Urinary chromium excretion in response to an insulin challenge is not a biomarker for chromium status

Mitigating the nephrotoxic impact of hexavalent chromium in Ctenopharyngodon idellus (grass carp) with Boerhavia diffusa (punarnava) leaf extract

In Ctenopharyngodon idellus, the ameliorative influence of rutin-containing leaf extract of Boerhavia diffusa was assessed against chronic exposure to hexavalent chromium. For this, alterations in chromium accumulation, oxidative stress, kidney function markers, histopathology (light and transmission electron microscopy), and transcriptional profiling (Nrf2 and MT2) were examined. RP-HPLC analysis confirmed the presence of rutin (90.45 ± 0.98 mg/g) in the ethanolic leaf extract of the plant. LD₅₀ of the extract to the fish was beyond 5000 mg/kg b.w. The fish was subjected to a sublethal concentration of hexavalent chromium (5.30 mg/L) accompanied by a dose of 250 mg/kg b.w./day of extract in the diet for the experimental duration of 45 days. The extract alone did not generate any adverse consequences in the nephric tissue. Chronic exposure to hexavalent chromium damaged tissue irreparably, demonstrated by elevated levels of kidney function markers (blood urea nitrogen and creatinine) and altered histoarchitecture (DTC value of 78.02 ± 10.5). The metal exposure increased chromium accumulation and malondialdehyde (MDA) and decreased the reduced glutathione (GSH) levels, the activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione-S-transferase) and gene expression in the tissue. The co-supplementation of leaf extract with metal exposure revealed a tissue architecture with normal to slight modifications, and the level of kidney markers, antioxidants, and genes expressed in a normalized range. Principal component analysis created two components with antioxidants (GSH, SOD, CAT, and GST) revealing a negative correlation with the second component comprising MDA, DTC, and chromium concentration. It can be concluded that B. diffusa leaves are safe additives in the fish diet and possess an ameliorative capacity for renal injury incurred by hexavalent chromium.

Impact of Environmental and Lifestyle Use of Chromium on Male Fertility: Focus on Antioxidant Activity and Oxidative Stress

Male reproductive tissues are strongly susceptible to several environmental and lifestyle stressors. In general, male reproductive health is highly sensitive to oxidative stress, which results in reversible and/or irreversible changes in testosterone-producing cells, spermatogenesis, and sperm quality. Chromium compounds are widely used in the +3 and +6 valence states, as food supplements, and in the industrial field, respectively. Chromium (III) compounds, i.e., Cr(III)-tris-picolinate, [Cr(pic)₃], known as chromium picolinate, are used as nutritional supplements for the control of diabetes, body weight, and muscular growth. However, previous studies showed that animal models exposed to chromium picolinate experienced degenerative changes in spermatogenesis. Contradictory results are documented in the literature and deserve discussion. Furthermore, the long-term effects of chromium picolinate on the antioxidant system of treated subjects have not been properly studied. Comprehensive studies on the role of this compound will help to establish the safe and useful use of chromium supplementation. On the other hand, chromium (VI) compounds are widely used in several industries, despite being well-known environmental pollutants (i.e., welding fumes). Chromium (VI) is known for its deleterious effects on male reproductive health as toxic, carcinogenic, and mutagenic. Previous studies have demonstrated severe lesions to mouse spermatogenesis after exposure to chromium (VI). However, workers worldwide are still exposed to hexavalent chromium, particularly in electronics and military industries. Data from the literature pinpoints mechanisms of oxidative stress induced by chromium compounds in somatic and germ cells that lead to apoptosis, thus underlining the impairment of fertility potential. In this review, we analyze the benefits and risks of chromium compounds on male fertility, as well as the mechanisms underlying (in)fertility outcomes. Although supplements with antioxidant properties may maximize male fertility, adverse effects need to be investigated and discussed.

Binding of metals in dacryoliths by means of biomineralization

Dacryoliths are organomineral aggregates released from human lacrimal ducts, and are known to include a 1 to 3 % (by volume) of a mineral (inorganic) component This study was based on a collection of approximately 800 dacryoliths collected from a patient in Siberia. The shapes and sizes of mineral grains, their composition and their distribution in the organic matrix are very diverse; our detailed investigation identifies a number of inorganic phases that were not previously recognized. These were imaged on a scanning electron microscope (Tescan VEGA II LMU), and the chemical composition of the inorganic component was determined by energy dispersive X-Ray spectroscopy (INCA Energy350, Oxford Instrument), and X-ray analysis (X-ray diffractometer XPert PRO (PANalytical). For the first time, we identified the following minerals which can be divided into three groups: 1) oxide Si, pyrite, calcium oxalate, barite, which are often present in the tissues of the living organism and are also known in geological processes; 2) abundant complex mineral phases, consisting of Al, Si, K and Ti or Fe (titanium and iron aluminosilicates), which are also present in organism but have no analogues in the abiogenic environment; and 3) oxygen-containing compounds of Ni and Pb-Cr (possibly nickel oxide and lead chromate, respectively) which are only found in the abiogenic environment. Those mineral phases of biogenic origin are due to an endogenous (pathological) process in the body caused by internal factors (hypoergosis and metabolic disorders). This biomineralization may have a role in the removal of toxic and / or excess ions of Fe, Ti, Cr, Pb, Ni, Al, and Si from tissues.

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.

New Evidence against Chromium as an Essential Trace Element

Nearly 60 y ago, chromium, as the trivalent ion, was proposed to be an essential element, but the results of new studies indicate that chromium currently can only be considered pharmacologically active and not an essential element. Regardless, articles still continue to appear in the literature claiming chromium is an essential element. Chromium has been marketed as an agent to reduce body mass and develop muscle; however, such marketing claims are no longer allowed in the United States because these claims, similar to claims of essential status, are not supported by experiments. Trivalent chromium has also been proposed as a therapeutic agent to increase insulin sensitivity and affect lipid metabolism. Although effective in certain rodent models, beneficial effects in humans have not been unequivocally established. Molecular mechanisms have been proposed for the beneficial effects but have not been definitively shown to occur in animals.

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.

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.

Biomarkers for nutrient intake with focus on alternative sampling techniques

Biomarkers of nutrient intake or nutrient status are important objective measures of foods/nutrients as one of the most important environmental factors people are exposed to. It is very difficult to obtain accurate data on individual food intake, and there is a large variation of nutrient composition of foods consumed in a population. Thus, it is difficult to obtain precise measures of exposure to different nutrients and thereby be able to understand the relationship between diet, health, and disease. This is the background for investing considerable resources in studying biomarkers of nutrients believed to be important in our foods. Modern technology with high sensitivity and specificity concerning many nutrient biomarkers has allowed an interesting development with analyses of very small amounts of blood or tissue material. In combination with non-professional collection of blood by finger-pricking and collection on filters or sticks, this may make collection of samples and analyses of biomarkers much more available for scientists as well as health professionals and even lay people in particular in relation to the marked trend of self-monitoring of body functions linked to mobile phone technology. Assuming standard operating procedures are used for collection, drying, transport, extraction, and analysis of samples, it turns out that many analytes of nutritional interest can be measured like metabolites, drugs, lipids, vitamins, minerals, and many types of peptides and proteins. The advantage of this alternative sampling technology is that non-professionals can collect, dry, and mail the samples; the samples can often be stored under room temperature in a dry atmosphere, requiring small amounts of blood. Another promising area is the potential relation between the microbiome and biomarkers that may be measured in feces as well as in blood.

Chromium does not belong in the diabetes treatment arsenal: Current evidence and future perspectives

Chromium is considered to have positive effects on insulin sensitivity and is marketed as an adjunctive therapy for inducing glucose tolerance in cases of insulin resistance (“the glucose tolerance factor”). Case reports on patients who received prolonged parenteral nutrition indeed showed that the absence of trivalent chromium caused insulin resistance and diabetes. However, whether patients with type 2 diabetes can develop a clinically relevant chromium deficiency is unclear. This review summarizes the available evidence regarding the potential effectiveness of chromium supplementation on glycemic control (Hemoglobin A1c levels) in patients with type 2 diabetes. No studies investigating the long-term safety of chromium in humans were found. All clinical trials that have been performed had a relative short follow-up period. None of the trials investigated whether the patients had risk factors for chromium deficiency. The evidence from randomized trials in patients with type 2 diabetes demonstrated that chromium supplementation does not effectively improve glycemic control. The meta-analyses showed that chromium supplementation did not improve fasting plasma glucose levels. Moreover, there were no clinically relevant chromium effects on body weight in individuals with or without diabetes. Future studies should focus on reliable methods to estimate chromium status to identify patients at risk for pathological alterations in their metabolism associated with chromium deficiency. Given the present data, there is no evidence that supports advising patients with type 2 diabetes to take chromium supplements.

Influence of training frequency on serum concentrations of some essential trace elements and electrolytes in male swimmers

Elemental fluctuations during physical performances have been a point of interest. This study was designed to investigate the effect of swimming frequency on serum concentrations of some trace elements (chromium, iron, copper, zinc, selenium) and electrolytes (sodium, magnesium, potassium, calcium). Three groups of different-level male swimmers were included in the study, as elite swimmers (n = 14), amateur swimmers (n = 11), and sedentary individuals (n = 10). Elite and amateur swimmer groups followed a 3-week training program. At the end of the period, all volunteers were subjected to a controlled swimming test, and blood samples were collected at the beginning of (pre-test), immediately after (post-test), and 1 h after this activity. Element concentrations were determined by inductively coupled plasma mass spectrometry using a dilute and shoot procedure. Apart from the swimming test applied, pre-test calcium and potassium levels were higher in elite swimmers compared to amateurs and controls. The difference in pre-test levels of these elements can be associated with adaptive mechanisms emerged by the frequent training. Regarding the test applied, changes in magnesium, calcium, copper, zinc, and selenium levels exhibited a common pattern in all study groups, with higher post-test serum concentrations. Another point of note was a drop of copper, zinc, and selenium levels at 1 h after the test in elite swimmers. The decrease in serum zinc was also observed in the other groups. Results highlight the value of regular control of elemental status to provide insight into transient effects and deficiencies.