Oral zinc supplementation does not improve oxidative stress or vascular function in patients with type 2 diabetes with normal zinc levels

Zinc Supplementation in Individuals with Prediabetes and type 2 Diabetes: a GRADE-Assessed Systematic Review and Dose-Response Meta-analysis

Zinc supplementation has therapeutic effects on cardiovascular disease (CVD) risk factors, including dyslipidemia, hyperglycemia, and inflammation as the main contributors to CVD pathogenesis. Since CVD is a major cause of mortality among people with type 2 diabetes mellitus (T2DM), this study aimed to overview the potential effects of zinc supplementation on CVD risk factors in T2DM patients. To determine appropriate randomized clinical trials (RCTs) investigating the effects of zinc supplementation on CVD risk factors, electronic sources including PubMed, Web of Science, and Scopus were systematically searched until January 2023. The heterogeneity of trials was checked using the I2 statistic. According to the heterogeneity tests, random-effects models were estimated, and pooled data were defined as the weighted mean difference (WMD) with a 95% confidence interval (CI). Of the 4004 initial records, 23 studies that met inclusion criteria were analyzed in this meta-analysis. The pooled findings indicated the significant lowering effects of zinc supplementation on triglycerides (TG), total cholesterol (TC), fasting blood glucose (FBG), hemoglobin A1C (HbA1C), and C-reactive protein (CRP), while high-density cholesterol (HDL) concentrations showed an elevation after zinc supplementation. In addition to statistical significance, the effect of zinc supplementation on most of the variables was clinically significant; however, the quality of evidence in the included studies is regarded as low or very low for most variables. Our study demonstrated that zinc supplementation has beneficial effects on glycemic control markers, lipid profile, and CRP levels as a classic marker of inflammation in T2DM. Due to the high degree of heterogeneity between studies and the low rate of quality in them, further well-designed studies are necessitated to strengthen our findings.

Association of Blood Trace Elements Levels with Cardiovascular Disease in US Adults: a Cross-Sectional Study from the National Health and Nutrition Examination Survey 2011-2016

We aimed to explore the overall association between trace elements and cardiovascular disease (CVD) and its types in humans. A total of 5101 participants' blood samples from the 2011-2016 National Health and Nutrition Examination Survey were included. Biochemical data were collected from laboratory tests conducted at mobile screening centers. After assessing linearity, weighted logistic regression estimated the association between trace elements and various CVD types. Weighted quantile sum (WQS) regression and quantile-based g-computation (Qgcomp) evaluated the overall relationship between biological trace elements and CVD types. After fully adjusting for confounding factors, the odds ratios of overall CVD morbidity corresponding to the second, third, and fourth quartiles of higher selenium (Se) concentration were 0.711 (95% CI, 0.529-0.956, p = 0.024), 0.734 (95% CI, 0.546-0.987, p = 0.041), and 0.738 (95% CI, 0.554-0.983, p = 0.038), respectively. Moreover, an increase in the concentration of copper (Cu) was associated with an increased risk of stroke (95% CI, 1.012-1.094, p = 0.01), heart failure (95% CI, 1.001-1.095, p = 0.046), and heart attack (95% CI, 1.001-1.083, p = 0.046). As the concentration of trace elements in the body increased, there was a significant positive association between Cu and CVD prevalence. On the other hand, Se and zinc were negatively associated with CVD prevalence. A nonlinear relationship between Se and CVD was found, and an appropriate Se intake may reduce the risk of CVD. Cu levels positively correlated with CVD risk. However, prospective cohort studies are warranted to confirm the causal effects of the micronutrients on CVD and its types.

Investigation of Zinc on hemorheological parameters in a rat model of diabetes

Diabetes mellitus (DM) is a complex, chronic metabolic disorder characterized by impaired regulation of blood glucose levels. Zinc (Zn) is an essential trace elements that plays a role in various physiological processes within the body, including those related to diabetes. The current study was investigated the effect of Zn supplementation on hemorheological parameters in a rat model of DM. After induction of DM, 32 male Wistar albino rats were divided into four groups: control, Zn, DM, and Zn+DM. Whole blood viscosity (WBV) was determined by using digital cone and plate viscometer and plasma viscosity (PV) was determined by a Coulter Harkness capillary viscometer. The rats in the DM Group showed a decrease in both Zn levels and body weight, as well as an increase in glucose levels when compared to the control group. Diabetic rats supplemented with Zn displayed lower blood glucose levels and higher concentrations of Zn compared to the DM Group. The higher PV and lower hematocrit level were measured in DM Group than control group and lower PV, higher hematocrit level were measured in Zn+DM group than DM Group. The WBV was measured at four different shear rates (57.6-115.2 - 172.8-230.4 s -1). A statistically significant increase was observed in the DM group compared to the control group. Additionally, a statistically significant decrease was observed in the Zn+DM Group compared to the DM Group at a shear rate of 230.4 s-1. Erythrocyte rigidity index (Tk) and oxygen delivery index (ODI) were computed under conditions of high shear rate. The rats in the DM group exhibited a reduction in ODI and an elevation in Tk in comparison to the control group. Conversely, the diabetic rats supplemented with Zn exhibited decreased Tk and increased ODI compared to the DM Group. Zn supplementation seems to have a potential beneficial effect for protecting adverse affect of diabetes on hemorheogical parameters and for maintaining vascular health.

The effect of chrono-nutritional manipulation of carbohydrate intake on sleep macrostructure: A randomized controlled trial

BACKGROUND & AIMS

Over the years, there is a rapid increase in the prevalence of inadequate sleep and its detrimental consequences. Yet, the impact of prolonged nutritional interventions on sleep optimization remains unexplored. To examine the effect of carbohydrate manipulation combined with exercise training on sleep macro-structure.

METHODS

Forty-two healthy, trained male volunteers were recruited for this study. The 4-week intervention consisted of three groups: i) Sleep Low-No Carbohydrates (SL-NCHO): participants consumed all their carbohydrate intake at regular intervals prior to evening training, ii) Sleep High-Low Glycemic Index (SH-LGI) and iii) Sleep High-High Glycemic Index (SH-HGI): Carbohydrate intake was spread throughout the day, both prior (60% of total CHO intake) and after evening training (40% of total CHO intake). The SH-LGI and SH-HGI groups differentiated by consuming either LGI or HGI foods in the evening, respectively. Alongside, participants performed a standardized exercise program combining resistance exercise and high-intensity interval training. Participants' sleep macro-structure was assessed with polysomnography, actigraphy, sleep diary, and sleep-wake questionnaires.

RESULTS

Objective assessments revealed a substantial time-effect on sleep initiation, duration, and continuity. After the intervention, sleep onset latency decreased (p < 0.001), sleep duration was prolonged (p = 0.006), sleep efficiency increased (p < 0.001), and wake after sleep onset decreased (p = 0.035). Sleep macroarchitecture did not significantly change, while the percentage of REM sleep stage to the total sleep time increased over time (p < 0.01). Consistent with the objective findings, subjects reported improved subjective sleep quality (p = 0.043) and reduced daytime sleepiness (p = 0.047).

CONCLUSION

The combination of a personalized dietary plan with exercise training enhances sleep initiation, sleep continuity, sleep duration, REM and N1 sleep stages, independently of carbohydrate type or timing. Lifestyle interventions should be investigated further to promote sleep quality and recovery.

REGISTRATION

The trial was registered at clinicaltrials.gov as NCT05464342.

Effect of Zinc Supplementation on Lipid Profile and Body Composition in Patients with Type 2 Diabetes Mellitus: A GRADE-Assessed Systematic Review and Dose-Response Meta-analysis

The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to investigate the overall effects of zinc supplementation on lipid profile and body composition such as body weight (BW), body mass index (BMI), triglycerides (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) in patients with type 2 diabetes mellitus (T2DM). Scopus, Web of Science, PubMed, and Embase databases were searched from inception through October, 2023. The I2 and Cochran's Q tests were used to assess heterogeneity between studies. Nineteen RCTs (n = 1357 participants) were included in the meta-analysis. Zinc supplementation significantly reduced TG (WMD = - 17.41 mg/dL; 95% CI: - 22.60, - 12.22; P < 0.001), TC (WMD: - 19.60 mg/dL; 95% CI: - 28.46, - 10.73, P < 0.001), LDL-C (WMD = - 8.80 mg/dL; 95% CI: - 14.80, - 2.81; P = 0.004), and BMI (WMD = - 0.53 kg/m2; 95% CI: - 1.05, - 0.01; P = 0.046) but not BW (WMD: - 0.51 kg, 95 % CI: - 1.99, 0.97, P = 0.498). Moreover, zinc supplementation increased HDL-C (WMD = 4.82 mg/dL; 95% CI: 0.88, 8.76; P = 0.016) in patients with T2DM. Our results propose that zinc supplementation may be an effective strategy for improving lipid profile and body composition in patients with T2DM.

The Effect of Zinc Supplementation on Lipid Profiles in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Dose-Response Meta-Analysis of Randomized Clinical Trials

Research on the effects of zinc supplementation on lipid profiles in people with type 2 diabetes mellitus (T2DM) has been inconsistent. This systematic review and meta-analysis was performed to summarize the current data on the effects of zinc supplementation on lipid profiles in patients with T2DM. Three online databases including PubMed, Scopus, and Web of Science were searched to find relevant studies published until September 2022. The exposure was zinc supplementation, and the outcomes were low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), and total cholesterol (TC). Fourteen randomized clinical trials consisting of 1067 patients were included in the statistical analysis. Significant improvement was observed in all 4 lipid profile components. Following zinc supplementation, a significant decrease was observed in TC (weighted mean difference [WMD]: -16.16; 95% confidence interval [CI]: -26.43, -5.89; P = 0.002), LDL (WMD: -6.18; 95% CI: -9.35, -3.02; P < 0.001), and TG (WMD: -13.08; 95% CI: -21.83, -4.34; P = 0.003). After analyzing 13 studies reporting HDL, a significant increase was seen (WMD: 3.76; 95% CI: 1.30, 6.22; P = 0.003). In a nonlinear dose-response analysis, a significant inverse association was observed between <12 wk zinc supplementation and TC, LDL, and TG (TC: WMD: -5, Pnonlinearity < 0.001; LDL: WMD: -5, Pnonlinearity = 0.07, TG: WMD: -16.5, Pnonlinearity = 0.006). Nonlinear dose-response analysis shows that the optimum elemental zinc dosage for the best response to the supplementation for TC, LDL, and TG are 120, 100, and 140 mg/d, respectively (TC: WMD: -5, Pnonlinearity < 0.001; LDL: WMD: -10, Pnonlinearity = 0.006, TG: WMD: -50, Pnonlinearity = 0.031). In conclusion, we found significant changes in all 4 components of the lipid profile through zinc supplementation in T2DM patients. Based on our findings, zinc supplementation may have profound favorable consequences on the lipid profile of T2DM patients, especially in the zinc-deficient group.

Zinc supplementation and cardiovascular disease risk factors: A GRADE-assessed systematic review and dose-response meta-analysis

BACKGROUND AND OBJECTIVE

A deficit in zinc has been related to a higher probability of developing cardiovascular diseases (CVDs). The anti-inflammatory and anti-oxidative capabilities of zinc may have a wide range of therapeutic impacts on CVDs. We conducted a comprehensive systematic review and meta-analysis of the possible impacts that zinc supplementation may have on the risk factors associated with CVDs.

METHODS

To identify eligible randomized clinical trials (RCTs) evaluating the effects of zinc supplementation on CVDs risk factors, electronic databases including PubMed, Web of Science, and Scopus were systematically searched up to January 2023. The heterogeneity of trials was checked using the I² statistic. According to the heterogeneity tests, random effects models were estimated and pooled data were defined as the weighted mean difference (WMD) with a 95% confidence interval (CI).

RESULTS

Of 23165 initial records, 75 studies that met inclusion criteria were analyzed in this meta-analysis. The pooled findings indicated the significant lowering effects of zinc supplementation on triglycerides (TG), total cholesterol (TC), fasting blood glucose (FBG), Hemoglobin A1C (HbA1C), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), C-reactive protein (CRP), interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), nitric oxide (NO), malondialdehyde (MDA), total antioxidant capacity (TAC), and glutathione (GSH), with no noticeable effects on low-density lipoprotein (LDL), high-density lipoprotein (HDL), insulin, systolic blood pressure (SBP), diastolic blood pressure (DBP), aspartate transaminase (AST), and Alanine aminotransferase (ALT).

CONCLUSION

Overall, zinc supplementation may boost recognized coronary risk factors that contribute to the development of CVDs. Future research should be conducted to bolster our results.

Effect of zinc supplementation in the management of type 2 diabetes: A grading of recommendations assessment, development, and evaluation-assessed, dose-response meta-analysis of randomized controlled trials

The question of whether zinc supplementation may improve cardio-metabolic health in patients with type 2 diabetes mellitus (T2DM) remains controversial and require further evaluation. This study aimed to summarize the effectiveness of oral zinc supplementation in improving cardio-metabolic risk markers in people with T2DM. We searched PubMed, Scopus, and Web of Science from inception to April 2023, for randomized controlled trials (RCTs). RCTs of type 2 diabetic adults (aged ≥18 years) comparing zinc supplementation with placebo were included. We excluded studies if not randomized, involved co-supplementation, and were conducted in children or pregnant women. Glycemic indices, lipid profiles, blood pressure, anthropometric measure, c-reactive protein (CRP), creatinine, and serum zinc were extracted. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methods. We used a random-effect model to perform the dose-response analysis. Effect sizes were presented as mean difference (MD) and 95% confidence interval (CI). 22 studies (n = 1442 participants) were included. The certainty of the evidence was rated as moderate to high. Zinc supplementation significantly reduced glycemic indices: including two-hour postprandial glucose (2hpp) (mean difference (MD): -34.34 mg/dl; 95%CI: -51.61∼ -17.07), fast blood sugar (FBS) (MD: -23.32 mg/dl; 95% CI: -33.81∼ -12.83), and hemoglobin A1c (HbA1c) (MD: -0.47; 95% CI: -0.71∼ -0.23). Zinc had a favorable effect on lipid profiles low-density lipoprotein (LDL) (MD: -10.76 mg/dl; CI: -17.79∼-3.73), triglyceride (TG) (MD: -18.23 mg/dl; CI: -32.81∼-3.65), total cholesterol (TC) (MD: -12.74 mg/dl; CI: -21.68∼-3.80), VLDL (MD: -5.39 mg/dl; CI: -7.35∼-3.43) and high-density lipoprotein (HDL) (MD: 4.04 mg/dl; CI: 0.96 ∼ 7.12). Systolic blood pressure (SBP) (MD): -3.64 mmHg; 95% CI: -6.77∼ -0.52), weight (MD: 1.00 kg; 95% CI: 0.34∼1.66), CRP (MD: -3.37 mg/l, 95% CI: -4.05∼ -2.70), and serum zinc (MD: 15.38 µg/dl; 95% CI: 10.74∼ 20.02) changed to a statistically significant extent with zinc supplementation. There was also a linear association between additional 10 mg/d zinc treatment with FBS, HbA1c, HDL, LDL, TG, TC, and serum zinc. A non-linear dose-response gradient was seen for FBS, HDL, and SBP (p < 0.05). Egger's test showed no substantial publication bias. Our findings strongly suggest a potential beneficial effect of zinc supplementation on type 2 diabetic patients. Further high-quality research is needed to determine the optimal form, dosage, and duration of zinc supplementation for this population.

Ability of a Polyphenol-Rich Nutraceutical to Reduce Central Nervous System Lipid Peroxidation by Analysis of Oxylipins in Urine: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Isoprostanes (IsoPs) are lipid peroxidation biomarkers that reveal the oxidative status of the organism without specifying which organs or tissues it occurs in. Similar compounds have recently been identified that can assess central nervous system (CNS) lipid peroxidation status, usually oxidated by reactive oxygen species. These compounds are the neuroprostanes (NeuroPs) derived from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the F2t-dihomo-isoprotanes derived from adrenic acid (AdA). The aim of the present investigation was to evaluate whether the long-term nutraceutical consumption of high polyphenolic contents (600 mg) from fruits (such as berries) and vegetables shows efficacy against CNS lipid peroxidation in urine biomarkers. A total of 92 subjects (47 females, 45 males, age 34 ± 11 years old, weight 73.10 ± 14.29 kg, height 1.72 ± 9 cm, body mass index (BMI) 24.40 ± 3.43 kg/m2) completed a randomized, cross-over, double-blind study after an intervention of two periods of 16 weeks consuming either extract (EXT) or placebo (PLA) separated by a 4-week washout period. The results showed significant reductions in three AdA-derived metabolites, namely, 17-epi-17-F2t-dihomo-IsoPs (Δ −1.65 ng/mL; p < 0.001), 17-F2t-dihomo-IsoPs (Δ −0.17 ng/mL; p < 0.015), and ent-7(RS)-7-F2t-dihomo-IsoPs (Δ −1.97 ng/mL; p < 0.001), and one DHA-derived metabolite, namely, 4-F4t-NeuroP (Δ −7.94 ng/mL; p < 0.001), after EXT consumption, which was not observed after PLA consumption. These data seem to show the effectiveness of the extract for preventing CNS lipid peroxidation, as determined by measurements of oxylipins in urine through Ultra-High-Performance Liquid Chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-ESI-MS/MS).

Zinc Chloride Enhances the Antioxidant Status, Improving the Functional and Structural Organic Disturbances in Streptozotocin-Induced Diabetes in Rats

Background and Objectives: Diabetes mellitus (DM) is a complex disease affecting the whole metabolic balance of the body and resulting in multiple organ complications: cardiovascular, neuronal, renal, etc. Our study focuses on investigating the effect of zinc chloride (Zn) on certain blood parameters suggestive for assessing the metabolic disturbances, the liver and kidney function, the oxidative stress and the immune defense capacity in experimental-induced DM with streptozotocin (STZ) and cholesterol in rats. Materials and Methods: The animals were assigned to three groups, as follows: Group 1 (Control): buffer citrate solution 0.1 mL/100 g body; Group 2 (STZ): 20 mg/kg body STZ and fat diet (10 g cholesterol/100 g diet); Group 3 (STZ+Zn): 20 mg/kg body STZ + 5 mg/kg body Zn chloride and the same fat diet. DM was induced by administering STZ in a single take daily, for three consecutive days, Zn and citrate buffer were administered orally for a month. The protocol was approved by the Ethics Committee of the University 'Grigore T Popa' Iasi, in agreement with the International Regulations about the handling of laboratory animals. Results: The use of STZ in rats fed with cholesterol was correlated with important weight gain, hyperglycemia, the intensification of the transaminases activity and the increase in serum alkaline phosphatase, cholesterol, triglyceride, urea, creatinine and in malondialdehyde. Conclusions: The treatment with Zn resulted in weight loss and a decrease in blood sugar in diabetic rats. Supplementation with Zn notably reduced oxidative stress, preserved the pancreatic architecture and restored the liver and kidney function and structure in STZ-induced DM in rats.

The Levels of Bioelements in Postmenopausal Women with Metabolic Syndrome

(1) Metabolic syndrome is a set of factors that considerably increase the risk of developing atherosclerosis, type 2 diabetes, and their cardiovascular complications. Studies show that menopause and the levels of elements may be significantly associated with increased risk of MetS. The present study evaluated the relationship between element levels (Ca, P, Na, K, Fe, Mg, Cu, Zn, Sr) and the incidence of MetS and concomitant metabolic disorders in peri-menopausal women. (2) The study involved 170 perimenopausal women. The methods used were: survey, anthropometric measurement (WC, height, BMI, WHtR), blood pressure measurement, and biochemical analysis of venous blood (lipid profile, glucose, insulin, HbA1C). (3) The study demonstrated statistically significantly higher WC, WHtR, SBP, and DBP values in women with pre-Mets than in those with Mets and the control group. Significantly higher FPG, TG, LDL, HbA1C, insulin, TG/HDL ratio, and TC/HDL ratio were recorded in the MetS group compared to the rest of respondents. In addition, post hoc analysis revealed statistically significant differences in mean K concentrations between pre-MetS and MetS women. (4) Low blood K levels in perimenopausal women are associated with an increased risk of MetS. Significantly higher Cu levels were observed in overweight women. The concentration of Cu negatively correlates with the values of TC, LDL, and SBP.

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).

Effects of zinc supplementation on inflammatory biomarkers and oxidative stress in adults: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE

Current evidence is debatable regarding the feasible effects of zinc supplementation on the inflammation and oxidative stress status of adults. This systematic review and meta-analysis aimed to clarify this inconclusiveness.

MATERIALS AND METHODS

Literature search was conducted via online databases such as PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar until June 2020. The overall effect was presented as the weighted mean difference (WMD) at 95 % confidence interval (CI) in a random-effects meta-analysis model. Publication bias was also assessed using Egger's and Begg's statistics.

RESULTS

In total, 25 clinical trials (n = 1428) were reviewed, which indicated that zinc supplementation significantly affects the concentration of C- reactive protein (WMD: -0.03 mg/l; 95 % CI: -0.06, 0.0; P = 0.029), interlukin-6 (WMD: -3.81 pg/mL; 95 % CI: -6.87, -0.76; P = 0.014), malondialdehyde (WMD: -0.78 μmol/l; 95 % CI: -1.14, -0.42; P < 0.001), and total antioxidant capacity (WMD: 95.96 mmol/l; 95 % CI: 22.47, 169.44; P = 0.010). In addition, a significant between-study heterogeneity and a non-significant increment was reported in nitric oxide (WMD: 1.47 μmol/l; 95 % CI: -2.45, 5.40; P = 0.461) and glutathione (WMD: 34.84 μmol/l; 95 % CI: -5.12, 74.80; P = 0.087).

CONCLUSION

According to the results, zinc supplementation may have beneficial anti-inflammatory and anti-oxidative effects in adults.

The Content of Minerals in the PCOS Group and the Correlation with the Parameters of Metabolism

Polycystic ovary syndrome (PCOS) is a common disease in women of childbearing age. It is characterized by excessive androgen production, ovulation disorders, and developing metabolic syndrome. The aim of the study was to check whether selected minerals were related to the pathophysiological mechanisms of PCOS. The concentrations of minerals were determined using an inductively coupled atomic plasma-emission spectrometer (ICP-AES Jobin Yvon JY-24). Blood samples from PCOS and control women were collected, processed, and digested with a microwave system in women with PCOS with and without insulin resistance and in the control group. It was found: zinc (Zn)-10.14 ± 2.11, 9.89 ± 1.44 and 10.30 ± 1.67; nickel (Ni) 0.001 ± 0.0009, 0.001 ± 0.0006 and 0.002 ± 0.00001; iron (Fe) 868.0 ± 155.8, 835.3 ± 156.4 and 833.0 ± 94.6; manganese (Mn) 0.017 ± 0.006, 0.017 ± 0.008 and 0.020 ± 0.009; copper (Cu) 0.714 ± 0.129, 0.713 ± 0.114 and 0.761 ± 0.146; magnesium (Mg) 48.4 ± 8.3, 50.0 ± 8.4 and 45.3 ± 10.7; sodium (Na) 374.3 ± 84.3, 396.3 ± 66.6 and 367.9 ± 88.9; potassium (K) 2541.8 ± 330.9, 2409.6 ± 347.1 and 2336.9 ± 211.4 (µg/g). Some micronutrient deficiencies may have a negative effect on the lipid profile in PCOS patients (Ni, Na). Further studies are needed to better understand dependencies.

Association of Serum Levels of Zinc, Copper, and Iron with Risk of Metabolic Syndrome

The association between serum concentrations of zinc, copper, or iron and the risk of metabolic syndrome are inconclusive. Therefore, we conduct a case-control study to explore the relationship between serum levels of zinc, copper, or iron and metabolic syndrome as well as each metabolic factor and insulin resistance. We enrolled 1165 adults, aged ≥ 40 (65.8 ± 10) years in a hospital-based population to compare the serum levels of zinc, copper, and iron between subjects with and without metabolic syndrome by using multivariate logistic regression analyses. The least square means were computed by general linear models to compare serum concentrations of zinc, copper, and iron in relation to the number of metabolic factors. The mean serum concentrations of zinc, copper, and iron were 941.91 ± 333.63 μg/L, 1043.45 ± 306.36 μg/L, and 1246.83 ± 538.13 μg/L, respectively. The odds ratios (ORs) of metabolic syndrome for the highest versus the lowest quartile were 5.83 (95% CI: 3.35-10.12; p for trend < 0.001) for zinc, 2.02 (95% CI: 1.25-3.25; p for trend: 0.013) for copper, and 2.11 (95% CI: 1.24-3.62; p for trend: 0.021) for iron after adjusting for age, sex, personal habits, body mass index, and homeostatic model assessment insulin resistance. Additionally, the serum zinc, copper, and iron concentrations increased as the number of metabolic factors rose (p for trend < 0.001). This was the first study to clearly demonstrate that higher serum levels of zinc, copper, and iron were associated with the risk of metabolic syndrome and the number of metabolic factors independent of BMI and insulin resistance.

Relationship between serum zinc, HOMA2 parameters and glycemic status in a regional Australian hospital population

BACKGROUND: Previous studies demonstrated lower serum zinc among prediabetics and diabetics, compared to normoglycemics, however no current data is available for regional Australia. OBJECTIVE: We aimed to determine the relationship between serum zinc, glycemic status and Homeostasis Model Assessment (HOMA2) parameters in a regional Australian hospital population. METHODS: Retrospective review of patients presenting to a regional Australian hospital between June-2004 and April-2017 was conducted. Patients ordered for fasting blood glucose (FBG)+serum zinc; or FBG+serum insulin; or FBG+serum zinc+serum insulin were included. Serum zinc, FBG, serum insulin, lipid profile, vitamin-D and demographic information were collected. β-cell function, insulin resistance and insulin sensitivity were calculated by HOMA2 calculator. RESULTS: Three hundred and thirteen patient records were retrieved: 75% normoglycemic, 19% prediabetic, 6% diabetic. Serum zinc was lowest in diabetics and lower in prediabetics than normoglycemics. In simple linear regression among all participants, higher serum zinc associated with increased insulin sensitivity, decreased insulin resistance and decreased β-cell function. CONCLUSIONS: The low serum zinc status exhibited in diabetic and prediabetic individuals may play a role in insulin resistance pathogenesis. Higher zinc levels associated with greater insulin sensitivity and lower insulin resistance signifying the importance of investigating zinc supplementation in prediabetics to prevent or delay diabetes in future studies.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.

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

BACKGROUND AND AIM

Findings on the effects of zinc supplementation on the lipid profile in patients with type 2 diabetes mellitus (T2DM) are conflicting. The current comprehensive systematic review and meta-analysis aimed to summarize available evidence in this regard.

METHODS AND RESULTS

After a systematic search in the online databases, we included the randomized controlled trials (RCTs) investigating the effect of zinc supplementation on lipid profile [total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG)] in patients with T2DM. Altogether, 9 studies with a total sample size of 424 patients with T2DM were included in the analysis. Combining 9 effect sizes from 9 RCTs, we found a significant lowering effect of zinc supplementation on serum levels of TG (weighted mean difference (WMD): -17.08, 95% CI: -30.59, -3.58 mg/dL, P = 0.01) and TC (WMD: -26.16, 95% CI: -49.69, -2.62 mg/dL, P = 0.02). Although the overall effect of zinc supplementation on LDL-C levels was not significant, a beneficial effect was seen in studies that administered <100 mg/d zinc. Based on the non-linear dose-response analysis, a greater reduction in serum levels of TC and LDL-C following zinc supplementation was seen at <12 weeks' duration of intervention. Unlike the overall effect size, we found a significant increasing effect of zinc supplementation on serum HDL-C concentrations in most subgroups of RCTs according to the subgroup analyses.

CONCLUSION

We found that zinc supplementation may beneficially influence lipid profile in patients with T2DM.

Combined effect of high-dose vitamin A, vitamin E supplementation, and zinc on adult patients with diabetes: A randomized trial

In type 2 diabetes mellitus (T2DM), hyperglycemia leads to oxidative insult. Vitamins A and E have antioxidant potentials and may help in managing diabetes. The combined effect of high-dose vitamin A plus E supplementation with and without zinc on T2DM, has never been examined. Thus, this study aimed to evaluate and compare the effect of high-dose vitamin A plus E supplementation (AE) versus high-dose vitamin A plus E with zinc (AEZ), on different diabetic parameters. Ninety-eight patients with T2DM were randomized to receive either: 50,000 IU vitamin A and 100 mg vitamin E (AE group, N = 36), an equivalent dose of vitamin A and E combined with 25 mg zinc (AEZ group, N = 35), or no supplements (control group, N = 27) for three months. Compared to control, AEZ group showed significant reductions in fasting blood glucose, 2 h postprandial blood glucose, and glycated hemoglobin (HbA1c) with significant increases in homeostasis model assessment of beta-cell function and difference value of fasting insulin. Two hair loss cases were recorded in both treated groups. Although vitamin A needs dose moderation, these results suggest that, high-dose vitamin A plus E supplementation combined with zinc may improve glycemic control, β-cell function, and insulin secretion in adults with T2DM.

Effects of Zinc Supplementation on Cardiometabolic Risk Factors: a Systematic Review and Meta-analysis of Randomized Controlled Trials

The prevalence of cardiometabolic risk factors has been increasing worldwide. The results of reported studies on the effects of zinc supplementation on cardiometabolic risk factors are unequivocal. This systematic review and meta-analysis of randomized controlled trials was conducted to evaluate the effects of zinc supplementation on cardiometabolic risk factors. A systematic search was conducted through international databases (PubMed/Medline, Institute of Scientific Information, and Scopus) until December 2018 to include all randomized controlled trials (RCT), quasi-RCT, and controlled clinical trials which assessed the effect of zinc supplementation on cardiometabolic risk factors including lipid profile, glycemic indices, blood pressure, and anthropometric indices. Random- or fixed-effects meta-analysis method was used to estimate the standardized mean difference (SMD) and 95% confidence interval (CI). A total of 20 studies were included in the meta-analysis, which included a total of 1141 participants in the intervention group. Meta-analysis showed that zinc supplementation significantly decreased plasma levels of triglyceride (SMD - 0.66, 95% CI - 1.27, - 0.06), very-low-density lipoprotein (SMD - 1.59, 95% CI - 2.86, - 0.31), and total cholesterol (SMD - 0.65, 95% CI - 1.15, - 0.15). Similarly, zinc supplementation significantly decreased fasting blood glucose (SMD - 0.52, 95% CI - 0.96, - 0.07) and HbA1c (SMD - 0.64, 95% CI - 1.27, - 0.02). The effects of zinc supplementation on blood pressure and anthropometric indices were not statistically significant (P > 0.05). Zinc supplements had beneficial effects on glycemic indices and lipid profile. Thus, it appeared that zinc supplementation might be associated with a decrease in cardiometabolic risk factors contributing to a reduction in risk of atherosclerosis.

Brief Report: Zinc Supplementation and Inflammation in Treated HIV

OBJECTIVE

In this study, we explored the effect of zinc supplementation on markers of inflammation and monocyte activation in antiretroviral therapy-treated HIV infection.

METHODS

This is a phase I open-labeled randomized double-arm study, exploring the efficacy and safety of zinc supplementation on inflammation in ≥18-year-old people living with HIV in the US, on stable antiretroviral therapy and with zinc levels ≤75 µg/dL in the last 60 days. Patients were randomized 1:1 to zinc gluconate capsules at a dose of 45 mg (low-dose), or 90 mg (high-dose) elemental zinc daily for 16 weeks. We assessed inflammatory and gut integrity biomarkers at baseline and 16 weeks.

RESULTS

Overall, a total of 52 participants were enrolled (25 participants in the low-dose arm and 27 participants in the high-dose arm). Median (Interquartile range) age was 49 (38, 60) years, 77% were men and 73% were African Americans. At baseline, median zinc levels were 73 (64, 86) µg/dL. Median circulating zinc levels increased to 91 µg/dL in the low-dose arm and to 100 µg/dL in the high-dose arm. Overall, 48%-60% of participants experienced a reduction in biomarkers levels. The margin of reduction ranged between 8% and 21%. This change was meaningful with large effect size (Cohen D ranging from 5 to 19).

CONCLUSIONS

In this pilot study, we found that zinc supplementation is effective at increasing circulating zinc levels. In addition, our findings provide novel data suggesting that zinc can affect a biological signature in people living with HIV and modulate biomarkers associated with clinical comorbidities.

The effect of zinc supplementation on blood pressure: a systematic review and dose-response meta-analysis of randomized-controlled trials

PURPOSE

Despite previous investigations on the effects of zinc supplementation on blood pressure, inconsistent findings are available in this regard. Therefore, we conducted a systematic review and meta-analysis of randomized clinical trials on the effects of zinc supplementation on blood pressure (BP) in adults.

METHODS

Relevant studies published up to September 2019 were searched through PubMed/Medline, Scopus, ISI Web of Science, and Google Scholar using suitable keywords. All randomized clinical trials (RCTs) that examined the effect of oral zinc supplementation on systolic blood pressure (SBP) or diastolic blood pressure (DBP) in adults were included.

RESULTS

Overall, nine trials were included in our study. Zinc supplementation significantly reduced SBP compared to the control [weighted mean differences (WMD) - 1.49 mmHg; 95% CI - 2.85 to - 0.13; P = 0.03]. However, zinc supplementation had no significant effects on DBP (WMD - 0.88 mmHg; 95% CI - 2.04 to 0.29; P = 0.14). Nonlinear analysis failed to indicate a significant influence of supplementation dosage or duration on both SBP and DBP. Sensitivity analysis showed that no individual study had a significant impact on our final results. In addition, we found no evidence for the presence of small-study effects among studies for both SBP and DBP.

CONCLUSION

We found a significant reduction in SBP following zinc supplementation. However, zinc supplementation had no significant effect on DBP. In addition, no nonlinear association was found between supplementation dosage and duration with changes in both SBP and DBP. Further RCTs using different dosages of zinc in various durations are required to confirm our conclusion.

The influence of zinc supplementation on metabolic status in gestational diabetes: a meta-analysis of randomized controlled studies

INTRODUCTION

Zinc supplementation has emerged as an important approach to improve metabolic status in gestational diabetes. However, its use has not been well established. We conduct a systematic review and meta-analysis to evaluate the efficacy of zinc supplementation to improve metabolic status for gestational diabetes.

METHODS

PubMed, Embase, and the Cochrane Central Register of Controlled Trials are searched. Randomized controlled trials (RCTs) assessing the influence of zinc supplementation (or its combination) versus placebo on metabolic status of gestational diabetes are included. Two investigators independently have searched articles, extracted data, and assessed the quality of included studies. Meta-analysis is performed using the random-effect model.

RESULTS

Five RCTs involving 263 patients are included in the meta-analysis. Compared with control intervention for gestational diabetes, zinc supplementation is associated with significantly reduced FPG (std. MD = -0.52; 95% CI = -0.82 to -0.21; p = .0008), insulin (std. MD = -0.68; 95% CI = -0.98 to -0.37; p < .0001), HOMA-IR (std. MD = -0.77; 95% CI = -1.08 to -0.45; p < .00001), and increased QUICKI (std. MD = 0.58; 95% CI = 0.28-0.89; p = .0002) as well as zinc change (std. MD = 0.90; 95% CI = 0.58-1.21; p < .00001), but has no remarkable influence on LDL-cholesterol (std. MD = -0.13; 95% CI = -0.43-0.17; p = .40), and total cholesterol (std. MD = -0.28; 95% CI = -0.63-0.07; p = .11).

CONCLUSIONS

Zinc supplementation is effective to decrease FPG, insulin, HOMA-IR and improve QUICKI in gestational diabetes, but has no significant impact on LDL-cholesterol and total cholesterol.

The effects of zinc supplementation on clinical response and metabolic profiles in pregnant women at risk for intrauterine growth restriction: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

This investigation was conducted to assess the effects of zinc supplementation on clinical response and metabolic status among pregnant women at risk for intrauterine growth restriction (IUGR).

METHODS

This randomized, double-blind, placebo-controlled, clinical trial was conducted among 52 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to take either 233 mg zinc gluconate (containing 30 mg zinc) supplements (n = 26) or placebo (n = 26) for 10 weeks from 17 to 27 weeks of gestation. Fasting blood samples were taken at baseline and after the 10-week treatment to quantify related variables.

RESULTS

After the 10-week intervention, taking zinc led to a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) (β ‒1.17 mg/L; 95% CI, -1.77, -0.57; p < .001) and plasma malondialdehyde (MDA) levels (β -0.23 µmol/L; 95% CI, -0.45, -0.02; p = .03); also a significant rise in total antioxidant capacity (TAC) (β 59.22 mmol/L; 95% CI, 25.07, 93.36; p = .001) was observed in comparison to placebo. In addition, zinc supplementation significantly reduced serum insulin (β -1.33 µIU/mL; 95% CI, -2.00, -0.67; p < .001) and insulin resistance (β -0.30; 95% CI, -0.44, -0.15; p < .001), and significantly increased insulin sensitivity (β 0.008; 95% CI, 0.003, 0.01; p < .001) compared with the placebo. Zinc supplementation did not influence pulsatility index (PI) and other metabolic parameters.

CONCLUSIONS

Overall, zinc supplementation in pregnant women at risk for IUGR had beneficial effects on TAC, MDA, hs-CRP, and insulin metabolism, but did not affect PI and other metabolic profiles.

Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Although many studies have shown that low zinc status is associated with diabetes, the putative effects of zinc supplementation on glycemic control are inconclusive.

OBJECTIVES

The aim of this meta-analysis of randomized controlled trials was to assess the effects of zinc supplementation in preventing and managing diabetes.

METHODS

PubMed, Embase, and the Cochrane Library were searched for articles that were published through February 10, 2019 and contained estimates for the outcomes of interest. The pooled results were then analyzed with the use of a random-effects model.

RESULTS

Thirty-two placebo-controlled interventions were extracted from 36 publications, involving a total of 1700 participants in 14 countries. Overall, compared with their respective control groups, the subjects in the zinc-supplementation group had a statistically significant reduction in fasting glucose [FG, weighted mean difference (WMD): -14.15 mg/dL; 95% CI: -17.36, -10.93 mg/dL], 2-h postprandial glucose (WMD: -36.85 mg/dL; 95% CI: -62.05, -11.65 mg/dL), fasting insulin (WMD: -1.82 mU/L; 95% CI: -3.10, -0.54 mU/L), homeostasis model assessment for insulin resistance (WMD: -0.73; 95% CI: -1.22, -0.24), glycated hemoglobin (WMD: -0.55%; 95% CI: -0.84, -0.27%), and high-sensitivity C-reactive protein (WMD: -1.31 mg/L; 95% CI: -2.05, -0.56 mg/L) concentrations. Moreover, subgroup analyses revealed that the effects of zinc supplementation on FG are significantly influenced by diabetic status and the formulation of the zinc supplement.

CONCLUSIONS

Our analysis revealed that several key glycemic indicators are significantly reduced by zinc supplementation, particularly the FG in subjects with diabetes and in subjects who received an inorganic zinc supplement. Together, these findings support the notion that zinc supplementation may have clinical potential as an adjunct therapy for preventing or managing diabetes. This trial was registered at PROSPERO as CRD42018111838.

Meta-Analysis: Effects of Zinc Supplementation Alone or with Multi-Nutrients, on Glucose Control and Lipid Levels in Patients with Type 2 Diabetes

The present study aims to assess the effects of zinc supplementation on metabolic parameters in patients with type 2 diabetes. A literature search was conducted in PubMed^TM, Google Scholar^TM, and Scopus^TM up to March 2018. Twenty randomized controlled trials met the predefined inclusion criteria and were included in the meta-analysis. Weighted mean difference (WMD) with 95% confidence intervals (CIs) were calculated for net changes in glycemic indices including fasting blood glucose (FBG) and hemoglobin A1c (HbA1c), and in lipid markers including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and high density lipoprotein cholesterol (HDL-c). Subgroup analyses were performed based on intervention and study quality. Compared to controls, zinc supplementation significantly reduced the concentrations of both FBG and HbA1c (FBG WMD: −19.66 mg/dL, 95% CI: −33.71, −5.62; HbA1c WMD: −0.43 mg/dL, 95% CI: −0.80, −0.07). The pooled estimate showed a significant decrease in serum TC and LDL-c, and increase in serum HDL-c levels in treatment group compared with the control group (TC WMD: −18.51 mg/dL, 95% CI: −21.36, −15.66; LDL-c WMD: −4.80 mg/dL, 95% CI: −6.07, −3.53; HDL-c WMD: 1.45 mg/dL, 95% CI: 1.40, 1.51). Subgroup analysis of “no co-supplement” intervention demonstrated significant differences for mean changes in HDL-c and FBG levels, whereas subgroup analysis of high quality studies showed significant differences for mean changes of LDL-c, HDL-c, and FBG levels. Results suggested that zinc supplementation reduces FBG, HbA1c and LDL-c levels and increases HDL-C levels; however, these changes were related to intervention and quality of studies.

Nutritional Effects of Zinc on Metabolic Syndrome and Type 2 Diabetes: Mechanisms and Main Findings in Human Studies

Zinc (Zn) plays crucial roles in mammalian metabolism. There is increasing interest about the potential beneficial effects of Zn on the prevention or treatment of non-communicable diseases. This review critically analyzes the information related to the role of Zn on the metabolic syndrome (MetS) as well as type 2 diabetes (T2D), and summarizes the biological basis of these potential effects of Zn. There are several mechanisms by which Zn may help to prevent the development or progression of MetS and T2D, respectively. Zn is involved in both insulin secretion and action in peripheral tissues. Specifically, Zn has insulin-mimetic properties that increase the activity of the insulin signaling pathway. Zn modulates long-chain polyunsaturated fatty acids levels through its action on the absorption of essential fatty acids in the intestine and its subsequent desaturation. Zn is also involved in both the assembly of chylomicrons and lipoproteins as well as their clearance, and thus, plays a role in lipolysis regulation. Finally, Zn has been found to play a role in redox metabolism, and in turn, on blood pressure. The evidence related to the association between Zn status and occurrence of MetS is inconsistent. Although there are several studies reporting an inverse relationship between Zn status or dietary Zn intake and MetS prevalence, others found a direct relationship between Zn status and MetS prevalence. Intervention studies also provide confusing information about this issue, making it hard to reach firm conclusions. Zn as part of the treatment for patients with T2D has been shown to have positive responses in terms of glucose control outcomes, but only among those with Zn deficiency.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

The effect of zinc and vitamin E cosupplementation on metabolic status and its related gene expression in patients with gestational diabetes

Objective: The aim of this study was to determine the effects of zinc and vitamin E cosupplementation on metabolic status and gene expression related to insulin and lipid metabolism in women with gestational diabetes mellitus (GDM).Methods: Fifty-four women, in the age range of 18-40 years, diagnosed with GDM were recruited for this randomized, double-blinded, placebo-controlled trial. Subjects were randomly allocated into two intervention groups to either taking 233 mg/day Zinc Gluconate plus 400-IU/day vitamin E supplements or placebo (n = 27 each group) for 6 weeks. Gene expression related to insulin and lipid metabolism was evaluated in peripheral blood mononuclear cells (PBMCs) of women with GDM using RT-PCR method.Results: Participants who received zinc plus vitamin E supplements had significantly lower serum insulin levels (β = -3.81; 95% CI, -5.90, -1.72; p = .001), homeostasis model of assessment-insulin resistance (β = -0.96; 95% CI, -1.54, -0.38; p = .002), serum total-cholesterol (β = -8.56; 95% CI, -16.69, -0.43; p = .03) and low density lipoprotein-cholesterol (LDL)-cholesterol (β = -8.72; 95% CI, -15.27, -2.16; p = .01), and higher quantitative insulin sensitivity check index (β = 0.01; 95% CI, 0.005, 0.02; p = .007) compared with the placebo. Moreover, zinc and vitamin E cosupplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ; p = .03) and low-density lipoprotein receptor (LDLR; p = .04) compared with the placebo. Though, zinc and vitamin E combination did not affect other metabolic parameters.Conclusions: Overall, zinc and vitamin E cosupplementation for 6 weeks in women with GDM significantly improved insulin metabolism, lipid profile, and the gene expression levels of PPAR-γ and LDLR.

The beneficial effects of Zn on Akt-mediated insulin and cell survival signaling pathways in diabetes

Zinc is one of the essential trace elements and participates in numerous physiological processes. Abnormalities in zinc homeostasis often result in the pathogenesis of various chronic metabolic disorders, such as diabetes and its complications. Zinc has insulin-mimetic and anti-diabetic effects and deficiency has been shown to aggravate diabetes-induced oxidative stress and tissue injury in diabetic rodent models and human subjects with diabetes. Akt signaling pathway plays a central role in insulin-stimulated glucose metabolism and cell survival. Anti-diabetic effects of zinc are largely dependent on the activation of Akt signaling. Zn is also an inducer of metallothionein that plays important role in anti-oxidative stress and damage. However, the exact molecular mechanisms underlying zinc-induced activation of Akt signaling pathway remains to be elucidated. This review summarizes the recent advances in deciphering the possible mechanisms of zinc on Akt-mediated insulin and cell survival signaling pathways in diabetes conditions. Insights into the effects of zinc on epigenetic regulation and autophagy in diabetic nephropathy are also discussed in the latter part of this review.

Relevance of 4-F4t-neuroprostane and 10-F4t-neuroprostane to neurological diseases

F₄-neuroprostanes (F₄-NeuroPs) are non-enzymatic oxidized products derived from docosahexaenoic acid (DHA) and are suggested to be oxidative damage biomarkers of neurological diseases. However, 128 isomers can be formed from DHA oxidation and among them, 4(RS)-4-F_4t-NeuroP (4-F_4t-NeuroP) and 10(RS)-10-F_4t-NeuroP (10-F_4t-NeuroP) are the most studied. Here, we report the identification and the clinical relevance of 4-F_4t-NeuroP and 10-F_4t-NeuroP in plasma of four different neurological diseases, including multiple sclerosis (MS), autism spectrum disorders (ASD), Rett syndrome (RTT), and Down syndrome (DS). The identification and the optimization of the method were carried out by gas chromatography/negative-ion chemical ionization tandem mass spectrometry (GC/NICI-MS/MS) using chemically synthesized 4-F_4t-NeuroP and 10-F_4t-NeuroP standards and in oxidized DHA liposome. Both 4-F_4t-NeuroP and 10-F_4t-NeuroP were detectable in all plasma samples from MS (n = 16), DS (n = 16), ASD (n = 9) and RTT (n = 20) patients. While plasma 10-F_4t-NeuroP content was significantly higher in patients of all diseases as compared to age and gender matched healthy control subjects (n = 61), 4-F_4t-NeuroP levels were significantly higher in MS and RTT as compared to healthy controls. Significant positive relationships were observed between relative disease severity and 4-F_4t-NeuroP levels (r = 0.469, P <0.0001), and 10-F_4t-NeuroP levels (r = 0.757, P < 0.0001). The study showed that the plasma amount ratio of 10-F_4t-NeuroP to 4-F_4t-NeuroP and the plasma amount as individual isomer can be used to discriminate between different brain diseases. Overall, by comparing the different types of disease, our plasma data indicates that 4-F_4t-NeuroP and 10-F_4t -NeuroP: i) are biologically synthesized in vivo and circulated, ii) are related to clinical severity of neurological diseases, iii) are useful to identify shared pathogenetic pathways in distinct brain diseases, and iv) appears to be distinctive for different neurological conditions, thus representing potentially new biological disease markers. Our data strongly suggest that in vivo DHA oxidation follows preferential chemical rearrangements according to different brain diseases.

Magnesium-zinc-calcium-vitamin D co-supplementation improves glycemic control and markers of cardiometabolic risk in gestational diabetes: a randomized, double-blind, placebo-controlled trial

To the best our knowledge, data on the effects of magnesium-zinc-calcium-vitamin D co-supplementation on glycemic control and markers of cardiometabolic risk in gestational diabetes mellitus (GDM) are scarce. The purpose of this study was to establish the effects of magnesium-zinc-calcium-vitamin D co-supplementation on glycemic control and markers of cardiometabolic risk of GDM patients. Sixty patients with GDM, aged 18-40 years, were randomized into 2 groups to intake either magnesium-zinc-calcium-vitamin D co-supplements or placebo (n = 30 each group) for 6 weeks in a randomized, double-blind, placebo-controlled trial. Fasting blood samples were taken at baseline and week 6 to quantify related markers. After the 6-week intervention, compared with the placebo, magnesium-zinc-calcium-vitamin D co-supplementation resulted in significant reductions in fasting plasma glucose (-0.37 ± 0.09 vs. +0.01 ± 0.09 mmol/L, P = 0.003), serum insulin levels (-21.0 ± 4.8 vs. +7.2 ± 4.8 pmol/L, P < 0.001), homeostatic model of assessment for insulin resistance (-1.0 ± 1.1 vs. +0.3 ± 1.3, P < 0.001), and a significant increase in quantitative insulin sensitivity check index (+0.02 ± 0.03 vs. -0.002 ± 0.03, P = 0.003). In addition, magnesium-zinc-calcium-vitamin D co-supplementation significantly decreased serum triglycerides (-0.25 ± 0.10 vs. +0.34 ± 0.10 mmol/L, P = 0.001) and very-low-density-cholesterol concentrations (-0.11 ± 0.04 vs. +0.15 ± 0.04 mmol/L, P = 0.001) compared with the placebo. Overall, the results of this study demonstrated that magnesium-zinc-calcium-vitamin D co-supplementation for 6 weeks among patients with GDM had beneficial effects on glycemic control and few markers of cardiometabolic risk.

Implications of impaired zinc homeostasis in diabetic cardiomyopathy and nephropathy

Impaired zinc homeostasis is observed in diabetes mellitus (DM2) and its complications. Zinc has a specific role in pancreatic β-cells via insulin synthesis, storage, and secretion. Intracellular zinc homeostasis is tightly controlled by zinc transporters (ZnT and Zip families) and metallothioneins (MT) which modulate the uptake, storage, and distribution of zinc. Several investigations in animal models demonstrate the protective role of MT in DM2 and its cardiovascular or renal complications, while a copious literature shows that a common polymorphism (R325W) in ZnT8, which affects the protein's zinc transport activity, is associated with increased DM2 risk. Emerging studies highlight a role of other zinc transporters in β-cell function, suggesting that targeting them could make a possible contribution in managing the hyperglycemia in diabetic patients. This article summarizes the current findings concerning the role of zinc homeostasis in DM2 pathogenesis and development of diabetic cardiomyopathy and nephropathy and suggests novel therapeutic targets. © 2017 BioFactors, 43(6):770-784, 2017.

Association of trace metal elements with lipid profiles in type 2 diabetes mellitus patients: a cross sectional study

BACKGROUND

It is well known that dyslipidemia and chronic hyperglycemia increase the onset of diabetes and diabetic complication. The aim of this study is to see the association of trace metals elements and lipid profile among type 2 diabetes mellitus patients.

METHODS

The study was conducted on 214 type 2 diabetic patients at Jimma University Specialized Hospital, Jimma, Ethiopia. All the eligible study participants responded to the structured interviewer administered questionnaire and fasting venous blood was drawn for biochemical analysis. Trace metal elements (zinc(Zn⁺²), magnesium(Mg⁺²), chromium(Cr⁺³), calcium(Ca⁺²), phosphorus(Po₄^-3), manganese(Mn⁺²), copper(Cu⁺²), and iron(Fe⁺³)) and lipid profiles (total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein (HDL-C), and triglycerides (TG)) were measured by atomic absorption spectrophotometry and enzymatic determination method respectively. Data were analyzed by SPSS version 24 software for windows. Bonferroni correction for multiple statistical comparisons was used and a p-value less than 0.01 were accepted as a level of significance.

RESULT

The mean age of study participants was 42.95(±12.6) with an average of 5.83(±3.1) years being diagnosed with diabetes mellitus. The BMI of female (27.1(±4.9)) was significantly higher than male (25.21(±4.2)). BMI shows positive and significant (p < 0.01) association with lipid profiles (TC, LDL-C, and TG) among type 2 diabetic patients in the liner regression model. In addition, WH-R was positively associated with TG. In Pearson partial correlation adjusted for sex and age, Za⁺² shown to have statistically significant and negative correlations with TC, LDL-C and with TG. Mg⁺² and Cr⁺² negatively and significantly correlated with the lipid profile TC and LDL-C. Ca⁺² negatively correlated with TC and TG. Po^-3₄ positively correlated with HDL-C; iron negatively correlated with TC. However, in the liner regression model, only calcium positively and significantly (Beta = -0.21, p < 0.01) associated with TG.

CONCLUSION

In the current study, a negative correlation was observed between trace metal elements (Zn⁺², Mg⁺², Cr⁺³, Ca⁺² and Fe⁺³) and lipid profile (TC, LDL-C and TG) among type 2 diabetes mellitus patients. In addition, Ca⁺² observed to be associated with TG. Future studies are highly advised to uncover the bidirectional association between trace metal element and dyslipidemia in diabetic patients.

Zinc status is associated with inflammation, oxidative stress, lipid, and glucose metabolism

A number of studies have reported that zinc plays a substantial role in the development of metabolic syndrome, taking part in the regulation of cytokine expression, suppressing inflammation, and is also required to activate antioxidant enzymes that scavenge reactive oxygen species, reducing oxidative stress. Zinc also plays a role in the correct functioning of lipid and glucose metabolism, regulating and forming the expression of insulin. In numerous studies, zinc supplementation has been found to improve blood pressure, glucose, and LDL cholesterol serum level. Deeper knowledge of zinc’s properties may help in treating metabolic syndrome, thus protecting against stroke and angina pectoris, and ultimately against death.

Isoprostanes, neuroprostanes and phytoprostanes: An overview of 25years of research in chemistry and biology

Since the beginning of the 1990's diverse types of metabolites originating from polyunsaturated fatty acids, formed under autooxidative conditions were discovered. Known as prostaglandin isomers (or isoprostanoids) originating from arachidonic acid, neuroprostanes from docosahexaenoic acid, and phytoprostanes from α-linolenic acid proved to be prevalent in biology. The syntheses of these compounds by organic chemists and the development of sophisticated mass spectrometry methods has boosted our understanding of the isoprostanoid biology. In recent years, it has become accepted that these molecules not only serve as markers of oxidative damage but also exhibit a wide range of bioactivities. In addition, isoprostanoids have emerged as indicators of oxidative stress in humans and their environment. This review explores in detail the isoprostanoid chemistry and biology that has been achieved in the past three decades.

Comparative study of cardio-protective effects of zinc oxide nanoparticles and zinc sulfate in streptozotocin-induced diabetic rats

The cardio-protective effects of zinc oxide nanoparticles (Zn NPs) against diabetes-induced cardiopathy were evaluated and compared with zinc sulfate (ZnSO₄). A total of 120 Wistar rats were randomly categorized as healthy and diabetic groups. Then, the 2 groups were classified in 5 subgroups. The animals received oral supplementations containing different Zn NP (ie, doses of 1, 3, and 10mg/kg) and ZnSO₄ (30mg/kg) concentrations over 8 weeks. Blood and cardiac tissue samples were collected in the different time intervals and subjected to biochemical and histopathological analysis. Zn NPs showed dual effects, as its middle dose played protective role and recovered cardiac damages evidenced by significant reduction of serum cholesterol, HDL-cholesterol, lipoprotein (a), atherogenic index, TNF-α, cardiac MDA, B-type natriuretic peptide and caspase-3 activity. Apoptosis indices and histopathological features also were improved. However, the highest dose was found to be toxic and resulted in aggravation of the injuries. Another interesting finding is the ability of the higher doses of Zn-NPs (3 and 10mg/kg) to elevate cardiac zinc levels above the normal range in healthy animal. ZnSO₄ also helped to recuperation of the damages, but the middle dose of Zn NPs was more efficient as compared to ZnSO₄. Conclusively, Zn NPs have the potential for Zn delivery in diabetic patients.

Does Zinc Really "Metal" with Diabetes? The Epidemiologic Evidence

Zinc (Zn) is important in a number of processes related to insulin secretion and insulin activity in peripheral tissues, making this element an interesting potential co-adjuvant in the treatment of patients with type 2 diabetes (T2D). This issue has been matter of interest in recent years. The available evidence is analyzed in this review. Information from epidemiologic studies evaluating the relationship between Zn and T2D is inconsistent. Furthermore, few studies examined the association between Zn status and insulin action and/or glucose homeostasis. In terms of usefulness of Zn as a preventive agent for T2D development, information is insufficient to reach firm conclusions. Results from Zn supplementation trials found some positive effects only in those with initial sub normal Zn status in a significant proportion of individuals. In conclusion, the effect of Zn on patients with type 2 diabetes is still an open question, and better study designs are needed to clarify the real impact and characteristics of the Zn-diabetes interaction.

Oxidative stress in relation to diet and physical activity among premenopausal women

Higher levels of oxidative stress, as measured by F2-isoprostanes, have been associated with chronic diseases such as CVD and some cancers. Improvements in diet and physical activity may help reduce oxidative stress; however, previous studies regarding associations between lifestyle factors and F2-isoprostane concentrations have been inconsistent. The aim of this cross-sectional study was to investigate whether physical activity and intakes of fruits/vegetables, antioxidant nutrients, dietary fat subgroups and alcohol are associated with concentrations of F2-isoprostane and the major F2-isoprostane metabolite. Urinary F2-isoprostane and its metabolite were measured in urine samples collected at enrolment from 912 premenopausal women (aged 35-54 years) participating in the Sister Study. Physical activity, alcohol consumption and dietary intakes were self-reported via questionnaires. With adjustment for potential confounders, the geometric means of F2-isoprostane and its metabolite were calculated according to quartiles of dietary intakes, alcohol consumption and physical activity, and linear regression models were used to evaluate trends. Significant inverse associations were found between F2-isoprostane and/or its metabolite and physical activity, vegetables, fruits, vitamin C, α-carotene, vitamin E, β-carotene, vitamin A, Se, lutein+zeaxanthin and long-chain n-3 fatty acids. Although trans fats were positively associated with both F2-isoprostane and its metabolite, other dietary fat subgroups including SFA, n-6 fatty acids, n-3 fatty acids, MUFA, PUFA, short-chain n-3 fatty acids, long-chain n-3 fatty acids and total fat were not associated with either F2-isoprostane or its metabolite. Our findings suggest that lower intake of antioxidant nutrients and higher intake of trans fats may be associated with greater oxidative stress among premenopausal women.

Zinc supplementation and the effects on metabolic status in gestational diabetes: A randomized, double-blind, placebo-controlled trial

OBJECTIVE

To the best of our knowledge, no reports are available indicating the effects of zinc supplementation on metabolic status in women with gestational diabetes (GDM). This study was designed to determine the effects of zinc supplementation on glucose homeostasis parameters and lipid concentrations in GDM women.

METHODS

This randomized, double-blind, placebo-controlled trial was performed among 58 women diagnosed with GDM, primigravida and aged 18-40years old. Patients were randomly divided into two groups to receive 233mg zinc gluconate (containing 30mg zinc) supplements (n=29) or placebo (n=29) per day for 6weeks. Fasting blood samples were taken at the beginning and end of the trial to quantify glucose, insulin and lipid concentrations.

RESULTS

Patients who received zinc supplements had significantly higher serum zinc concentrations (+6.9±13.2 vs. -1.5±16.5mg/dL, P=0.03) than those received the placebo. In addition, zinc-supplemented patients had reduced fasting plasma glucose (FPG) (-6.6±11.2 vs. +0.6±6.7mg/dL, P=0.005), serum insulin levels (-1.3±6.6 vs. +6.6±12.2μIU/mL, P=0.003), homeostasis model of assessment-insulin resistance (HOMA-IR) (-0.5±1.6 vs. +1.5±2.7, P=0.001), homeostatic model assessment-Beta cell function (HOMA-B) (-0.7±25.0 vs. +26.5±49.5, P=0.01) and increased quantitative insulin sensitivity check index (QUICKI) (+0.01±0.01 vs. -0.01±0.02, P=0.004) compared with the placebo. Additionally, significant differences in serum triglycerides (+13.6±61.4 vs. +45.9±36.5mg/dL, P=0.01) and VLDL-cholesterol concentrations (+2.7±12.3 vs. +9.2±7.3mg/dL, P=0.01) were observed following the administration of zinc supplements compared with the placebo.We did not observe any significant effects of taking zinc supplements on other lipid profiles.

CONCLUSIONS

Taken together, 30mg zinc supplementation per day for 6weeks among GDM women had beneficial effects on metabolic profiles.

Effects of Zinc supplementation on serum lipids: a systematic review and meta-analysis

Zinc is a mineral that plays a vital role in many biological processes and plays an important role in insulin action and carbohydrate metabolism. It may also have a protective role in the prevention of atherogenesis. Numerous studies have evaluated the effects of Zinc supplementation on serum lipids in humans and have demonstrated varying results. We systematically evaluated the literature and performed a meta-analysis on the effects of Zinc supplementation on serum lipids. A five staged comprehensive search of the literature was conducted in the following databases; PubMed, Web of Science and SciVerse Scopus for studies published before 31st December 2014. All controlled clinical trial in humans, that included a Zinc supplement intervention, either alone or in combination with other micronutrients and evaluated effects on serum lipids (total cholesterol [TC], triglycerides [TG], LDL cholesterol [LDL-c] and HDL cholesterol [HDL-c]). A meta-analysis of selected studies was performed using RevMan v5.3. The Jaded scale was used to assess the methodological quality of the trials included in the systematic review. A total of 24 studies were included in Meta analysis, which included a total of 33 Zinc interventions, in a total of 14,515 participants in the Zinc intervention or control group. The duration of Zinc supplementation ranged from 1 month to 7.5 years. The dose of elemental Zinc supplemented ranged from 15–240 mg/day. The pooled mean difference for TC between Zinc supplemented and placebo groups from random effects analysis was −10.92 mg/dl (95 % CI: −15.33, −6.52; p < 0.0001, I² = 83 %), while for HDL cholesterol it was 2.12 mg/dl (95 % CI: −0.74, 4.98; p = 0.15, I² = 83 %). The pooled mean difference for LDL-c between Zinc supplemented and placebo group from random effect analysis was −6.87 mg/dl (95 % CI: −11.16,-2.58; p < 0.001, I² = 31) and for TG it was −10.92 mg/dl (95 % CI: −18.56, − 3.28; p < 0.01, I² = 69 %). In conclusion, Zinc supplementation has favourable effects on plasma lipid parameters. Zinc supplementation significantly reduced total cholesterol, LDL cholesterol and triglycerides. Therefore it may have the potential to reduce the incidence of atherosclerosis related morbidity and mortality.

Potential drugs which activate nuclear factor E2-related factor 2 signaling to prevent diabetic cardiovascular complications: A focus on fumaric acid esters

Diabetes and its cardiovascular complications have been a major public health issue. These complications are mainly attributable to a severe imbalance between free radical and reactive oxygen species production and the antioxidant defense systems. Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that controls the basal and inducible expression of a battery of antioxidant enzyme genes and other cyto-protective phase II detoxifying enzymes. As a result, Nrf2 has gained great attention as a promising drug target for preventing diabetic cardiovascular complications. And while animal studies have shown that several Nrf2 activators manifest a potential to efficiently prevent the diabetic complications, their use in humans has not been approved due to the lack of substantial evidence regarding safety and efficacy of the Nrf2 activation. We provide here a brief review of a few clinically-used drugs that can up-regulate Nrf2 with the potential of extending their usage to diabetic patients for the prevention of cardiovascular complications and conclude with a closer inspection of dimethyl fumarate and its mimic members.