Influence of chromium-enriched yeast on blood glucose and insulin variables, blood lipids, and markers of oxidative stress in subjects with type 2 diabetes mellitus

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

INTRODUCTION

Several randomized controlled trials (RCTs) have demonstrated the beneficial effects of chromium supplementation in managing type 2 diabetes mellitus (T2DM). The current systematic review and meta-analysis aimed to investigate the associations between chromium supplementation and body composition in patients with T2DM.

METHODS

To achieve this, PubMed, Scopus, Embase, Cochrane Library, and Web of Science were searched for randomized clinical trials (RCTs) that reported the effects of chromium supplementation on body composition such as body weight (BW), body mass index (BMI), fat mass (FM), and waist circumference (WC) in patients with T2DM from inception until July 2023. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated using a fixed-effects model.

RESULTS

The meta-analysis included a total of 14 RCTs. The results showed that chromium supplementation did not have any significant effect on FM (WMD = -0.43%; 95% CI -0.94, 0.09), BMI (WMD: 0.09 kg/M2, 95% CI: -0.03, 0.20), WC (WMD: -0.47 cm, 95% CI: -1.10, 0.16), and BW (WMD: -0.26 kg, 95% CI: -0.69, 0.16). However, subgroup analysis revealed that chromium intake decreased FM in subjects aged ≥ 55 years and when chromium picolinate was used as an intervention. Additionally, there was a non-linear association between the dose of chromium supplementation and BW.

CONCLUSIONS

The meta-analysis suggests that chromium supplementation does not significantly reduce BW, BMI, WC, and FM in patients with T2DM. Further RCTs with large-scale are required to determine the possible anti-obesity effects of chromium in patients with T2DM.

The role of chromium supplementation in cardiovascular risk factors: A comprehensive reviews of putative molecular mechanisms

In the recent years, micronutrients play an important role in improving body health with preventing and treating of chronic diseases. Chromium is one of the vital minerals involved in the regulation of insulin action. According to abundant evidences this mineral seems to be an essential factor involved in the reduction of insulin resistance and decreasing the risk of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Moreover, it has been proposed that Chromium supplementation affects mechanisms involved in blood pressure, lipid metabolism, inflammation, and oxidative stress. For instance, it may affect blood pressure through alteration of the renin-angiotensin system, as well as reducing the angiotensin-converting enzyme activity. Furthermore, Chromium supplementation might help reduce the coronary heart disease rates. This study aims to provide a comprehensive review regarding to the effects of Chromium supplementation on CVDs risk factors with an emphasis on possible molecular mechanisms.

Pharmacokinetics of chromium-enriched yeast in rats following oral administration

Chromium (Cr) is required for carbohydrate, lipid, and protein metabolisms in humans and animals. Cr insufficiency is associated with diabetes and cardiovascular disease. Chromium-enriched yeast (CrY) is a widely used Cr dietary supplement, but its pharmacokinetics remains unavailable. CrY was orally administered to rats at a single dose of 1 mg Cr/kg, and plasma Cr concentration at different time points was measured by inductively coupled plasma mass spectrometry. Pharmacokinetics of CrY in rats was well fitted to a non-compartmental model. Plasma Cr concentration reached the maximum of 8.68 ± 2.87 ng/mL at 0.25 h, and gradually decreased to 4.05 ± 0.47 ng/mL at 24 h. CrY was rapidly absorbed into the blood and was slowly eliminated after the oral administration, which could lead to the accumulation of Cr in vivo.

Effects of Chromium Supplementation on Lipid Profile: an Umbrella of Systematic Review and Meta-analysis

Dyslipidemia is one of the most well-established modifiable risk factors for cardiovascular disease (CVD) development. Several meta-analyses have revealed the improving effects of chromium on dyslipidemia, while some studies have reported controversial results. This study aimed to summarize meta-analyses of randomized controlled trials (RCTs) that examined the effects of chromium supplementation on lipid profiles in adults. The literature search was conducted using Embase, Scopus, Web of Science, Cochrane Central Library, and PubMed databases with appropriate keywords from the beginning to May 2022. Based on the pooled analysis results, a random-effects model was used to determine the effects of chromium on blood lipid levels. Heterogeneity, publication bias, and sensitivity analysis were also evaluated using standard methods. A total of eight meta-analyses were included in this study. The pooled analysis of eight meta-analyses did not find any significant effect of chromium supplementation on triglycerides (TG) (ES =  - 0.20 mg/dl; 95% CI: - 0.50, 0.10, p = 0.185), total cholesterol (TC) (ES =  - 0.14 mg/dl, 95% CI: - 0.43, 0.16; p = 0.369), low-density lipoprotein cholesterol (LDL-c) (ES =  - 0.08 mg/dl; 95% CI: - 0.19, 0.03; p = 0.142), and high-density lipoprotein cholesterol (HDL-C) levels (ES: 0.05 mg/dl, 95% CI: - 0.05, 0.14, p = 0.312). However, subgroup analysis by the intervention dose suggested that chromium supplementation in doses higher than 500 µg/day could significantly decrease TG. The available evidence proposes no beneficial effects of chromium intervention on blood lipids. As a result, it cannot be used as a single therapy to treat adults with lipid abnormalities.

Could nutrient supplements provide additional glycemic control in diabetes management? A systematic review and meta-analysis of randomized controlled trials of as an add-on nutritional supplementation therapy

This systematic review and meta-analysis assessed the antidiabetic effect of pharmaconutrients as an add-on in type 2 diabetes mellitus patients by pooling data from currently available randomized controlled trials (RCTs). Data sources included the PubMed and EMBASE, Cochrane Central Register of Controlled Trials. RCTs reporting changes in glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), or homeostasis model assessment of insulin resistance (HOMA-IR) levels following add-on pharmaconutritional therapies for T2DM patients consuming antidiabetic drugs were targeted. Using random-effects meta-analyses, we identified pharmaconutrients with effects on glycemic outcomes. Heterogeneity among studies was presented using I² values. Among 9537 articles, 119 RCTs with nine pharmaconutrients (chromium; coenzyme Q10; omega-3 fatty acids; vitamins C, D, and E; alpha-lipoic acid; selenium; and zinc) were included. Chromium (HbA1c, FBG, and HOMA-IR), coenzyme Q10 (HbA1c and FBG), vitamin C (HbA1c and FBG), and vitamin E (HbA1c and HOMA-IR) significantly improved glycemic control. Baseline HbA1c level and study duration influenced the effects of chromium and vitamin E on HbA1c level. Sensitivity analyses did not modify the pooled effects of pharmaconutrients on glycemic control. Administration of chromium, coenzyme Q10, and vitamins C and E for T2DM significantly improved glycemic control. This study has been registered in PROSPERO (CRD42018115229).

Effect of Chromium Supplementation on Blood Glucose and Lipid Levels in Patients with Type 2 Diabetes Mellitus: a Systematic Review and Meta-analysis

In recent years, the prevalence and incidence of diabetes mellitus (DM) have increased sharply worldwide. In order to evaluate the effect of chromium supplementation on patients with type 2 diabetes, a meta-analysis was conducted by searching the relevant literature. Randomized controlled trials on the effects of chromium supplements on glucose metabolism or lipid profile in patients with type 2 diabetes were retrieved from multiple databases. Literature screening, quality evaluation, and data extraction were conducted according to the inclusion and exclusion criteria, and Review Manager 5.4.0 was used for data analysis. A total of 10 randomized controlled trials involving 509 patients were included, including 269 cases in the experimental group and 240 cases in the placebo control group. Statistical analysis was conducted on the glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) to evaluate the blood glucose and lipid levels. Meta-analysis results showed that the differences between the experimental group and the control group in only one indicator of HbA1c were statistically significant, while there were no statistically significant differences in other indicators. The use of chromium supplements can reduce the glycosylated hemoglobin of type 2 diabetic patients to a certain extent, but it cannot effectively improve the fasting blood glucose and blood lipid levels of type 2 diabetic patients.

Biotic and Abiotic Biostimulation for the Reduction of Hexavalent Chromium in Contaminated Aquifers

Hexavalent chromium is a carcinogenic heavy metal that needs to be removed effectively from polluted aquifers in order to protect public health and the environment. This work aims to evaluate the reduction of Cr(VI) to Cr(III) in a contaminated aquifer through the stimulation of indigenous microbial communities with the addition of reductive agents. Soil-column experiments were conducted in the absence of oxygen and at hexavalent chromium (Cr(VI)) groundwater concentrations in the 1000–2000 μg/L range. Two carbon sources (molasses and EVO) and one iron electron donor (FeSO4·7H2O) were used as ways to stimulate the metabolism and proliferation of Cr(VI) reducing bacteria in-situ. The obtained results indicate that microbial anaerobic respiration and electron transfer can be fundamental to alleviate polluted groundwater from hazardous Cr(VI). The addition of organic electron donors increased significantly Cr(VI) reduction rates in comparison to natural soil attenuation rates. Furthermore, a combination of organic carbon and iron electron donors led to a longer life span of the remediation process and thus increased total Cr(VI) removal. This is the first study to investigate biotic and abiotic Cr(VI) removal by conducting experiments with natural soil and by applying biostimulation to modify the natural existing microbial communities.

The effect of chromium intake on oxidative stress parameters: A systematic review and meta-analysis

BACKGROUND

Trivalent chromium is a trace element thought to have a beneficial effect on oxidative stress (OS) parameters and inflammation. This review aimed to investigate the dose-response of chromium and summarize the effects of chromium supplementation on OS parameters in the literature.

METHODS

MEDLINE, Scopus, Web of Science and Cochrane CENTRAL databases were searched for RCTs published from inception to January 2021 evaluating the effect of chromium supplementation on OS parameters, namely MDA, TBARS, SOD, TAS, CAT, GPx, and GSH. A random-effects model was used to pool data and calculated standard mean difference and 95 % confidence intervals. Quantified heterogeneity among studies was assessed through Cochrane's I² values.

RESULTS

Nine studies enrolling 550 participants met the inclusion criteria. The obtained results indicate that chromium supplementation significantly increases TAC (SMD: 0.46; 95 % CI: 0.08, 0.84; I² = 00.0 % n = 2) and significantly decreases MDA levels (SMD: -0.46; 95 % CI: -0.86, -0.07; I² = 52.4 % n = 5). Supplementation did not significantly change CAT, GPx, GSH, SOD, TAS, and TBARS.

CONCLUSION

Chromium supplementation may improve OS parameters, however, due to high heterogeneity observed in the included studies, these findings should be interpreted with caution. Large RCTs on various patient groups evaluating the impact of chromium supplementation are needed to allow an adequate generalization of the benefits of chromium on human health.

Saccharomyces cerevisiae biomass as a source of next-generation food preservatives: Evaluating potential proteins as a source of antimicrobial peptides

Saccharomyces cerevisiae is the main biotechnological tool for the production of Baker's or Brewer's biomasses, largely applied in beverage and fermented-food production. Through its gene expression reprogramming and production of compounds that inactivate the growth of other microorganisms, S. cerevisiae is able to grow in adverse environments and in complex microbial consortia, as in fruit pulps and root flour fermentations. The distinct set of up-regulated genes throughout yeast biomass propagation includes those involved in sugar fermentation, ethanol metabolization, and in protective responses against abiotic stresses. These high abundant proteins are precursors of several peptides with promising health-beneficial activities such as antihypertensive, antioxidant, antimicrobial, immunomodulatory, anti-obesity, antidiabetes, and mitogenic properties. An in silico investigation of these S. cerevisiae derived peptides produced during yeast biomass propagation or induced by physicochemical treatments were performed using four algorithms to predict antimicrobial candidates encrypted in abundantly expressed stress-related proteins encoded by different genes like AHP1, TSA1, HSP26, SOD1, HSP10, and UTR2, or metabolic enzymes involved in carbon source utilization, like ENO1/2, TDH1/2/3, ADH1/2, FBA1, and PDC1. Glyceraldehyde-3-phosphate dehydrogenase and enolase II are noteworthy precursor proteins, since they exhibited the highest scores concerning the release of antimicrobial peptide candidates. Considering the set of genes upregulated during biomass propagation, we conclude that S. cerevisiae biomass, a food-grade product consumed and marketed worldwide, should be considered a safe and nonseasonal source for designing next-generation bioactive agents, especially protein encrypting antimicrobial peptides that display broad spectra activity and could reduce the emergence of microbial resistance while also avoiding cytotoxicity.

Effects of chromium supplementation on blood pressure, body mass index, liver function enzymes and malondialdehyde in patients with type 2 diabetes: A systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Several studies reported beneficial effects of chromium supplementation for management of type 2 diabetes mellitus (T2DM). The present study aimed to provide a systematic review and meta-analysis of randomized controlled trials (RCTs) examining the effects of chromium supplementation on blood pressure, body mass index (BMI), liver function enzymes and malondialdehyde (MDA) in patients with T2DM.

METHODS

PubMed, Scopus, and Embase were searched up to 15 November 2020 with no language and time restriction. RCTs that reported the effects of chromium supplementation on blood pressure, BMI, liver function enzymes and MDA in patients with T2DM were included. A random-effects model was used to compute weighted mean differences (WMDs) with 95 % confidence intervals (CIs). Between-study heterogeneity was assessed by Cochran's Q test and quantified by I² statistic.

RESULTS

Of 3586 publications, 15 RCTs were included for the meta-analysis. Pooled effect sizes indicated that chromium significantly reduced diastolic blood pressure (DBP) (WMD): -2.36 mmHg, 95 % CI: -4.14, -0.60; P = 0.008), and MDA (WMD: -0.55 umol/l, 95 % CI: -0.96, -0.14; P = 0.008). However, chromium supplementation did not significantly affect BMI, systolic blood pressure (SBP), alanine aminotransferase (ALT), aspartate aminotransferase (AST). Meta-regression analysis did not show significant linear relationship between dose of chromium and change in BMI (p = 0.412), SBP (p = 0. 319), DBP (p = 0.102), ALT (p = 0.923), AST (p = 0.986) and MDA (p = 0.055).

CONCLUSION

The present systematic review and meta-analysis shows that supplementation with chromium at dose of 200-1000 μg/day may reduce DBP and MDA in T2DM patients.

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

BACKGROUND

The purpose of this study was to determine the influence of chromium supplementation on lipid profile in patients with type 2 diabetes mellitus (T2DM).

METHODS

A systematic search was performed in Scopus, Embase, Web of Science, the Cochrane library and PubMed databases to find randomized controlled trials (RCTs) related to the effect of chromium supplementation on lipid profile in patients with T2DM, up to June 2020. Meta-analyses were performed using the random-effects model, and I² index was used to evaluate heterogeneity.

RESULTS

The primary search yielded 725 publications. 24 RCTs (with 28 effect size) were eligible. Our meta-analysis indicated that chromium supplementation resulted in a significant decrease in serum levels of triglyceride (TG) (MD: -6.54 mg/dl, 95 % CI: -13.08 to -0.00, P = 0.050) and total cholesterol (TC) (WMD: -7.77 mg/dl, 95 % CI: -11.35 to -4.18, P < 0.001). Furthermore, chromium significantly increases high-density lipoprotein (HDL) (WMD: 2.23 mg/dl, 95 % CI: 0.07-4.40, P = 0.043) level. However, chromium supplementation did not have significant effects on low-density lipoprotein (LDL) (WMD: -8.54 mg/dl, 95 % CI: -19.58 to 2.49, P = 0.129) level.

CONCLUSION

Chromium supplementation may significantly improve lipid profile in patients with T2DM by decreasing TG and TC and increasing HDL. However, based on our analysis, chromium failed to affect LDL. It should be noted that the lipid-lowering properties of chromium supplementation were small and may not reach clinical importance.

Effects of chromium supplementation on oxidative Stress biomarkers

Aim: This systematic review and meta-analysis aimed to evaluate the effects of chromium supplementation on oxidative stress biomarkers such as superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPX), malondialdehyde (MDA), total antioxidant status (TAS), thiobarbituric acid reactive substances (TBARS), catalase (CAT), nitric oxide (NO), total antioxidant capacity (TAC) and protein carbonyl. Methods: Relevant studies, published from inception until July 2019, were searched through PubMed/Medline, Scopus, ISI Web of Science, Embase, and Google Scholar. All randomized clinical trials investigating the effect of chromium supplementation on oxidative stress were included. Results: Out of 252 citations, 10 trials that enrolled 595 subjects were included. Chromium supplementation resulted in a significant increase in GSH (WMD: 64.79 mg/dl, 95% CI: 22.43 to 107.15; P=0.003) but no significant change in MDA, TAS, TBARS levels, SOD, CAT levels and GPX. Chromium picolinate supplementation resulted in a significant increase in TAC while failing to have a significant effect on NO. Moreover, both chromium picolinate and chromium dinicocysteinate supplementation reduced protein carbonyl levels. Conclusion: Overall, this meta-analysis demonstrated that chromium supplementation increased GSH without any significant changes in the mean of GPX, MDA, TAS, TBARS, CAT and SOD.

A Comprehensive insight into the effect of chromium supplementation on oxidative stress indices in diabetes mellitus: A systematic review

Diabetes mellitus is a metabolic disorder defined as an increase in blood glucose levels (hyperglycaemia) and insufficient production or action of insulin produced by the pancreas. Chronic hyperglycaemia leads to increased reactive oxygen species (ROS) production and oxidative stress, which consequently results in insulin resistance, beta cell degeneration, dyslipidaemia, and glucose intolerance in diabetic patients. Chromium has an essential role in the metabolism of proteins, lipids, and carbohydrates through increasing insulin efficiency. This systematic review aimed to evaluate chromium supplementation's potential roles in oxidative stress indices in diabetes mellitus. A systematic search was performed in PubMed, Scopus, Google Scholar, Cochrane, and Science Direct databases until November 2020. All clinical trials and animal studies that assessed chromium's effect on oxidative stress indices in diabetes mellitus and were published in English-language journals were included. Finally, only 33 out of 633 articles met the required criteria for further analysis. Among 33 papers, 25 studies were performed on animals, and eight investigations were conducted on humans. Twenty-eight studies of chromium supplementation lead to reducing oxidative stress indices. Also, 23 studies showed that chromium supplementation markedly increased antioxidant enzymes' activity and improved levels of antioxidant indices. In conclusion, chromium supplementation decreased oxidative stress in diabetes mellitus. However, further clinical trials are suggested in a bid to determine the exact mechanisms.

Saccharomyces cerevisiae Yeast-Based Supplementation as a Galactagogue in Breastfeeding Women? A Review of Evidence from Animal and Human Studies

Perceived insufficient milk production (PIM) adversely affects breastfeeding duration. Women sometimes use galactagogues with the intent to increase breast milk production and support lactation. Saccharomyces cerevisiae yeast-based supplement (SCYS) is an inactive form of Saccharomyces cerevisiae yeast (SCY) either obtained from the fermentation process or grown on molasses. Anecdotal evidence suggests SCYS is a galactagogue. SCYS is promoted on the internet as a galactagogue in various forms and doses. Dietary supplementation with SCYS during gestation and lactation significantly increases milk yield in ruminants. No human study has evaluated efficacy of SCYS as a galactagogue. SCYS is rich in B vitamins, beta-glucan, mannan oligosaccharides and bioavailable chromium; these may impact breast milk production or composition, thus may alleviate PIM. The safety of taking SCYS during lactation is not well studied. Studies have reported contamination of SCYS with ochratoxin A (OTA) as well as minor side effects from SCYS. Studies are needed to evaluate the efficacy of SCYS on breast milk production and composition and to assess the safety of taking SCYS during lactation in humans.

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

BACKGROUND

Evaluating the impact of chromium picolinate supplementation on glycemic status, lipid profile, inflammatory markers and fetuin-A in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

In present research, participants (N = 46) were randomized to (400 mcg/day, n = 23) chromium picolinate and placebo (n = 23) for 3 months.

RESULTS

Glucose indices, and lipid profiles, inflammatory biomarker and fetuin-A were measured before and after the intervention. Chromium reduced triglyceride (TG), atherogenic index of plasma (AIP), very-low-density lipoprotein (VLDL), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), high-sensitivity C-reactive protein (hs-CRP), interleukin (IL) -6, tumor necrosis factor-alpha (TNF-α) and fetuin-A significantly compared to placebo group (p < 0.05). Furthermore, chromium significantly increased the quantitative insulin sensitivity check index (QUICKI). There were no significant differences in total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), fasting blood sugar (FBS), Hemoglobin A1c (HbA1C), interleukin (IL)-17 between the two groups (p < 0.05).

CONCLUSION

Chromium picolinate significantly decreased TG, insulin, HOMA-IR, fetuin-A, the number of inflammatory factors, and increased QUICKI without changing FBS, HbA1C, TC, LDL, HDL, IL-17 levels and liver steatosis intensity in patients with NAFLD. Further studies by examining the effect of different doses of chromium and mechanisms of cellular action, would help further clarify the subject.

Insulin-like and mimetic molecules from non-mammalian organisms: potential relevance for drug discovery

Insulin was first discovered in extracts of vertebrate pancreas during a focused search for a therapy for diabetes. Subsequent efforts to discover and isolate a similar active principle from yeast and plants driven by the hope to identify insulin-like/mimetic molecules with critical advantages in the pharmacokinetic profile and expenditure of production compared to authentic human insulin were not successful. As a consequence, it has generally been assumed that hormones evolved exclusively during course of the evolution of vertebrate endocrine organs, implying a rather recent origin. Concomitantly, the existence and physiological role of vertebrate hormones in lower multi- and unicellular eukaryotes have remained a rather controversial subject over decades, albeit there is some evidence that hormones and hormone-binding proteins resembling those of vertebrates are expressed in fungi and yeast. Past and recent findings on the existence of insulin-like and mimetic materials, such as the glucose tolerance factor, in lower eukaryotes, in particular Neurospora crassa and yeast, will be presented. These data provide further evidence for the provocative view that the evolutionary roots of the vertebrate endocrine system may be far more ancient than is generally believed and that the identification and characterisation of insulin-like/mimetic molecules from lower eukaryotes may be useful for future drug discovery efforts.

The effects of chromium supplementation on lipidprofile in humans: A systematic review and meta-analysis ofrandomized controlled trials

BACKGROUND AND AIM

This systematic review and meta-analysis aimed to evaluate the effects of chromium supplementation on lipid profile consisting of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and very low-density lipoprotein (VLDL) in humans.

METHODS

The PubMed/Medline, Scopus, Web of sciences, Google Scholar and Cochrane library were systematically searched for randomised control trails (RCTs) available which published before August 2020. The meta-analysis was conducted using Random or fixed-effects models, and between-study heterogeneity was assessed by I².

RESULTS

Thirty-eight studies comprising 41 treatment arms and 7605 participants included to the present meta-analysis. Our results of overall analysis show only a significant reduction in serum TC level in response to chromium supplementation (WMD: -0.17 mmol/l, 95 % CI: -0.27, -0.07, P = 0.001). In accordance with the results of the subgroup analyses, the lowering-effect of chromium supplementation may be synergist during short-term (less than 12 weeks), low dose (less than 200), diabetics patient, younger adults (less than 54 years) and picolinate and elemental form for TC, older and non-obese subjects (>54 years and ≤ 29 kg/m2, respectively), women, Asian and Australian and picolinate form for TG, short-term, low dose, non-obese subjects, women, and Asian for VLDL, and nicotinate form for HDL-C, but had no effect on LDL-C.

CONCLUSION

Our meta-analysis reveals that there was only an overall significant association between chromium supplementation with decreases in the concentration of TC. Additionally, we found considerable evidence of subgroup analysis that support a significant lowering effect of chromium supplementation on TC, TG and VLDL. Further RCTs with short-term and low dose chromium supplementation in subjects with diabetes are necessitated for a firm conclusion of the lipid-modulating properties.

The effect of chromium supplementation on apolipoproteins: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Apos play a role in lipoprotein metabolism. Several studies have been carried out on the effect of chromium supplement in improving CVD risk factors.

OBJECTIVE

This study is a systematic review and meta-analysis that aimed to investigate the effect of chromium supplementation on Apos levels of human studies.

MATERIALS AND METHODS

We searched PubMed, Scopus up to May 2020 up to September 2019. We retrieved studies from identified articles. The studies' quality was evaluated using Cochrane Risk of Bias Tool. We estimated the effect of chromium supplementation on Apo A, Apo A1, and Apo B by pooling mean and standard deviation (SD) values.

RESULTS

We obtained six trials involving 231 participants. Chromium consumption resulted significantly decreased Apo B while the subjects were ingesting chromium picolinate. Chromium supplementation did not significantly decrease Apo A (WMD: -3.89 mg/dl; 95% CI, -11.96 to 4.18) with no significant heterogeneity (I² = 0.00%, p = 0.37). The serum level of Apo A1 did not statistically change following chromium intervention (WMD: 6.11 mg/dl; 95% CI, -7.01 to 19.23) with no significant heterogeneity (I² = 0.00%, p = 0.68). Chromium supplementation did not significantly decrease Apo B (WMD: 3.81 mg/dl; 95% CI, -5.32 to 12.94). With no significant heterogeneity (I² = 42.3%, p = 0.12).

CONCLUSIONS

The chromium supplement did not have a significant effect on the Apolipoproteins (Apo A, ApoA1 and Apo B).

Effects of chromium supplementation on glycemic control in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

We aimed to investigate the effect of chromium supplementation on glycemic control indices in patients with type 2 diabetes (T2DM).

METHODS

Randomized controlled trials examining the effect of chromium supplementation on glycemic control indices and published before February 2020 were detected by searching online databases, including PubMed, Scopus, Embase, Web of sciences and The Cochrane Library, using a combination of suitable keywords. Mean change and standard deviation (SD) of the outcome measures were used to estimate the mean difference between the supplementation group and the control group at follow-up.

RESULTS

Twenty-eight studies reported fasting plasma glucose (FPG), insulin, hemoglobin A1C (HbA1C) and homeostatic model assessment for insulin resistance (HOMA-IR) as an outcome measure. Results revealed significant reduction in FPG (weighted mean difference (WMD): -19.00 mg/dl, 95% CI: -36.15, -1.85, P = 0.030; I²: 99.8%, p < 0.001), insulin level (WMD: -12.35 pmol/l, 95% CI: -17.86, -6.83, P < 0.001), HbA1C (WMD: -0.71 %, 95% CI: -1.19, -0.23, P = 0.004) and HOMA-IR (WMD: -1.53, 95% CI: -2.35, -0.72, P < 0.001; I²: 89.9%, p < 0.001) after chromium supplementation.

CONCLUSION

The results of the current meta-analysis study might support the use of chromium supplementation for the improvement of glycemic control indices in T2DM patients.

Long-term chromium picolinate supplementation improves colostrum profile of Santa Ines ewe

Chromium (Cr) is a micromineral that is involved in the metabolism of carbohydrates, lipids, ammonia, and nucleic acids; thus, its supplementation can influence the nutritional status of ruminants, and consequently, colostrum profile, since this secretion depends on products secreted by the mammary gland and elements of the maternal bloodstream. The present study investigated the influence of supplementation with Cr bound to organic molecule on the nutritional, immune, and antioxidant quality of ewe colostrum. Thirty-two multiparous Santa Ines ewes (55.3 ± 8.00 kg body weight) were randomly assigned into four groups: T1 (0.0 mg of chromium picolinate (CrPic) supplementation per ewe, n = 8), T2 (0.15 mg of CrPic per ewe, n = 9), T3 (0.30 mg of CrPic per ewe, n = 7), and T4 (0.45 mg of CrPic per ewe, n = 8). Supplementation was supplied during the breeding season, pregnancy, and lactation. Shortly after calving, the first milking colostrum was collected to determine its chemical composition, activity of lysozyme, lactoperoxidase, ceruloplasmin, catalase, glutathione peroxidase, and oxygen radical absorbance capacity. The results show that lactoperoxidase activity decreased with CrPic supplementation (P < 0.01), revealing that this micromineral reduces an important component of defense mechanism in the body. Therefore, the results of this work show that supplementation with chromium picolinate influences colostrum quality.

Potential roles of chromium on inflammatory biomarkers in diabetes: A Systematic

Diabetes, as a low-grade chronic inflammatory disease, causes disruption in proper function of immune and metabolic system. Chromium is an important element required for normal lipid and glucose metabolism. Chromium deficiency is correlated with elevation in cardiometabolic risk, which results from increased inflammation. This systematic review was conducted to discover the potential roles of chromium on inflammatory biomarkers. Eligible studies were all in vitro, animal and human studies published in English-language journals from inception until October 2018. PubMed, Scopus, Embase, ProQuest and Google Scholar databases were searched to fined interventional studies from the effects of chromium on inflammatory biomarkers such as tumour necrosis factor a (TNF-a), C-reactive protein (CRP), interleukins, monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1) and adipocytokines in hyperglycaemia and diabetes. Out of 647 articles found in the search, only 14 articles were eligible for analysis, three in vitro studies, eight animal studies and three human studies. Twelve of the 14 studies included in this review, chromium significantly decreased inflammatory factors. The findings of this review indicate, based on in vitro and in vivo studies, that chromium might have potential anti-inflammatory properties, but some of the studies did not show anti-inflammatory effects for chromium (two studies). There are only three studies in humans with controversial results. Therefore, more consistent randomized double-blind controlled trials are needed to reach relevant clinical recommendations, as well as to determine the precise mechanism, of chromium on inflammation in diabetes.

Antidiabetic Effect of High-Chromium Yeast Against Type 2 Diabetic KK-Ay Mice

High chromium yeast has attracted many researchers for its high efficiency and high safety among chromium supplements. The preventive effect of oral high-chromium yeast on diabetes was assessed using KK-A^Y mice. Sixteen-wk-old type 2 diabetic KK-A^Y mice were divided into five groups and orally administered with two types of drying processed high-chromium yeast, chromium picolinate at 1000 μg Cr/kg/d, metformin (positive control), and normal yeast (negative control) for 13 weeks. The spray-dried high-chromium yeast significantly delayed the onset of hyperglycemia in type 2 diabetic KK-A^Y mice (P < 0.05) and significantly improved fasting blood glucose, TG(triglyceride), and TCHO(total cholesterol) . Histopathological analysis showed that the spray-dried high-chromium yeast led to high affinities for the stains to the β-cells in the islets of Langerhans and alleviated hepatic steatosis. High-chromium yeast could be a potential candidate for nutritional supplement to ameliorate diabetes.

PRACTICAL APPLICATION

Chromium plays an important role in fat and carbohydrate metabolism. The result show that spray-dried high chromium yeast significantly delayed the onset of hyperglycemia in type 2 diabetic KK-A^Y mice. As one of chromium supplements, the purpose of this study is to examine the efficacy of high chromium yeast on the type 2 diabetes and drying method on its bioactivity, which will be useful for research and development of high-chromium yeast and improvement of pharmacological activity-based quality control.

Hypoglycemic and Hypolipidemic Effects of Leucine, Zinc, and Chromium, Alone and in Combination, in Rats with Type 2 Diabetes

For the increasing development of diabetes, dietary habits and using appropriate supplements can play important roles in the treatment or reduction of risk for this disease. The objective of this study was to investigate the effects of leucine (Leu), zinc (Zn), and chromium (Cr) supplementation, alone or in combination, in rats with type 2 diabetes (T2D). Seventy-seven adult male Wistar rats were randomly assigned in 11 groups, using nutritional supplements and insulin (INS) or glibenclamide (GLC). Supplementing Leu significantly reduced blood glucose, triglycerides (TG), nonesterified fatty acids (NEFA), low-density lipoprotein (LDL), and increased high-density lipoprotein (HDL) concentrations compared to vehicle-treated T2D animals, and those improvements were associated with reduced area under the 2-h blood glucose response curve (AUC). Supplementation of T2D animals with Zn improved serum lipid profile as well as blood glucose concentrations but was not comparable with the INS, GLC, and Leu groups. Supplementary Cr did not improve blood glucose and AUC in T2D rats, whereas it reduced serum TG and LDL and increased HDL concentrations. In conclusion, supplementation of diabetic rats with Leu was more effective in improving blood glucose and consequently decreasing glucose AUC than other nutritional supplements. Supplementary Zn and Cr only improved serum lipid profile. The combination of the nutritional supplements did not improve blood glucose level. Nevertheless, supplementation with Leu-Zn, Leu-Cr, Zn-Cr, and Leu-Zn-Cr led to an improved response in serum lipid profile over each supplement given alone.

Chromium supplementation for adjuvant treatment of type 2 diabetes mellitus: Results from a pooled analysis

SCOPE

We conducted a pooled analysis of randomized controlled trials to evaluate the effects of chromium supplementation on clinically relevant metabolic biomarkers in type 2 diabetes mellitus (T2DM) patients.

METHODS AND RESULTS

Electronic searches were conducted and the bibliographies of located articles were searched, and 28 studies were suitable for statistical pooling. Endpoints were calculated as weighted mean differences (WMDs) with 95% confidence intervals (CIs) by using fixed-effects or random-effects models. Statistical heterogeneity, publication bias, subgroup analyses, sensitivity analysis and meta-regression assessments were also assessed. Chromium reduced levels of fasting plasma glucose (WMD, -0.99 mmol/L; 95% CI, -1.72 to -0.25; p = 0.008), hemoglobin A1c (WMD, -0.54 %; 95% CI, -0.82 to -0.25; p = 0.0002), triglycerides (WMD, -11.71 mg/dL; 95% CI, -18.38 to -5.04; p = 0.0006). Chromium also increased levels of high-density lipoprotein cholesterol (WMD, 1.73 mg/dL; 95% CI, 0.50 to 2.96; p = 0.006). These results were robust in sensitivity analysis and were not dependent on the chromium dose and duration of supplementation. Subgroup analyses indicated that these notably favorable effects were presented in T2DM subjects ingesting chromium chloride and chromium picolinate formulations.

CONCLUSION

Our pooled analysis suggested that chromium supplementation might be a candidate as an adjunct to pharmacological management in patients with T2DM.

Selenium, Vanadium, and Chromium as Micronutrients to Improve Metabolic Syndrome

Trace metals play an important role in the proper functioning of carbohydrate and lipid metabolism. Some of the trace metals are thus essential for maintaining homeostasis, while deficiency of these trace metals can cause disorders with metabolic and physiological imbalances. This article concentrates on three trace metals (selenium, vanadium, and chromium) that may play crucial roles in controlling blood glucose concentrations possibly through their insulin-mimetic effects. For these trace metals, the level of evidence available for their health effects as supplements is weak. Thus, their potential is not fully exploited for the target of metabolic syndrome, a constellation that increases the risk for cardiovascular disease and type 2 diabetes. Given that the prevalence of metabolic syndrome is increasing throughout the world, a simpler option of interventions with food supplemented with well-studied trace metals could serve as an answer to this problem. The oxidation state and coordination chemistry play crucial roles in defining the responses to these trace metals, so further research is warranted to understand fully their metabolic and cardiovascular effects in human metabolic syndrome.

Chromium supplements for glycemic control in type 2 diabetes: limited evidence of effectiveness

Some adults with type 2 diabetes mellitus (T2DM) believe that chromium-containing supplements will help control their disease, but the evidence is mixed. This narrative review examines the efficacy of chromium supplements for improving glycemic control as measured by decreases in fasting plasma glucose (FPG) or hemoglobin A1c (HbA1c). Using systematic search criteria, 20 randomized controlled trials of chromium supplementation in T2DM patients were identified. Clinically meaningful treatment goals were defined as an FPG of ≤7.2 mmol/dL, a decline in HbA1c to ≤7%, or a decrease of ≥0.5% in HbA1c. In only a few randomized controlled trials did FPG (5 of 20), HbA1c (3 of 14), or both (1 of 14) reach the treatment goals with chromium supplementation. HbA1c declined by ≥0.5% in 5 of 14 studies. On the basis of the low strength of existing evidence, chromium supplements have limited effectiveness, and there is little rationale to recommend their use for glycemic control in patients with existing T2DM. Future meta-analyses should include only high-quality studies with similar forms of chromium and comparable inclusion/exclusion criteria to provide scientifically sound recommendations for clinicians.

Effect of a fermented dietary supplement containing chromium and zinc on metabolic control in patients with type 2 diabetes: a randomized, placebo-controlled, double-blind cross-over study

BACKGROUND

For the increasing development of type 2 diabetes dietary habits play an important role. In this regard, dietary supplements are of growing interest to influence the progression of this disease.

OBJECTIVE

The aim of this study was to investigate the effect of a cascade-fermented dietary supplement based on fruits, nuts, and vegetables fortified with chromium and zinc on metabolic control in patients with type 2 diabetes mellitus.

METHODS

This was a randomized, placebo-controlled, double-blind, intervention study under free-living conditions using a cross-over design. Thirty-six patients with type 2 diabetes mellitus were enrolled and randomized either to receive a cascade-fermented dietary supplement enriched with chromium (100 µg/d) and zinc (15 mg/d) or a placebo similar in taste but without supplements, over a period of 12 weeks. After a wash-out period of 12 weeks, the patients received the other test product. The main outcome variable was the levels of glycated hemoglobin (HbA1c). Other outcome variables were fasting blood glucose, fructosamine, and lipid parameters.

RESULTS

Thirty-one patients completed the study. HbA1c showed no relevant changes during both treatment periods, nor was there a relevant difference between the two treatments (HbA1c: p=0.48). The same results were found for fructosamine and fasting glucose (fructosamine: p=0.9; fasting glucose: p=0.31). In addition, there was no effect on lipid metabolism.

CONCLUSION

This intervention study does not provide evidence that a cascade-fermented plant-based dietary supplement enriched with a combination of chromium and zinc improves glucose metabolism in patients with type 2 diabetes mellitus under free-living conditions.

Risk of Type 2 Diabetes Is Lower in US Adults Taking Chromium-Containing Supplements

BACKGROUND

Dietary supplement use is widespread in the United States. Although it has been suggested in both in vitro and small in vivo human studies that chromium has potentially beneficial effects in type 2 diabetes (T2D), chromium supplementation in diabetes has not been investigated at the population level.

OBJECTIVE

The objective of this study was to examine the use and potential benefits of chromium supplementation in T2D by examining NHANES data.

METHODS

An individual was defined as having diabetes if he or she had a glycated hemoglobin (HbA1c) value of ≥6.5%, or reported having been diagnosed with diabetes. Data on all consumed dietary supplements from the NHANES database were analyzed, with the OR of having diabetes as the main outcome of interest based on chromium supplement use.

RESULTS

The NHANES for the years 1999-2010 included information on 62,160 individuals. After filtering the database for the required covariates (gender, ethnicity, socioeconomic status, body mass index, diabetes diagnosis, supplement usage, and laboratory HbA1c values), and when restricted to adults, the study cohort included 28,539 people. A total of 58.3% of people reported consuming a dietary supplement in the previous 30 d, 28.8% reported consuming a dietary supplement that contained chromium, and 0.7% consumed supplements that had "chromium" in the title. Compared with nonusers, the odds of having T2D (HbA1c ≥6.5%) were lower in persons who consumed chromium-containing supplements within the previous 30 d than in those who did not (OR: 0.73; 95% CI: 0.62, 0.86; P = 0.001). Supplement use alone (without chromium) did not influence the odds of having T2D (OR: 0.89; 95% CI: 0.77, 1.03; P = 0.11).

CONCLUSIONS

Over one-half the adult US population consumes nutritional supplements, and over one-quarter consumes supplemental chromium. The odds of having T2D were lower in those who, in the previous 30 d, had consumed supplements containing chromium. Given the magnitude of exposure, studies on safety and efficacy are warranted.

Effect of chromium supplementation on glycated hemoglobin and fasting plasma glucose in patients with diabetes mellitus

Aims

Chromium (Cr) is a trace element involved in glucose homeostasis. We aim to evaluate and quantify the effects of Cr supplementation on A1C and FPG in patients with T2DM.

Materials and methods

A systematic literature search of Pubmed, EMBASE and the Cochrane Library (from database inception to 11/2014) with no language restrictions sought RCTs or cohort studies evaluating Cr supplementation in T2DM vs control and reporting either change in glycated hemoglobin (A1C) or fasting plasma glucose (FPG). Meta-analysis was conducted on each subtype of Cr supplement separately, and was analyzed by random effects model to yield the weighted mean differences (WMD) and 95% confidence intervals (CIs). Heterogeneity was assessed by using the I² statistic.

Results

A total of 14 RCTs (n = 875 participants, mean age range: 30 to 83 years old, 8 to 24 weeks of follow-up) were identified (Cr chloride: n = 3 study, Cr picolinate: n = 5 study, brewer’s yeast: n = 4 study and Cr yeast: n = 3 study). Compared with placebo, Cr yeast, brewer’s yeast and Cr picolinate did not show statistically significant effects on A1C. Furthermore, compared to control, Cr chloride, Cr yeast and Cr picolinate showed no effect on FPG, however, brewer’s yeast showed a statistically significant decrease in FPG -19.23 mg/dL (95% CI = -35.30 to -3.16, I² = 21%, n = 137).

Conclusions

Cr supplementation with brewer’s yeast may provide marginal benefits in lowering FPG in patients with T2DM compared to placebo however it did not have any effect on A1C.

Effect of glucose tolerance factor (GTF) from high chromium yeast on glucose metabolism in insulin-resistant 3T3-L1 adipocytes

Relative expression of IR, IRS-1, IRS-2 and GLUT4 mRNA was determined in insulin-resistant 3T3-L1 adipocytes with different treatments.

Systematic review and meta-analysis of the efficacy and safety of chromium supplementation in diabetes

WHAT IS KNOWN AND OBJECTIVE

Chromium is an essential mineral for carbohydrate and lipid metabolism. Results of previous systematic reviews and meta-analyses of chromium supplementation and metabolic profiles in diabetes have been inconsistent. Recently, several published trials have emerged. We conducted a systematic review and meta-analysis to assess the effects on metabolic profiles and safety of chromium supplementation in diabetes mellitus.

METHODS

Clinical trials were identified through MEDLINE, the Cochrane library, CINAHL, Web of Science, Scopus and www.clinicaltrial.gov up to May 2013. Historical search of reference lists of related articles was also conducted. Studies were included if they (i) were randomized controlled trials comparing chromium mono- or combined supplementation against placebo, (ii) reported HbA1c or fasting plasma glucose and (iii) were of at least 3 weeks when reporting fasting plasma glucose, or of at least 8 weeks if HbA1c was reported. No language restriction was imposed. Treatment effect and adverse events were estimated with mean difference and odds ratio, respectively.

RESULTS AND DISCUSSION

Twenty-five randomized controlled trials met the inclusion criteria. Of these, 22 studies evaluated chromium monosupplementation. One study evaluated chromium yeast combined with vitamins C and E, and two others evaluated chromium picolinate plus biotin (CPB). Overall, chromium mono- and combined supplementation significantly improved glycaemic control (mean difference for HbA1c -0·55%; 95% CI -0·88 to -0·22%; P = 0·001, mean difference for FPG -1·15 mm; 95% CI -1·84 to -0·47 mm; P = 0·001). In particular, chromium monotherapy significantly reduced triglycerides and increased HDL-C levels. The effects on glucose and triglycerides levels were shown especially with chromium picolinate. Glycaemic control may improve with chromium monosupplementation of more than 200 μg daily. HbA1c and FPG also improved in patients with inadequate glycaemic control at baseline. The risk of adverse events did not differ between chromium and placebo.

WHAT IS NEW AND CONCLUSIONS

The available evidence suggests favourable effects of chromium supplementation on glycaemic control in patients with diabetes. Chromium monosupplement may additionally improve triglycerides and HDL-C levels. Chromium supplementation at usual doses does not increase the risk of adverse events compared with placebo. Data on chromium combined supplementation are limited and inconclusive. Long-term benefit and safety of chromium supplementation remain to be further investigated.

Improved meta-analytic methods show no effect of chromium supplements on fasting glucose

The trace mineral chromium has been extensively researched over the years in its role in glucose metabolism. Dietary supplement companies have attempted to make claims that chromium may be able to treat or prevent diabetes. Previous meta-analyses/systematic reviews have indicated that chromium supplementation results in a significant lowering of fasting glucose in diabetics but not in nondiabetics. A meta-analysis was conducted using an alternative measure of effect size, d(ppc2) in order to account for changes in the control group as well as the chromium group. The literature search included MEDLINE, the Cochrane Controlled Trials Register, and previously published article reviews, systematic reviews, and meta-analyses. Included studies were randomized, placebo-controlled trials in the English language with subjects that were nonpregnant adults, both with and without diabetes. Sixteen studies with 809 participants (440 diabetics and 369 nondiabetics) were included in the analysis. Screening for publication bias indicated symmetry of the data. Tests of heterogeneity indicated the use of a fixed-effect model (I² = 0 %). The analysis indicated that there was no significant effect of chromium supplementation in diabetics or nondiabetics, with a weighted average effect size of 0.02 (SE = 0.07), p = 0.787, CI 95 % = -0.12 to 0.16. Chromium supplementation appears to provide no benefits to populations where chromium deficiency is unlikely.

Effect of chromium-enriched yeast on fasting plasma glucose, glycated haemoglobin and serum lipid levels in patients with type 2 diabetes mellitus treated with insulin

Chromium is required for a normal insulin function, and low levels have been linked with insulin resistance. The aim of this study was to follow the effect of chromium supplementation on fasting plasma glucose (FPG), glycated haemoglobin (HbA1c) and serum lipids in patients with type 2 diabetes mellitus (DM2) on insulin therapy. Eleven randomly selected patients with DM2 on insulin therapy were supplemented with a daily dose of 100 μg chromium yeast for the first supplementation period of 2 weeks. In the second supplementation period, the chromium dose was doubled and continued for the next 6 weeks. The third phase was a 6-week washout period. After each period, the levels of FPG and HbA1c were compared with the corresponding values at the end of the previous period. Serum triglycerides, total HDL and LDL cholesterol values after supplementation were compared with the baseline values. FPG decreased significantly after the first period of chromium supplementation (p < 0.001), and a tendency to a further reduction was observed after the second supplementation period. Similarly, HbA1c decreased significantly in both periods (p < 0.02 and p < 0.002, respectively). Eight weeks after withdrawal of chromium supplementation, both FPG and HbA1c levels returned to their pre-intervention values. The serum lipid concentrations were not significantly influenced by chromium supplementation. Chromium supplementation could be beneficial in patients with DM2 treated with insulin, most likely due to lowered insulin resistance leading to improved glucose tolerance. This finding needs to be confirmed in a larger study.

Anti-atherogenic effect of chromium picolinate in streptozotocin-induced experimental diabetes

BACKGROUND

Several studies have implicated changes in the levels of trace elements in diabetes. Chromium is one such element that seems to potentiate insulin action, thereby regulating carbohydrate and lipid metabolism. The aim of the present study was to evaluate the effect of chromium supplementation as chromium picolinate on the lipid profile of streptozotocin (STZ)-induced diabetic rats.

METHODS

Rats were rendered diabetic by a single injection of STZ (50 mg/kg, i.p.). Chromium picolinate (1 mg/kg per day, p.o.) was administered to rats for a period of 4 weeks. At the end of the treatment period, plasma total lipids, triglycerides, total cholesterol and lipoprotein levels were determined, as was hepatic glucose-6-phosphate dehydrogenase activity.

RESULTS

Total plasma lipids increased significantly in diabetic rats and this increase was ameliorated by chromium treatment for 4 weeks. Elevated total lipids in diabetic rats were due to increased plasma triglyceride and cholesterol levels. Chromium supplementation lowered plasma triglyceride and cholesterol levels to near normal. Chromium treatment also normalized low-density lipoprotein-cholesterol (LDL-C) and very low-density lipoprotein-cholesterol levels and improved the total cholesterol:high-density lipoprotein-cholesterol (HDL-C) and HDL-C:LDL-C ratios, suggesting an anti-atherogenic effect. In addition to improving the plasma lipid profile, chromium supplementation normalized liver glucose-6-phosphate dehydrogenase activity in diabetic rats.

CONCLUSIONS

These results provide evidence that chromium picolinate effectively attenuates the dyslipidemia associated with diabetes and thus can be used as an adjuvant therapy in the treatment of diabetes and its associated complications.

Purification and characterization of chromium-binding substances from high-chromium yeast

As a highly efficient and easily absorbable source of chromium, the identities of the chromium-binding substances in yeast remain unclear. In this study, a mild extraction procedure involving extraction with ammonia, three-gel filtration, and high-performance liquid chromatography was adopted to obtain two chromium-binding substances from high-chromium yeast. A low-molecular-weight chromium-binding substance was identified, with mass-to-charge ratios (m/z) of 769 and 712, which included glutamic acid, glycine, and cysteine in an approximate ratio of 1:1:1, as well as nicotinic acid and chromium(III). Furthermore, it significantly potentiated (by 51%) the action of insulin to stimulate the conversion of (14)C-glucose into lipid in adipocytes. A novel high-molecular-weight chromium-binding substance was also isolated: electrospray ionization tandem mass spectrometry tentatively identified it as HUB1 target protein-1, glyceraldehyde-3-phosphate dehydrogenase, or ribosomal protein L2A(L5A)(rp8)(YL6). This is the first report of a high-molecular-weight chromium-binding substance in yeast and merits further studies.

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.

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

BACKGROUND

The use of chromium supplements is widespread for the prevention and treatment of diabetes mellitus but there are conflicting reports on efficacy, possibly reflecting discrepant effects across different populations. In the present studies, we test the hypothesis that chromium supplementation raises serum chromium levels and correspondingly improves insulin sensitivity.

METHODS

A double blind placebo-controlled randomized trial was conducted on 31 non-obese, normoglycemic subjects. After baseline studies, the subjects were randomized to placebo or chromium picolinate 500 μg twice a day. The primary endpoint was change in insulin sensitivity as measured by euglycemic hyperinsulinemic clamp. Pre-specified secondary endpoints included fasting lipids, blood pressure, weight, body composition measured by DXA scan.

RESULTS

After 16 weeks of chromium picolinate therapy there was no significant change in insulin sensitivity between groups (p=0.83). There was, however, a strong association between serum chromium and change in insulin resistance (β = -0.83, p=0.01), where subjects with the highest serum chromium had a worsening of insulin sensitivity. This effect could not be explained by changes in physiological parameters such as body weight, truncal fat and serum lipids with chromium therapy.

CONCLUSIONS

Chromium therapy did not improve insulin sensitivity in non-obese normoglycemic individuals. Further, subjects who have high serum chromium levels paradoxically had a decline in insulin sensitivity. Caution therefore should be exercised in recommending the use of this supplement.

TRIAL REGISTRATION

The study was registered on the NIH registry (clinicaltrials.gov) and the identifier is NCT00846248.

Favorable effects on metabolic risk factors with daily brewer's yeast in type 2 diabetic patients with hypercholesterolemia: a semi-experimental study

BACKGROUND

The aim of the present study was to investigate the effect of brewer's yeast on plasma glucose and lipid profiles in patients with type 2 diabetes (T2D).

METHODS

The present semi-experimental study was performed on 55 T2D patients with hypercholesterolemia. All patients received 12 tablets of 300 mg yeast per day for 8 weeks. Each tablet contained 1.2 μg chromium. Fasting plasma glucose, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and triglyceride levels were measured at baseline and then again at Weeks 4 and 8.

RESULTS

Although there was a tendency for plasma glucose levels to decrease at Week 4, the difference failed to reach statistical significance (P = 0.065). However, after 8 weeks, the decrease in plasma glucose was significant (P = 0.043). Again, although there was a tendency for decreased plasma cholesterol at Week 8 compared with baseline, the difference failed to reach statistical significance (215 ± 29 vs 226 ± 37 mg/dL, respectively; P = 0.056). Brewer's yeast significantly decreased plasma triglyceride and LDL-C levels at Weeks 4 and 8. In contrast, plasma HDL-C levels were significantly increased at both 4 and 8 weeks compared with baseline (41.3 ± 8.8 and 43.3 ± 7.5 vs 36 ± 5 mg/dL, respectively; P < 0.01 and P < 0.01, respectively).

CONCLUSION

In conclusion, the consumption of brewer's yeast over a period of 8 weeks may improve cardiometabolic risk factors in T2D patients. However, these findings need to be confirmed in a large double-blind clinical trial.

Chromium, selenium, and zinc multimineral enriched yeast supplementation ameliorates diabetes symptom in streptozocin-induced mice

Chromium, selenium, and zinc malnutrition has been implicated in the pathogenesis of diabetic mellitus. This study aims to investigate the effects of novel multiminerals-enriched yeast (MMEY) which are minerals supplementation containing elevated levels of chromium, selenium, and zinc simultaneously in a diabetic animal model. Streptozocin-induced diabetic male Balb/c mice (n = 80) were randomly divided into diabetes control group and three treatment groups. They were administrated oral gavages with low, medium, or high doses of MMEY, respectively. Meanwhile, healthy male Balb/c mice (n = 40) of the same body weight were randomly assigned into normal control group and high dose of MMEY control group. After 8 weeks duration of treatment, the animals were sacrificed by cervical dislocation. Serum glucose concentrations, lipid profiles, oxidative/antioxidant, and immunity status were determined. No significant adverse effects were observed in the high-dose MMEY control group. Treatment of the diabetic mice with medium- or high-dose MMEY significantly decreased serum glucose, triglyceride, total cholesterol, and malondialdehyde and increased high-density lipoprotein cholesterol, glutathione, and the activities of superoxide dismutase and glutathione peroxidase. In addition, MMEY ameliorated the pathological damage of the pancreatic islets, elevated the thymus or spleen coefficient, and increased the expressions of interleukin-2 and -4 in spleen lymphocytes compared with unsupplemented diabetic mice. In conclusion, these results indicate that supplemental MMEY inhibits hyperglycemia, abates oxidative stress, modulates disorders of lipid metabolism, and reduces the impairment of immune function in diabetic mice; especially notable are the protective effects of medium doses of MMEY on the islet cells of diabetic mice.

Effects of chromium brewer's yeast supplementation on body mass, blood carbohydrates, and lipids and minerals in type 2 diabetic patients

Chromium(III) is considered as an essential element for carbohydrate and lipid metabolism. The aim of this clinical study was to evaluate the efficacy of Cr brewer's yeast supplementation on body mass, carbohydrate, lipids and mineral indices in type 2 diabetic patients. Twenty adult type 2 diabetic subjects (11 males and 9 females aged 37-63) were supplemented with Cr brewer's yeast in dosages of 500 μg Cr/person/day or placebo for 8 weeks in a double-blind, placebo-controlled crossover design. It was found that supplemental Cr did not affect body mass, blood lipid profile, resistin levels, and the serum and hair Zn, Fe, and Cu levels, but increased serum Cr (by 116%) and hair Cr (by 20.6%) concentrations and improved some blood carbohydrate indices (significant increase in the β cell function index by 18.8%) in type 2 diabetic patients. In conclusion, Cr brewer's yeast has a weak hypoglycemic potential, but does not affect body mass, blood biochemical profile, and microelement levels in type 2 diabetic subjects.

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.

Beneficial effect of chromium supplementation on glucose, HbA1C and lipid variables in individuals with newly onset type-2 diabetes

PROJECT

Chromium is an essential nutrient involved in normal carbohydrate and lipid metabolism. It influences glucose metabolism by potentiating the action as taking part in insulin signal amplification mechanism. A placebo-controlled single blind, prospective study was carried out to investigate the effect of chromium supplementation on blood glucose, HbA(1)C and lipid profile in newly onset patients with type-2 diabetes.

PROCEDURE

Total 40 newly onset type-2 diabetics were selected and after 1 month stabilization further randomly divided into two groups viz. study group and placebo group. The study group received 9 g brewer's yeast (42 μg Cr) daily and the other placebo group received yeast devoid of chromium for 3 months. Subjects were instructed not to change their normal eating and living habits. Fasting blood glucose, HbA(1)C and lipid profile were analyzed at beginning and completion of the study.

RESULTS

Results revealed that fasting blood glucose level significantly reduced in the subjects consuming yeast supplemented with chromium (197.65±6.68 to 103.68±6.64 mg/dL; p<0.001). HbA(1)C values improved significantly from 9.51±0.26% to 6.86±0.28%; p<0.001 indicating better glycaemic control. In experimental group total cholesterol, TG and LDL levels were also significantly reduced from 199.66±3.11 to 189.26±3.01 mg/dL; p<0.02, 144.94±8.31 to 126.01±8.26; p<0.05 and 119.19±1.71 to 99.58±1.10; p<0.001 respectively.

CONCLUSIONS

These data demonstrate beneficial effect of chromium supplementation on glycaemic control and lipid variables in subjects with newly onset type-2 diabetes.

Oral administration of the high-chromium yeast improve blood plasma variables and pancreatic islet tissue in diabetic mice

The in vivo effects of oral administration of the high-chromium yeast to healthy and diabetic mice are described. Given that these complexes are proposed to function by potentiating the actions of insulin and activating the insulin receptor kinase, changes in lipid and carbohydrate metabolism would be expected. After 15 weeks administration (500 μg Cr/kg body mass) to healthy mice, abnormal metabolism and pathological change were not observed. After 15 weeks of treatment (0-1,000 μg Cr/kg body mass) of diabetic mice, the effect of high-chromium yeast on blood lipids and blood glycosylated hemoglobin (GHb) of diabetes are not consistent. High-chromium yeast results in a lowering (P < 0.05) of GHb and triglyceride, lowering (P < 0.01) of total cholesterol, and restoration (P < 0.01) of insulin; these results are in stark contrast to those of diabetic mice of administration of normal yeast, which have no effect on these parameters and serve as control group. The histopathological analysis of pancreas islet shows that high-chromium yeast could profoundly protect the impaired pancreatic islet and β-cells from inflammatory infiltration and fibrosis.