Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study

Neurotoxic mixture effects of chemicals extracted from blood of pregnant women

Human biomonitoring studies typically capture only a small and unknown fraction of the entire chemical universe. We combined chemical analysis with a high-throughput in vitro assay for neurotoxicity to capture complex mixtures of organic chemicals in blood. Plasma samples of 624 pregnant women from the German LiNA cohort were extracted with a nonselective extraction method for organic chemicals. 294 of >1000 target analytes were detected and quantified. Many of the detected chemicals as well as the whole extracts interfered with neurite development. Experimental testing of simulated complex mixtures of detected chemicals in the neurotoxicity assay confirmed additive mixture effects at concentrations less than individual chemicals' effect thresholds. The use of high-throughput target screening combined with bioassays has the potential to improve human biomonitoring and provide a new approach to including mixture effects in epidemiological studies.

Vitamin D and allergic diseases

In recent years, the relationship between vitamin D and allergic diseases has received widespread attention. As a fat-soluble vitamin, vitamin D plays a crucial role in regulating the immune system and may influence the onset and progression of diseases such as atopic dermatitis, allergic rhinitis, and asthma. To understand the underlying mechanisms, we have summarized the current research on the association between vitamin D and allergic diseases. We also discuss the impact of vitamin D on the immune system and its role in the course of allergic diseases, particularly focusing on how vitamin D supplementation affects the treatment outcomes of these conditions. We aim to provide a theoretical basis and practical guidance for optimizing the management and treatment of allergic diseases by modulating vitamin D levels.

Gene editing in allergic diseases: Identification of novel pathways and impact of deleting allergen genes

Gene editing technology has emerged as a powerful tool in all aspects of health research and continues to advance our understanding of critical and essential elements in disease pathophysiology. The clustered regularly interspaced short palindromic repeats (CRISPR) gene editing technology has been used with precision to generate gene knockouts, alter genes, and identify genes that cause disease. The full spectrum of allergic/atopic diseases, in part because of shared pathophysiology, is ripe for studies with this technology. In this way, novel culprit genes are being identified and allow for manipulation of triggering allergens to reduce allergenicity and disease. Notwithstanding current limitations on precision and potential off-target effects, newer approaches are rapidly being introduced to more fully understand specific gene functions as well as the consequences of genetic manipulation. In this review, we examine the impact of editing technologies of novel genes relevant to peanut allergy and asthma as well as how gene modification of common allergens may lead to the deletion of allergenic proteins.

Novel Perspective on the Regulation of Offspring Food Allergy by Maternal Diet and Nutrients

There has been a dramatic surge in the prevalence of food allergy (FA) that cannot be explained solely by genetics, identifying mechanisms of sensitization that are driven by environmental factors has become increasingly important. Diet, gut microbiota, and their metabolites have been shown to play an important role in the development of FA. In this review, we discuss the latest epidemiological evidence on the impact of two major dietary patterns and key nutrients in early life on the risk of offspring developing FA. The Western diet typically includes high sugar and high fat, which may affect the immune system of offspring and increase susceptibility to FA. In contrast, the Mediterranean diet is rich in fiber, which may reduce the risk of FA in offspring. Furthermore, we explore the potential mechanisms by which maternal dietary nutrients during a window of opportunity (pregnancy, birth, and lactation) influences the susceptibility of offspring to FA through multi-interface crosstalk. Finally, we discuss the limitations and gaps in the available evidence regarding the relationship between maternal dietary nutrients and the risk of FA in offspring. This review provides novel perspective on the regulation of offspring FA by maternal diet and nutrients.

Low vitamin D during pregnancy is associated with infantile eczema by up-regulation of PI3K/AKT/mTOR signaling pathway and affecting FOXP3 expression: A bidirectional cohort study

Vitamin D has received increasing attention because of its association with atopic disease development. Limited studies that have been done on the impact of maternal vitamin D levels during pregnancy on infantile eczema are still debatable. We wanted to discover the effect of maternal vitamin D on infantile eczema and explore whether regulatory T cells (Treg) play a role in this process. 219 pairs of mothers and children were enrolled. Maternal fasting venous blood was collected in pregnancy's second and third trimesters to determine vitamin D levels. Cord blood and placenta samples were collected during childbirth for detecting levels of genes, proteins and cytokines. Pediatricians followed up the prevalence of eczema in infants within 1 year. The reported rate of vitamin D deficiency and insufficiency was 35.6% and 28.3%. Lower maternal 25(OH)D3 levels were related to a higher risk of infantile eczema. Foxp3 gene expression is lower in cord blood of infants with eczema compared to infants without eczema. There was a positive correlation between maternal 25(OH)D3 levels and the expression of FOXP3 gene in cord blood. Compared to vitamin D sufficiency women, vitamin D deficiency women's placental FOXP3 protein expression was decreased and PI3K/AKT/mTOR protein was up-regulated. Our study demonstrates that low prenatal maternal vitamin D levels increased the risk of infantile eczema aged 0-1 year, which might be related to the downregulating of the FOXP3 gene expression in cord blood and decreased placental FOXP3 protein expression. Low placental FOXP3 protein was related with activating PI3K/AKT/mTOR signaling pathway.

Early-life risk factors for food allergy: Dietary and environmental factors revisited

There appears a steep increase in the prevalence of food allergy worldwide in the past few decades. It is believed that, rather than genetic factors, the recently altered dietary and environmental factors are the driving forces behind the rapid increase of this disease. Accumulating evidence has implied that external exposures that occurred in prenatal and postnatal periods could affect the development of oral tolerance in later life. Understanding the potential risk factors for food allergy would greatly benefit the progress of intervention and therapy. In this review, we present updated knowledge on the dietary and environmental risk factors in early life that have been shown to impact the development of food allergy. These predominantly include dietary habits, microbial exposures, allergen exposure routes, environmental pollutants, and so on. The key evidence, conflicts, and potential research topics of each theory are discussed, and associated interventional strategies to prevent the disease development and ameliorate treatment burden are included. Accumulating evidence has supported the causative role of certain dietary and environmental factors in the establishment of oral tolerance in early life, especially the time of introducing allergenic foods, skin barrier function, and microbial exposures. In addition to certain immunomodulatory factors, increasing interest is raised toward modern dietary patterns, where adequately powered studies are required to identify contributions of those modifiable risk factors. This review broadens our understanding of the connections between diet, environment, and early-life immunity, thus benefiting the progress of intervention and therapy of food allergy.

The First 1000 Days of Life: How Changes in the Microbiota Can Influence Food Allergy Onset in Children

BACKGROUND

Allergic disease, including food allergies (FA)s, has been identified as a major global disease. The first 1000 days of life can be a "window of opportunity" or a "window of susceptibility", during which several factors can predispose children to FA development. Changes in the composition of the gut microbiota from pregnancy to infancy may play a pivotal role in this regard: some bacterial genera, such as Lactobacillus and Bifidobacterium, seem to be protective against FA development. On the contrary, Clostridium and Staphylococcus appear to be unprotective.

METHODS

We conducted research on the most recent literature (2013-2023) using the PubMed and Scopus databases. We included original papers, clinical trials, meta-analyses, and reviews in English. Case reports, series, and letters were excluded.

RESULTS

During pregnancy, the maternal diet can play a fundamental role in influencing the gut microbiota composition of newborns. After birth, human milk can promote the development of protective microbial species via human milk oligosaccharides (HMOs), which play a prebiotic role. Moreover, complementary feeding can modify the gut microbiota's composition.

CONCLUSIONS

The first two years of life are a critical period, during which several factors can increase the risk of FA development in genetically predisposed children.

A comprehensive review on the impact of calcium and vitamin D insufficiency and allied metabolic disorders in females

Calcium is imperative in maintaining a quality life, particularly during later ages. Its deficiency results in a wide range of metabolic disorders such as dental changes, cataracts, alterations in brain function, and osteoporosis. These deficiencies are more pronounced in females due to increased calcium turnover throughout their life cycle, especially during pregnancy and lactation. Vitamin D perform a central role in the metabolism of calcium. Recent scientific interventions have linked calcium with an array of metabolic disorders in females including hypertension, obesity, premenstrual dysphoric disorder, polycystic ovary syndrome (PCOS), multiple sclerosis, and breast cancer. This review encompasses these female metabolic disorders with special reference to calcium and vitamin D deficiency. This review article aims to present and elaborate on available data regarding the worldwide occurrence of insufficient calcium consumption in females and allied health risks, to provide a basis for formulating strategies and population-level scientific studies to adequately boost calcium intake and position where required.

Environmental Exposure to Foods as a Risk Factor for Food Allergy

PURPOSE OF REVIEW

Many factors have been reported to contribute to the development of food allergy. Here, we summarize the role of environmental exposure to foods as a major risk factor for developing food allergy.

RECENT FINDINGS

Peanut proteins are detectable and biologically active in household environments, where infants spend a majority of their time, providing an environmental source of allergen exposure. Recent evidence from clinical studies and mouse models suggests both the airway and skin are routes of exposure that lead to peanut sensitization. Environmental exposure to peanut has been clearly associated with the development of peanut allergy, although other factors such as genetic predisposition, microbial exposures, and timing of oral feeding of allergens also likely contribute. Future studies should more comprehensively assess the contributions of each of these factors for a variety of food allergens to provide more clear targets for prevention of food allergy.

Is antenatal or early-life vitamin D associated with eczema or food allergy in childhood? A systematic review

OBJECTIVE

To summarise the associations between antenatal or early-life blood vitamin D and the development of eczema/food allergy in childhood.

DESIGN

A systematic review and meta-analyses were conducted to synthesize the published literature. Two reviewers independently performed the study selection and data extraction on Covidence. We assessed the risk of bias for observational studies by using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool for clinical trials. The certainty of the evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

DATA SOURCES

We systematically searched PubMed and Embase from inception and April 2022.

ELIGIBILITY CRITERIA

Human studies that investigated prospective associations between antenatal or early-life blood vitamin D levels, dietary intake or supplementation and childhood eczema/food allergy.

RESULTS

Forty-three articles including six randomised controlled trials (RCTs) were included. Four RCTs of vitamin D supplementation during pregnancy showed no evidence of an effect on the incidence of eczema (pooled odds ratio [OR] = 0.85; 0.67-1.08, I2  = 6.7%, n = 2074). Three RCTs reported null associations between supplementation in pregnancy/infancy and food allergy. From six cohort studies, increasing cord blood vitamin D levels were associated with reduced prevalence of eczema at/close to age one (OR per 10 nmol/L increase = 0.89; 0.84-0.94, I2  = 0%, 2025 participants). We found no evidence of an association between maternal antenatal or infant vitamin D level or dietary intake and the development of food allergy or eczema in offspring.

CONCLUSIONS

We found an association between higher vitamin D levels in cord blood and reduced risk of eczema in cohort studies. Further trials with maternal and infant supplementation are needed to confirm if vitamin D supplementation can effectively prevent eczema or food allergy in childhood.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, No. CRD42013005559.

A systematic review of quality and consistency of clinical practice guidelines on the primary prevention of food allergy and atopic dermatitis

Background and aims

With an increasing number of Clinical Practice Guidelines (CPGs) addressing primary prevention of food allergy and atopic dermatitis, it is timely to undertake a comprehensive assessment of the quality and consistency of recommendations and evaluation of their implementability in different geographical settings.

Methods

We systematically reviewed CPGs from 8 international databases and extensive website searches. Seven reviewers screened records in any language and then used the AGREE II and AGREE REX instruments to critically appraise CPGs published between January 2011 and April 2022.

Results

Our search identified 2138 relevant articles, of which 30 CPGs were eventually included. Eight (27%) CPGs were shortlisted based on our predefined quality criteria of achieving scores >70% in the "Scope and Purpose" and "Rigour of Development" domains of the AGREE II instrument. Among the shortlisted CPGs, scores on the "Applicability" domain were generally low, and only 3 CPGs rated highly in the "Implementability" domain of AGREE-REX, suggesting that the majority of CPGs fared poorly on global applicability. Recommendations on maternal diet and complementary feeding in infants were mostly consistent, but recommendations on use of hydrolysed formula and supplements varied considerably.

Conclusion

The overall quality of a CPG for Food Allergy and Atopic Dermatitis prevention did not correlate well with its global applicability. It is imperative that CPG developers consider stakeholders' preferences, local applicability, and adapt existing recommendations to each individual population and healthcare system to ensure successful implementation. There is a need for development of high-quality CPGs for allergy prevention outside of North America and Europe.

PROSPERO registration number

CRD42021265689.

Vitamin D and Omega-3 (Fatty Acid) Supplementation in Pregnancy for the Primary Prevention of Food Allergy in Children-Literature Review

During the last decades the prevalence of food allergy (FA), an adverse immune response to a specific food antigen, has risen, with negative effects on the quality of life (QoL) of many children and their families. The pathogenesis of FA is complex, involving both genetic and environmental factors. SPINK5, STAT6, HLA and FOXP3 are some of the genes that are reported to be implicated in FA development. Regarding environmental factors, particular interest has been focused on modification of the dietary habits of pregnant women for the primary prevention of FA. Specifically, Vitamin D and omega-3 (Ω-3) fatty acid supplementation during pregnancy may influence the development of FA in the offspring. Vitamin D is a hormone with various actions, including mediation of the immune system, reducing the production of inflammatory cytokines and promoting tolerance. Vitamin D deficiency in pregnancy suppresses T-regulatory cells in the fetus, and Vitamin D supplementation might protect against FA development. Dietary Ω-3 fatty acids are found mainly in fish and vegetable oils. They are beneficial for human health, playing a role in the immune system as anti-inflammatory agents, and providing cell membrane stabilization with inhibition of antigen presentation. It is documented that maternal supplementation with Ω-3 during pregnancy may protect from allergic sensitization in the children. The aim of this literature review was to explore the potential preventive role of maternal supplementation during pregnancy with Vitamin D and Ω-3 in the development of FA in the offspring. With the prevalence of FA rising, all the possible protective mechanisms and measures for FA prevention need to be explored, starting with those that can be modified.

Association of food allergy in children with vitamin D insufficiency: a systematic review and meta-analysis

Current literature regarding the association of vitamin D insufficiency and food allergy is contradicting. The purpose of our study was to investigate this association. This is a systematic review and meta-analysis according to the PRISMA statement. PubMeD and Scopus databases were systematically searched for case-control studies investigating the association between pediatric food allergy and vitamin D insufficiency. Our search yielded 806 studies. Ten final studies were considered eligible for qualitative and quantitative analysis. Children with vitamin D insufficiency were found to have 68% more probability to present a food allergy episode (adjusted pooled OR: 1.68, 95% CI [1.25-2.27], p-value: 0.001). In their second year of life they were 4 times more likely to present a food allergy episode (adjusted pooled OR: 4.06, 95% CI [1.93-8.56], p-value: < 0.001), and 56% more probable to develop food sensitization (OR: 1.56, 95% CI [1.15-2.11], p-value: < 0.004). Children in Australia with vitamin D insufficiency were almost 4 times more likely to develop egg sensitization (adjusted OR: 3.79, 95% CI [1.19-12.08], p-value: 0.024). Children with vitamin D insufficiency were almost twice as likely to have peanut sensitization (OR: 1.96, 95% CI [1.08-3.57], p-value: 0.028).  Conclusion: Decreased maternal vitamin D levels and infant vitamin D insufficiency appear to increase the incidence of food allergies, particularly in the second year of life. To confirm this association, multicenter longitudinal studies are required. What is Known: • In newborns and young children, vitamin D deficiency and insufficiency are prevalent. • The exact role of vitamin D in atopic diseases remains controversial. What is New: • Decreased maternal vitamin D levels and infant vitamin D insufficiency appear to increase the incidence of food allergies. This association is more evident in the second year of life.

Maternal Macro- and Micronutrient Intake During Pregnancy: Does It Affect Allergic Predisposition in Offspring?

This review article explores the available literature on the association of maternal nutrient intake with development of allergies in offspring. It examines the mechanisms for maternal diet-mediated effects on offspring immunity and dissects recent human and animal studies that evaluate the role of both maternal macro- and micronutrient intake on offspring susceptibility to asthma, eczema, food allergy, and atopy.

Nutritional management of food allergies: Prevention and treatment

An individualized allergen avoidance plan is the cornerstone of the nutritional management of food allergy (FA). In pediatric age, the main objective is preventing the occurrence of acute and chronic symptoms by avoiding the offending food(s) and providing an adequate, nutritionally balanced and personalized diet at the same time. For this reason, the presence of a trained dietitian is recommended in order to meet nutritional needs of patients with FA and to provide a tailored nutritional plan, minimizing the impact of FA on quality of life and maintaining optimal growth.

Vitamin D supplementation in patients with atopic dermatitis, chronic urticaria and contact irritant and allergic dermatitis - possible improvement without risk

Abstract.

Pro-inflammatory Diet Pictured in Children With Atopic Dermatitis or Food Allergy: Nutritional Data of the LiNA Cohort

Background

Lifestyle and environmental factors are known to contribute to allergic disease development, especially very early in life. However, the link between diet composition and allergic outcomes remains unclear.

Methods

In the present population-based cohort study we evaluated the dietary intake of 10-year-old children and analyses were performed with particular focus on atopic dermatitis or food allergy, allergic diseases known to be affected by dietary allergens. Dietary intake was assessed via semi-quantitative food frequency questionnaires. Based on these data, individual nutrient intake as well as children’s Dietary Inflammatory Index (C-DII™) scores were calculated. Information about atopic manifestations during the first 10 years of life and confounding factors were obtained from standardized questionnaires during pregnancy and annually thereafter.

Results

Analyses from confounder-adjusted logistic regression models (n = 211) revealed that having atopic outcomes was associated with having a pro-inflammatory pattern at the age of 10 years: OR = 2.22 (95% CI: 1.14–4.31) for children with atopic dermatitis and OR = 3.82 (95% CI: 1.47–9.93) for children with food allergy in the first 10 years of life.

Conclusion

A pro-inflammatory dietary pattern might worsen the atopic outcome and reduce the buffering capacity of the individual against harmful environmental exposures or triggers. For pediatricians it is recommended to test for the individual tolerance of allergenic foods and to increase the nutrient density of tolerable food items to avoid undesirable effects of eating a pro-inflammatory diet.

Nutrition during Pregnancy and Lactation: Epigenetic Effects on Infants’ Immune System in Food Allergy

Food allergies are an increasing health problem worldwide. They are multifactorial diseases, in which the genome alone does not explain the development of the disease, but a genetic predisposition and various environmental factors contribute to their onset. Environmental factors, in particular nutritional factors, in the early stages of life are recognized as key elements in the etiology of food allergies. There is growing evidence advising that nutrition can affect the risk of developing food allergies through epigenetic mechanisms elicited by the nutritional factors themselves or by modulating the gut microbiota and its functional products. Gut microbiota and postbiotics can in turn influence the risk of food allergy development through epigenetic mechanisms. Epigenetic programming accounts not only for the short-term effects on the individual’s health status, but also for those observed in adulthood. The first thousand days of life represent an important window of susceptibility in which environmental factors, including nutritional ones, can influence the risk of developing allergies through epigenetic mechanisms. From this point of view, it represents an interesting window of opportunity and intervention. This review reports the main nutritional factors that in the early stages of life can influence immune oral tolerance through the modulation of epigenetic mechanisms.

Pre- and Postnatal Vitamin D Status and Allergy Outcomes in Early Childhood

The dramatic increase in the prevalence of allergic disease in recent decades reflects environmental and behavioural changes that have altered patterns of early immune development. The very early onset of allergic diseases points to the specific vulnerability of the developing immune system to environmental changes and the development of primary intervention strategies is crucial to address this unparalleled burden. Vitamin D is known to have immunomodulatory functions. While allergic disease is multifactorial, associations with reduced sunlight exposure have led to the hypothesis that suboptimal vitamin D levels during critical early periods may be one possible explanation. Interventions to improve vitamin D status, especially in early life, may be the key to allergic disease prevention.

Associations between grass pollen exposures in utero and in early life with food allergy in 12-month-old infants

Birth during pollen seasons may influence food allergy risk but no study has assessed pollen exposure. Using the HealthNuts population-based cohort of 5276 infants, we assessed grass pollen exposures, in utero and up to the first 6 months of life, on hen's egg, sesame and peanut allergy outcomes at 12 months. Cumulative pollen exposure in the first 7 days of life increased risk of peanut sensitization aMOR (adjusted multinomial odds ratio) = 1.21 (95% CI: 1.01-1.44). Exposure between first 4-6 months of life increased risk of hen's egg aMOR = 1.02 (95% CI: 1.004-1.04) and sensitization to all foods aMOR = 1.02 (95% CI: 1.003-1.04). Grass pollen exposure was associated with food challenge diagnosed food allergy, but only among infants with a maternal history of food allergy. Exposure to grass pollen in the intrauterine period and infancy may be important but more studies are needed to replicate these findings.

Cord blood 25(OH)D3, cord blood total immunoglobulin E levels, and food allergies in infancy: A birth cohort study in Chongqing, China

Background

Food allergy (FA) in infants has become a common disease worldwide. There are many controversies surrounding the relationships among levels of cord blood 25-hydroxy vitamin D3 [25(OH)D3], total immunoglobulin E (IgE), and FA.

Methods

In this study, we recruited pregnant women in the third trimester undergoing obstetric examination in Chongqing City, Western China. Healthy full-term singleton births between May to August 2018 and November 2018 to January 2019 were included in the summer-birth and winter-birth cohorts, respectively. Questionnaires on vitamin D status in pregnancy and family allergies were used to investigate the pregnant women. The levels of <12 ng/mL, 12～20 ng/mL, and >20 ng/mL 25(OH)D3 in cord blood detected by liquid chromatography tandem mass spectrometry were considered deficient, insufficient, and sufficient, respectively. The electrochemiluminescence method was used to detect the total lgE levels in cord blood, classified into low-IgE (<0.35 IU/mL) and high-IgE (≥0.35 IU/mL) levels, respectively. Within postnatal 6 months, allergic symptoms in infants were investigated using questionnaire during the infants' monthly physical examinations. Suspected cases of FA underwent a history inquiry, skin prick test, food elimination test, and open-food challenge for diagnosis of FA. Multivariate logistic regression was used to analyze the risk factors of FA in infants.

Results

In this study, we recruited 741 pairs of pregnant women and infants, including 343 infants in the summer-birth cohort and 398 infants in the winter-birth cohort. The incidence of FA within postnatal 6 months was 6.88%, showing significantly higher incidence of FA in the winter-birth cohorts than in the summer-birth cohorts (10.3% vs. 2.9%, χ2 = 15.682, P = 0.000). Among the 741 infants, 47.1%, 27.5%, and 13.8% of infants had deficient, insufficient, and sufficient 25(OH)D3, respectively, in the cord blood; 81.5% and 18.5% of infants had total low-IgE and total high-IgE levels, respectively, in the cord blood. No significant correlation was found between the 25(OH)D3 and IgE levels (r = -0.038, P = 0.300). Logistic regression analysis showed that winter birth [odds ratio (OR) 95% confidence interval (CI): 4.292 (2.003～8.359)] compared with infants in summer birth group, and sufficient (>20 ng/mL) 25(OH)D3 levels in cord blood [OR (95% CI): 2.355 (1.129～4.911) compared with infants in the deficient group (<12 ng/mL) and 3.782 (1.680～8.514) compared with infants in the insufficient group (12～20 ng/mL)] were independent risk factors for FA in infants within postnatal 6 months.

Conclusions

Winter birth and sufficient 25(OH)D3 levels in infant cord blood were independent risk factors for FA in infants. 25(OH)D3 and total IgE levels in cord blood cannot be used as predictors of FA in early infancy.

Effects of exposure to single and multiple parabens on asthma development in an experimental mouse model and a prospective cohort study

Parabens are widely used preservatives present in consumer products like cosmetics and food. Although several epidemiological studies suggest that early-life exposure to parabens might alter the immune response and allergy risk in childhood, the evidence with respect to asthma is not clear. Therefore, we investigated the effect of paraben exposure on asthma development in mice and humans. Using a murine asthma model the experimental data show both, an asthma-reducing effect after direct exposure of adult mice to n-butyl paraben (nBuP) as well as an asthma-promoting effect after maternal exposure to ethyl paraben (EtP) in the female offspring. Interestingly, exposure of mice to a mixture of EtP and nBuP starting prenatally until the end of asthma induction in the adult offspring was without effect on allergic airway inflammation. In addition, parabens were determined within the German prospective mother-child cohort LINA and their single and mixture effect on asthma development in children within the first 10 years of life was estimated by logistic and Bayesian kernel machine regression (BKMR). Both approaches revealed no adverse effects of parabens on children's asthma development, neither when stratified for being at risk due to a positive family history of atopy nor when analysed separately for sex specificity. Therefore, we conclude that although single parabens might differentially impact asthma development, an adverse effect could not be seen in a multiple paraben exposure setting. Consequently, not only the time point of exposure but also multiple exposure scenarios to parabens should be considered in the evaluation of individuals' specific disease risk.

Maternal serum 25-hydroxyvitamin D levels and infant atopic dermatitis: A prospective cohort study

BACKGROUND

Maternal vitamin D status during pregnancy has been linked with the risk of atopic dermatitis (AD) in children, while the results were inconsistent. The objective of this study was to assess the potential association.

METHODS

Serum 25-hydroxyvitamin D (25(OH)D) levels were measured in pregnant women from the birth cohort MKFOAD. Infant AD was diagnosed according to Williams' criteria. Multivariate logistic regression model was used to examine the association of maternal serum 25(OH)D levels in the first, second, and third trimester of gestation with the risk of infant AD at first year of age.

RESULTS

In total, 121 (26.5%) of 456 infants developed AD prior to 1 year of age. In general, higher maternal serum 25(OH)D levels throughout pregnancy were associated with increased risks of AD in infants prior to 1 year of age in multivariate logistic regression models, with borderline statistical significance in the first (per ln unit increase: adjusted OR = 1.93, 95% CI: 0.96, 3.88) and second (per ln unit increase: adjusted OR = 1.72, 95% CI: 0.93, 3.19) trimester. Multivariate logistic regression models using categorical variables of maternal 25(OH)D levels by tertiles showed similar results: Infants born to mothers with serum 25(OH)D levels in the highest tertile had higher risk of AD than those with 25(OH)D in the lowest tertile.

CONCLUSIONS

The present study found some evidence supporting that higher maternal 25(OH)D levels during pregnancy increased the risk of infant AD. However, the clinical implication of the findings should be limited for those with blood levels over the recommendations.

A narrative review of vitamin D and food allergy in infants and children

OBJECTIVE

This article summarizes the research progress on the association of vitamin D and food allergy in infants and children.

BACKGROUND

In recent years, food allergy seriously has affected the quality of life of children and adults. Vitamin D is known to be involved in calcium and phosphorus metabolism, and recent research has demonstrated that vitamin D can also affect the immune regulation of food allergy.

METHODS

The present study summarizes the research progress on the association of vitamin D and food allergy in infants and children. We searched the PubMed database to identify studies on the association of vitamin D and food allergy published between January 2003 and August 2021.

CONCLUSIONS

Vitamin D in the body through a number of steps into the final formation of biological effects. The implications of postnatal vitamin D levels for food allergy may be even greater. Vitamin D can prevent the intestinal immune system from being exposed to allergens by maintaining the integrity of the mucosal barrier. Many clinical studies believe that vitamin D supplementation can improve infants' and children's food allergy, however, some show negative results or opposite results. A lot of laboratory studies have confirmed that vitamin D is involved in the immune regulation of food allergy. Evidence indicates there may be a nonlinear relationship between vitamin D and food allergy. Further researches need to be launched.

Maternal Nutritional Status and Development of Atopic Dermatitis in Their Offspring

Atopic dermatitis (AD) is the leading chronic skin inflammatory disease and the initial manifestation of atopic march. Available evidence supports the notion that primary prevention early in life leads to a decreased incidence of AD, thus possibly decreasing the subsequent occurrence of atopic march. Nutritional status is essential to a proper functioning immune system and is valued for its important role in AD. Essential nutrients, which include carbohydrates, proteins, lipids, vitamins, and minerals, are transferred from the mother to the fetus through the placenta during gestation. Various nutrients, such as polyunsaturated fatty acids (PUFAs) and vitamin D, were studied in relation to maternal status and offspring allergy. However, no strong evidence indicates that a single nutrient or food in mothers' diet significantly affects the risk of childhood AD. In the light of current evidence, mothers should not either increase nor avoid consuming these nutrients to prevent or ameliorate allergic diseases in their offspring. Each essential nutrient has an important role in fetal development, and current government recommendations suggest specific intake amounts for pregnant women. This review discusses evidence on how various nutrients, including lipids (monounsaturated fatty acids, PUFAs, saturated fatty acids, and short-chain fatty acids), carbohydrates (oligosaccharides and polysaccharides), proteins, vitamins (A, B, C, D, and E), and trace minerals (magnesium, iron, zinc, copper, selenium, and strontium) in maternal status are associated with the development of AD and their possible mechanisms.

Longitudinal Vitamin D Deficiency Among Malaysian Pregnant Women and Its Correlation With Neonatal Serum 25-Hydroxyvitamin D Levels

Objective: This study aimed to investigate the longitudinal relationship between maternal vitamin D concentrations during pregnancy and neonatal vitamin D concentrations at birth.

Materials and Methods: A prospective cohort of 236 healthy pregnant women from various ethnicity in early pregnancy (≤20 weeks of pregnancy) was followed at late pregnancy (28–40 weeks of pregnancy) and birth. Maternal serum 25-hydroxyvitamin D (25(OH)D) was assessed at early pregnancy (baseline) and late pregnancy, while neonatal cord serum 25(OH)D at birth. General estimating equations (GEE) were used to analyze the longitudinal association of maternal serum 25(OH)D levels during pregnancy and neonatal cord serum 25(OH)D levels at birth with adjusting for the time exposure, maternal weight gain, ethnicity, and skin type.

Results: The results showed that the prevalence of vitamin D deficiency (25(OH)D <50 nmol/L) was at 89.9, 92.2, and 96.1% in early, late pregnancy and in neonatal cord serum, respectively. The GEE analysis showed a trend that longitudinal vitamin D deficiency during pregnancy leads to lower vitamin D concentrations in neonatal cord blood (RR = 1.17; 95% CI (1.05–1.36); p = 0.04).

Conclusion: Longitudinal vitamin D deficiency during pregnancy leads to vitamin D deficiency in neonates at birth. A further trial is needed to affirm this association.

Impact of COVID-19 Pandemic on Serum Vitamin D Level among Infants and Toddlers: An Interrupted Time Series Analysis and before-and-after Comparison

Background: During the coronavirus disease 2019 (COVID-19) pandemic, the implementation of social distancing and home confinement measures may elevate the risk of vitamin D deficiency particularly for infants. This study aimed to quantify changes in vitamin D level among infants and toddlers in Hong Kong after the COVID-19 outbreak. Methods: We recruited 303 infants and toddlers aged 2–24 months by stratified random sampling from 1 June 2019 to November 30, 2020. Regression models were used to estimate the effect of time on infants’ serum 25-hydroxyvitamin D (25(OH)D) level overall and by age groups before and after the outbreak. Interrupted time series (ITS) analysis was performed to examine the sustained effect of COVID-19 on their serum 25(OH)D level. Results: The ITS results showed no immediate reduction in serum 25(OH)D level among infants, but a decreasing trend was observed in the subsequent months post-outbreak at a monthly decline rate of −6.32 nmol/L. When analyzed by age group, the magnitude of post-outbreak reduction in 25(OH)D was stronger among younger infants (aged 2–6 months). Conclusion: Guidelines and recommendations should be given to pregnant women and mothers to ensure sufficient vitamin D level in their infants during the COVID-19 period.

Non-association between low vitamin d levels and aeroallergen-positivity evaluated using multiple allergen simultaneous test in Korean adults

Background

Studies on the association between vitamin D levels and allergen sensitization have reported conflicting results. We aimed to evaluate the association between low vitamin D levels and sensitization to 59 aeroallergens in Korean adults.

Methods

We retrospectively reviewed serum 25-hydroxyvitamin D (25[OH]D) measurements of participants (n = 57,467) in a healthcare center between May 2003 and June 2020. Serum 25(OH)D levels were categorized as follows: severe deficiency (< 10 ng/mL), deficiency (10 to < 20 ng/mL), insufficiency (20 to < 30 ng/mL), and sufficiency (≥ 30 ng/mL). Among all subjects, 1277 simultaneously underwent the multiple allergen simultaneous test. Multiple linear and logistic regression analyses were used to estimate coefficients and odds ratios (ORs) with 95% confidence interval (CI) for the association between serum vitamin D deficiency and aeroallergen sensitization after adjustment for potential confounders. Subgroup analyses were conducted for the types of aeroallergen (house dust mites, pollens, animal dander, foods, cockroach, and fungus).

Results

Vitamin D deficiency, defined as serum 25(OH)D level < 20 ng/mL, was noted in 56.4% of participants. There were significant differences in serum 25(OH)D levels according to sex, age, season, and bone mineral density (all P < 0.001). In multiple linear regression analyses, serum 25(OH)D levels were significantly lower in young subjects (adjusted coefficient [95% CI], 0.188 [0.101, 0.275]) and during winter (− 4.114 [− 6.528, − 1.699]). However, no significant association was observed between serum 25(OH)D levels and allergen sensitization (adjusted coefficients [95% CI], − 0.211 [− 1.989, 1.567], P = 0.816). In multivariate logistic regression analyses, male sex, young age, and winter season were significant risk factors for vitamin D deficiency. However, allergen sensitization showed no significant association with 25(OD)D levels after adjusting for confounders (adjusted OR [95% CI], 1.037 [0.642, 1.674] in insufficiency; 0.910 [0.573, 1.445] in deficiency; 0.869 [0.298, 2.539] in severe deficiency groups, P for trend = 0.334). There were consistent findings across subgroups regarding type of aeroallergen sensitized.

Conclusion

Vitamin D deficiency was prevalent but was not significantly associated with aeroallergen sensitization in Korean adults. To the best of our knowledge, this is the first large-scale study to evaluate the association between vitamin D deficiency and sensitization to 59 different aeroallergens.

Maternal and Cord Blood 25-Hydroxyvitamin D3 Are Associated with Increased Cord Blood and Naive and Activated Regulatory T Cells: The Barwon Infant Study

Vitamin D has shown immune-modulatory effects but mostly in in vitro and animal studies. Regulatory T cells (Treg) are important for a balanced immune system. The relationship between vitamin D on the number of circulating neonatal Treg is unclear. We sought to investigate the association between maternal and neonatal vitamin D metabolites and cord blood (CB) Treg subsets. In a cohort of Australian infants (n = 1074), recruited using an unselected antenatal sampling frame, 158 mother-infant pairs had data on the following: 1) 25-hydroxyvitamin D₃ (25(OH)D₃) measures in both maternal peripheral blood (28- to 32-wk gestation) and infant CB; 2) proportions (percentage of CD4⁺ T cells) of CB Treg subsets (CD4⁺CD45RA⁺ FOXP3^low naive Treg, and CD4⁺CD45RA^- FOXP3^high activated Treg [aTreg]); and 3) possible confounders, including maternal personal UV radiation. Multiple regression analyses were used. The median 25(OH)D₃ was 85.4 and 50.7 nmol/l for maternal and CB samples, respectively. Higher maternal 25(OH)D₃ levels were associated with increased CB naive Treg (relative adjusted mean difference [AMD] per 25 nmol/l increase: 5%; 95% confidence interval [CI]: 1-9%), and aTreg (AMD per 25 nmol/l increase: 17%; 95% CI: 6-28%). Furthermore, a positive association between CB 25(OH)D₃ levels and CB aTreg (AMD per 25 nmol/l increase: 29%; 95% CI: 13-48%) was also evident. These results persisted after adjustment for other factors such as maternal personal UV radiation and season of birth. 25(OH)D_3, may play a role in the adaptive neonatal immune system via induction of FOXP3⁺ Tregs. Further studies of immune priming actions of antenatal 25(OH)D₃ are warranted.

Food allergy prevention, including early food introduction

As the prevalence of immunoglobulin E (IgE)-mediated food allergy continues to increase without an imminent cure, prevention has become an urgent need. A breakthrough study that shows that early consumption of peanut can prevent the development of peanut allergy has led for a push in early interventions. Theories associated with the increasing prevalence of food allergy lend themselves to areas of potential intervention, e.g., age at time of food introduction, infant feeding practices, microbiome influences, diet composition, vitamin D deficiency, and increasing rates of eczema. This review focused on the available data from studies that investigated early interventions to decrease the risk of food allergy.

Role of Vitamin D in Prevention of Food Allergy in Infants

The prevalence of food allergy is increasing over the last decades. The role of vitamin D in the prevention of food allergy has been largely investigated. Its role on the physiology of calcium and bone is known, but calcitriol (active form of the vitamin D) also influences the epithelial cells, T cells, B cells, macrophages, and dendritic cells. Almost all cells of the adaptive immune system express the vitamin D receptor, making them also capable of being vitamin responsive. Specifically considering the potential role of vitamins in food allergy, vitamin D has been shown to affect several mechanisms that promote immunologic tolerance, including the T regulatory cell function and the induction of tolerogenic dendritic cells. The target of our review is to evaluate the role of vitamin D in the prevention of food allergy in children. There are contradictory data on the relationship among the vitamin D deficiency and the developing of food allergy. Some studies associate lower exposure to sunlight to food allergy; on the other hand, further research has found that higher vitamin D levels could increase the likelihood of allergic sensitization and food allergy. Therefore, there is an urgent need for well-planned randomized controlled trials on vitamin D supplementation, with particular regard to the prevention of food allergy. The role of vitamin D beyond bone and calcium metabolism is not fully understood.

Maternal Vitamin D Levels during Late Pregnancy and Risk of Allergic Diseases and Sensitization during the First Year of Life-A Birth Cohort Study

Allergic diseases are the most common chronic illness in childhood. Findings from developed countries have reported associations between Vitamin D levels during pregnancy and offspring allergy risk. This prospective cohort study aimed to determine the associations between maternal Vitamin D levels during late pregnancy and allergic diseases in Malaysian infants during the first year of life. Serum 25(OH)D concentrations of 380 pregnant women in the third trimester were measured using a chemiluminescent immunoassay. Children's allergic outcomes were assessed at 3, 6, and 12 months based on parental reports. Specific IgE antibodies against food and inhalant allergens were measured in infants at 12 months of age. A total of 43.2% pregnant women were Vitamin D deficient (<30 nmol/L) and 56.8% were nondeficient (≥30 nmol/L). A total of 27.6% of the infants had eczema, 6.1% had wheeze, 27.4% had food sensitization, 10.8% had inhalant allergen sensitization, and 3.8% had IgE-mediated food allergy during the first year of life. Compared with the nondeficient group, maternal Vitamin D deficiency in late pregnancy was not associated with any allergic outcomes after adjustment for potential confounding factors. In conclusion, the present study does not support an association between maternal Vitamin D levels in late pregnancy and allergic outcomes during the first year of life.

Screening of vitamin D and calcium concentrations in neonates of mothers at high risk of vitamin D deficiency

OBJECTIVE

The aim of this study was to determine, retrospectively, the serum 25OHD and calcium concentrations of screened neonates of mothers at high risk of 25OHD deficiency and examine whether their measurement contributes to the management of these neonates.

METHODS

Serum 25OHD and calcium concentrations from 600 samples of umbilical cord blood or venous blood collected from neonates over a 12-month period were analysed.

RESULTS

There was a high prevalence of vitamin D insufficiency (27.6%, 30-50 nmol/L) and deficiency (21.3%, < 30 nmol/L) in neonates from high-risk maternal groups. There was a statistically positive but weak correlation (ρ = 0.22, P < 0.0001) between 25OHD and serum calcium. Only 7 neonates out of 569 (1.2%) had calcium concentrations in the hypocalcaemic range; however, a significant number (47.6%) were reported to be in the hypercalcaemic range. Nearly all of these were venous samples collected in first 24 h after birth.

CONCLUSION

Vitamin D deficiency is prevalent in neonates of high-risk mothers but the risk of hypocalcaemia due to vitamin D deficiency at birth is low. Screening neonates entails blood testing which can cause distress to neonates and their parents, substantial imposition on staff and financial burden on the health care system. Vitamin D supplementation of these neonates from birth without routine screening appears more reasonable. Also, the data from this study suggest that the paediatric reference range for corrected calcium concentrations in neonates should be re-evaluated.

Risk of eczema, wheezing and respiratory tract infections in the first year of life: A systematic review of vitamin D concentrations during pregnancy and at birth

BACKGROUND

Allergic conditions and respiratory tract infections (RTIs) are common causes of morbidity and mortality in childhood. The relationship between vitamin D status in pregnancy (mothers), early life (infants) and health outcomes such as allergies and RTIs in infancy is unclear. To date, studies have shown conflicting results.

OBJECTIVE

This systematic review aims to gather and appraise existing evidence on the associations between serum vitamin D concentrations during pregnancy and at birth and the development of eczema, wheezing, and RTIs in infants.

DATA SOURCES

PubMed, MEDLINE, ProQuest, Scopus, CINAHL, Cochrane Library and Academic Search Premier databases were searched systematically using specified search terms and keywords.

STUDY SELECTION

Articles on the associations between serum vitamin D concentrations during pregnancy and at birth and eczema, wheezing, and RTIs among infants (1-year-old and younger) published up to 31 March 2019 were identified, screened and retrieved.

RESULTS

From the initial 2678 articles screened, ten met the inclusion criteria and were included in the final analysis. There were mixed and conflicting results with regards to the relationship between maternal and cord blood vitamin D concentrations and the three health outcomes-eczema, wheezing and RTIs-in infants.

CONCLUSION

Current findings revealed no robust and consistent associations between vitamin D status in early life and the risk of developing eczema, wheezing and RTIs in infants. PROSPERO registration no. CRD42018093039.

Expression and activation of the steroidogenic enzyme CYP11A1 is associated with IL-13 production in T cells from peanut allergic children

Activation of the steroidogenic enzyme CYP11A1 was shown to be necessary for the development of peanut-induced intestinal anaphylaxis and IL-13 production in allergic mice. We determined if levels of CYP11A1 in peripheral blood T cells from peanut-allergic (PA) children compared to non-allergic controls were increased and if levels correlated to IL-13 production and oral challenge outcomes to peanut. CYP11A1 mRNA and protein levels were significantly increased in activated CD4⁺ T cells from PA patients. In parallel, IL-13 production was significantly increased; IFNγ levels were not different between groups. There were significant correlations between expression levels of CYP11A1 mRNA and levels of IL13 mRNA and protein, levels of serum IgE anti-Ara h 2 and to outcomes of peanut challenge. The importance of CYP11A1 on cytokine production was tested using a CYP11A1 CRISPR/Cas9 KO plasmid or an inhibitor of enzymatic CYP11A1 activity. Inhibition of CYP11A1 activation in patient cells treated with the inhibitor, aminoglutethimide, or CD4⁺ T cell line transfected with the CYP11A1 KO plasmid resulted in reduced IL-13 production. These data suggest that the CYP11A1-CD4⁺Tcell-IL-13 axis in activated CD4⁺ T cells from PA children is associated with development of PA reactions. CYP11A1 may represent a novel target for therapeutic intervention in PA children.

Vitamin D and Immunity in Infants and Children

The last couple of decades have seen an explosion in our interest and understanding of the role of vitamin D in the regulation of immunity. At the molecular level, the hormonal form of vitamin D signals through the nuclear vitamin D receptor (VDR), a ligand-regulated transcription factor. The VDR and vitamin D metabolic enzymes are expressed throughout the innate and adaptive arms of the immune system. The advent of genome-wide approaches to gene expression profiling have led to the identification of numerous VDR-regulated genes implicated in the regulation of innate and adaptive immunity. The molecular data infer that vitamin D signaling should boost innate immunity against pathogens of bacterial or viral origin. Vitamin D signaling also suppresses inflammatory immune responses that underlie autoimmunity and regulate allergic responses. These findings have been bolstered by clinical studies linking vitamin D deficiency to increased rates of infections, autoimmunity, and allergies. Our goals here are to provide an overview of the molecular basis for immune system regulation and to survey the clinical data from pediatric populations, using randomized placebo-controlled trials and meta-analyses where possible, linking vitamin D deficiency to increased rates of infections, autoimmune conditions, and allergies, and addressing the impact of supplementation on these conditions.

Lower vitamin D levels in the breast milk is associated with atopic dermatitis in early infancy

BACKGROUND

Our previous study showed that the discontinuation of breastfeeding could improve atopic dermatitis (AD) symptoms in exclusively breastfed infants. As vitamins A and D are influential on the immune system, we aimed to analyze the association of vitamin A and D levels in breast milk (BM) with AD.

METHODS

We enrolled two- to four-month-old exclusively breastfed infants. The objective SCORing Atopic Dermatitis (objSCORAD) was evaluated. The lipid layer of BM was extracted and analyzed by liquid chromatography for vitamin A and D levels. Medical charts were reviewed for the clinical course of AD.

RESULTS

Forty-five AD patients and 45 healthy controls were enrolled. The objSCORAD was 20.54 ± 1.73 (shown as mean ± SEM) in the AD group. The sex, parental atopy history, nutrient intake of mothers, and vitamin A levels in BM were not significantly different between the two groups. The 25-(OH) D₃ level in BM was significantly lower in the AD group than in the control group (1.72 ± 0.30 and 3.95 ± 0.64 ng/mL, respectively; P = .001). The 25-(OH) D₃ level negatively correlated with objSCORAD (P = .003). The only factor that is significantly associated with persistent AD is the objSCORAD in infancy (P = .003) after adjusting for age, sex, parental atopy history, and 25-(OH) D₃ level by multiple regression.

CONCLUSION

Vitamin D levels in BM for exclusively breastfed infants were negatively associated with objSCORAD. Lower vitamin D levels in BM might be a risk factor for infantile AD.

Primary Prevention of Cow's Milk Sensitization and Food Allergy by Avoiding Supplementation With Cow's Milk Formula at Birth: A Randomized Clinical Trial

IMPORTANCE

Cow's milk formula (CMF) is used to supplement breastfeeding (BF) at birth without clear clinical evidence to support the practice.

OBJECTIVE

To determine whether avoiding supplementation with CMF at birth can decrease risks of sensitization to cow's milk protein and/or clinical food allergy, including cow's milk allergy (CMA), overall and in subgroups stratified by 25-hydroxyvitamin D (25[OH]D) levels.

DESIGN, SETTING, AND PARTICIPANTS

The Atopy Induced by Breastfeeding or Cow's Milk Formula (ABC) trial, a randomized, nonblinded clinical trial, began enrollment October 1, 2013, and completed follow-up May 31, 2018, at a single university hospital in Japan. Participants included 330 newborns at risk for atopy; of these, 312 were included in the analysis. Data were analyzed from September 1 through October 31, 2018.

INTERVENTIONS

Immediately after birth, newborns were randomized (1:1 ratio) to BF with or without amino acid-based elemental formula (EF) for at least the first 3 days of life (BF/EF group) or BF supplemented with CMF (≥5 mL/d) from the first day of life to 5 months of age (BF plus CMF group).

MAIN OUTCOMES AND MEASURES

The primary outcome was sensitization to cow's milk (IgE level, ≥0.35 allergen units [UA]/mL) at the infant's second birthday. Secondary outcomes were immediate and anaphylactic types of food allergy, including CMA, diagnosed by oral food challenge test or triggered by food ingestion, with food-specific IgE levels of at least 0.35 UA/mL. Subgroup analysis was prespecified by tertiles of serum 25(OH)D levels at 5 months of age.

RESULTS

Of the 312 infants included in the analysis (160 female [51.3%] and 152 male [48.7%]), 151 of 156 (96.8%) in the BF/EF and BF plus CMF groups were followed up until their second birthday. The primary outcome occurred in 24 infants (16.8%) in the BF/EF group, which was significantly fewer than the 46 infants (32.2%) in the BF plus CMF group (relative risk [RR], 0.52; 95% CI, 0.34-0.81). The middle tertile of the 25(OH)D subgroup, but not the low and high tertiles, had a significant interaction with the intervention (RR, 0.19; 95% CI, 0.07-0.50; P = .02). The prevalence of food allergy at the second birthday was significantly lower in the BF/EF than in the BF plus CMF groups for immediate (4 [2.6%] vs 20 [13.2%]; RR, 0.20; 95% CI, 0.07-0.57) and anaphylactic (1 [0.7%] vs 13 [8.6%]; RR, 0.08; 95% CI, 0.01-0.58) types.

CONCLUSIONS AND RELEVANCE

The evidence suggests that sensitization to cow's milk and food allergy, including CMA and anaphylaxis, are primarily preventable by avoiding CMF supplementation for at least the first 3 days of life.

TRIAL REGISTRATION

http://umin.ac.jp Identifier: UMIN000011577.

[Research advances in influencing factors for immune tolerance to food allergens in children]

Food allergen-specific immune tolerance is defined as nonresponsiveness of the adaptive immune system to food antigens. Failed development or inhibition of such tolerance may cause food allergy. With the increasing incidence rate of food allergy year by year, more and more studies have found the association between food allergy and various diseases. The development of food allergen-specific immune tolerance in childhood has been taken more and more seriously. In recent years, many studies have shown that the development of food allergen-specific immune tolerance is influenced by various factors, which can be roughly divided into antigens, organisms, and environment. This article reviews the influencing factors for the development of immune tolerance to food allergens in children, in order to provide help for reducing the incidence of food allergy and improving the prognosis of food allergy.

High-Dose Vitamin D Supplementation Does Not Prevent Allergic Sensitization of Infants

OBJECTIVE

To investigate the effect of vitamin D supplementation dose on allergic sensitization and allergic diseases in infants, and to evaluate whether vitamin D status in pregnancy and at birth are associated with infant allergy outcomes.

STUDY DESIGN

Altogether, 975 infants participated in a randomized, controlled trial of daily vitamin D supplementation of 10 μg (400 IU) or 30 μg (1200 IU) from the age of 2 weeks. At 12 months of age, food and aeroallergen IgE antibodies were measured, and the occurrence of allergic diseases and wheezing were evaluated.

RESULTS

We found no differences between the vitamin D supplementation groups in food (OR, 0.98; 95% CI, 0.66-1.46) or aeroallergen sensitization at 12 months (OR, 0.76; 95% CI,0.34-1.71). Allergic diseases or wheezing did not differ between groups, except for milk allergy which occurred more often in infants administered 30 μg vitamin D compared with the 10 μg dose (OR, 2.23; 95% CI, 1.00-4.96). Infants with high cord blood 25-hydroxyvitamin D (≥100 nmol/L) had a higher risk of food allergen sensitization compared with those with lower 25(OH)D concentration (75-99.9 nmol/L; OR, 2.00; 95% CI, 1.19-3.39).

CONCLUSIONS

High-dose vitamin D supplementation did not prevent allergic sensitization, allergic diseases, or wheezing during the first year of life. In contrast, we observed an increased risk of milk allergy in infants randomized to higher vitamin D supplementation, and an increased risk of allergic sensitization in infants with high cord blood vitamin D status, indicating a possible adverse effect of high concentrations of vitamin D.

Food allergy is linked to season of birth, sun exposure, and vitamin D deficiency

The season of birth and ultraviolet B exposure have been related to the occurrence of food allergy. The levels of vitamin D produced from skin by ultraviolet B exposure might reflect this relationship. Vitamin D is known to induce antimicrobial peptides, protect intestinal flora, enhance the gut epithelial barrier, suppress mast cell activation and IgE synthesis from B cells, and increase the number of tolerogenic dendritic cells and IL-10-producing regulatory T cells. Vitamin D deficiency has been shown to exacerbate sensitization and allergic symptoms in a murine model of food allergy. However, in clinical situations, contradictory observations have been reported regarding the relationship between food allergy and vitamin D deficiency/supplementation. In this review, we have explored the links between food allergy and vitamin D levels. One explanation for the discrepant findings is confounding factors such as race, age, residency, skin color, and epigenetic changes that contribute to vitamin D levels. In addition, the season of birth influences the development of atopic dermatitis, which could lead to food sensitization. Finally, ultraviolet radiation could lead to regulatory T cell expansion and immunosuppression, irrespective of vitamin D status. Based on our current understanding, we believe that correction of vitamin D deficiency by supplementation, appropriate skin care, and sufficient ultraviolet radiation exposure could alter the prognosis of food allergy. To identify potential treatment strategies for food allergy, it is essential to gain a better understanding of the appropriate levels of vitamin D and ultraviolet radiation exposure.

Micronutrients in Atopic Dermatitis: A Systematic Review

Objective: The pathophysiology of atopic dermatitis (AD) involves a complex interplay between immune system dysfunction, genetics, and environmental factors. It is well known that nutritional status is essential to a proper functioning immune system, leading to a highly debated question regarding the role of dietary factors in the pathogenesis of AD. Food allergies and elimination diets have been broadly studied in atopy; however, less consideration has been given to how vitamins, minerals, and other micronutrients influence the risk for AD and severity of symptoms. This systematic review discusses evidence on how various micronutrients, including vitamins (C, E, and D) and trace minerals (zinc, selenium, iron, copper, magnesium, and strontium) are associated with AD, and how supplementation influence disease severity. Design: A systematic search was conducted to identify the role that oral micronutrients have on AD. The authors reviewed 49 studies herein. Results: While there are weak associations between vitamins C or E and AD, there is sufficient evidence to suggest that vitamin D supplementation provides benefit in AD patients. Deficiency of selenium and zinc may exacerbate AD. Current reports are not sufficient to confidently discern the role of other vitamins and trace minerals on AD. Conclusions: Though oral micronutrients may play a role in AD, the current literature is limited, and there is a need for more comprehensive randomized controlled trials (RCTs) to truly decipher the role between oral micronutrients and AD.

Mouse Chow Composition Influences Immune Responses and Food Allergy Development in a Mouse Model

Our diet is known to substantially influence the immune response not only by support of mucosal barriers but also via direct impact on immune cells. Thus, it was of great interest to compare the immunological effect of two mouse chows with substantial differences regarding micro-, macronutrient, lipid and vitamin content on the food allergic response in our previously established mouse model. As the two mouse chows of interest, we used a soy containing feed with lower fatty acid (FA) amount (soy-containing feed) and compared it to a soy free mouse chow (soy-free feed) in an established protocol of oral immunizations with Ovalbumin (OVA) under gastric acid suppression. In the animals receiving soy-containing feed, OVA-specific IgE, IgG1, IgG2a antibody levels were significantly elevated and food allergy was evidenced by a drop of body temperature after oral immunizations. In contrast, mice on soy-free diet had significantly higher levels of IL-10 and were protected from food allergy development. In conclusion, soy-containing feed was auxiliary during sensitizations, while soy-free feed supported oral tolerance development and food allergy prevention.

Antenatal vitamin D exposure and childhood eczema, food allergy, asthma and allergic rhinitis at 2 and 5 years of age in the atopic disease-specific Cork BASELINE Birth Cohort Study

BACKGROUND

Prospective studies of antenatal and infant vitamin D exposure and atopic disease from extensively characterised, disease-specific, maternal-infant cohorts with gold standard analysis of vitamin D status and clinically validated atopic outcomes are lacking. This study aimed to investigate associations between intrauterine vitamin D status and atopic outcomes in an extensively characterised, disease-specific, maternal-infant cohort.

METHODS

Circulating 25-hydroxyvitamin D (25(OH)D) was measured in maternal sera at 15 weeks of gestation (n = 1537) and umbilical cord blood (n = 1050) using a CDC-accredited LC-MS/MS platform, and the association with clinically validated atopic disease outcomes (eczema, food allergy, asthma, allergic rhinitis) at 2 and 5 years was explored using multivariable logistic regression.

RESULTS

Persistent eczema in the first 2 years of life was present in 5% of infants. Food allergy at 2 years was confirmed in 4%. The prevalence of aeroallergen sensitisation at 2 years was 8%. Asthma at 5 years was reported in 15% and allergic rhinitis in 5% of 5-year-olds. There were no significant differences in the distributions of maternal 25(OH)D at 15 weeks of gestation (mean [SD] 58.4 [26.2] and 58.5 [26.1] nmol/L) and cord 25(OH)D concentrations (mean [SD] 35.2 [17.8] and 35.4 [18.3] nmol/L) between children with and without atopic disease. Neither maternal (aOR [95% CI]: 1.02 [0.97, 1.08], P = 0.450) nor cord 25(OH)D (aOR [95% CI]: 1.00 [0.91, 1.09], P = 0.991) were significant predictors of atopic disease outcomes in fully adjusted models.

CONCLUSION

These data in a disease-specific cohort with prospectively collected, validated atopic outcomes do not support an association between antenatal exposure to vitamin D and atopic disease outcomes in childhood.

Vitamin D: effects on pregnancy, maternal, fetal and postnatal outcomes

A high prevalence of vitamin D deficiency and its negative consequences for health is identified as area of primary concern for scientists and clinicians worldwide. Vitamin D deficiency affects not only bone health but many socially significant acute and chronic diseases. Observational studies support that pregnant and lactating women, children and teenagers represent the high risk groups for developing vitamin D deficiency. Current evidence highlights a crucial role of vitamin D in providing the fetal life-support system and fetus development, including implantation, placental formation, intra - and postpartum periods. Hypovitaminosis D during pregnancy is associated with a higher incidence of placental insufficiency, spontaneous abortions and preterm birth, preeclampsia, gestational diabetes, impaired fetal and childhood growth, increased risk of autoimmune diseases for offsprings. Potential mechanisms for the observed associations contain metabolic, immunomodulatory and antiinflammatory effects of vitamin D. Epigenetic modifications in vitamin D-associated genes and fetal programming are of particular interest. The concept of preventing vitamin D deficiency is actively discussed, including supplementation in different ethnic groups, required doses, time of initiation and therapy duration, influence on gestation and childbirth. An adequate supply of vitamin D during pregnancy improves the maternal and fetal outcomes, short and long term health of the offspring. Still current data on relationship between maternal vitamin D status and pregnancy outcomes remains controversial. The large observational and interventional randomized control trials are required to create evidence-based guidelines for the supplementation of vitamin D in pregnant and lactating women.

Immune suppression of food allergy by maternal IgG in murine models

BACKGROUND

Most of the patients develop food allergy early in life. The factors related to parental immune condition might be one of the conceivable causes.

METHODS

We reported murine models of food allergy and oral OVA tolerance. To investigate the influence of parental immune condition on infant food allergy, female and male mice with food allergy or oral tolerance were mated with each other.

RESULTS

Food allergy was suppressed by decreased IgE production in the offspring of mice with food allergy. On the contrary, anaphylaxis for OVA was induced in the offspring of mice with oral tolerance. The suppression of food allergy being dependent on a maternal factor was revealed in the offspring after cross-mating mice with food allergy and oral tolerance. Because OVA-specific IgG, presumed to be from the allergic mother, was detected in the serum of naïve infants from mothers allergic to food, we assumed that the suppression was dependent on a specific IgG. The serum IgG purified by a G-protein column was administered before OVA sensitization in the food allergy model, and OVA-specific IgE production was found to be diminished in the administered mice. However, OVA-specific monoclonal IgG₁ and IgG_2a administration could not suppress food allergy. Because we detected OVA-IgG immune complex in the serum of mothers allergic to food, it might be a cause of maternal immune suppression.

CONCLUSIONS

We demonstrated that maternal specific IgG conjugated food antigen is an important factor related to the development of food allergy and acquiring tolerance.

High Dose Vitamin D supplementation alters faecal microbiome and predisposes mice to more severe colitis

Vitamin D has been suggested as a possible adjunctive treatment to ameliorate disease severity in human inflammatory bowel disease. In this study, the effects of diets containing high (D++, 10,000 IU/kg), moderate (D+, 2,280 IU/kg) or no vitamin D (D−) on the severity of dextran sodium sulphate (DSS) colitis in female C57Bl/6 mice were investigated. The group on high dose vitamin D (D++) developed the most severe colitis as measured by blinded endoscopic (p < 0.001) and histologic (p < 0.05) assessment, weight loss (p < 0.001), drop in serum albumin (p = 0.05) and increased expression of colonic TNF-α (p < 0.05). Microbiota analysis of faecal DNA showed that the microbial composition of D++ control mice was more similar to that of DSS mice. Serum 25(OH)D₃ levels reduced by 63% in the D++ group and 23% in the D+ group after 6 days of DSS treatment. Thus, high dose vitamin D supplementation is associated with a shift to a more inflammatory faecal microbiome and increased susceptibility to colitis, with a fall in circulating vitamin D occurring as a secondary event in response to the inflammatory process.