Cr3 (10 and 100 mg Cr· kg-1 b.m.) given for 4 weeks affected the mineral status of Fe, Zn, Cu and Ca in the tissues of healthy female Wistar rats.

Effects of Oral Administration of CrCl3 on the Contents of Ca, Mg, Mn, Fe, Cu, and Zn in the Liver, Kidney, and Heart of Chicken

This study aimed to investigate the effects of oral administration of trivalent chromium on the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney. Different levels of 1/8, 1/4, and 1/2 LD50 (LD50 = 5000 mg/kg body mass) CrCl3 milligrams per kilogram body mass daily were added into the water to establish the chronic poisoning model. Ca, Mg, Mn, Fe, Cu, and Zn were detected with the flame atomic absorption spectrometry in the organs exposed 14, 28, and 42 days to CrCl3, respectively. Results showed that Cr was accumulated in the heart, liver, and kidney significantly (P < 0.05) with extended time and dose. The contents of Ca and Fe increased, whereas those of Mg, Mn, Cu, and Zn decreased in the heart, liver, and kidney of each treated group, which had a dose- and time-dependent relationship, but the contents of Mg and Zn in the heart took on a fluctuated change. These particular observations were different from those in the control group. In conclusion, the oral administration of CrCl3 could change the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney, which may cause disorders in the absorption and metabolism of the metal elements of chickens.

The Effects of High Dietary Doses of Chromium(III) Complex with Propionic Acid on Nutritional and Selected Blood Indices in Healthy Female Rats

People taking dietary supplements are usually determined to lose weight, supplement nutrition or reduce the risk of illness and negative effects of their state of health. Chromium(III) supplementation influence body composition and mass, glucose and lipid metabolism and it enhance insulin action. This fact could be of general interest because diabetes mellitus is an increasing health problem in many countries. The study describes the effects of high dietary doses of chromium(III) complex with propionic acid [Cr3] (from 100 to 1000 mg Cr · kg(-1) diet) on the organisms of healthy female rats, with special regard to overall nutritional, carbohydrate, lipid and blood biochemical and morphological and haematological indices. The study was carried out on 30 10-week-old female Wistar rats, which were divided into five equal groups (six animals in each): the control group and four groups of tested animals which had free access to the diet supplemented with 100, 200, 500 and 1000 mg Cr · kg(-1) (equivalent of 10, 20, 50 and 100 mg Cr · kg body weight (b.w.) · day(-1)), given as [Cr3O(O2CCH2CH3)6(H2O)3]⋅NO3, also known as Cr3, for 4 weeks. There were no significant differences in body mass gains, feeding efficiency ratio, internal organ masses or blood serum glucose concentrations, except for some changes in the serum triglycerides concentration, which decreased in the rats that received 500 and 1000 mg Cr · kg(-1) diet, as opposed to the group treated with 200 mg Cr · kg(-1) diet. The dietary supplementation of Cr3 for 4 weeks at doses of 100 to 1000 mg Cr · kg(-1) diet did not affect overall nutritional indices and most blood biochemical, morphological and haematological indices.

The need for combined inorganic, biochemical, and nutritional studies of chromium(III)

The history of biochemical and nutritional studies of the element is unfortunately full of twists and turns, most leading to dead ends. Chromium (Cr), as the trivalent ion, has been proposed to be an essential element, a body mass and muscle development agent, and, in the form of the most popular Cr-containing nutritional supplement, to be toxic when given orally to mammals. None of these proposals, despite significant attention in the popular media, has proven to be correct. Trivalent chromium has also been proposed as a therapeutic agent to increase insulin sensitivity and affect lipid metabolism, although a molecular mechanism for such actions has not been elucidated. Greater cooperative research interactions between nutritionists, biochemists, and chemists might have avoided the earlier issues in nutritional and biochemical Cr research and is necessary to establish the potential role of Cr as a therapeutic agent at a molecular level.

Hepatoprotective activity of CrPic against alloxan-induced hepatotoxicity in mice

This study focused on oxidation hepatic injury induced by alloxan treatment in mice and the hepatoprotective effect of chromium picolinate (CrPic) against such injury. The mice were randomly divided into three groups (control, alloxan, and CrPic). The CrPic mice were given Cr(3+) (40 μg/kg bm/day), and other mice were given equivalent intragastric doses of water every day. After 4 weeks, the groups alloxan and CrPic were treated with alloxan (40 mg/kg/day) through intraperitoneal injection daily for 6 days. Biochemical and enzymatic characteristics were assayed in these animals. The MDA levels of the control and CrPic groups were 33.93 % and 28.45 % lower, respectively, than that of the alloxan group. The levels of superoxide dismutase (SOD) and GSH-Px in the alloxan group were 15.30 % and 15.69 % higher, respectively,than those of the control group. Both the SOD and GSH-Px levels of the control and CrPic groups were about the same. Levels of CuZnSOD mRNA of the control and CrPic groups were 0.27 fold and 1.03 fold lower than in the alloxan group. The transcription levels of GSH-Px in the control and CrPic groups were 1.57 fold and 0.99 fold below those of the alloxan group. These results show that significant hepatic injury can be induced by alloxan treatment in mice; in addition, CrPic may be useful in health products meant to treat human liver disease.

Comparing anti-hyperglycemic activity and acute oral toxicity of three different trivalent chromium complexes in mice

Three different ligands (rutin, folate and stachyose) of chromium(III) complexes were compared to examine whether they have similar effect on anti-hyperglycemic activity as well as the acute toxicity status. Anti-hyperglycemic activities of chromium rutin complex (CrRC), chromium folate complex (CrFC) and chromium stachyose complex (CrSC) were examined in alloxan-induced diabetic mice with daily oral gavage for a period of 2 weeks at the dose of 0.5-3.0 mg Cr/kg. Acute toxicities of CrRC and CrFC were tested using ICR mice at the dose of 1.0-5.0 g/kg with a single oral gavage and observed for a period of 2 weeks. Biological activities results indicated that only CrRC and CrFC could decrease blood glucose level, reduce the activities of aspartate transaminase, alanine transaminase, alkaline phosphatase, and increase liver glycogen level. In acute toxicity study, LD(50) values for both CrRC and CrFC were above 5.0 g/kg. The minimum lethal dose for CrFC was above 5.0 g/kg, while that for CrRC was 1.0 g/kg. Anti-diabetic activity of those chromium complexes was not similar and their acute toxicities were also different. CrFC represent an optimal chromium supplement among those chromium complexes with potential therapeutic value to control blood glucose in diabetes and non-toxicity in acute toxicity.

Evaluation of the acute oral toxicity class of trinuclear chromium(III) glycinate complex in rat

Chromium(III) is considered as an essential element playing a role in carbohydrate and lipid metabolism, and various chemical forms of this element are widely used in dietary supplements. A new trinuclear chromium(III) glycinate complex [Cr(3)O(NH(2)CH(2)CO(2))(6)(H(2)O)(3)](+)NO(3)(-) (CrGly), an analogue of Cr3 (trinuclear Cr(III) propionate complex) has been synthesized as a potential source of supplementary Cr. In this study, we evaluated the acute toxicity class of CrGly in Wistar rats applying the OECD 423 procedure. Male and female Wistar rats (n = 12, 6 ♀ and 6 ♂) were given by gavage either a single dose of CrGly 2,000 mg/kg body mass (equals to 300 mg Cr(III)/kg body mass; in aqueous solution) or equivalent volumes of distilled water and fed ad libitum commercial Labofeed B diet, and observed carefully for 14 days, then sacrificed to collect blood and internal organs for biochemical and histologic examination. No death cases were detected. No abnormalities in animal behavior, body mass gains, gross organ histology, or blood morphology and biochemistry were observed. The results demonstrate that LD(50) of CrGly is greater than 2,000 mg/kg when administrated orally to rat; thus, this compound appears to belong to the fifth category in the GHS system or the fourth class ("unclassified") in the EU classification system.

Evaluation of anti-diabetic potential of chromium(III) propionate complex in high-fat diet fed and STZ injected rats

The aim of this study was to examine the anti-diabetic potential of the chromium(III) propionate complex (CrProp) in a diabetic rat model. Male Wistar rats (n=28, 8-week old) were divided into 4 groups (with 7 rats each) and fed at libitum: the control diet (AIN-93M), and high-fat diets with or without supplementary CrProp (10 and 50mg Crkg(-1) diet; 1 and 5 mg kg(-1) body mass per day) for 5 weeks, and subsequently injected with STZ to induce diabetes. Rats were further fed the same diets for another week until the end of the experiment. Blood indices and the contents of minerals (Fe, Zn, Cu and Cr) in rat tissues were determined by atomic absorption spectrometry. Supplementary CrProp did not affect blood glucose level, but significantly improved insulin sensitivity (HOMA-IR index) and reduced serum levels of triacylglycerols, total and LDL cholesterols. Both supplementary dosages of CrProp (10 and 50mg Cr kg(-1) diet) normalized the increased liver Fe content, reduced hepatic and renal Cu levels and elevated renal Cr contents in diabetic rats. In conclusion, CrProp has a significant anti-diabetic (insulin-sensitizing and hypolipidemic) potential; thus it might be a candidate for a therapeutic agent in diabetes.

Chromium(III) propionate complex supplementation improves carbohydrate metabolism in insulin-resistance rat model

The purpose of this study was to evaluate the antidiabetic potential and safety of the chromium(III) propionate complex (CrProp) in insulin resistance induced by a high-fructose diet in rats. The experiment was carried out on 32 nine-week old male Wistar rats divided into 4 groups of 8 rats each. Animals were fed at libitum: the control diet (AIN-93M), and high-fructose diets (HF) containing various levels of Cr(III) given as CrProp (1 mg Cr kg(-1) diet (HF) and supplemented with 10 mg Cr kg(-1) diet (HFCr10), or 50 mg Cr kg(-1) diet (HFCr50), equal to approx. 0.1, 1 and 5 mg kg(-1) body mass per day) for 8 weeks. It was found that supplemental CrProp improved carbohydrate metabolism indices (decreasing serum insulin levels and insulin resistance indices HOMA-IR and HOMA-B, while increasing insulin sensitivity index QUICKI). Supplemental CrProp did not affect overall nutritional indices, blood morphology, most of the toxicity indices, blood glucose and lipids levels, while it increased kidney Cr level (HFCr50), normalized decreased liver Cu concentrations, and decreased kidney Fe and Cu levels (HFCr50). Supplemental CrProp administered at 10- and 50-fold doses of the basal dietary Cr level has a significant antidiabetic effect in insulin resistant rats. However, a prolonged treatment with this compound can affect Fe status.

Evaluation of the acute oral toxicity class of tricentric chromium(III) propionate complex in rat

Chromium(III) is an essential element for carbohydrate and lipid metabolism, and various chemical forms of this element are widely used in dietary supplements. Of particular interest is [Cr(3)O(O(2)CCH(2)CH(3))(6)(H(2)O)(3)](+) cation (CrProp), that has been proposed as an alternative source of Cr. However, its safety has not been studied completely. In this study, we evaluated the acute toxicity class of CrProp in Wistar rats applying the OECD 423 procedure. Male and female Wistar rats (n=12, 6 female symbol and 6 male symbol) were given by gavage either a single dose of CrProp 2000 mg kg(-1) body mass or equivalent volumes of distilled water, and fed Labofeed B diet, and observed carefully for 14 days, than sacrificed to collect samples for biochemical and histologic examination. No death cases were detected, no major abnormalities in animal behaviour, body mass gains, gross organ histology, and blood morphology, and biochemistry were observed, except some changes of liver mass and the activity of ALT in female rats. The results demonstrate that LD(50) of CrProp is greater than 2000 mg kg(-1) when administrated orally to rat, thus this compound appears to be belong the fifth category in the GHS system or the fourth class ("unclassified") in the EU classification system.