The status of zinc in type 2 diabetic patients and its association with glycemic control

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.

Effect of zinc supplementation on glycemic biomarkers: an umbrella of interventional meta-analyses

BACKGROUND

Several studies have evaluated the effects of zinc supplementation on glycemic biomarkers in humans and have demonstrated varying results. We systematically evaluated the literature and performed an umbrella meta-analysis of the effects of zinc supplementation on type 2 diabetes biomarkers.

METHODS

A comprehensive literature search was conducted in the following databases; PubMed, Embase, Embase, Cochrane Library, Scopus, and Web of Science for studies published up to March 10, 2024.

RESULTS

Zinc supplementation was effective in reducing serum FBS (WMD: - 13.58, 95% CI: - 17.38, - 9.77; p < 0.001; SMD: - 0.52, 95% CI - 0.79, - 0.25; p =  < 0.001), insulin (SMD: - 0.67, 95% CI - 0.96, - 0.38; p < 0.001), HOMA-IR levels (WMD - 0.52, 95% CI - 0.66, - 0.38; p < 0.001; SMD: - 0.78, 95% CI - 1.02, - 0.42; p < 0.001), and HbA1c (WMD: - 0.35, 95% CI - 0.43, - 0.27; p < 0.001).

CONCLUSION

Zinc supplementation significantly reduced FBS, HOMA-IR, insulin and HbA1c. These findings suggest that zinc is potentially an effective complementary intervention to improve type 2 diabetes biomarkers.

Association between circulating micronutrient pattern, glycemic control, and insulin resistance in type 2 diabetes mellitus

The circulating micronutrient pattern in type 2 diabetes mellitus (T2DM) may impact glycemic control and insulin resistance; however, there is a scarcity of studies that have evaluated the circulating micronutrient pattern in the T2DM population. Therefore, our objective was to identify circulating micronutrient pattern and their association with markers of glycemic control and insulin resistance in individuals with T2DM. We developed a cross-sectional observational study involving adults with T2DM in Sergipe, Brazil. We assessed plasma levels of magnesium, zinc, calcium, potassium, and serum 25-hydroxyvitamin D. Additionally, also measured fasting glucose levels, the percentage of glycated hemoglobin (%HbA1c), and calculated the homeostatic model assessment for insulin resistance (HOMA-IR). Patterns of body reserve were established using principal component analysis and categorized into quartiles. Binary logistic regression models were employed. We evaluated 114 individuals (63.7% women), with a median age and body mass index of 49 years and 29.6 kg/m², respectively. Two circulating micronutrient patterns were identified, explaining 62.5% of the variance: Pattern 1 (positive contributions from magnesium, zinc, calcium, and potassium) and Pattern 2 (positive contributions from 25-hydroxyvitamin D and zinc, with a negative contribution from potassium). Lowest quartile for Pattern 1 and Pattern 2 exhibiting a 4.32-fold (p = 0.019) and 3.97-fold (p = 0.038) higher likelihood of increasing HOMA-IR and %HbA1c values, respectively, compared to the larger quartiles. However, no associations were found between these patterns and fasting glucose values. Lowest quartile for both patterns of micronutrients was associated with inadequate metabolic control in individuals with T2DM.

Combined Inositols, α-Lactalbumin, Gymnema Sylvestre and Zinc Improve the Lipid Metabolic Profile of Patients with Type 2 Diabetes Mellitus: A Randomized Clinical Trial

Type 2 diabetes mellitus (T2DM) is characterized by high blood glucose levels and lipid alterations. Besides pharmacological treatment, lifestyle modifications and nutraceuticals can be used to manage glucose and lipid profiles, which is crucial for preventing, or avoiding, serious consequences associated with the condition. This randomized controlled clinical trial on 75 patients with T2DM evaluated the effects of a combination of myo-inositol and d-chiro-inositol (40:1), α-lactalbumin, Gymnema sylvestre, and zinc on glucose and lipid profile. The intention-to-treat analysis displayed no significant differences in glucose parameters between the groups; however, the study group displayed reduced levels of total cholesterol (p = 0.01) and LDL (p = 0.03) after 3 months of supplementation. A subgroup analysis involving patients who did not modify their antidiabetic therapy, after 6 months displayed improved levels of total cholesterol (p = 0.03) and LDL (p = 0.04) in the study group versus placebo, along with a greater body weight reduction (p = 0.03) after 3 months. Furthermore, within the study group, levels of HDL (p = 0.03) and triglycerides (p = 0.04) improved after 3 months. These findings support supplementation with myo-inositol and d-chiro-inositol (40:1), α-lactalbumin, Gymnema sylvestre, and zinc as an adjuvant and safe strategy to manage the lipid profiles of patients with T2DM.

Synthesis, Sensing Performance and DFT Studies of a Novel Coumarin-based Schiff Base As a Turn-on Fluorescence Probe for Zinc Ion Detection

The design and development of novel efficient fluorescent chemical sensors for the selective detection of ions is currently of significant importance in supramolecular chemistry. Since zinc is a ubiquitous, indispensable and the second most abundant metal ion in the human body, developing chemosensors that can accurately discriminate between Zn2+ and Cd2+ ions has been a challenge due to their similar properties as they are in the same group of the periodic table. Therefore, a technique to trace and visualize free zinc ions is demanded. In this study, an innovative coumarin-based Schiff base (L) was synthesized and characterized by 1H NMR, 13C NMR and mass spectroscopy. A novel "Turn On" fluorescence chemosensor platform was developed for trace amounts of Zn2+ ions. The fluorescence Job's plot measurement was used to determine the complexation ratio between the probe and Zn2+ ion, which showed a maximum point indicating the formation of a ML2 adduct. Additionally, the geometrical parameters calculated using DFT and TD-DFT calculations were in close agreement with the experimentally observed values.

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.

Ratiometric Detection of Zn2+ Using DNAzyme-Based Bioluminescence Resonance Energy Transfer Sensors

While fluorescent sensors have been developed for monitoring metal ions in health and diseases, they are limited by the requirement of an excitation light source that can lead to photobleaching and a high autofluorescence background. To address these issues, bioluminescence resonance energy transfer (BRET)-based protein or small molecule sensors have been developed; however, most of them are not highly selective nor generalizable to different metal ions. Taking advantage of the high selectivity and generalizability of DNAzymes, we report herein DNAzyme-based ratiometric sensors for Zn2+ based on BRET. The 8-17 DNAzyme was labeled with luciferase and Cy3. The proximity between luciferase and Cy3 permiQed BRET when coelenterazine, the substrate for luciferase, was introduced. Adding samples containing Zn2+ resulted in a cleavage of the substrate strand, causing dehybridization of the DNAzyme construct, thus increasing the distance between Cy3 and luciferase and changing the BRET signals. Using these sensors, we detected Zn2+ in serum samples and achieved Zn2+ detection with a smartphone camera. Moreover, since the BRET pair is not the component that determines the selectivity of the sensors, this sensing platform has the potential to be adapted for the detection of other metal ions with other metal-dependent DNAzymes.

Metal mixtures and DNA methylation measures of biological aging in American Indian populations

INTRODUCTION

Native American communities suffer disproportionately from elevated metal exposures and increased risk for cardiovascular diseases and diabetes. DNA methylation is a sensitive biomarker of aging-related processes and novel epigenetic-based "clocks" can be used to estimate accelerated biological aging that may underlie increased risk. Metals alter DNA methylation, yet little is known about their individual and combined impact on epigenetic age acceleration. Our objective was to investigate the associations of metals on several DNA methylation-based aging measures in the Strong Heart Study (SHS) cohort.

METHODS

Blood DNA methylation data from 2,301 SHS participants was used to calculate age acceleration of epigenetic clocks (PhenoAge, GrimAge, DunedinPACE, Hannum, Horvath). Urinary metals [arsenic (As), cadmium (Cd), tungsten (W), zinc (Zn), selenium (Se), molybdenum (Mo)] were creatinine-adjusted and categorized into quartiles. We examined associations of individual metals through linear regression models and used Bayesian Kernel Machine Regression (BKMR) for the impact of the total metal mixture on epigenetic age acceleration.

RESULTS

The mixture of nonessential metals (W, As, Cd) was associated with greater GrimAge acceleration and DunedinPACE, while the essential metal mixture (Se, Zn, Mo) was associated with lower epigenetic age acceleration. Cd was associated with increased epigenetic age acceleration across all clocks and BKMR analysis suggested nonlinear associations between Se and DunedinPACE, GrimAge, and PhenoAge acceleration. No interactions between individual metals were observed. The associations between Cd, Zn, and epigenetic age acceleration were greater in never smokers in comparison to current/former smokers.

CONCLUSION

Nonessential metals were positively associated with greater epigenetic age acceleration, with strongest associations observed between Cd and DunedinPACE and GrimAge acceleration. In contrast, essential metals were associated with lower epigenetic aging. Examining the influence of metal mixtures on epigenetic age acceleration can provide insight into metals and aging-related diseases.

The potential role of human islet amyloid polypeptide in type 2 diabetes mellitus and Alzheimer's diseases

Human Islet amyloid polypeptide (hIAPP) from pancreatic β cells in the islet of Langerhans has different physiological functions including inhibiting the release of insulin and glucagon. Type 2 diabetes mellitus (T2DM) is an endocrine disorder due to relative insulin insufficiency and insulin resistance (IR) is associated with increased circulating hIAPP. Remarkably, hIAPP has structural similarity with amyloid beta (Aβ) and can engage in the pathogenesis of T2DM and Alzheimer's disease (AD). Therefore, the present review aimed to elucidate how hIAPP acts as a link between T2DM and AD. IR, aging and low β cell mass increase expression of hIAPP which binds cell membrane leading to the aberrant release of Ca²⁺ and activation of the proteolytic enzymes leading to a series of events causing loss of β cells. Peripheral hIAPP plays a major role in the pathogenesis of AD, and high circulating hIAPP level increase AD risk in T2DM patients. However, there is no hard evidence for the role of brain-derived hIAPP in the pathogenesis of AD. Nevertheless, oxidative stress, mitochondrial dysfunction, chaperon-mediated autophagy, heparan sulfate proteoglycan (HSPG), immune response, and zinc homeostasis in T2DM could be the possible mechanisms for the induction of the aggregation of hIAPP which increase AD risk. In conclusion, increasing hIAPP circulating levels in T2DM patients predispose them to the development and progression of AD. Dipeptidyl peptidase 4 (DPP4) inhibitors and glucagon-like peptide-1 (GLP-1) agonists attenuate AD in T2DM by inhibiting expression and deposition of hIAP.

Inverse Correlation of Superoxide Dismutase and Catalase with Type 2 Diabetes among Rural Thais

Oxidative stress contributes to defective antioxidant defenses, which may lead to type 2 diabetes (T2D). This study aimed to elucidate the T2D risks and antioxidant defenses by investigating the superoxide dismutase (SOD), catalase (CAT), vitamin A, and vitamin E status. We observed 102 participants aged 35-66 years from Sung Neon, Nakhon Ratchasima, Thailand. The blood samples were collected to measure the SOD, CAT, vitamin A, and vitamin E concentrations. The SOD and CAT activities were inversely associated with T2D risk. When compared with participants in the highest quartile of SOD and CAT, those in the lowest quartile for T2D risk obtained multivariable-adjusted odds ratios of 4.77 (SOD: 95% confident interval CI, 1.01-22.40; p = 0.047) and 4.22 (CAT: 95% CI, 1.07-16.60; p = 0.039). The possible influencing factors (e.g., physical activity, total cholesterol, and triglyceride) might mediate the association of SOD and CAT with T2D risk. Meanwhile, the relationship between vitamin A and vitamin E concentrations and T2D risk was insignificant. In conclusion, lower concentrations of antioxidant enzyme activity (SOD and CAT) may be an additional risk factor for T2D.

Association of Serum Zinc Level with severity of chronic kidney disease in diabetic patients: a cross-sectional study

BACKGROUND

In recent years, it has been reported that diabetic patients tend to have a lower zinc intake due to unbalanced diet accompanying changes in lifestyle habits. We investigated serum zinc concentration in diabetic patients according to the stage of nephropathy.

METHODS

We enrolled 227 diabetic patients (119 men, 108 women, average age 65.7 ± 14.7 [mean ± standard deviation]) who were hospitalized for diabetes treatment due to poor blood glucose control. We investigated the relationship between fasting serum zinc concentration and estimated glomerular filtration rate (eGFR) and albuminuria (urinary albumin-to-creatinine ratio, UACR), as well as serum zinc concentration by stage of diabetic kidney disease and chronic kidney disease.

RESULTS

The mean HbA1c value was 10.5 ± 2.1%. Serum zinc concentration was 75.5 ± 16.0 μg/dL in males and 75.7 ± 12.2 μg/dL in females, showing no gender difference and no significant relationship with diabetes type. The serum zinc concentration was negatively correlated with age (r = - 0.309, P < 0.001) and positively correlated with eGFR (r = 0.144, P = 0.030). A tendency was observed of serum zinc concentration to decrease after overt nephropathy, with values of 76.4 ± 14.1 μg/dL in pre-nephropathy (stage 1, n = 131), 78.5 ± 13.2 μg/dL in incipient nephropathy (stage 2, n = 65), 66.4 ± 14.3 μg/dL in overt nephropathy (stage 3, n = 25), and 65.7 ± 11.9 μg/dL in kidney failure (stage 4, n = 6). Serum zinc showed a negative trend with estimated GFR (P = 0.004) and significant reduction in albuminuria, with stage A3 (n = 29, 65.7 ± 13.9 μg/dL) having lower levels than A1 (n = 131, 76.4 ± 14.1 μg/dL, P = 0.001) and A2 (n = 67, 78.4 ± 13.1 μg/dL, P < 0.001).

CONCLUSIONS

In diabetic patients, serum zinc concentration tended to decrease as age increased and also as renal function deteriorated. This study suggests that consideration of zinc deficiency is necessary in patients with overt albuminuria.

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.

Second Sphere Interactions in Amyloidogenic Diseases

Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.

Zinc status, insulin resistance and glycoxidative stress in elderly subjects with type 2 diabetes mellitus

Zinc deficiencies have been reported in numerous pathologies, such as diabetes mellitus, but also in the physiological process of ageing. Similarly, the end products of glycoxidation processes, advanced glycation end products (AGEs), are damaging compounds, a myriad of reports linking them to the development and progression of several age-associated chronic diseases. The aim of the present study was to analyze the relationships between zinc status, glycoxidative stress and insulin resistance (IR) in elderly subjects with type 2 diabetes mellitus (T2DM). A group of 52 non-smoking subjects (9 men and 43 women, aged 65-83 years) were enrolled in this cross-sectional study: 27 patients with T2DM, and 25 apparently healthy control subjects. Serum zinc (Zn) levels were assessed using a commercial kit based on an end-point colorimetric method, and serum AGEs were evaluated with a fluorimetric analytic procedure. The calculated glucose-to-zinc ratio (Gly/Zn), insulin-to-zinc ratio (Ins/Zn) and insulin-zinc resistance index (HOMA-IR/Zn) were further used to study the associations between serum Zn levels, secretory function of β-pancreatic cells and AGEs. T2DM patients presented significantly higher serum insulin and Zn levels, as compared to the controls. We found a significant inverse correlation between Zn and AGEs, and a strong positive correlation between AGEs and the Gly/Zn ratio, suggesting that both Zn and AGEs are biomarkers that could reflect the persistence of hyperglycemia. We identified new surrogate biomarkers useful for the assessment of glycemic control with great potential for the development of preventive and therapeutic strategies for elderly diabetics, based on the evaluation of serum Zn levels.

An observational study to estimate the level of essential trace elements and its implications in type 2 diabetes mellitus patients

Background and Objectives:

Insulin action of reducing blood glucose has been found to be enhanced by trace elements.

Material and Methods:

This was a cross sectional study including 150 patients with Type 2 Diabetes Mellitus (T2DM) and 50 controls. Serum concentrations of zinc, copper, chromium, selenium and magnesium was measured by colorimetric kit. Fasting Blood Glucose and Glycated Haemoglobin (HbA1c) were assayed using the standard kit.

Results:

Out of 150 patients, 85.4% (n = 128) of the cases had uncontrolled blood sugar with HbA1c ≥7 and only 14.6% (n = 22) had good control of blood sugar with HbA1c <7%. Hypertension (42%) and hypothyroidism (14%) were the most commonly associated comorbidities among patients with T2DM. Following percentage of diabetic patients had complications such as peripheral neuropathy (45.3%), diabetic retinopathy (36.7%), coronary artery disease (20.7%), diabetic nephropathy (17.3%), peripheral vascular disease (8.7%), and cerebrovascular accident (6%) respectively. The mean level of zinc, copper, selenium and magnesium was significantly lower in patients with T2DM than the control cases (62.89 vs. 74.95 μg/dL, P < 0.05; 116.30 vs. 150.39 μg/dL, P < 0.001; 8.57 vs. 16.16 μg/dL, P < 0.001; 1.92 vs. 2.31 mg/dL, P < 0.05, respectively). Multivariate analysis showed that there was a significant trend between levels of zinc, copper, selenium, and magnesium and the prevalence of T2DM.

Conclusions:

The levels of selenium, zinc, copper, and magnesium were significantly lower in patients with T2DM when compared to healthy counterparts.

COVID-19: Zinc and Angiotensin-Converting Enzyme 2 (ACE2) Deficiencies as Determinants of Risk and Severity of Disease: A Narrative Review

A growing body of evidence supports the premise that deficiencies of zinc and angiotensin-converting enzyme 2 (ACE2, a zinc enzyme) determine severity of coronavirus disease 2019 (COVID-19). ACE2 is part of the renin-angiotensin system (RAS) and acts as a feedback control system moderating blood pressure, keeping blood pressure within normal limits. For a virus to infect a person, the virus has to get inside the person's cells. The virus that causes COVID-19 uses ACE2 to get into the cell. Think of this like an invader from outer space attacking your car by getting in through your cruise control; the RAS is like the cruise control of your car. What happens next depends on how robust your cruise control is. If your cruise control is young and healthy perhaps very little happens; your car may slow down or speed up a bit. But if your cruise control is in poor condition the attack might disrupt the entire speed control system; your car may brake suddenly or speed out of control and crash. Feedback control systems (natural or man-made) are designed to keep dynamic systems in control, but under certain situations can drive the system completely out of control. The RAS is composed of two feedback loops: the ACE loop provides amplification, increasing pro-inflammatory cytokines and blood pressure; the ACE2 loop provides fine control and mitigates the vasoconstrictive, pro-inflammatory, and thrombotic actions of the ACE loop. Usually, there is balance, but in the setting of COVID-19, underlying deficiencies of zinc and ACE2 can lead to an imbalance. Exacerbated by the severe downregulation of ACE2 seen with viral entry, a "tipping point" is reached with loss of control of the RAS system resulting in increased angiotensin II (Ang II) causing downstream vasoconstriction, inflammation, and thromboses. These, in turn, lead to complications often seen in "severe COVID-19" such as acute respiratory distress syndrome (ARDS) or cytokine storm, often seen in high-risk patients in the second week of illness. This model suggests that supplemental zinc could replenish zinc in ACE2, stabilize the ACE2 axis, and prevent disruption of the RAS. This would prevent the vasoconstrictive, inflammatory, and thrombotic actions of Ang II, thus preventing the severe COVID-19 complications which cause the high morbidity and mortality seen in high-risk patients with underlying zinc deficiency. Zinc supplements are available, easy to use, and relatively safe. Randomized clinical trials are needed to confirm safety and efficacy of zinc supplementation to decrease severity of and morality from COVID-19 in high-risk patients. Since replenishment of zinc and active ACE2 in patients in whom these are deficient may take weeks, supplementation in high-risk populations prior to COVID infection may be required. Such supplementation should not replace vaccination but may be useful in populations for whom vaccination is not available or for populations exposed to viral variants to which available vaccines have insufficient coverage.

The Association between Zinc and Copper Circulating Levels and Cardiometabolic Risk Factors in Adults: A Study of Qatar Biobank Data

Cardiometabolic risk (CMR) factors increase the likelihood of developing cardiovascular diseases (CVD). In Qatar, 24% of the total deaths are attributed to CVDs. Several nutritional disturbances have been linked to high risk of CVD. Many studies have discussed the effects of zinc (Zn) and copper (Cu) on CMR factors; however, evidence has been controversial. This investigated the association between CMR factors and the status of Zn and Cu, in addition to Zn/Cu ratio. A total of 575 Qatari men and women aged 18 years and older were obtained from Qatar Biobank. Plasma levels of Zn and Cu were determined using inductively coupled plasma mass spectrometry (ICP-MS). Anthropometric data and CMR factors were determined using standard methods. Adjusted associations between trace minerals and CMR were estimated by logistic regression. Partial correlation was performed to test the strength of the associations. Zn was not strongly correlated (p-value ˃ 0.01) or significantly associated with CMR factors and metabolic syndrome (MetS). Cu levels correlated positively with body mass index (BMI) (0.23; p ˂ 0.001), pulse rate (PR) (0.18; p ˂ 0.001), total cholesterol (0.13; p = 0.01), and high-density lipoproteins (HDL) (0.27; p ˂ 0.001); and negatively with diastolic blood pressure (DBP) (−0.13; p = 0.01). High plasma Cu significantly decreased the risk of metabolic syndrome (MetS) (0.121; p ˂ 0.001). Furthermore, Zn/Cu ratio positively correlated with waist circumference (0.13; p = 0.01), systolic blood pressure (0.13; p ˂ 0.01), and DBP (0.14; p ˂ 0.01); and negatively with BMI (−0.19; p ˂ 0.001), PR (−0.17; p ˂ 0.001), and HDL (−0.27; p ˂ 0.001). High Zn/Cu ratio increased the prevalence of low HDL (4.508; p ˂ 0.001) and MetS (5.570; p ˂ 0.01). These findings suggest that high plasma Cu levels are associated with a protective effect on DBP, HDL and MetS and that high plasma Zn/Cu ratio is associated with the risk of having low HDL and MetS.

Association of Zinc Deficiency with Development of CVD Events in Patients with CKD

Deficiency of the micronutrient zinc is common in patients with chronic kidney disease (CKD). The aim of this review is to summarize evidence presented in literature for consolidation of current knowledge regarding zinc status in CKD patients, including those undergoing hemodialysis. Zinc deficiency is known to be associated with various risk factors for cardiovascular disease (CVD), such as increased blood pressure, dyslipidemia, type 2 diabetes mellitus, inflammation, and oxidative stress. Zinc may protect against phosphate-induced arterial calcification by suppressing activation of nuclear factor kappa light chain enhancer of activated B. Serum zinc levels have been shown to be positively correlated with T₅₀ (shorter T₅₀ indicates higher calcification propensity) in patients with type 2 diabetes mellitus as well as those with CKD. Additionally, higher intake of dietary zinc was associated with a lower risk of severe abdominal aortic calcification. In hemodialysis patients, the beneficial effects of zinc supplementation in relation to serum zinc and oxidative stress levels was demonstrated in a meta-analysis of 15 randomized controlled trials. Thus, evidence presented supports important roles of zinc regarding antioxidative stress and suppression of calcification and indicates that zinc intake/supplementation may help to ameliorate CVD risk factors in CKD patients.

Zinc against COVID-19? Symptom surveillance and deficiency risk groups

A wide variety of symptoms is associated with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, and these symptoms can overlap with other conditions and diseases. Knowing the distribution of symptoms across diseases and individuals can support clinical actions on timelines shorter than those for drug and vaccine development. Here, we focus on zinc deficiency symptoms, symptom overlap with other conditions, as well as zinc effects on immune health and mechanistic zinc deficiency risk groups. There are well-studied beneficial effects of zinc on the immune system including a decreased susceptibility to and improved clinical outcomes for infectious pathogens including multiple viruses. Zinc is also an anti-inflammatory and anti-oxidative stress agent, relevant to some severe Coronavirus Disease 2019 (COVID-19) symptoms. Unfortunately, zinc deficiency is common worldwide and not exclusive to the developing world. Lifestyle choices and preexisting conditions alone can result in zinc deficiency, and we compile zinc risk groups based on a review of the literature. It is also important to distinguish chronic zinc deficiency from deficiency acquired upon viral infection and immune response and their different supplementation strategies. Zinc is being considered as prophylactic or adjunct therapy for COVID-19, with 12 clinical trials underway, highlighting the relevance of this trace element for global pandemics. Using the example of zinc, we show that there is a critical need for a deeper understanding of essential trace elements in human health, and the resulting deficiency symptoms and their overlap with other conditions. This knowledge will directly support human immune health for decreasing susceptibility, shortening illness duration, and preventing progression to severe cases in the current and future pandemics.

Zinc as nutritional intervention and prevention measure for COVID-19 disease

The present spread of severe acute respiratory syndrome coronavirus 2, provoking COVID–19 disease, progresses rapidly worldwide. In current absence of a curative treatment and an effective, safe vaccine, there is a pressing need to focus on identifying and correcting deficits in immune function in order to reduce risk of severe progress of the disease and to lower the number of infections and fatalities. This paper evaluates the most recent literature on zinc status related to antiviral immunity and its possible role in COVID–19. It is concluded that zinc is a critical factor for antiviral immunity. There is ample evidence suggesting that zinc depletion, also prevalent in high–income nations, compromises immune functions. Notably, major risk groups for COVID–19, the elderly, men more than women, obese individuals and patients with diabetes are all at risk of zinc deficiency. Moreover, various widely used antihypertensive drugs and statin therapy have been reported to negatively influence zinc status. As zinc depletion impairs antiviral immunity, it is hypothesised to increase susceptibility for COVID–19. Therefore, dietary preventive measures and prompt implementation of zinc supplementation for risk groups should be considered. Large–scale studies are urgently needed to investigate the role of micronutrients and antiviral immunity, in particular drug–micronutrient immunity interaction.