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.

The Potential of L-Arginine in Prevention and Treatment of Disturbed Carbohydrate and Lipid Metabolism-A Review.

L-arginine, an endogenous amino acid, is a safe substance that can be found in food. The compound is involved in synthesis of various products responsible for regulatory functions in the body. Particularly noteworthy is, among others, nitric oxide, a signaling molecule regulating carbohydrate and lipid metabolism. The increasing experimental and clinical data indicate that L-arginine supplementation may be helpful in managing disturbed metabolism in obesity, regulate arterial blood pressure or alleviate type 2 diabetes symptoms, but the mechanisms underlying these effects have not been sufficiently elucidated. This review aims to present the up-to-date information regarding the current uses and health-promoting potential of L-arginine, its effects on nitric oxide, carbohydrate and lipid metabolisms, based on the results of in vivo, in vitro studies, and clinical human trials. Available literature suggests that L-arginine may have beneficial effects on human health. However, some studies found that higher dietary L-arginine is associated with worsening of an existing disease or may be potential risk factor for development of some diseases. The mechanisms of regulatory effects of L-arginine on carbohydrate and lipid metabolism have not been fully understood and are currently under investigation.

Antimicrobial Activities Evaluation and Phytochemical Screening of Some Selected Plant Materials Used in Traditional Medicine.

Plant extracts are a source of valuable ingredients that can be used in many industries. This paper presents research on the content of selected bioactive compounds in extracts obtained from various plant materials. Raw materials have a documented use in traditional medicine not only in Poland. The tested plants were: bitter melon (fruit), elderberry (flowers, fruit, leaves), wild rose (fruit, flesh, seeds), mountain ash (fruit), guelder rose (fruit), and sea buckthorn (fruit, leaves, pomace). The main goal of these tests is to indicate the potential raw materials that may constitute an alternative source of bioactive compounds with antimicrobial activity. The plant material was tested for the content of bioactive antioxidant compounds and possible antimicrobial activity. The content of polyphenols (phenolic acids and flavonoids) was analyzed using UPLC/PDA, sterols, organic acids, and other bioactive compounds. The minimum inhibitory concentration (MIC) was determined. The total free phenolic acids (TPC) and total free flavonoids (TFC) of all plant raw materials was varied and ranged from 0.21 (mg RUTE/1 g of extract) to 38.30 mg RUTE/1 g of extract) for TFC. The concentration of sterols was, on average, about 10 mg/1 g of extract. The value of approx. 20 mg/1 g of the extract was recorded for bitter melon and beach rose. The content of organic acids was about 1.5 mg/1 g of the extract to even 13 mg/1 g of the extract for sea buckthorn berries. The most sensitive to the extracts' activity were the following bacteria: M. luteus, P. mirabilis, P. fragii, S. enteritidis, and E. coli. The tested plant materials can be used in various industries as a source of bioactive compounds of an antibacterial nature.

Sambucus Nigra Extracts-Natural Antioxidants and Antimicrobial Compounds.

Due to the health-promoting properties of elderberry fruits, which result from their rich chemical composition, this raw material is widely used in herbal medicine and the food industry. The aim of the study was to demonstrate the antibacterial activity of the elderberry fruit extracts. The research showed that the content of phenolic acids and flavonoids in the extracts determined their antibacterial activity. The research showed that the content of phenolic acids and flavonoids in the extracts determined their antibacterial activity. The following phenolic acids were predominant: chlorogenic acid, sinapic acid, and t-cinnamic acid. Their average content was, respectively, 139.09, 72.84, 51.29 mg/g extract. Rutin and quercetin (their average content was 1105.39 and 306.6 mg/g extract, respectively) were the dominant flavonoids. The research showed that the elderberry polyphenol extracts exhibited activity against selected strains of bacteria within the concentration range of 0.5-0.05%. The following bacteria were the most sensitive to the extracts: Micrococcus luteus, Proteus mirabilis, Pseudomonas fragii, and Escherichia coli. Of the compounds under analysis, apigenin, kaempferol and ferulic, protocatechuic, and p-coumarin acids had the greatest influence on the high antibacterial activity of elderberry extracts. The results of the microbiological and chemical analyses of the composition of the extracts were analyzed statistically to indicate the bioactive compounds of the greatest antimicrobial significance.

Effects of Bitter Melon and a Chromium Propionate Complex on Symptoms of Insulin Resistance and Type 2 Diabetes in Rat Models.

Trivalent chromium (Cr) and bitter melon (Momordica charantia L., BM) have been shown to independently interact with the insulin signaling pathway leading to improvements in the symptoms of insulin resistance and diabetes in some animal models and human subjects. The aim of this study was to examine whether the combination of the two nutritional supplements could potentially have additive effects on treating these conditions in high-fat-fed streptozotocin (STZ)-induced diabetic rats. The experiment was conducted with 110 male Wistar rats divided into eleven groups and fed either a control or high-fat diet for 7 weeks. Half of the rats on the high-fat diet were injected with STZ (30 mg/kg body mass) to induce diabetes. The high-fat (HF) diets were then supplemented with a combination of Cr (as chromium(III) propionate complex, Cr3: either 10 or 50 mg Cr/kg diet) and bitter melon (lyophilized whole fruit: either 10 or 50 g/kg diet) for 6 weeks. After termination of the experiment, blood and internal organs were harvested for blood biochemical, hematological, and mineral (Cr) analyses using appropriate analytical methods. It was found that neither Cr(III) nor BM was able to significantly affect blood indices in HF and diabetic rats, but BM tended to improve body mass gain, blood glucose, and LDL cholesterol values, but decreased Cr content in the liver and kidneys of the Cr-co-supplemented type 2 diabetic model of rats. Supplementary Cr(III) had no appreciable effect on glucose and lipid metabolism in high-fat-fed STZ-induced diabetic rats. Supplementary BM fruit powder had some observable effects on body mass of high-fat-fed rats; these effects seem to be dampened when BM was co-administered with Cr. Cr(III) and BM appear to act as nutritional antagonists when both administered in food, probably due to binding of Cr by the polyphenol-type compounds present in the plant material. Graphical Abstract.

A Comparative Study of the Bioavailability of Fe, Cu and Zn from Gluten-Free Breads Enriched with Natural and Synthetic Additives.

The aim of this study was to compare the bioavailability of iron, copper and zinc from newly designed gluten-free breads enriched with natural and synthetic additives. The study was conducted on rats with induced Fe, Cu and Zn deficiency. The nutritional intervention with diets supplemented with a 70% addition of gluten-free breads enriched with natural additives and organic compounds to the control diet AIN-93M lasted 40 days. After the intervention, the rats were euthanized, the organs were collected and their mineral content was measured. Chemical analysis of diets with the addition of fortified gluten-free breads showed significantly higher amounts of iron, zinc and copper in diets with the addition of fortified breads compared to diets with the addition of unenriched breads. The type of additives did not influence the amount of minerals in diets. It is necessary to conduct further research to explain the interactions of ingredients and the factors affecting the bioavailability of Fe, Cu and Zn from gluten-free breads in order to obtain a product with a high bioavailability of these ingredients.

Steviol Glycosides Supplementation Affects Lipid Metabolism in High-Fat Fed STZ-Induced Diabetic Rats.

A number of health-promoting properties of Stevia rebaudiana Bertoni and its glycosides, including the antihyperglycemic activity, have been found. The mechanisms of the antidiabetic action of stevia have not been fully understood. The aim of this study was to evaluate the effects of supplementary steviol glycosides on high-fat fed streptozotocin-induced diabetic rats with particular attention to lipid metabolism. The experiment was conducted on 70 male Wistar rats, of which 60 were fed a high-fat diet for 8 weeks followed by intraperitoneal injection of streptozotocin, to induce type 2 diabetes. Afterwards, rats were divided into six groups and fed a high-fat diet supplemented with pure stevioside or rebaudioside A, at two levels (500 or 2500 mg/kg body weight (b.w.)) for 5 weeks. Three additional groups: diabetic untreated, diabetic treated with metformin, and healthy, served as respective controls. Blood and dissected internal organs were collected for hematological, biochemical, and histopathological tests. It was found that dietary supplementation with steviol glycosides did not affect blood glucose, insulin, and insulin resistance indices, antioxidant biomarkers, but normalized hyperlipidemia and affected the appetite, as well as attenuated blood liver and kidney function indices, and reduced tissular damage in diabetic rats. Steviol glycosides normalize lipid metabolism and attenuate internal organs damage in diabetes.

Chromium(III) Glycinate Complex Supplementation Improves the Blood Glucose Level and Attenuates the Tissular Copper to Zinc Ratio in Rats with Mild Hyperglycaemia.

The aim of the study was to evaluate the hypoglycaemic potential of supplementary Cr in the form of chromium(III) glycinate (CrGly) in the diabetic model of rats. The experiment was conducted on 40 male Wistar rats, of which 30 were made diabetic by injection of a single dose of streptozotocin (55 mg/kg b.m.), while the remaining 10 rats served as the healthy control. After inducing hyperglycaemia, 2 groups of diabetic rats (10 rats each) were supplemented with Cr either as CrGly or chromium(III) picolinate (CrPic) given orally at a dose of 10 mg/kg diet (about 0.75 mg Cr/kg b.m.) with adequate AIN-93M diet for 7 weeks. At the termination of experiment, all animals were sacrificed to collect blood and internal organs for biochemical assays. Blood biochemical indices and tissular trace element contents (Fe, Zn, Cu, Cr) were measured and compared with the values of the untreated groups. It was found that CrGly significantly decreased blood glucose, total cholesterol, HDL cholesterol and triacylglycerol levels more efficiently than CrPic. Furthermore, both Cr compounds normalized disturbed the serum, renal and cardiac molar Cu/Zn ratio, as well as restored the kidney Zn and Cu levels in rats with hyperglycaemia. Supplementary Cr did not increase the tissular Cr levels in diabetic rats. The study confirmed the hypoglycaemic potential of CrGly in the diabetic model of rats.

Chia seeds (Salvia hispanica): health promoting properties and therapeutic applications ­ a review

Chia has been known for over 5,500 years. Chia seeds were one of the most important components of the diet of Mayas and Aztecs. The chemical composition and technological properties of chia give the plant a high nutritional potential. Chia is a good source of polyunsaturated fatty acids: omega-3 and omega-6, soluble dietary fiber. It also contains appreciable amount of proteins and phytochemicals. Nutritional value of chia is the reason why it is used in prophylaxis of several non-infectious diseases such as obesity, hypertension, cardiovascular diseases (CVDs), cancer and diabetes. Nutritional and therapeutic aspects of chia are currently being researched by many scientific centres. The aim of this article is to present the nutritional and therapeutic values of chia.

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.

Effect of Elderberry (Sambucus nigra L.) Extract Supplementation in STZ-Induced Diabetic Rats Fed with a High-Fat Diet.

Elderberry (Sambucus nigra L.) lipophilic and polar extract dietary supplementation effects were evaluated according to diabetes management indices, using an in vivo model. A research pipeline was constructed, that ranged from extract preparation, partial chemical characterization and toxicity evaluation, to examining the elderberry extract dietary supplementation effects on biofluid and tissues. Extracts toxicity was screened using an Aliivibrio fischeri bioluminescence model. A concentration of up to 60 mg/L was selected, and rat doses for oral supplementation were computed applying the interspecies correlation between A. fischeri and rats. Wistar type 2 diabetic rats, induced by streptozotocin (STZ), were fed a high-fat diet and supplemented for 4 weeks at doses of 190 and 350 mg/kg body weight/day of lipophilic and polar extract, respectively. As far as we know, lipophilic elderberry extract supplementation was assessed for the first time, while polar extract was administrated at higher doses and for a shorter period compared to previous studies, aiming to evaluate subacute supplementation effects. The polar extract modulated glucose metabolism by correcting hyperglycemia, while the lipophilic extract lowered insulin secretion. Both extracts lowered insulin resistance, without remarkable alterations to hematological indices, sera lipids and sera and tissular trace element homeostasis. In conclusion, elderberries are a potential source of bioactive compounds for formulations to be used as co-adjuvants in diabetes management.

Iron bioavailability from cereal products enriched with Pleurotus ostreatus mushrooms in rats with induced anaemia.

INTRODUCTION AND OBJECTIVE: Oyster mushroom Pleurotus ostreatus is good source of iron. However, there is a limited data concerning bioavailability of iron from oyster mushroom and also cereal products containing this mushroom. The aim of this study was to assess bioavailability of iron from products with an addition of Pleurotus ostreatus in male rats with anaemia. MATERIAL AND METHODS: Investigations were conducted in two stages. In the first stage iron deficiency was developed in rats. For this purpose 6 weeks old 36 male Wistar rats were fed a AIN-93M diet deficient in iron and 6 males received a standard AIN-93M diet. In the second stage of the study the assessment of Fe bioavailability from cereal products enriched with dried Pleurotus ostreatus. After experiment the animals were killed and blood and heart, liver, spleen and kidneys were collected for biochemical tests. RESULTS: Feeding male Wistar rats supplemented with dried Pleurotus ostreatus mushrooms diets resulted in the restitution of the systemic Fe level, as manifested by an increase of the level comparable to the control group for: iron transferrin saturation rate, haemoglobin and mean corpuscular volume. Values of hematocrit, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration in animals fed products supplemented with Pleurotus ostreatus were significantly higher compared to animals fed products with no Fe added. The highest MCV value was recorded when 20% of dried oyster mushrooms were added. Iron levels in the blood serum, the liver and kidneys in animals fed cereal products considerably exceeded values recorded at the beginning of the experiment and were similar to the control values. CONCLUSIONS: Product may be a valuable source of iron in the nutrition of individuals with a deficiency of this element, first of all patients with absorption and metabolism disorders, but also may add variety to the traditional daily diet.

The Effects of Supplementary Mulberry Leaf (Morus alba) Extracts on the Trace Element Status (Fe, Zn and Cu) in Relation to Diabetes Management and Antioxidant Indices in Diabetic Rats.

Mulberry leaves (Morus alba) have been used in folk medicine to mitigate symptoms of diabetes. The mulberry plant contains phenolic compounds that are able to decrease blood glucose concentration. Since various phenolics have antioxidant and metal binding properties, they can be used to alleviate oxidative stress and chelate trace elements involved in redox reactions. The aim of this study was to evaluate the effects of dietary supplementation with mulberry leaf extracts (acetone-water (AE) and ethanol-water (EE)) on the trace element status (Fe, Zn and Cu) in relation to diabetes management and antioxidant indices in high-fat diet-fed/STZ diabetic rats. The experiment was performed on 38 male Wistar rats with diabetes (induced by high-fat diet (HF) and streptozotocin injection) or the control fed with AIN-93M or high-fat diet. As a result, five experimental groups were used: (1) a healthy control group fed with AIN-93M; (2) an HF control group; (3) a diabetic HF group; (4) a diabetic HF + AE group (6 g/kg diet); (5) a diabetic HF + EE group (6 g/kg diet). The rats were fed with appropriate diets for 4 weeks. The content of trace elements (Fe, Zn and Cu) in the serum and tissues was measured by means of atomic absorption spectrometry (AAS). Biochemical analyses (glucose, TBARS, FRAP) were performed on the blood serum. It was shown that the AE decreased hepatic and renal Fe stores, while the EE increased hepatic Cu levels in diabetic rats and confirmed their ability to regulate the Fe and Cu status in diabetes. The results confirmed a significant hypoglycaemic and antioxidant potential of both mulberry leaf extracts in diabetic rats.

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.

Effect of L-arginine supplementation on insulin resistance and serum adiponectin concentration in rats with fat diet.

OBJECT: The purpose of this study was to determine whether supplementation with L-arginine, a substrate used in the production of nitric oxide, had an effect on adiponectin concentration in rats fed a high-fat diet. The influence of L-arginine on insulin resistance was also evaluated. MATERIALS AND METHODS: The experiment was performed using 36 Wistar rats divided into three groups: group 1 was fed a standard diet, group 2 a high-fat (HF) diet, group 3 a HF diet supplemented with L-arginine. After 42 days, serum levels of lipids, glucose, insulin, NO, and adiponectin were measured. Insulin resistance (IR) was estimated by the Homeostasis Model Assessment (HOMA). RESULTS: Body mass was equal in all 3 groups, at the beginning as well as at the end of the study, however, in group 2 the amount of visceral fat was greater after 42 days. In group 3, there was a tendency for visceral fat to decrease. An increase in cholesterol, triglycerides, insulin and HOMA-IR, as well as a decrease in NO and adiponectin were seen in group 2, while in group 3, L-arginine supplementation ameliorated these disturbances. CONCLUSIONS: Our study shows that L-arginine supplementation in rats fed a HF diet is associated with an increase in insulin sensitivity. Our findings suggest that the underlying mechanism could be at least partially related to an increase in adiponectin concentration.

Evaluation of nutritional and biochemical parameters in spontaneously hypertensive rats following antihypertensive treatment.

INTRODUCTION: One side effect of antihypertensive drugs is their impact on nutritional status and metabolism. The purpose of this study was to assess the nutritional and biochemical parameters in spontaneously hypertensive rats following treatment with antihypertensive drugs. MATERIAL AND METHODS: The experiment was performed on 50 male spontaneously hypertensive rats (SHR), which were assigned to five groups: control (C), with perindopril (PR), with metoprolol (MT), with indapamide (ID), and with amlodipine (AM). All rats were provided ad libitum standard diet (with or without drugs) and distilled water. After 45 days, the animals were weighed and killed. Liver, kidney, heart, spleen, pancreas, and blood samples were collected. Concentrations of glucose, cholesterol, triglycerides, and albumin were assayed in serum. Morphology parameters, such as white blood cell, red blood cell, hematocrit, and lymphocyte counts were measured in the blood. Blood pressure was measured using a tail-cuff plethysmograph. RESULTS: The results obtained indicate that the hypotensive drugs under investigation had no effect on the selected nutritional parameters. Perindopril significantly decreased the relative mass of the heart and amlodipine markedly decreased the relative mass of the pancreas. A markedly higher concentration of glucose in the group with indapamid, and a significantly lower concentration of triglycerides in the group with metoprolol, were observed. Indapamide and amlodipine markedly increased the value of red blood cells and hematocrit in the blood of SHR. CONCLUSIONS: Long-term therapy with antihypertension drugs may influence tissue mass and biochemical and morphological status in the body.

Supplementary chromium(III) propionate complex does not protect against insulin resistance in high-fat-fed rats.

Improper eating habits such as high-fat or high-carbohydrate diets are responsible for metabolic changes resulting in impaired glucose tolerance, hyperinsulinemia, insulin resistance, and ultimately diabetes. Although the essentiality of trivalent chromium for humans has been recently questioned by researchers, pharmacological dosages of this element can improve insulin sensitivity in experimental animals and diabetic subjects. The aim of the study was to assess the preventive potential of the supplementary chromium(III) propionate complex (CrProp) in rats fed a high-fat diet. The experiment was conducted on 32 male Wistar rats divided into four groups and fed the following diets: the control (C, AIN-93G), high-fat diets (HF, 40% energy from fat), and a high-fat diet supplemented with CrProp at dosages of 10 and 50 mg Cr/kg diet (HF + Cr10 and HF + Cr50, respectively). After 8 weeks, high-fat feeding led to an increased body mass, hyperinsulinemia, insulin resistance, a decreased serum urea concentration, accumulation of lipid droplets in hepatocytes, and increased renal Fe and splenic Cu contents. Supplementary CrProp in both dosages did not alleviate these changes but increased renal Cr content and normalized splenic Cu content in high-fat-fed rats. Supplementary CrProp does not prevent the development of insulin resistance in rats fed a high-fat diet.

The effects of L-arginine, alone and combined with vitamin C, on mineral status in relation to its antidiabetic, anti-inflammatory, and antioxidant properties in male rats on a high-fat diet.

The aim of this study was to evaluate the influence of the intake of L-arginine alone and of L-arginine with vitamin C on mineral concentration in rats fed with a high-fat diet, and to assess the lipid glucose, insulin, and total antioxidant status (TAS) and tumor necrosis factor (TNF) alpha serum levels that result. Wistar rats were assigned to groups fed with either a standard control diet (C), a diet high in fat (FD), a diet high in fat with L-arginine, or a diet high in fat with L-arginine and vitamin C. After 6 weeks, the length and weight of the rats were measured, and the animals were euthanized. The liver, spleen, kidneys, pancreas, heart, and gonads were collected, as were blood samples. The total serum cholesterol, triglyceride, fasting glucose, insulin, TAS, and TNF alpha levels were measured. The tissue calcium, magnesium, iron, zinc, and copper concentrations were determined. It was found that L-arginine supplementation diminished the effect of the modified diet on the concentration of iron in the liver and spleen and of copper in heart. At the same time, it was observed that L-arginine supplementation reduced the effect of the high-fat diet on insulin, TNF alpha, and TAS. The combination of L-arginine and vitamin C produced a similar effect on the mineral levels in the tissues as did L-arginine used alone. Moreover, positive correlations between serum insulin and iron in the liver, between TNF alpha and iron in the liver, and between TNF alpha and copper in the heart were observed. The level of TAS in serum was inversely correlated with the copper level in the heart and the iron level in the liver. We concluded that the beneficial influence of L-arginine on insulin, TAS, and TNF alpha serum level is associated with changes in the iron and copper status in rats fed with a high-fat diet. No synergistic effect of L-arginine and vitamin C in the biochemical parameters or in the mineral status in rats fed with the modified diet was observed.

Comparison of tissue metal concentrations in Zucker lean, Zucker obese, and Zucker diabetic fatty rats and the effects of chromium supplementation on tissue metal concentrations.

Diabetes results in several metabolic changes, including alterations in the transport, distribution, excretion, and accumulation of metals. While changes have been examined in several rat models of insulin resistance and diabetes, the metal ion concentrations in the tissues of Zucker lean, Zucker obese (an insulin resistance and early stage diabetes model), and Zucker diabetic fatty (ZDF, a type 2 diabetes model) have not previously been examined in detail. The concentration of Cu, Zn, Fe, Mg, and Ca were examined in the liver, kidney, heart and spleen, and Cr concentration in the liver and kidney of these rats were examined. Zucker obese rats have a reduction in the concentration of Cu, Zn, Fe, Mg in the liver compared to ZDF and/or lean Zucker rats, presumably as a result of the increased fat content of the liver of the obese rats. ZDF rats have increased concentrations of kidney Cu compared to the lean rats, while kidney Ca concentrations are increased in the Zucker obese rats. Spleen Fe concentrations are decreased in Zucker obese rats compared to the lean rats. No effects on metal concentrations in the heart were observed between the lean, obese, and ZDF rats, and no effects on Cr concentrations were identified. Cr(III) complexes have previously been shown to have beneficial effects on the signs of insulin resistance in Zucker obese and ZDF rats. The effects of daily gavage administration of chromium picolinate ([Cr(pic)(3)]) (1 mg Cr/kg body mass), CrCl(3) (1 mg Cr/kg body mass), and Cr3 ([Cr(3)O(propionate)(6)(H(2)O)(3)](+)) (33 µg and 1 mg Cr/kg body mass) on metal concentrations in these tissues were examined. Treatment with CrCl(3) and Cr3, but not [Cr(pic)(3)], at 1 mg Cr/kg resulted in a statistically significant accumulation of Cr in the kidney of lean and obese but not ZDF rats but resulted in lowering the elevated levels of kidney Cu in ZDF rats, suggesting a beneficial effect on this symptom of type 2 diabetes.

Effects of combined dietary chromium(III) propionate complex and thiamine supplementation on insulin sensitivity, blood biochemical indices, and mineral levels in high-fructose-fed rats.

Insulin resistance is the first step in glucose intolerance and the development of type 2 diabetes mellitus, thus effective prevention strategies should also include dietary interventions to enhance insulin sensitivity. Nutrients, such as microelement chromium(III) and thiamine, play regulatory roles in carbohydrate metabolism. The objective of this study was to evaluate the insulin-sensitizing potential of the combined supplementary chromium(III) propionate complex (CrProp) and thiamine in insulin resistance animal model (rats fed a high-fructose diet). The experiment was carried out on 40 nine-week-old male Wistar rats divided into five groups (eight animals each). Animals were fed ad libitum: the control diet (AIN-93 M) and high-fructose diets with and without a combination of two levels of CrProp (0.1 and 1 mg Cr/kg body mass/day) and two levels of thiamine (0.5 and 10 mg/kg body mass/day) for 8 weeks. At the end of the experiment rats were sacrificed to collect blood and internal organs for analyses of blood biochemical and hematologic indices as well as tissular microelement levels that were measured using appropriate methods. It was found that both supplementary CrProp and thiamine (given alone) have significant insulin-sensitizing and moderate blood-lipid-lowering properties, while the combined supplementation with these agents does not give synergistic effects in insulin-resistant rats. CrProp given separately increased kidney Cu and Cr levels, while thiamine alone increased hepatic Cu contents and decreased renal Zn and Cu contents.