Serum Zinc, Selenium and Total Antioxidant Contents of Nigerian Children with Asthma: Association with Disease Severity and Symptoms Control

Association Between Circulating Zinc and Risk for Childhood Asthma and Wheezing: A Meta-analysis on 21 Articles and 2205 Children

Asthma is one of the most frequent chronic diseases in children, and growing focus is placed on the exploration of attributable risk factors. Currently, no consensus has been reached on the implication of circulating zinc in the development of asthma. We aimed to conduct a meta-analysis to examine the association between circulating zinc and risk for childhood asthma and wheezing. We searched PubMed, Web of Science, EMBASE, and Google Scholar from inception until December 1, 2022. All procedures were performed independently and in duplicate. Random-effects model was adopted to derive standardized mean difference (SMD) and 95% confidence interval (95% CI). Statistical analyses were completed using the STATA software. Twenty-one articles and 2205 children were meta-analyzed. Overall, there was a statistically significant association between circulating zinc and risk for childhood asthma and wheezing (SMD: -0.38; 95% CI: -0.60 to -0.17; I2=82.6%, p<0.001), without evidence of publication bias as revealed by Begg's (p=0.608) and Egger (p=0.408) tests. Subgroup analyses showed that children with asthma or wheezing in Middle Eastern countries had significantly lower circulating zinc levels than controls (SMD: -0.42; 95% CI: -0.69 to -0.14; p<0.001; I2=87.1%). Additionally, average circulating zinc levels in asthma children were 0.41 μg/dl lower than that in controls, and the difference was statistically significant (SMD: -0.41; 95% CI: -0.65 to -0.16; p<0.001; I2=83.7%). By contrast, children with wheezing were 0.20 μg/dl lower than that in controls, and no between-group difference was noted (SMD=-0.20; 95% CI: -0.58 to 0.17; p=0.072; I2=69.1%). Our findings indicated that circulating zinc was associated with a significant risk for childhood asthma and its related symptom wheezing.

Macronutrient and Micronutrient Intake in Children with Lung Disease

This review article aims to summarize the literature findings regarding the role of micronutrients in children with lung disease. The nutritional and respiratory statuses of critically ill children are interrelated, and malnutrition is commonly associated with respiratory failure. The most recent nutrition support guidelines for critically ill children have recommended an adequate macronutrient intake in the first week of admission due to its association with good outcomes. In children with lung disease, it is important not to exceed the proportion of carbohydrates in the diet to avoid increased carbon dioxide production and increased work of breathing, which potentially could delay the weaning of the ventilator. Indirect calorimetry can guide the process of estimating adequate caloric intake and adjusting the proportion of carbohydrates in the diet based on the results of the respiratory quotient. Micronutrients, including vitamins, trace elements, and others, have been shown to play a role in the structure and function of the immune system, antioxidant properties, and the production of antimicrobial proteins supporting the defense mechanisms against infections. Sufficient levels of micronutrients and adequate supplementation have been associated with better outcomes in children with lung diseases, including pneumonia, cystic fibrosis, asthma, bronchiolitis, and acute respiratory failure.

The Role of Diet and Nutrition in Allergic Diseases

Allergic diseases are a set of chronic inflammatory disorders of lung, skin, and nose epithelium characterized by aberrant IgE and Th2 cytokine-mediated immune responses to exposed allergens. The prevalence of allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, has increased dramatically worldwide in the past several decades. Evidence suggests that diet and nutrition play a key role in the development and severity of allergic diseases. Dietary components can differentially regulate allergic inflammation pathways through host and gut microbiota-derived metabolites, therefore influencing allergy outcomes in positive or negative ways. A broad range of nutrients and dietary components (vitamins A, D, and E, minerals Zn, Iron, and Se, dietary fiber, fatty acids, and phytochemicals) are found to be effective in the prevention or treatment of allergic diseases through the suppression of type 2 inflammation. This paper aims to review recent advances in the role of diet and nutrition in the etiology of allergies, nutritional regulation of allergic inflammation, and clinical findings about nutrient supplementation in treating allergic diseases. The current literature suggests the potential efficacy of plant-based diets in reducing allergic symptoms. Further clinical trials are warranted to examine the potential beneficial effects of plant-based diets and anti-allergic nutrients in the prevention and management of allergic diseases.

Low Serum Levels of Zinc, Selenium, and Vitamin D3 Are Biomarkers of Airway Inflammation and Poor Asthma Control: A Two-Centre Study

Background Asthma is a chronic inflammatory disease with its control being affected by underlying oxidative stress. Trace elements, along with vitamin D3, play an important role in immune alterations leading to an imbalance of Th1/Th2 helper cells. However, their role in asthma pathogenesis and control is inconsistent and inconclusive. The objective of our study was to assess levels of serum trace elements like zinc, copper, selenium, iron, magnesium, vitamin D3 levels, IgE, and HsCRP in asthmatic children, compare with healthy controls, and assess their association with the level of asthma control. Methods A cross-sectional study was conducted from 2019 to 2021 enrolling 100 asthmatic children and 75 healthy controls. The level of asthma control was assessed as uncontrolled, partly controlled, and controlled asthma as per GINA Guidelines. Mean and standard deviation were calculated for each element and mean differences between groups were analyzed by student t-test. A p-value of <0.05 was considered significant. Results The mean age was 8.75±2.89 yrs in cases and 9.04±2.79 in controls. A total of 57.6% of cases had atopic comorbidities. The mean serum zinc levels were 51±12.8 mg/dl, which was very low in asthmatic children as compared to 60±18.2mg/dl (p-value 0.0002) in healthy controls. Serum selenium was 13±3 µg/dl in asthmatics vs. 15±4 µg/dl (p-value 0.0002) in healthy controls. Serum copper was 115.2±21.92µg/dl vs. 125.3±31.99µg/dl (p-value 0.015), Serum vitamin D3 levels were 13.07±7.82ng/ml vs. 17.82±14.62 ng/ml(p-value 0.006) in both groups, respectively. SIgE and HsCRP were high in asthmatic children suggestive of eosinophilic inflammation. Serum zinc was 49±5.45 mg/dl in the uncontrolled group, 53±6.1 in the partly controlled, and 58±8.0 in the well-controlled group (p<0.0001). Serum selenium was 10± 3.0 µg/dl in the uncontrolled group vs. 13± 2.0 and 14± 2.0 µg/dl in the partly controlled and well-controlled groups, respectively (p-value <0.0001). Vitamin D3 was significantly low (9.32±5.95ng/dl) in the uncontrolled group vs. 12.99±4.97 and 13.40±5.92 ng/dl(p<0.005) in the partly controlled and well-controlled groups respectively. Vitamin D3 showed a strong positive correlation with zinc (r=0.4,p< 0.0001) and a negative correlation with inflammatory markers like SIgE and HsCRP. Conclusion Children with asthma had low zinc, selenium, and vitamin D3 levels, and were associated with airway inflammation and poor asthma control.

Oxidative Stress, Environmental Pollution, and Lifestyle as Determinants of Asthma in Children

Exposure to cigarette smoke, allergens, viruses, and other environmental contaminants, as well as a detrimental lifestyle, are the main factors supporting elevated levels of airway oxidative stress. Elevated oxidative stress results from an imbalance in reactive oxygen species (ROS) production and efficiency in antioxidant defense systems. Uncontrolled increased oxidative stress amplifies inflammatory processes and tissue damage and alters innate and adaptive immunity, thus compromising airway homeostasis. Oxidative stress events reduce responsiveness to corticosteroids. These events can increase risk of asthma into adolescence and prompt evolution of asthma toward its most severe forms. Development of new therapies aimed to restore oxidant/antioxidant balance and active interventions aimed to improve physical activity and quality/quantity of food are all necessary strategies to prevent asthma onset and avoid in asthmatics evolution toward severe forms of the disease.

Neonatal Selenium Deficiency Decreases Selenoproteins in the Lung and Impairs Pulmonary Alveolar Development

Decreased selenium (Se) levels during childhood and infancy are associated with worse respiratory health. Se is biologically active after incorporation into Se-containing antioxidant enzymes (AOE) and proteins. It is unknown how decreased maternal Se during pregnancy and lactation impacts neonatal pulmonary selenoproteins, growth, and lung development. Using a model of neonatal Se deficiency that limits Se intake to the dam during pregnancy and lactation, we evaluated which neonatal pulmonary selenoproteins are decreased in both the saccular (postnatal day 0, P0) and early alveolar (postnatal day 7, P7) stages of lung development. We found that Se deficient (SeD) pups weigh less and exhibit impaired alveolar development compared to Se sufficient (SeS) pups at P7. The activity levels of glutathione peroxidase (GPx) and thioredoxin reductase (Txnrd) were decreased at P0 and P7 in SeD lungs compared to SeS lungs. Protein content of GPx1, GPx3 and Txnrd1 were decreased in SeD lungs at P0 and P7, whereas Txnrd2 content was unaltered compared to SeS controls. The expression of NRF-2 dependent genes and several non-Se containing AOE were similar between SeS and SeD lungs. SeD lungs exhibited a decrease in selenoprotein N, an endoplasmic reticulum protein implicated in alveolar development, at both time points. We conclude that exposure to Se deficiency during pregnancy and lactation impairs weight gain and lung growth in offspring. Our data identify multiple selenoproteins in the neonatal lung that are vulnerable to decreased Se intake, which may impact oxidative stress and cell signaling under physiologic conditions as well as after oxidative stressors.

The Role of Zinc in the Pathogenesis of Lung Disease

Lung diseases, such as asthma, chronic obstructive pulmonary diseases (COPD), and cystic fibrosis (CF), are among the leading causes of mortality and morbidity globally. They contribute to substantial economic burdens on society and individuals. Currently, only a few treatments are available to slow the development and progression of these diseases. Thus, there is an urgent unmet need to develop effective therapies to improve quality of life and limit healthcare costs. An increasing body of clinical and experimental evidence suggests that altered zinc and its regulatory protein levels in the systemic circulation and in the lungs are associated with these disease’s development and progression. Zinc plays a crucial role in human enzyme activity, making it an essential trace element. As a cofactor in metalloenzymes and metalloproteins, zinc involves a wide range of biological processes, such as gene transcription, translation, phagocytosis, and immunoglobulin and cytokine production in both health and disease. Zinc has gained considerable interest in these lung diseases because of its anti-inflammatory, antioxidant, immune, and metabolic modulatory properties. Here we highlight the role and mechanisms of zinc in the pathogenesis of asthma, COPD, CF, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, and pulmonary hypertension.

Mineral Micronutrients in Asthma

Asthma represents one of the most common medical issues in the modern world. It is a chronic inflammatory disease characterized by persistent inflammation of the airways and disturbances in redox status, leading to hyperresponsiveness of bronchi and airway obstruction. Apart from classical risk factors such as air pollution, family history, allergies, or obesity, disturbances of the levels of micronutrients lead to impairments in the defense mechanisms of the affected organism against oxidative stress and proinflammatory stimuli. In the present review, the impact of micronutrients on the prevalence, severity, and possible risk factors of asthma is discussed. Although the influence of classical micronutrients such as selenium, copper, or zinc are well known, the effects of those such as iodine or manganese are only rarely mentioned. As a consequence, the aim of this paper is to demonstrate how disturbances in the levels of micronutrients and their supplementation might affect the course of asthma.

Evaluation of blood and tooth element status in asthma cases: a preliminary case-control study

Background

Asthma is a common respiratory disorder; some data were present on the correlation between increased levels of trace elements and the risk of asthma development. It was aimed to evaluate the levels of 13 selected blood and tooth elements (magnesium, phosphorus, calcium, chromium, manganese, iron, copper, zinc, strontium, molybdenum, cadmium, lead, mercury) in a well-controlled asthma group and the control group.

Methods

During the study period, 17 asthma patients and 26 age and gender-matched healthy children donated shed deciduous teeth having neither decay nor filling and enrolled for the study. The element levels in blood and teeth matrixes were analyzed with inductively coupled plasma mass spectrometry. Differences in blood and tooth elements in groups were evaluated with generalized linear models after adjusting confounding factors.

Results

After adjusting the child’s “z scores of body mass index for age”, history of iron deficiency anemia, and status of parental smoking, the generalized linear model revealed significantly lower tooth magnesium levels, lower blood zinc levels, and lower blood zinc/copper ratio in the asthma group than the control group (p = 0.042, p = 0.034, p = 0.002, respectively). Other studied elements for tooth and blood matrixes were similar in groups.

Conclusion

Our study revealed some differences in tooth and blood element levels in the asthma group. Further studies on zinc and magnesium levels of severe asthma cases are necessary for the interpretation of the results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01565-9.

Role of intracellular zinc in molecular and cellular function in allergic inflammatory diseases

Zinc is an essential micronutrient in human body and a vital cofactor for the function of numerous proteins encoded by the human genome. Zinc has a critical role in maintaining many biochemical and physiological processes at the molecular, cellular, and multiple organ and systemic levels. The alteration of zinc homeostasis causes dysfunction of many organs and systems. In the immune system, zinc regulates the differentiation, proliferation and function of inflammatory cells, including T cells, eosinophils, and B cells, by modifying several signaling pathways such as NFκB signaling pathways and TCR signals. An adequate zinc level is essential for proper immune responses and decreased zinc levels were reported in many allergic inflammatory diseases, including atopic dermatitis, bronchial asthma, and chronic rhinosinusitis. Decreased zinc levels often enhance inflammatory activation. On the other hand, the inflammatory conditions alter the intracellular homeostasis of zinc, often decreasing zinc levels. These findings implied that there could be a vicious cycle between zinc deficiency and inflammatory conditions. In this review, we present recent evidence on the involvement of zinc in atopic dermatitis, bronchial asthma, and chronic rhinosinusitis, with insights into the involvement of zinc in the underlying molecular and cellular mechanisms related to these allergic inflammatory diseases.

Relationship between serum 25-hydroxyvitamin D, total antioxidant capacity and pneumonia incidence, severity and outcome in Nigerian children

Background

The pathologic basis of childhood community-acquired pneumonia (CAP) involves the generation of reactive oxygen species by immune cells leading to cellular damage and lung congestion. Serum antioxidants and vitamin D with immunomodulatory properties therefore hold prospects in the prevention and management of pneumonia in children. This case–control study set out to compare the serum 25-hydroxyvitamin D (25-OHD) and total antioxidant capacity (TAC) in Nigerian children with CAP and age- and sex-matched controls and to relate these parameters with pneumonia severity and outcome—length of hospital stay (LOH).

Results

A total of 160 children (80 each for CAP and controls) were recruited. The median (IQR) age was 1.8 (0.6–4.0) years, male:female 1.7:1, 63 (78.8%) and 11 (13.8%) of CAP group had severe pneumonia and parapneumonic effusions, respectively. Serum 25-OHD (33.8 (18.3) ng/ml vs. 41.9 (12.3) ng/ml; p = 0.010) and TAC (6.1 (4.4–8.1) ng/dl vs. 7.2 (4.7–17.5) ng/dl; p = 0.023) were lower in children with CAP than controls. Lower serum 25-OHD was observed in severe than non-severe pneumonia (30.5(17.1) ng/ml vs. 46.3 (17.6) ng/ml; p = 0.001) but LOH did not correlate with serum 25-OHD and TAC.

Conclusion

Children with CAP had lower serum vitamin D and antioxidants than controls, and severe pneumonia was significantly associated with suboptimal serum vitamin D. They however were not related to pneumonia outcome. Optimal serum vitamin D and antioxidants may play a role in reducing the incidence of childhood CAP in Nigerian children.