Low Zinc Concentrations Research Articles

Segmented flow capillary microreactors for determination of kinetic rate constants of reactive zinc extraction system

Conventional techniques for kinetic rate constant acquisition are limited by diffusive transport, which can be well addressed by microfluidic techniques. Segmented flow capillary microreactors were used for the first time in this study to obtain kinetic rate constants for a reactive zinc extraction system. The influences of initial zinc ion concentration, total flow velocity, pH of the aqueous phase, and ionic strength on the kinetic rate constant determination were investigated. The control regimes were determined with the ratio of reaction to total resistance R, and the Hatta number. The kinetic rate constants obtained at low initial zinc concentrations, low acidity and high flow velocities exhibited minor deviations, indicating that the zinc sulfate/D2EHPA system could be under the kinetic control regime with the capillary microreactors, which also demonstrated the viability of the segmented flow approach. The kinetic rate constant data obtained with the segmented flow capillary microreactor from this work were much higher than those obtained from previous studies, which may be attributed to the fact that the microreactor minimizes the influence of diffusive transport. The purpose of this work was to provide reliable kinetic data of the reactive zinc extraction system and to verify the efficiency and superiority of the segmented flow microreactor approach over other techniques.

Increased lipid peroxidation, depleted non-enzymatic antioxidant, and variability in trace elements concentration in serum are correlated with Bangladeshi end-stage renal disease population.

IntroductionEnd‐stage renal disease (ESRD) is an abnormality where the kidneys are not usually working. This case‐control study was planned to determine the extent of serum lipid peroxidation, non‐enzymatic antioxidant (vitamin c), and trace elements in 50 patients with ESRD as cases and 50 normal healthy individuals as controls.MethodsDetermination of lipid peroxidation was carried out by ascertaining concentration of malondialdehyde (MDA) and vitamin C in serum using UV spectrophotometry whereas atomic absorption spectroscopy was used for trace elements estimation. The statistical analysis was conducted via the independent t‐test samples and Pearson correlation test.ResultsThe blood serum study has shown substantially higher MDA values than the control level and lowers vitamin C levels in the patient population (P < .001). A negative correlation was found between the vitamin C in serum with BMI and MDA for both patients (r = −0.017 and r = −0.132, respectively) and the control group (r = −0.014 and r = −0.229, respectively) after Pearson's correlation analysis. Regarding trace elements, significantly (P < .001) lower concentrations of zinc, copper, and manganese were found in the patient group than control subjects. Inter‐element‐relationship established a strong positive harmonization between these studied elements in both the cases of patients and control subjects.ConclusionOur results indicate strong associations of the pathogenesis of ESRD with depleted non‐enzymatic antioxidant, increased lipid peroxidation, and inconsistency in trace elements concentration in serum, which may provide a prognostic tool for the treatment of this concerning the disease.

Prevalence of low serum zinc concentrations in Indian children and adolescents: findings from the Comprehensive National Nutrition Survey 2016–18

It is thought that there is a high risk of zinc deficiency in India, but there are no representative national estimates. We aimed to evaluate the national and state-level prevalence of low serum zinc concentrations (SZCs) in Indian children from the nationally representative Comprehensive National Nutrition Survey. Prevalence of low SZC, adjusted for C-reactive protein, was estimated among preschool (1-4 y; n=7874) and school-age children (5-9 y; n=10,430) and adolescents (10-19 y; n=10,140), using SZC cutoffs defined by the International Zinc Nutrition Consultative Group. Prevalence of low SZC was high among adolescents (31.1%; 95% CI: 29.8%, 32.4%), compared with school-age (15.8%; 95% CI: 15.3%, 16.3%) or preschool children (17.4%; 95% CI: 16.7%, 18.0%). However, stratification of prevalence by fasting status or using an alternative lower SZC cutoff independent of fasting status led to a reduction in prevalence by 3.7% or 7.8% in children <10 y, respectively. The prevalence of low SZC was higher among rural preschool children, those belonging to households with poor socioeconomic status, and those with severe stunting or underweight. Preschool children with diarrhea (22.6%; 95% CI: 20.8%, 24.4%), productive cough (22.7%; 95% CI: 18.5%, 27.5%), or malaria/dengue (38.5%; 95% CI: 29.4%, 48.2%) in the 2 wk preceding the survey had a higher prevalence of low SZC than those without morbidity (16.5%; 95% CI: 15.9%, 17.2%; 17.6%; 95% CI: 16.9%, 18.2%; and 17.5%; 95% CI: 16.8%, 18.1%, respectively). The national prevalence of low SZC among preschool (17%) or school-age children (16%) was <20%, which is considered the cutoff indicating a problem of public health significance; but there were variations by state and socioeconomic status. In adolescents, however, the prevalence of low SZC was 31%, which warrants further investigation. The association of low SZC with diarrhea in preschool children necessitates better coverage of Zn administration in the management of diarrhea.

Testing metal, proving mettle—findings from the 2016–2018 India Comprehensive National Nutrition Survey regarding the prevalence of low serum zinc concentrations among children and adolescents, and their implications for public health

Testing metal, proving mettle—findings from the 2016–2018 India Comprehensive National Nutrition Survey regarding the prevalence of low serum zinc concentrations among children and adolescents, and their implications for public health

Zinc ion sorption onto solution-precursor plasma-sprayed hydroxyapatite coatings via raman and X-ray photoelectron spectroscopies

This paper reports the unusual ion sorption of zinc ions to the structure of solution-precursor plasma-sprayed hydroxyapatite coatings studied via X-ray photoelectron and Raman spectroscopy techniques. Raman peak deconvolution revealed no significant band shifting or peak broadening for 5 mol% and 10 mol% zinc-added hydroxyapatite coatings suggesting no distortion in the unit cell. The calculated bond length-wavenumber correlation also showed no significant changes in the bond length of the phosphate group after zinc addition. On the other hand, X-ray photoelectron spectroscopic analysis showed that a significant binding energy shift was observed for the calcium-oxygen and phosphorous-oxygen bonds when 10 mol% of zinc ion is added. It is likely that for low zinc concentration (5 mol%) in plasma-sprayed hydroxyapatite coating, zinc ions possibly inserted at the interstitial site of hydroxyapatite contrary to the presumed substitution at the calcium site. Such insertion did not disturb phosphate Raman signals and caused no shifting in the calcium-oxygen and phosphorous-oxygen Raman peaks. On the other hand, X-ray photoelectron spectroscopic analysis revealed a calcium deficient hydroxyapatite coating and significant peak shifting was observed when 10 mol% of zinc ion is added. The evolution of X-ray photoelectron spectroscopy peaks indicates that substitution of zinc ion in the calcium site is predominant for 10 mol% of zinc concentration. The substituted zinc ion forms a tetrahedral coordination with the phosphate group as revealed in X-ray photoelectron spectroscopic analysis.

Protective primers with reduced zinc powder content caused by the addition of core-shell micro talc/polyaniline pigment

This study aims to verify the possibility of replacing a portion of zinc (up to 30 wt.%) with a newly designed micro talc/polyaniline (PANI) core-shell pigment that can be used in the protective primer compositions for metals. Measurements of the electrode potential of painted steel and the electrical capacity of the steel/coating/electrolyte system showed that synthesized pigment bears two functions. Firstly, its presence in the epoxy-amine coatings provides a cathodic protection mechanism for steel with the lower zinc content. Secondly, it allows long-term preservation of the sacrificial metal activity and passive state of the substrate due to the autocatalytic redox cycle based on the reversible conversion of PANI from its emeraldine to leucoemeraldine form. The corresponding mechanism that allows the retaining of sacrificial metal activity and the passive state of the substrate is proposed.

Investigation of some trace elements and hematological and biochemical parameters in the blood of emaciated Omani goats.

Background and Aim:The analysis of hematological and biochemical parameters is widely used in assessing animal health status. Limited information is available on trace element levels and their association with hematological and biochemical parameters in Omani goats suffering from emaciation. Therefore, the current study aimed to determine the levels of some trace elements in emaciated Omani goats and their relationship with hematological and biochemical parameters.Materials and Methods:Goats suffering from emaciation and muscular dystrophy (n=18) were compared with healthy goats (n=12). Venous blood samples for the hematological, biochemical, and trace element analysis were collected from the jugular vein.Results:Emaciated goats showed significantly lower white blood cell, lymphocyte, and red blood cell counts than the healthy goats. In contrast, the percentages of monocytes and eosinophils were higher in emaciated goats than in healthy ones. In addition, emaciated goats showed higher levels of biochemical parameters alkaline phosphatase, alanine aminotransferase, gamma-glutamyl transferase, aspartate aminotransferase, creatine kinase, and total bilirubin but lower levels of albumin than the healthy goats. The results of trace element analysis revealed lower concentrations of zinc, iron, and selenium in serum from emaciated goats than in serum from healthy goats.Conclusion:This study identified significant differences in the serum levels of some trace elements and hematological and biochemical parameters between healthy and emaciated Omani goats. The identified differences represent valuable diagnostic biomarkers for the evaluation of the health status of Omani goats.

Evaluation of the hair cell regeneration and claudin b and phoenix gene expression during exposure to low concentrations of cadmium and zinc in early developing zebrafish larvae

Zebrafish possess hair cells on the body surface similar to that of mammals inner hear, in particular in the neuromasts, and due to its ability in regenerating damaged hair cells, is regularly used as a powerful animal model to study in vivo cytotoxicity.Among the factors leading to hair cell disruption, metal ions are of particular concern since they are important environmental pollutants. To date, several studies on zebrafish hair cell regeneration after metal exposure exist, while no data on regeneration during continuous metal exposure are available. In the present study, neuromast hair cell disruption and regeneration were assessed in zebrafish larvae for the first time during zinc (Zn) and cadmium (Cd) continuous exposure and a visual and molecular approach was adopted.Fluorescent vital dye DASPEI was used to assess hair cell regeneration and the gene expression of claudin b (cldnb) and phoenix (pho), was analyzed. Metallotionein-2 (mt2) gene expression was used as standard molecular marker of metal toxicity and confirmed the higher toxicity of Cd compared to Zn. In addition, Cd caused a delay in hair cell regeneration compared to Zn. Molecular analysis showed cldnb gene expression increased in relation to the metal concentrations used, confirming the involvement of this gene in hair cell regeneration. On the contrary, a dramatic decrease of pho gene expression was observed in Cd exposed groups, suggesting a negative impact of Cd on pho expression, thus negatively interfering with hair cell regeneration in zebrafish larvae exposed to this metal.

Serum levels of selected micronutrients in patients with inflammatory bowel disease in clinical remission

Patients with inflammatory bowel disease (IBD) can experience micronutrient deficiency regardless of disease activity and extent. We aimed to evaluate serum concentrations of selected trace elements in adult patients with IBD in clinical remission with involvement limited to the colon who received immunosuppressive treatment. We enrolled 32 patients with IBD (mean [SD] age, 41 [15.2] years) and 30 healthy controls (mean [SD] age, 39.1 [11.8] years). Serum selenium, iron, copper, and zinc levels as well as complete blood count were measured in both groups. Patients with IBD had lower zinc concentrations than controls (mean [SD], 0.76 [0.13] mg/l vs 0.83 [0.13] mg/l; P = 0.047). No differences were observed for selenium (mean [SD], 0.90 [0.24] μmol/l vs 0.93 [0.19] μmol/l) and copper levels (mean [SD], 1.03 [0.27] mg/l vs 0.97 [0.22] mg/l). Compared with controls, patients with IBD had lower red blood cell count (mean [SD], 4.4 [0.6] 106/μl vs 4.7 [0.4] 106/μl; P = 0.03), hemoglobin (mean [SD], 12.7 [2.2] g/dl vs 14.3 [0.8] g/dl; P = 0.001), and iron levels (mean [SD], 14.2 [9.4] μmol/l vs 23.4 [2.7] μmol/l; P = 0.0001). Patients with IBD showed a positive correlation between selenium and iron (R = 0.499; P = 0.004) as well as selenium and hemoglobin levels (R = 0.579; P = 0.001). Patients with IBD, despite maintaining clinical remission, should undergo systematic laboratory test for anemia or micronutrient deficiencies.

The Impact of Early Pregnancy and Exposure to Tobacco Smoke on Blood Antioxidant Status and Copper, Zinc, Cadmium Concentration-A Pilot Study.

The aim of the study was to evaluate the impact of early pregnancy and exposure to tobacco smoke on antioxidant status and copper, zinc, and cadmium concentrations in the blood of non-smoking and smoking, as well as non-pregnant or pregnant women. The study included 213 women. More specifically, 150 women in first trimester of pregnancy and 63 non-pregnant women. Women were divided into subgroups according to exposure to tobacco smoke. Pregnancy significant influences higher copper and lower zinc concentration in the serum, whereas exposure to tobacco smoke during pregnancy is mainly associated with an elevation in cadmium and zinc concentration. It seems that metallothionein, superoxide dismutase, and glutathione peroxidase are the important antioxidants during early pregnancy, when exposure to tobacco smoke occurs, whereas the pregnancy itself is associated with a higher concentration of metallothionein and activity of catalase. Both pregnancy in the first trimester and exposure to tobacco smoke decrease glutathione concentration. In addition, active and passive maternal smoking have a similarly negative effect on antioxidant status in the first trimester. Early pregnancy as well as exposure to tobacco smoke is associated with significant alteration in antioxidant status and copper, zinc, and cadmium concentration. Due to a small number of smoking subjects (11 cases of non-pregnant, active smokers and 14 pregnant active smokers), the obtained results should be treated as a pilot, and this should be considered for future studies.

Establishment of flow stress model and optimization of process parameters for ZK10 magnesium alloy with low zinc-content during isothermal compression

Under the condition of strain rates of 0.001–1 s−1 and temperatures of 473–723 K, the flow behaviors of the cast-homogenized ZK10 magnesium alloy were studied through the isothermal compression test with final true strain of 1. In view of this, the Arrhenius equation subject to strain was treated with a comprehensive correction, the deformation activation energy Q of ZK10 alloy was calculated to be 181.87 kJ/mol, and a reliable flow stress model of ZK10 alloy was established. Meanwhile, the processing maps and microstructure evolution of ZK10 alloy were analyzed, which indicated that obvious dynamic recrystallization occurred during thermal compression deformation of ZK10 alloy under the above process conditions. When ZK10 alloy was hot compressed at 473 K in the instability zone, serious instability deformation and macro cracks occurred at strain rates of 0.001 s−1 and 0.01 s−1. The optimum process parameter of ZK10 alloy under the experimental conditions was obtained to be 673 K/1 s−1, and the corresponding microstructure was the most uniform and finest, which provides useful guidance for the selection of process parameters of ZK10 alloy.

The interaction of zinc with the multi-functional plasma thyroid hormone distributor protein, transthyretin: evolutionary and cross-species comparative aspects

A considerable body of evidence has been accumulated showing the interrelationship between zinc and the plasma thyroid hormone (TH) distributor protein, transthyretin (TTR). TTR is a multi-functional protein, which emerged from 5-hydroxyisourate hydrolase (HIUHase) by neo-functionalization after gene duplication during early chordate evolution. HIUHase is also a zinc-binding protein. Most biochemical and molecular biological findings have been obtained from mammalian studies. However, in the past two decades, it has become clear that fish TTR displays zinc-dependent TH binding. After a brief introduction on plasma zinc, THs and their binding proteins, this review will focus on the role of zinc in TTR functions of various vertebrates. In particular primitive fish TTR has an extremely high zinc content, with an increased number of histidine residues which are involved in TH binding. However, zinc-dependent TH binding may have been gradually lost from TTRs during higher vertebrate evolution. Although human TTR has a low zinc content, zinc plays an essential role in TTR functions other than TH binding: the stability of TTR-holo retinol binding protein 4 (holoRBP4) complex, TTR amyloidogenesis, the sequestration of amyloid β (Aβ) fibrils and cryptic proteolytic activity. The interaction of TTR with metallothioneins may be a critical step in the exertion of some of these functions. Evolutionary and physiological insights on zinc-dependent functions of TTRs are also discussed.

Low Serum Zinc Concentration Is Associated With Infection Particularly in Patients With Stage 5 Chronic Kidney Disease Medicated with Proton Pump Inhibitors

Zinc (Zn) plays an important role in immune function. Several studies have identified an association between a Zn deficiency and infection. Infectious diseases are major complications of chronic kidney disease (CKD). We investigated whether serum Zn concentrations are associated with risk of infection in patients with advanced CKD. We retrospectively analyzed data from 299 patients with CKD whose serum Zn values were measured to evaluate anemia between January 2013 and December 2016. Among them, 9 who were supplemented with Zn and 67 who had started urgent dialysis at the time of measurement were excluded. We analyzed infection events, length of infection-related hospitalization and infection-related and all-cause mortality in the remaining 223 patients during a median follow-up of 36months. We assigned the patients to groups with low or high Zn values (≤50 and>50μg/dL, respectively) based on a median value of 50μg/dL. Data were analyzed using Kaplan-Meier curves and Cox hazards models. During a median follow-up of 36months, 40 patients were hospitalized with infections. The rate of infection-related and long-term hospitalization (>10days) due to infection was higher for patients with low, than high, Zn values (23.3% vs. 12.6%; P=.042 and 26.2% vs. 12.4%; P=.007, respectively). After adjustment in Cox hazards models, low serum Zn values remained an independent risk factor for infection-related hospitalization (Hazard ratio [HR], 1.93; 95% confidence interval [CI], 1.01-3.71; P=.048), especially for patients on proton pump inhibitor (PPI) medications (HR, 2.66, 95%; CI, 1.22-5.81; P=.014). Patients with advanced CKD accompanied by low serum Zn concentration, and particularly those medicated with PPI, are at high risk of infection-related hospitalization, which results in long-term hospitalization.

Low blood zinc concentrations in patients with poor clinical outcome during SARS-CoV-2 infection: is there a need to supplement with zinc COVID-19 patients?

Among 275 patients with COVID-19, we found that median blood zinc level was significantly lower in patients with poor clinical outcome (N = 75) as compared to patients with good clinical outcome (N = 200) (840 μg/L versus 970 μg/L; p < 0.0001), suggesting that zinc supplementation could be useful for patients with severe COVID-19.

Low Zinc Status Among Palestinian University Students is Related to Hair Loss But Not Diet Score

Introduction: Zinc is an essential nutrient that is related to many health issues, including cutaneous and hair health Aims: To study the prevalence of low and high zinc concentrations among university students and to evaluate the association between zinc status and various health issues including hair loss, skin health, immunity, diarrhea and weight status. Methods: Study outcomes which included age, BMI, gender, health variables such as diarrhea, hair loss, weight loss and others were collected using a structured questionnaire, whereas serum zinc concentration was measured using spectrophotometry. Results: 33% of the study participants had low zinc level, whereas 34.7% had zinc levels higher than normal. Both high and low zinc status were associated with significant hair loss (p&lt;0.0001). High and low zinc status were not significantly related to other study outcomes such as diarrhea, acne and weight loss. Healthy diet score was not significantly different between zinc status categories and was not significantly related to other study outcomes. Conclusion: Appropriate intake of zinc and zinc concentration may protect from hair loss and should be promoted.

Reduced Serum Zinc Ion Concentration Is Associated with Coronary Heart Disease.

Imbalances in trace element concentrations in the blood as a result of poor nutrition may affect the development of coronary heart disease. To study the relationship between zinc ion concentration in the peripheral blood and coronary heart disease, we performed multiple logistic regression and hierarchical analyses on blood measurements of 3541 patients. The experimental group comprised 1253 patients diagnosed with coronary heart disease, and the control group included 2288 healthy patients. The zinc ion concentrations were measured by a color rendering method, and the results were analyzed using SPSS software. Fifteen laboratory quality evaluation samples from the Clinical Laboratory Center of the Chinese Ministry of Health were selected for analysis. The mean values and average bias were calculated. The estimated qualified judgment standard was < 1/2 TEa (the allowable total error for zinc). A hierarchical analysis of risk factors, including smoking, age, sex, and menopause in women, was performed. The results revealed that non-smoking, aging (especially postmenopausal women), and low blood zinc concentrations were independent risk factors for the development of coronary heart disease (P ≤ 0.05, zinc ion concentration less than 13.82 ± 2.91). The findings strongly suggest that decreased zinc ion concentrations in the peripheral blood can be used as an independent risk factor for the prediction of coronary heart disease, especially in older patients, non-smokers, and women, in particular, postmenopausal women.

Dough rheology and the impact of zinc sulfate on the quality of cookies

Zinc deficiency is a growing issue in developing countries. Moreover, it is a well-known fact that the bakery products have very low zinc content and the further loss of zinc occurs during milling of wheat and under baking of end products, which makes it hard to produce nutritional bakery products. For this purpose, zinc sulfate has been incorporated in wheat flour at 0, 32.5, 65, and 97.5 mg/100 g to prepare cookies and determine their physicochemical and nutritional properties as well as stability under controlled storage conditions, i.e. temperature (23-25 °C) and relative humidity (45-55%). The findings exhibited that the cookies-percentage of fat and protein decreased after the addition of zinc sulfate. The fiber content of cookies was non-significantly changed, while the moisture content increased. Moreover, the diameter of cookies significantly increased from 45.65 ± 1.46 cm to 45.84 ± 1.34 cm. The thickness and spread factor of cookies were also effects ranged from 1.49 to 1.54 cm and 30.63 ± 2.98 to 29.76 ± 1.64 respectively. The results revealed that zinc sulfate was stable up to 90 days and under normal baking conditions. Based on the sensorial attributes, it was unveiled that the nutritional cookies were prepared by using 65 mg zinc sulfate with (AARI-2011) wheat flour.

Chemical Composition and Nutritional Evaluation of Cake Made with Flour Mixture of Pigeonpea and Rice

This study aimed to develop and characterize a cake based on a flour mixture of pigeonpea and rice. Four cake formulations of different percentages of pigeonpea flour (PF) and Rice Flour (RF) (0% PF + 100% RF, 10% PF + 90% RF, 20% PF + 80% RF, 30% PF + 70% RF) were developed based on a traditional formulation. Microbiological, physicochemical and sensory evaluations were performed. The tasters preferred the mix formulation containing 30% pigeonpea and 70% rice (p product, with good acceptance and technological potential. This product meets the needs of the food industry, such as: 1) it is gluten-free; 2) contributes for the adoption of healthy eating habits; 3) promotes family farming; and 4) stimulates the consumption of regional vegetables that can be incorporated into school meals menus, rescuing the consumption habits of rice and beans and eventually valuing the traditional Brazilian diet. It is worth noting the low lipid, high fiber, iron and zinc content characteristic of the developed product.

Энтеропатический акродерматит у детей

Enteropathic acrodermatitis is a rare hereditary form of zinc deficiency, characterized by periorial and acral dermatitis, alopecia and diarrhea. Refers to congenital disorders of zinc metabolism, inherited as an autosomal recessive disease resulting from mutations in the gene for the zinc transporter SLC39A4. The prevalence ranges from 1 to 9:1,000,000, with an overall incidence of 1:500,000 newborns. The disease usually manifests itself in infancy, within a few weeks of stopping breastfeeding and switching the baby to a cow's milk-based formula, or in the first days of life if artificially fed from birth. The classical clinical manifestations of acrodermatitis enteropathic are characterized by the triad: acral and periofital dermatitis, alopecia and diarrhea, but all three signs together occur only in 20% of cases. Diarrhea may develop concurrently with skin symptoms, may precede or occur later. Characteristic signs of skin lesions include sharply demarcated, dry, scaly erythematous plaques or edematous foci with vesicles and pustules on the skin of the elbow and knee joints, distal extremities, genitals, in the inguinal folds, which are usually symmetrically distributed, have sharp boundaries and irregular outlines. The course of the skin syndrome is long, as it progresses, non-healing erosive and ulcerative areas appear. Plasma zinc deficiency is the gold standard for diagnosis. Most infants with AE have low plasma zinc concentrations (&lt;500 mcg/L or &lt;50 mcg/dl), but a level of less than 70 mcg/L on an empty stomach or less than 65 mcg/dl in older non-dieting children is considered diagnostically significant. Treatment for this disease usually includes enteral or parenteral zinc administration, at a dose of 1-3 mg/kg/day. for elemental zinc. A clinical response is observed within 5–10 days. Supportive zinc therapy is necessary throughout the patient's life, although periods of remission have been reported. Topical therapy is also used: Dexpanthenol in the form of a cream, applied 3 times a day in the area of dermatitis, can enhance re-epithelialization. There is no significant evidence of improvement with topical zinc application. No activity restrictions are required for patients with acrodermatitis enteropathic. Key words: zinc deficiency, enteropathic acrodermatitis, children

Reference Cut-Offs to Define Low Serum Zinc Concentrations in 1-19 Year Old Indian Children and Adolescents

Background: The quantification of population zinc (Zn) deficiency is based on serum zinc concentration (SZC) cut-offs, defined by International Zinc Nutrition Consultative Group (IZiNCG), derived from the 2·5th centile of age- and sex-specific SZC distributions from a high-income country. However, the SZC distributions, and its 2·5tthcentile cut-offs, can left-shift for a variety of reasons in lower middle-income countries (LMICs). The recent quality-controlled Indian Comprehensive National Nutrition Survey (CNNS) offered an opportunity to re-examine the SZC cut-offs in healthy 1–19-year-old children and adolescents and evaluate whether Zn deficiency was truly a public health problem in India. Methods: A healthy population (n=12473) of children was selected by including the highest 2 wealth quintiles, and excluding stunted, thin and obese children, and those with CRP >5mg/L, anemia, hypo-albuminemia, diabetes, recent diarrhea and a history of smoking. The 2·5th centile of the SZC distribution from this sample yielded the present cut-off to re-evaluate the prevalence of Zn deficiency against the IZiNCG cut-offs. Findings: The present study SZC cut-offs were significantly lower, by 10–18 µg/dL, than the IZiNCG cut-offs; more in adolescents. Thus, the prevalence of Zn deficiency in the entire CNNS sample, with the present cut-offs, was 2·7 to 5·5 times lower than with the IZiNCG cut-offs. No geographical state, nor any age group, showed Zn deficiency as a serious public health problem (≥20%). In contrast, with the IZiNCG cut-offs, between 9 to 27 states (depending on age group) had a serious public health problem with Zn deficiency. Interpretation: The present study reference SZC cut-offs for Zn deficiency are lower than the IZiNCG cut-offs, and since they were selected rigorously from a national sample, are more appropriate for use in India. A re-examination of the global applicability of IZiNCG recommended cut-offs to quantify Zn deficiency in other LMICs is required. Funding Source: CNNS is funded by The Mittal Foundation. However, there is no specific funding for this secondary analysis. Declaration of Interests: HSS designed the draft protocol of the CNNS with consultancy support from UNICEF, India. HSS, UK, and AVK were members of the Technical Advisory Committee of the CNNS, constituted by the Ministry of Health and Family Welfare of the Government of India, to oversee its conduct and analysis. HSS is a member of the WHO Nutrition Guidance Expert Advisory Subgroup on Diet and Health and Guideline Development Group on the use and interpretation of haemoglobin concentrations for assessing anaemia status in individuals and populations, member of the World Health Organization Nutrition Guidance Expert Advisory Subgroup on Diet and Health and Expert group on nutrient requirements: setting calcium, vitamin D and Zn nutrient intake values for children aged 0-4 years. He is also member of Expert Groups of the Ministry of Health and Family Welfare on Nutrition and Child Health. SD was involved in the CNNS study implementation. There were no other conflicts to declare. Ethics Approval Statement: The Population Council’s International Review Board (New York, USA) and the Ethics Committee of the Post Graduate Institute of Medical Education and Research (Chandigarh, India) gave ethical approval. Written consent from parent/caregiver for children under 10 years, consent of parent/caregiver as well as assent from adolescents (11-17 years) and written consent of adolescents above 17 years were obtained after due description of study details in local languages.