A Question Mark on Zinc Deficiency in 185 Million People in Pakistan—Possible Way Out

Prevalence and determinants of low plasma zinc levels in adult peritoneal dialysis patients

OBJECTIVE

Zinc is an essential trace element, being a cofactor for almost 300 enzymes. As zinc is widely available in the diet, the European Best Practice Guidelines do not recommend routine supplementation in dialysis patients. However, some medicines prescribed to dialysis patients may potentially reduce absorption, and there may be increased losses with dialysis. As older and co-morbid patients are now treated by peritoneal dialysis (PD) we wished to determine the prevalence of patients with low plasma zinc levels.

DESIGN AND METHODS

We prospectively measured plasma zinc in 550 PD patients attending for their first peritoneal membrane assessment using atomic absorption spectroscopy. Body composition was determined by bioimpedance.

RESULTS

Plasma zinc was measured in 550 patients, mean age 58.7 years, 60.6% male, mean value 10.8 ± 2.2 umol/L, with 66.5% having low zinc levels (<11.5 umol/L). Normal plasma zinc was associated with haemoglobin (odds ratio (OR) 1.41 (95% confidence limits (95%CL) 1.22-1.63), serum albumin (OR 1.04 (95%CL 1.002-1.087), higher glucose dialysates L/day (OR 1.06 (1.001-1.129), and negatively with 24-hour urinary protein losses (OR 0.786 (95%CL 0.673-0.918) and age (OR 0.985 (95%CL 0.972-1.0). There was no association with dialysis adequacy, original renal disease or dietary protein estimation. Prescription of phosphate binders had no effect on zinc levels (10.7 ± 2.2 vs 10.8 ± 2.3 umol/L).

CONCLUSIONS

Most PD patients had low plasma zinc levels, associated with older age, probably reflecting reduced intake, urinary protein losses, and lower albumin and haemoglobin most likely linked to greater co-morbidity, low grade inflammation and volume expansion requiring higher glucose dialysates.

Assessment of serum, dietary zinc levels, and other risk factors during the third trimester among pregnant women with and without pregnancy-induced hypertension: a case-control study

Background

This study assessed serum, dietary zinc levels, and other risk factors during the third trimester among pregnant women with and without pregnancy-induced hypertension (PIH).

Methods

This case-control study was conducted in 2022, in the three main Obstetrics and Gynecology departments in Gaza Strip, Palestine. One hundred sixty pregnant women, during the third trimester, aged ≥20 years, were selected using a convenient sampling method. Data were obtained using an interview-based questionnaire, food frequency questionnaire, anthropometric measures, and biochemical tests. Statistical analysis was performed using SPSS version 24.

Results

The participants' mean age was 30.7 ± 5.6 years. A total of 47 (58.8%) of cases and 6 (7.5%) of controls were insufficiently active; and the mean of blood pressure (mmHg) was 133.3 ± 11.9/85.11 ± 10.0 for cases and 112.8 ± 9.5/68.02 ± 7.2 for controls with significant differences between the two groups (P = <0.005). The mean serum zinc level (μg/dl) was 67.15 ± 16.5 for cases and 68.45 ± 18.0 for controls without significant differences between the two groups (P = 0.636). For newborns, the mean birth weight (g) was 2,904.6 ± 486 for cases, and 3,128.3 ± 501 for controls, and the mean Apgar score was 8.03 ± 0.62 for cases and 8.30 ± 1.17 for controls, with significant differences between the two groups (P = <0.005). Furthermore, 43 (53.8%) of cases have family history of hypertension; 5 (6.2%) were primiparous; 19 (23.8%) have previous caesarian section; 33 (41.2%) have history of preeclampsia; and 62 (77.5%) have edema, with significant differences between the two groups (P = <0.005). Additionally, the total zinc dietary daily intake (mg/day) was 4.15 ± 2.10 for cases and 4.88 ± 3.02 for controls, with significant differences between the two groups (P = 0.041). After adjustment for confounding variables, participants in the case group have higher odds of having low total zinc dietary intake compared to those in the control group [OR = 1.185, 95% CI = (1.016-1.382), P = 0.030].

Conclusion

The current study showed the main risk factors of PIH among pregnant women in the Gaza Strip, Palestine. Furthermore, low maternal dietary zinc intake was associated with a high level of PIH. Moreover, having PIH could increase the risk of low birth weight and low Apgar scores. Therefore, reducing the main risk factors of PIH could reduce the adverse effect on both mother and birth outcomes.

Role of Nutrition Information in Acceptance and Willingness to Pay for Biofortified Cereal Food: Implications for Better Health and Sustainable Diet

A range of nutritional needs are met through the use of fortified farm-based foods. Wheat biorfortification with zinc is such an example where biorfortification is carried out for a crucial element like Zinc. Zinc-biofortified wheat (Zn-wheat) has been officially launched in Pakistan since 2016 but its wide-scale dissemination, adoption and consumption have not taken place till to date. On the other hand, essential nutrients deficiencies have wide-ranging implications for public health especially for children and lactating mothers. This study is undertaken to know the reasons for the slow progression of scaling up of biofortified wheat varieties in Pakistan, people’s awareness about biofortified wheat and to recognize the role of information in acceptance and willingness to pay for this wheat. For this purpose, randomly selected 474 households were interviewed from four districts of Punjab province. They were categorized into four groups based on their exposure to information in real and hypothetical cheap talk (game theory context). Study findings reveal that respondents were ready to pay for fortified wheat if they are aware about nutrient aspects and Zn deficiency. Using Discrete Choice Experiment, the preferences for and factors affecting the willingness to pay for fortified wheat are evaluated. Main factors having positive impact include household head’s education and income, having pregnant women and children <5 years age. It was also found that people having valid information about nutrients of a food would be willing to pay more. The study highlights need for policy focus on educating people about nutritional aspects as well as making available biofortified foods to promote healthy living.

Zinc deficiency and associated factors among pregnant women’s attending antenatal clinics in public health facilities of Konso Zone, Southern Ethiopia

Background

Zinc is an essential mineral known to be important for the normal physiological functions of the immune system. It is one of the basic nutrients required during pregnancy for the normal development and growth of the fetus. However, Zinc deficiency during pregnancy causes irreversible effects on the newborn such as growth impairment, spontaneous abortion, congenital malformations and poor birth outcomes. Even though, the effect of Zinc deficiency is devastating during pregnancy, there is scarcity of evidence on Zinc deficiency and related factors among pregnant women in the current study area.

Objective

To assess Zinc deficiency and associated factors among pregnant women attending antenatal clinics in public health facilities of Konso Zone, Southern Ethiopia.

Methods

Institution based cross-sectional study was conducted among randomly selected 424 pregnant mothers. Data were collected using pre tested questionnaire (for interview part), and 5 blood sample was drawn for serum zinc level determination. Data were entered to Epi-Data version 3.1 software and exported to SPSS version 25 for analysis. Binary logistic regression analysis was computed and independent variables with a p-value ≤ 0.25 were included in multivariable analysis. Serum zinc level was determined using atomic absorption spectroscopy by applying clean and standard procedures in the laboratory. Finally adjusted odds ratio with 95% confidence level, P-value < 0.05 was used to identify significant factors for Zinc deficiency.

Result

The prevalence of Zinc deficiency was found to be 128 (30.26%) with the mean serum zinc level of 0.56±0.12 g/dl. Age, 25–34 years [AOR 2.14 (1.19,3.82)], and 35–49 years [AOR 2.59 (1.15, 5.85)], type of occupation, farming [AOR 6.17 (1.36, 28.06)], lack of antenatal follow up during pregnancy [AOR 3.57 (1.05,12.14)], lack of freedom to purchase food items from market [AOR 3.61 (1.27, 10.27)], and inadequate knowledge on nutrition [AOR 3.10(1.58, 6.08)] were factors associated with Zinc deficiency.

Conclusion

Zinc deficiency is a public health problem among pregnant mothers in the current study area. Improving maternal nutritional knowledge, motivating to have frequent antenatal follow up, and empowering to have financial freedom to purchase food items from market were the modifiable factors to reduce Zinc deficiency. Nutritional intervention that focused on improving nutritional knowledge and insuring access to Zinc sources food items should be delivered for pregnant mothers.

Relationships Between Biological Heavy Metals and Breast Cancer: A Systematic Review and Meta-Analysis

Introduction

Heavy metals were classified as essential, probably essential, and potentially toxic in the general population. Until now, it has been reported inconsistently on the association between heavy metals and BC. In this meta-analysis, we aimed to assess the association between heavy metals and BC and review the potential mechanisms systematically.

Methods

We searched for epidemiological studies in English about the association between heavy metals and BC published before September 2020 in PubMed, Web of Science, and Embase databases. In total 36 studies, comprising 4,151 individuals from five continents around the world were identified and included.

Results

In all biological specimens, Cu, Cd, and Pb concentrations were higher, but Zn and Mn concentrations were lower in patients with BC than in non-BC participants [SMD (95% CIs): 0.62 (0.12, 1.12); 1.64 (0.76, 2.52); 2.03 (0.11, 3.95); −1.40 (−1.96, −0.85); −2.26 (−3.39, −1.13); p = 0.01, 0.0003, 0.04, <0.0001, <0.0001]. Specifically, higher plasma or serum Cu and Cd, as well as lower Zn and Mn, were found in cases [SMD (95% CIs): 0.98 (0.36, 1.60); 2.55 (1.16, 3.94); −1.53 (−2.28, −0.78); −2.40 (−3.69, −1.10); p = 0.002, 0.0003, <0.0001, 0.0003]; in hair, only lower Zn was observed [SMD (95% CIs): −2.12 (−3.55, −0.68); p = 0.0004]. Furthermore, the status of trace elements probably needs to be re-explored, particularly in BC. More prospective studies, randomized clinical trials, and specific pathogenic studies are needed to prevent BC. The main mechanisms underlying above-mentioned findings are comprehensively reviewed.

Conclusion

For BC, this review identified the current knowledge gaps which we currently have in understanding the impact of different heavy metals on BC.

Systematic Review Registration

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020176934, identifier: CRD42020176934.

Zinc Status Impacts the Epidermal Growth Factor Receptor and Downstream Protein Expression in A549 Cells

Zinc has been suggested to play a role in carcinogenesis and tumor progression. Serum zinc levels of lung cancer patients are for example lower than in healthy individuals. The activation and expression of the epidermal growth factor receptor (EGFR), which plays a role in tumor biology, are presumably influenced by zinc. EGFR activation influences cell adhesion and immune escape. This study provides insights into the impacts of zinc on the EGFR activation and expression of downstream proteins such as E-cadherin and PD-L1 in the alveolar carcinoma cell line A549. To model chronic changes in zinc homeostasis, A549 cells were cultured in media with different zinc contents. EGFR surface expression of unstimulated and stimulated A549 cells was determined by flow cytometry. EGFR phosphorylation as well as the protein expression of E-cadherin and PD-L1 were analyzed by Western blot. In our hands, chronic zinc deficiency led to increased EGFR surface expression, decreased E-cadherin protein expression and increased PD-L1 protein expression. Zinc supplementation decreased EGFR surface expression and PD-L1 protein expression. In summary, zinc-deficient A549 cells may display a more malignant phenotype. Thus, future clinical research should further focus on the possible benefits of restoring disturbed zinc homeostasis, especially in lung cancer patients.

The Role of Mineral Deficiencies in Insulin Resistance and Obesity

Minerals are critical for maintaining overall health. These tiny chemical compounds are responsible for enzymatic activation, maintaining healthy teeth and bones, regulating energy metabolism, enhancing immunity, and aiding muscle and brain function. However, mineral deficiency in the form of inadequate or under nourished intake affects millions of people throughout the world, with well-documented adverse health consequences of malnutrition. Conversely, mineral deficiency may also be a risk factor for Insulin Resistance (IR) and obesity. This review focuses on another, more "less discussed" form of malnutrition, namely mineral deficiency and its contribution to metabolic disorders. At the cellular level, minerals maintain not only molecular communication but also trigger several key biochemical pathways. Disturbances in these processes due to mineral insufficiency may gradually lead to metabolic disorders such as insulin resistance, pre-diabetes, and central obesity, which might lead to renal failure, cardiac arrest, hepatic carcinoma, and various neurodegenerative diseases. Here we discuss the burden of disease promoted by mineral deficiencies and the medical, social, and economic consequences. Mineral deficiency-mediated IR and obesity have a considerable negative impact on individual well-being, physical consideration, and economic productivity. We discuss possible molecular mechanisms of mineral deficiency that may lead to IR and obesity and suggest strategies to counter these metabolic disorders. To protect mankind from mineral nutrient deficiencies, the key is to take a variety of foods in reasonable quantities, such as organic and pasture-raised eggs, low fat dairy, and grass-fed and finished meats, insecticide, and pesticide-free vegetables and fruits.

Bioactive Nutrient Fortified Fertilizer: A Novel Hybrid Approach for the Enrichment of Wheat Grains With Zinc

Zinc (Zn) is a critical micronutrient that synergizes nutrient use efficiency, and improves plant growth and human health. Low Zn bioavailability in soils affects produce quality and agricultural productivity worldwide ultimately inducing deficiency in humans and animals. Zn deficiency is a leading cause of malnutrition in underdeveloped countries where a widespread population depends upon staple cereals for daily intake of calories. Modern cereal cultivars are inherently low in Zn, eventually, plants need to be enriched with soil application of ZnSO₄, but due to higher fixation losses, it becomes an inefficient source. Rhizosphere microbiome contains Zn-solubilizing bacteria (ZSB) that improve Zn bioavailability, thus increase the root function, Zn uptake, and plant growth. Niha Corp developed a hybrid process of bioactive nutrient fortified fertilizer (BNFF), which has been used to formulate Zabardast Urea (ZU) by coating bioactive Zn (BAZ) and ZSB on urea. Data obtained for 15 wheat varieties from 119 farmer field demonstration plots and eight replicated trials on 42 locations across multi-environment conditions conclude that ZU significantly improved the plant biomass and yield by 12% over non-Zn control and produced grains with 57 μg/g Zn contents, which can meet a major part of the recommended dietary allowance (RDA) of humans. The study recommends that this microbe-mediated hybrid invention (ZU) is a feasible approach to boost Zn bioavailability and Zn use efficiency, with enhanced yield and quality that may contribute to improve human health. To the best of our knowledge, this is the first wide-scale field testing of Zn enrichment in the grains of bread wheat using an innovative BNFF Urea Z technology.

Zinc Micronutrient Deficiency and Its Prevalence in Malnourished Pediatric Children as Compared to Well-Nourished Children: A Nutritional Emergency

Pediatric populations from lower-income countries may experience a higher incidence of zinc deficiency, which may cause physical and neurological dysfunctions. This case control study aims to assess different levels of zinc between malnourished and well-nourished children. Our study included 108 participants, all children less than 12 years of age. Out of the 108, 54 were malnourished children (cases), while 54 were well nourished (control group) and were screened for zinc deficiencies. Zinc deficiencies were 4 times more common in malnourished cases than in controls (OR: 3.89 95% CI: 1.1-14.9) with median value of zinc in cases being 91.69 and that of controls was 117.6. Our findings indicate significant deficiencies in malnourished children as compared to well-nourished children. Additionally, our findings support literature surveyed that suggest dietary changes alone would not be able to replenish zinc levels in children.

Transcriptional dynamics of Zn-accumulation in developing kernels of maize reveals important Zn-uptake mechanisms

In the present study, transcriptomic analysis of 10-days old baby kernels of two contrasting maize genotypes, namely VQL-2 (high kernel Zn accumulator) and CM-145 (low kernel Zn accumulator), under low- and optimum- soil Zn conditions generated 1948 differentially expressed transcripts. Among these, 666 and 437 transcripts were up-regulated and down-regulated respectively in VQL-2; whereas, 437 and 408 transcripts were up-regulated and down-regulated respectively in CM-145. Remarkably, 135 transcription factors and 77 known Zn transporters expressed differentially. By comparing the transcripts differentially expressed between the optimum-Zn and low-Zn libraries of the contrasting genotypes, we identified 21,986 and 26,871 SNPs, respectively. Similarly, 6810 and 8192 InDels were found between optimum- and low-Zn growing conditions, respectively. Further, 21 differentially expressed genes were co-localized with already known QTLs associated with Zn uptake, such as qZn10, CQZnK9-1 and YNZnK6. These findings will be useful to develop high Zn-accumulator maize through marker-assisted breeding in future.

Nano-particles of Trace Minerals in Poultry Nutrition: Potential Applications and Future Prospects

Nano-technology is an emerging technology with tremendous potential and diverse applications in human health, agriculture, and animal nutrition. It also offers potential advantages in supporting research in many areas of life sciences. Nano-technology has many vital biological applications as living systems depend on many nano-scale objects like proteins, DNA, and enzymes. Trace minerals are normally used in very minute quantity in animal nutrition but issues like lower bioavailability, antagonism, and higher excretion rates from body limit their efficiency. Nano-technology offers opportunity to mediate these issues as nano-particles possess different physical and chemical properties than other forms of minerals. Nano-particles possess higher physical activity and chemical neutrality. Bioavailability can be enhanced by increasing the surface area of respective minerals by making their nano-particles. Owing to potential advantages of nano-particles, interest in exploring their potential use and efficacy in animal production has increased significantly in this decade. Although limited literature is available regarding potential effects of nano-particles in poultry nutrition, still some convincing evidences have suggested the feeding of trace minerals (zinc, copper, silver, selenium, iron, chromium, and manganese) in the diets of broilers, layers, turkeys, quails, etc. Excellent antimicrobial activities of nano-particles of Ag, Cu, and Zn, against key poultry pathogens like Salmonella and Campylobacter, indicate their potential for effective use in poultry production. Recent studies have also demonstrated modulation of gut health by nano-particle through increasing abundance of beneficial microbes (Lactobacillus and Faecalibacterium) and production of short-chain fatty acids. This review aims to provide insights on absorption, metabolism, and distribution of nano-minerals in the body. Moreover, potential applications and various aspects of using nano-trace minerals in different poultry species with potential effects on performance and health of birds are discussed.

Pretreatment with zinc protects Kupffer cells following administration of microbial products

BACKGROUND

Systemic inflammation and severe fibrosis can reduce serum zinc levels, while zinc supplementation is reported to improve the prognosis of patients with chronic liver disease (CLD).

OBJECTIVES

We aimed to investigate the clinical application of serum zinc in patients with CLD and the anti-infective mechanism of zinc supplementation.

METHODS

Based on the serum zinc level, 149 CLD patients were divided into 3 groups and their clinical parameters were compared. In in-vitro experiments, microbial isolates derived from patients were used to stimulate human liver non-parenchymal cells, and the zinc sulfate solution was added in certain experiments. The effect of zinc was compared by LDH and thromboxane A₂ levels in the cell supernatant.

RESULT

Compared with other groups, patients with low serum zinc levels had significantly higher C-reactive protein (CRP), total bilirubin, INR, creatinine, and MELD scores, while albumin and GOT levels were reduced. Only CRP and albumin were significantly correlated with serum zinc in both low and normal-zinc groups. Bacterial isolates significantly increased LDH levels in Kupffer cells (KCs) and stellate cells but had no effect on sinusoidal endothelial cells, whereas zinc pretreatment protected KCs but not stellate cells. Thromboxane A₂ secreted by KCs can also be induced by bacterial stimulation, accompanied by increased gene expression of Myd88, MAPK and NF-kB, while zinc pretreatment can attenuate that.

CONCLUSION

Serum zinc levels can be used to estimate infection and liver fibrosis in CLD patients. As a new antibacterial weapon, zinc supplementation acts on KCs through Myd88-MAPK related pathways.

Zinc at the crossroads of exercise and proteostasis

Zinc is an essential element for all forms of life, and one in every ten human proteins is a zinc protein. Zinc has catalytic, structural and signalling functions and its correct homeostasis affects many cellular processes. Zinc deficiency leads to detrimental consequences, especially in tissues with high demand such as skeletal muscle. Zinc cellular homeostasis is tightly regulated by different transport and buffer protein systems. Specifically, in skeletal muscle, zinc has been found to affect myogenesis and muscle regeneration due to its effects on muscle cell activation, proliferation and differentiation. In relation to skeletal muscle, exercise has been shown to modulate zinc serum and urinary levels and could directly affect cellular zinc transport. The oxidative stress induced by exercise may provide the basis for the mild zinc deficiency observed in athletes and could have severe consequences on health and sport performance. Proteostasis is induced during exercise and zinc plays an essential role in several of the associated pathways.

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Zinc deficiency could be a crucial issue in sport performance for athletes.

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Exercise could modulate zinc serum and cellular homeostasis.

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Zinc is part of proteostatic systems critical during exercise.

Nanocarrier-mediated foliar zinc fertilization influences expression of metal homeostasis related genes in flag leaves and enhances gluten content in durum wheat

BACKGROUND

Wheat is the staple food for most of the world's population; however, it is a poor source of zinc. Foliar fertilization of zinc via zinc loaded chitosan nanocarriers (Zn-CNP) post-anthesis has proved to be a promising approach for grain zinc enhancement in durum wheat as evidenced in our earlier study. However, the molecular mechanism of uptake of zinc via Zn-CNP remains unclear.

METHODS/PRINCIPLE FINDINGS

Foliar application of Zn-CNP was performed at post anthesis stages in two durum wheat cultivars (MACS 3125 and UC1114, containing the Gpc-B1 gene), and expression levels of several metal-related genes were analyzed during early senescence. Zn-CNP application indeed caused changes in gene expression as revealed by qPCR data on representative genes involved in metal homeostasis, phloem transporters, and leaf senescence. Furthermore, zinc-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) family [ZIP1, ZIP7, ZIP15], CA (carbonic anhydrase), and DMAS (2'-deoxymugineic acid synthase) in flag leaves exhibited significant correlation with zinc content in the seeds. The analysis of grain endosperm proteins showed enhancement of gamma gliadins while other gluten subunits decreased. Gene expression within ZIP family members varied with the type of cultivar mostly attributed to the Gpc-B1, concentration of external zinc ions as well as the type of tissue analyzed. Correlation analysis revealed the involvement of the selected genes in zinc enhancement.

CONCLUSION

At the molecular level, uptake of zinc via Zn-CNP nanocarrier was comparable to the uptake of zinc via common zinc fertilizers i.e. ZnSO4.

Zinc Bioavailability from Phytate-Rich Foods and Zinc Supplements. Modeling the Effects of Food Components with Oxygen, Nitrogen, and Sulfur Donor Ligands

Aqueous solubility of zinc phytate (K_sp = (2.6 ± 0.2) × 10^-47 mol⁷/L⁷), essential for zinc bioavailability from plant foods, was found to decrease with increasing temperature corresponding to ΔH_dis of -301 ± 22 kJ/mol and ΔS_dis of -1901 ± 72 J/(mol K). Binding of zinc to phytate was found to be exothermic for the stronger binding site and endothermic for the weaker binding site. The solubility of the slightly soluble zinc citrate and insoluble zinc phytate was found to be considerably enhanced by the food components with oxygen donor, nitrogen donor, and sulfur donor ligands. The driving force for the enhanced solubility is mainly due to the complex formation between zinc and the investigated food components rather than ligand exchange and ternary complex formation as revealed by quantum mechanical calculations and isothermal titration calorimetry. Histidine and citrate are promising ligands for improving zinc absorption from phytate-rich foods.

The effect of the zinc concentration in breast milk on neonatal weight gain

The change in breast milk zinc (Zn) concentration in a feeding period during lactation may affect neonatal weight gain. The aim of this study was to determine how to change the Zn concentrations in breast milk during a feeding period in early and late lactation periods and identify the relationship between the differences in the Zn levels in breast milk during lactation and neonatal weight gain. Breast milk was collected in the early and late lactation periods with samples being obtained before (foremilk) and after (hindmilk) a feeding period. Then, we determined the Zn concentrations in the breast milk and measured the weight of the infants before and after the same feeding period. The study was composed of 37 newborns and their mothers. During the feeding period, the Zn concentrations in both the transitional and mature milk decreased significantly. During the lactation period, the Zn levels were markedly lower in only the hindmilk. The body weights of the infants both before and after feeding in the early lactation period were negatively correlated with the delta Zn concentration in the same period, but the delta body weights in the early lactation period were positively correlated with the Zn levels in the hindmilk in the same period. In addition, body weights before feeding in the late lactation period were also positively correlated with Zn levels in hindmilk in the early lactation period. This study suggests that the Zn concentrations in both the transitional and mature milk decreased, which suggests that changes in the Zn content of breast milk during lactation might play a role in the weight gain of healthy neonates.

Characterization of Zinc Carbonate Basic as a Source of Zinc in a Rodent Study Investigating the Effects of Dietary Deficiency or Excess

Zinc deficiency and excess can result in adverse health outcomes. There is conflicting evidence regarding whether excess or deficient zinc in the diet can contribute to carcinogenicity. The objective of this study was to characterize zinc carbonate basic for use as a source of dietary zinc in a rodent toxicity and carcinogenicity study investigating the effects of zinc deficiency and excess. Because of the complex chemistries of zinc carbonate basic compounds, inconsistent nomenclature, and literature and reference spectra gaps, it was necessary to employ multiple analytical techniques, including Karl Fischer titration, combustion analysis, inductively coupled plasma-optical emission spectrometry, X-ray diffraction, infrared spectroscopy, X-ray fluorescence spectrometry, and thermogravimetric analysis to characterize the test article. Based on the collective evidence and through the process of elimination, the test article was found to be composed mainly of zinc carbonate basic with zinc oxide as a minor component. The zinc content was determined to be 56.6% (w/w) with heavy metals such as arsenic, cadmium, mercury and lead below the limit of quantitation of less than or equal to 0.01%. The test material was stable at ambient temperature. Based on the work described in this manuscript, the test article was suitable for use as a source of zinc in studies of deficiency and excess in the diet.

Stability Performance of Inductively Coupled Plasma Mass Spectrometry-Phenotyped Kernel Minerals Concentration and Grain Yield in Maize in Different Agro-Climatic Zones

Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS) revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg^–1; zinc: 5.41 to 30.85 mg kg^–1; manganese: 3.30 to17.73 mg kg^–1; copper: 0.53 to 5.48 mg kg^–1) and grain yield (826.6 to 5413 kg ha^–1). Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05) and across locations (r = 0.44, p < 0.01). Variance components of the additive main effects and multiplicative interactions (AMMI) model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%), manganese (41.34%) and copper (41.12%), and environment main effects for both kernel zinc (40.5%) and grain yield (37.0%). Genotype main effect plus genotype-by-environment interaction (GGE) biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV) as the better representative of the AMMI stability parameters. Dynamic stability parameter GGE distance (GGED) showed strong and positive correlation with both mean kernel concentrations and grain yield. Inbreds (CM-501, SKV-775, HUZM-185) identified from the present investigation will be useful in developing micronutrient-rich as well as stable maize hybrids without compromising grain yield.