Maternal dietary folate, folic acid and vitamin D intakes during pregnancy and lactation and the risk of cows’ milk allergy in the offspring

The pathogenesis of food allergy and protection offered by dietary compounds from the perspective of epigenetics

Food allergy is a global food safety concern, with an increasing prevalence in recent decades. However, the immunological and cellular mechanisms involved in allergic reactions remain incompletely understood, which impedes the development of effective prevention and treatment strategies. Current evidence supports those epigenetic modifications regulate the activation of immune cells, and their dysregulation can contribute to the development of food allergies. Patients with food allergy show epigenetic alterations that lead to the onset, duration and recovery of allergic disease. Moreover, many preclinical studies have shown that certain dietary components exert nutriepigenetic effects in changing the course of food allergies. In this review, we provide an up-to-date overview of DNA methylation, noncoding RNA and histone modification, with a focus on their connections to food allergies. Following this, we discuss the epigenetic mechanisms that regulate the activation and differentiation of innate and adapted immune cell in the context of food allergies. Subsequently, this study specifically focuses on the multidimensional epigenetic effects of dietary components in modulating the immune response, which holds promise for preventing food allergies in the future.

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.

Food Allergy Risk: A Comprehensive Review of Maternal Interventions for Food Allergy Prevention

Food allergy represents a global health problem impacting patients' and caregivers' quality of life and contributing to increased healthcare costs. Efforts to identify preventive measures starting from pregnancy have recently intensified. This review aims to provide an overview of the role of maternal factors in food allergy prevention. Several studies indicate that avoiding food allergens during pregnancy does not reduce the risk of developing food allergies. International guidelines unanimously discourage avoidance diets due to potential adverse effects on essential nutrient intake and overall health for both women and children. Research on probiotics and prebiotics during pregnancy as preventive measures is promising, though evidence remains limited. Consequently, guidelines lack specific recommendations for their use in preventing food allergies. Similarly, given the absence of conclusive evidence, it is not possible to formulate definitive conclusions on the supplementation of vitamins, omega-3 fatty acids (n-3 PUFAs), and other antioxidant substances. A combination of maternal interventions, breastfeeding, and early introduction of foods to infants can reduce the risk of food allergies in the child. Further studies are needed to clarify the interaction between genetics, immunological pathways, and environmental factors.

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.

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.

Maternal energy-adjusted fatty acid intake during pregnancy and the development of cows' milk allergy in the offspring

Cows' milk allergy (CMA) is one of the earliest manifestations of allergic diseases. Early dietary factors, like maternal diet during pregnancy, may play a role in the development of allergic diseases in the offspring. We aimed to investigate the association between maternal intake of fatty acids during pregnancy and the risk of CMA in the offspring. Our study was conducted in a population-based cohort, the Finnish Type 1 Diabetes Prediction and Prevention study. We collected the maternal dietary data by a validated FFQ. We obtained the information on CMA in the study participants (n 448) from registers and from the parents. Dietary data and information on CMA were available for 4921 children. We used logistic regression in the analyses, and fatty acid intakes were energy adjusted. The maternal intake of SFA, MUFA, PUFA, n-3 PUFA, n-6 PUFA, trans fatty acids, ratio of n-3 PUFA to n-6 PUFA or ratio of linoleic acid to α-linolenic acid was not associated with the risk of CMA in the offspring when adjusted for perinatal factors, background factors, parental history of asthma or allergic rhinitis and infant animal contacts. The intake of α-linolenic acid was associated with a decreased risk (OR 0·72; 95 % CI 0·56, 0·93) of CMA in the offspring of mothers without a history of allergic rhinitis or asthma. In conclusion, the maternal intake of fatty acids during pregnancy is not associated with the risk of CMA in the offspring.

Consumption of dietary folate estimates and its implication for reproductive outcome among women of reproductive age in Kersa: cross-sectional survey

Background

Dietary folate inadequacy is one the most common micronutrient deficiencies that cause neural tube defect (NTD) among infants in Sub-Saharan African countries. This study aims to determine the dietary intake of folate among women of reproductive age (WRA) of Kersa, Eastern Ethiopia.

Methods

A cross-sectional study took place among voluntary women that were selected from 1140 random households. Using a validated Food Frequency Questionnaire, participant’s weekly dietary intake history of Ethiopian foods and dietary folate intake was worked out. Statistical analysis was done at a 95% confidence interval. Modified Poisson regression was used to identify factors associated with dietary folate consumption.

Result

The estimated median usual intake of folate was 170 μg/d (IQR: 118.3; 252.2) and about 33% of WRA had low folate intake and 73.9% were at risk for folate inadequacy. From the reported food groups, Beans and Peas, Starchy staples, and Vitamin-A rich dark-green leafy vegetables were the top three ranked foods that contributed much of the dietary folate. The following conditions were statistically related to dietary folate inadequacy; women’s age, being in poor wealth index, low dietary diversity, having seasonal employment, and reliance on market food sources.

Conclusions

We found that women’s dietary intake of folate in Kersa is very low and cannot protect their offspring from the risk of having NTD. They could also potentially be predisposed to poor health outcomes. Diversifying and fortification of Ethiopian wheats and salts could decrease the burden of folate deficiency in the country.

Maternal antioxidant intake during pregnancy and the development of cows' milk allergy in the offspring

Cows' milk allergy (CMA) is the most common food allergy in young children, and it is often the first manifestation of atopic diseases. Accordingly, very early environmental factors, such as maternal diet during pregnancy, may play a role in the development of CMA, but the evidence is limited. The aim of this study was to investigate the association between maternal intake of antioxidant nutrients during pregnancy and the subsequent development of CMA in the offspring in a prospective, population-based birth cohort within the Finnish Type 1 Diabetes Prediction and Prevention Study. Maternal dietary information during pregnancy was collected with a detailed, validated FFQ. The maternal dietary information and the information on putative confounding factors were available for 4403 children. Information on diagnosed CMA (n 448) was obtained from a medical registry and queried from the parents up to child's age of 3 years. The Finnish food composition database was used to calculate the average daily intake of nutrients. Logistic regression was applied for statistical analyses, and the nutrient intakes were adjusted for energy intake. OR are presented per 1 sd increment of the particular nutrient intake. Maternal total and dietary intake of β-carotene was associated with an increased risk of CMA in the offspring when adjusted for the putative confounding factors (total OR 1·10, 95 % CI 1·02, 1·20; dietary OR 1·10; 95 % CI 1·01, 1·19). Using dietary supplements containing antioxidants in addition to a balanced diet may not confer any additional benefits.

Maternal caffeine intake during pregnancy and risk of food allergy in young Japanese children

AIM

To examine the association between maternal caffeine intake during pregnancy and the development of food allergy in young Japanese children up to 3 years of age.

METHODS

The study involved 1522 mother-child pairs. Data on maternal caffeine intake during pregnancy were assessed with a validated diet history questionnaire. Food allergy was defined by a self-reported claim of having a physicians' diagnosis of food allergy or of having an acute reaction to a food.

RESULTS

Compared with the lowest tertile of maternal caffeine intake during pregnancy, the second tertile, but not the highest tertile, was significantly associated with an increased risk of food allergy. Further adjustment on suspicion or diagnosis of atopic eczema at around 4 months postpartum in a follow-up survey did not substantially change the association between maternal caffeine intake during pregnancy and the risk of food allergy in children: further adjusted hazard ratios (95% confidence intervals) for the second (T2), the highest tertiles (T3) and the second and the highest tertiles combined (T2 + T3) were 1.46 (1.10-1.96), 1.16 (0.85-1.56) and 1.31 (1.01-1.70), respectively.

CONCLUSIONS

Our findings suggest that maternal caffeine intake during pregnancy may be positively associated with the risk of food allergy in children.

Development of a prediction model for infants at high risk of food allergy

Background

Identification of risk factors for food allergy (FA) in infants is an active research area. An important reason is to identify optimal target infants for early introduction of specific food antigens. Although eczema has been used for this purpose, multivariable prediction scores have not been reported.

Objective

The aim of this research is to develop a multivariable prediction score for infants at high risk of FA.

Methods

We performed a cross-sectional analysis of a self-administered questionnaire for the parents of 18-month-old children at well-child visits between April 2016 and March 2017 (development dataset) and between April 2017 and March 2018 (validation dataset). We developed and validated the prediction score.

Results

The questionnaire collection rate was 18,549 of 20,198 (92%) in the development dataset and 18,620 of 19,977 (93%) in the validation dataset. Risk factors for FA were being born in August–December, first child, eczema, atopic dermatitis in father and mother, and FA in mother and sibling(s). For identifying infants with FA, the developed multivariable prediction score showed higher discrimination ability (area under the curve [AUC] = 0.75) than focusing on eczema (AUC = 0.70) in the validation dataset. The score was also useful for identifying infants with a history of anaphylaxis (AUC = 0.73) than focusing on eczema (AUC = 0.67) in the validation dataset.

Conclusion

The new prediction score enables more efficient identification of infants at high risk of FA, who may be the optimal target group for the early introduction of specific antigens.

Maternal B-vitamin intake and B-vitamin supplementation during pregnancy in relation to neonatal congenital heart defects: a case-control study with propensity score matching

BACKGROUND/OBJECTIVES

The effect of dietary folate intake or folic acid (FA) supplementation during pregnancy on neonatal congenital heart defects (CHDs) remains inconclusive. There are limited data about non-folate-B-vitamin intake and the risk of CHDs. Furthermore, few studies have investigated dietary B-vitamin intake and B-vitamin supplement use simultaneously in relation to the risk of CHDs. This study aimed to explore the associations between maternal folate, vitamin B₆, and vitamin B₁₂ intake (dietary intake, total intake from diet and supplements); B-vitamin supplement use during pregnancy; and the risk of CHDs using the propensity score matching (PSM) method.

METHODS

We conducted a case-control study and included 760 cases and 1600 controls in Shaanxi Province, China. Diet, supplement use and other information were collected through a questionnaire interview. By using the 1:2 ratio PSM method, 396 cases were matched with 792 controls. Conditional logistic regression was used to investigate the associations between maternal B-vitamin intake and supplement use during pregnancy and CHDs.

RESULTS

Higher maternal dietary and total intake of folate and vitamin B₁₂ were associated with reduced risk of CHDs, and the tests for linear trend were significant. Compared with non-users, maternal FA + VB₆ + VB₁₂ containing supplement use during pregnancy (OR 0.61, 95%CI 0.40-0.94), FA supplement use during pregnancy (OR 0.70, 95%CI 0.50-0.98) and in the first trimester (OR 0.62, 95%CI 0.46-0.85) were associated with a lower risk of CHDs.

CONCLUSIONS

The findings of this study suggest that a higher intake of folate and vitamin B₁₂ during pregnancy reduces the risk of CHDs.

Vitamin D supplementation in pregnancy and early infancy in relation to gut microbiota composition and C. difficile colonization: implications for viral respiratory infections

In Canada and the US, the infant diet is supplemented with vitamin D via supplement drops or formula. Pregnant and nursing mothers often take vitamin D supplements. Since little is known about the impact of this supplementation on infant gut microbiota, we undertook a study to determine the association between maternal and infant vitamin D supplementation, infant gut microbiota composition and Clostridioides difficile colonization in 1,157 mother-infant pairs of the CHILD (Canadian Healthy Infant Longitudinal Development) Cohort Study over 2009-2012. Logistic and MaAsLin regression were employed to assess associations between vitamin D supplementation, and C. difficile colonization, or other gut microbiota, respectively. Sixty-five percent of infants received a vitamin D supplement. Among all infants, infant vitamin D supplementation was associated with a lower abundance of genus Megamonas (q = 0.01) in gut microbiota. Among those exclusively breastfed, maternal prenatal supplementation was associated with lower abundance of Bilophila (q = 0.01) and of Lachnospiraceae (q = 0.02) but higher abundance of Haemophilus (q = 0.02). There were no differences in microbiota composition with vitamin D supplementation among partially and not breastfed infants. Neither infant nor maternal vitamin D supplementation were associated with C. difficile colonization, after adjusting for breastfeeding status and other factors. However, maternal consumption of vitamin-D fortified milk reduced the likelihood of C. difficile colonization in infants (adjustedOR: 0.40, 95% CI: 0.19-0.82). The impact of this compositional difference on later childhood health, especially defense against viral respiratory infection, may go beyond the expected effects of vitamin D supplements and remains to be ascertained.

Dietary factors during pregnancy and atopic outcomes in childhood: A systematic review from the European Academy of Allergy and Clinical Immunology

RATIONALE

Allergic diseases are an increasing public health concern, and early life environment is critical to immune development. Maternal diet during pregnancy has been linked to offspring allergy risk. In turn, maternal diet is a potentially modifiable factor, which could be targeted as an allergy prevention strategy. In this systematic review, we focused on non-allergen-specific modifying factors of the maternal diet in pregnancy on allergy outcomes in their offspring.

METHODS

We undertook a systematic review of studies investigating the association between maternal diet during pregnancy and allergic outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis (AD), food allergies, and allergic sensitization) in offspring. Studies evaluating the effect of food allergen intake were excluded. We searched three bibliographic databases (MEDLINE, EMBASE, and Web of Science) through February 26, 2019. Evidence was critically appraised using modified versions of the Cochrane Collaboration Risk of Bias tool for intervention trials and the National Institute for Clinical Excellence methodological checklist for cohort and case-control studies and meta-analysis performed from RCTs.

RESULTS

We identified 95 papers: 17 RCTs and 78 observational (case-control, cross-sectional, and cohort) studies. Observational studies varied in design and dietary intakes and often had contradictory findings. Based on our meta-analysis, RCTs showed that vitamin D supplementation (OR: 0.72; 95% CI: 0.56-0.92) is associated with a reduced risk of wheeze/asthma. A positive trend for omega-3 fatty acids was observed for asthma/wheeze, but this did not reach statistical significance (OR: 0.70; 95% CI: 0.45-1.08). Omega-3 supplementation was also associated with a non-significant decreased risk of allergic rhinitis (OR: 0.76; 95% CI: 0.56-1.04). Neither vitamin D nor omega-3 fatty acids were associated with an altered risk of AD or food allergy.

CONCLUSIONS

Prenatal supplementation with vitamin D may have beneficial effects for prevention of asthma. Additional nutritional factors seem to be required for modulating the risk of skin and gastrointestinal outcomes. We found no consistent evidence regarding other dietary factors, perhaps due to differences in study design and host features that were not considered. While confirmatory studies are required, there is also a need for performing RCTs beyond single nutrients/foods.

Allergy Modulation by N-3 Long Chain Polyunsaturated Fatty Acids and Fat Soluble Nutrients of the Mediterranean Diet

The Mediterranean diet, containing valuable nutrients such as n-3 long chain poly-unsaturated fatty acids (LCPUFAs) and other fat-soluble micronutrients, is known for its health promoting and anti-inflammatory effects. Its valuable elements might help in the battle against the rising prevalence of non-communicable diseases (NCD), including the development of allergic diseases and other (chronic) inflammatory diseases. The fat fraction of the Mediterranean diet contains bioactive fatty acids but can also serve as a matrix to dissolve and increase the uptake of fat-soluble vitamins and phytochemicals, such as luteolin, quercetin, resveratrol and lycopene with known immunomodulatory and anti-inflammatory capacities. Especially n-3 LCPUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine oils can target specific receptors or signaling cascades, act as eicosanoid precursors and/or alter membrane fluidity and lipid raft formation, hereby exhibiting anti-inflammatory properties. Beyond n-3 LCPUFAs, fat-soluble vitamins A, D, E, and K1/2 have the potential to affect pro-inflammatory signaling cascades by interacting with receptors or activating/inhibiting signaling proteins or phosphorylation in immune cells (DCs, T-cells, mast cells) involved in allergic sensitization or the elicitation/effector phase of allergic reactions. Moreover, fat-soluble plant-derived phytochemicals can manipulate signaling cascades, mostly by interacting with other receptors or signaling proteins compared to those modified by fat-soluble vitamins, suggesting potential additive or synergistic actions by applying a combination of these nutrients which are all part of the regular Mediterranean diet. Research concerning the effects of phytochemicals such as polyphenols has been hampered due to their poor bio-availability. However, their solubility and uptake are improved by applying them within the dietary fat matrix. Alternatively, they can be prepared for targeted delivery by means of pharmaceutical approaches such as encapsulation within liposomes or even unique nanoparticles. This review illuminates the molecular mechanisms of action and possible immunomodulatory effects of n-3 LCPUFAs and fat-soluble micronutrients from the Mediterranean diet in allergic disease development and allergic inflammation. This will enable us to further appreciate how to make use of the beneficial effects of n-3 LCPUFAs, fat-soluble vitamins and a selection of phytochemicals as active biological components in allergy prevention and/or symptom reduction.

Maternal Folic Acid Supplementation Mediates Offspring Health via DNA Methylation

The clinical significance of periconceptional folic acid supplementation (FAS) in the prevention of neonatal neural tube defects (NTDs) has been recognized for decades. Epidemiological data and experimental findings have consistently been indicating an association between folate deficiency in the first trimester of pregnancy and poor fetal development as well as offspring health (i.e., NTDs, isolated orofacial clefts, neurodevelopmental disorders). Moreover, compelling evidence has suggested adverse effects of folate overload during perinatal period on offspring health (i.e., immune diseases, autism, lipid disorders). In addition to several single-nucleotide polymorphisms (SNPs) in genes related to folate one-carbon metabolism (FOCM), folate concentrations in maternal serum/plasma/red blood cells must be considered when counseling FAS. Epigenetic information encoded by 5-methylcytosines (5mC) plays a critical role in fetal development and offspring health. S-adenosylmethionine (SAM), a methyl donor for 5mC, could be derived from FOCM. As such, folic acid plays a double-edged sword role in offspring health via mediating DNA methylation. However, the underlying epigenetic mechanism is still largely unclear. In this review, we summarized the link across DNA methylation, maternal FAS, and offspring health to provide more evidence for clinical guidance in terms of precise FAS dosage and time point. Future studies are, therefore, required to set up the reference intervals of folate concentrations at different trimesters of pregnancy for different populations and to clarify the epigenetic mechanism for specific offspring diseases.

Nutritional Issues in Food Allergy

Diet and nutrition play an important role in the development and management of food allergy. The diet of expectant mothers can have an effect on their offspring in terms of allergic outcomes. A host of confounding factors may influence this, with a maternal diet rich in fruits and vegetables, fish, vitamin D-rich foods associated with a lower risk of allergic disease in their children. More surprisingly, the consumption of milk and butter has also been shown to have a protective effect, especially in a farm environment. Similarly, the diet of the infant can also be important, not only in terms of breast feeding, but also the timing of the introduction of complementary foods, the diversity of the diet and the effect of individual foods on the development of allergy. One factor which has clearly been shown not to influence the development of food allergy is allergen avoidance by expectant mothers. In the infant diet, the manipulation of the gut microbiome to prevent the development of atopic disease is clearly an area which promises much, although studies have yet to provide a breakthrough in the prevention of atopic dermatitis. More concrete evidence of the value of diet in prevention has come from studies evaluating infant eating patterns which may protect gut health, through the consumption of large amounts of home-processed fruits and vegetables. The consumption of fish during the first year of life has also been shown to be protective. The importance of nutritional issues in children and adults who have a food allergy has become much more accepted in recent years. The primary allergenic foods in infancy and childhood, milk, egg, wheat and soy are also ones which are present in many foods and thus their avoidance can be problematic from a nutritional perspective. Thus, children with a food allergy can have their growth compromised through avoidance, especially pre-diagnosis, when foods may be excluded without any expert nutritional input. The management of a food allergy largely remains the exclusion of the offending food(s), but it is now clear that in doing so, children in particular can be at nutritional risk if insufficient attention is paid to the rest of the diet. Adults with food allergy are often thought not to need nutritional counselling; however, many will exclude a wide range of foods due to anxiety about trace exposure, or similar foods causing reactions. The avoidance of staple foods such as milk and wheat are common, but substitute foods very often do not have comparable nutritional profiles. Adults may also be more susceptible to on-line promotion of extreme nutritional regimes which can be extremely harmful. All food allergic individuals, whatever their age, should have a nutrition review to ensure they are consuming a healthy, balanced diet, and are not avoiding food groups unnecessarily.

Association Between Folate Metabolites and the Development of Food Allergy in Children

BACKGROUND

Studies on the association between folate/folic acid exposure and the development of allergic disease have yielded inconsistent results, which may be due, in part, to lack of data distinguishing folate from folic acid exposure.

OBJECTIVE

To examine the association between total folate, 5-methyltetrahydrofolate (5-MTHF), and unmetabolized folic acid (UMFA) concentrations at birth and in early childhood and the development of food sensitization (FS) and food allergy (FA).

METHODS

A nested case control study was performed in the Boston Birth Cohort (BBC). Total folate, 5-MTHF, and UMFA were measured at birth and in early childhood. Based on food-specific IgE (sIgE) levels, diet, and clinical history, children were classified as FS (sIgE ≥0.35 kU/L), FA, or non-FS/FA (controls). Folate concentrations were divided into quartiles, and multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of a total of 1394 children, 507 children with FS and 78 with FA were identified. Although mean total folate concentrations at birth were lower among those who developed FA (30.2 vs 35.3 nmol/L; P = .02), mean concentrations of the synthetic folic acid derivative, UMFA, were higher (1.7 vs 1.3 nmol/L, P = .001). Higher quartiles of UMFA at birth were associated more strongly with FA (OR 8.50; 95% CI 1.7-42.8; test for trend P = .001). Neither early childhood concentrations of 5-MTHF nor UMFA were associated with the development of FS or FA.

CONCLUSION

Among children in the BBC, higher concentrations of UMFA at birth were associated with the development of FA, which may be due to increased exposure to synthetic folic acid in utero or underlying genetic differences in synthetic folic acid metabolism.

The impact of immunomodulatory factors from maternal diet during pregnancy on cow's milk allergy in offspring - A pilot study in the paediatric population of the Kuyavian-Pomeranian Voivodship

BACKGROUND

The key role of dietary factors in immunotolerance promotion and allergic diseases prevention has been emphasised. The aim of the study was the analysis of the impact of immunomodulatory dietary components, consumed by pregnant women, on the development of cow's milk allergy (CMA) in their offspring.

MATERIALS AND METHODS

Fifty-one pairs of mothers and their CMA-offspring were included in the study group. The analysis of a daily intake of selected dietary components was conducted retrospectively with the application of a seven-day diet of a mother in the third trimester of gestation and the authors' own questionnaire. The Diet 5.D programme was used.

RESULTS

An average daily retinol intake by study-group mothers was significantly lower than by control-group mothers and valued 375.6μg/d vs. 543.7μg/d (p=0.040), respectively. Folates intake in the study group was 598.8μg/d vs. 361.1μg/d in the control group (p=0.001). Vitamin D in the study group was statistically lower - 3.6μg/d, comparing to the control group - 6.9μg/d (p=0.038). Average LC-PUFA intake by mothers with allergic children was 0.09g/d, while in the control group 0.18g/d (p=0.016). An analysis of the diet revealed that significantly more mothers of children from the control group (n=12; 48%) consumed fish 2-3 times per month in comparison to the study group (n=9; 17.6%) (p=0.007).

CONCLUSIONS

Vitamin D, A, LC-PUFA, retinol, riboflavin and fish consumption by pregnant mothers of CMA-children was significantly lower, whereas beta-carotene and folates consumption was significantly higher than that of mothers with non-allergic children.

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.

Prenatal Diet and the Development of Childhood Allergic Diseases: Food for Thought

PURPOSE OF REVIEW

The development of allergic disease is shaped by genetics and the environment, including diet. Many studies suggest a role for maternal diet during pregnancy. In this article, we discuss potential mechanisms by which specific nutrients, particular foods, and dietary patterns may influence allergic disease development and review studies examining the relationship between prenatal diet and the risk of childhood allergy.

RECENT FINDINGS

The combination of in utero exposures and genetic predisposition may contribute to the development of allergic disease by altering immune and organ development. Inflammation predominates in the first and third trimesters whereas the second trimester is characterized by anti-inflammatory and Th2 immune responses. Maternal dietary exposures during pregnancy may interact with inherited genetic risk factors influence immune system development. There are varied results regarding the impact of maternal prenatal diet on the development of childhood allergies. Well-designed randomized controlled studies are needed to clarify this area.

It's not just the food you eat: Environmental factors in the development of food allergies

The dramatic rise in the prevalence of food allergy and food allergy-associated anaphylaxis in the past few decades has fueled investigative interest into understanding this puzzling trend. Here, we review the question as to whether important external environmental determinants beyond dietary habits and exposure to food allergens are involved. This review will summarize our current understanding of these environment determinants, derived from the latest experimental and epidemiological research. Specifically, we will review the role of exposures that affect skin barrier function, development of a diverse microbiome, and food processing. Additional exposures of concern are insufficient sunlight, endocrine disrupting chemicals and pesticides, and use of specific pharmaceutical agents that may drive or modify the risk for food allergy. Despite limitations in the quantity and quality of research to date, many new epidemiological associations and experimental data in support of this paradigm have emerged.

Dietary intervention for preventing food allergy in children

PURPOSE OF REVIEW

In the past decade, food allergy has been increasingly recognized as an important public health issue. The role of maternal and infant diet in the development of food allergy has been a major focus of research throughout this period. Recently, research in this area has moved from observational studies to intervention trials, and the findings from these trials have started to influence infant feeding guidelines. In this article, we review recent studies of dietary interventions for preventing food allergy, summarize current knowledge and discuss future research directions.

RECENT FINDINGS

The latest result from an intervention trial shows that introduction of peanut in the first year of life reduces the risk of peanut allergy in high-risk infants. A systematic review and meta-analysis of intervention trials also suggests a protective effect of egg introduction from around 4 to 6 months of age for reducing the risk of egg allergy, with most studies conducted in high-risk infants. Despite several intervention trials involving modifications to the maternal diet, the effect of maternal diet during pregnancy and lactation in preventing food allergy remains unclear.

SUMMARY

Earlier introduction of allergenic foods is a promising intervention to reduce the risk of some food allergies in high-risk infants. Further work is needed to improve knowledge of how to prevent food allergy in the general population.

Late-gestation maternal dietary methyl donor and cofactor supplementation in sheep partially reverses protection against allergic sensitization by IUGR

Perinatal exposures are associated with altered risks of childhood allergy. Human studies and our previous work suggest that restricted growth in utero (IUGR) is protective against allergic disease. The mechanisms are not clearly defined, but reduced fetal abundance and altered metabolism of methyl donors are hypothesized as possible underlying mechanisms. Therefore, we examined whether late-gestation maternal dietary methyl donor and cofactor supplementation of the placentally restricted (PR) sheep pregnancy would reverse allergic protection in progeny. Allergic outcomes were compared between progeny from control pregnancies (CON; n = 49), from PR pregnancies without intervention (PR; n = 28), and from PR pregnancies where the dam was fed a methyl donor plus cofactor supplement from day 120 of pregnancy until delivery (PR + Methyl; n = 25). Both PR and PR + Methyl progeny were smaller than CON; supplementation did not alter birth size. PR was protective against cutaneous hypersensitivity responses to ovalbumin (OVA; P < 0.01 in singletons). Cutaneous hypersensitivity responses to OVA in PR + Methyl progeny were intermediate to and not different from the responses of CON and PR sheep. Cutaneous hypersensitivity responses to house dust mites did not differ between treatments. In singleton progeny, upper dermal mast cell density was greater in PR + Methyl than in PR or CON (each P < 0.05). The differences in the cutaneous allergic response were not explained by treatment effects on circulating immune cells or antibodies. Our results suggest that mechanisms underlying in utero programming of allergic susceptibility by IUGR and methyl donor availability may differ and imply that late-gestation methyl donor supplementation may increase allergy risk.

The Implications of DNA Methylation on Food Allergy

Food allergy is a major clinical and public health concern worldwide. The risk factors are well defined, however, the mechanisms by which they affect immune development remain largely unknown, and unfortunately the effective treatment or prevention of food allergy is still being researched. Recent studies show that the genes that are critical for the development of food allergy are regulated through DNA methylation. Environmental factors can affect host DNA methylation status and subsequently predispose people to food allergy. DNA methylation is therefore an important mediator of gene-environment interactions in food allergy and key to understanding the mechanisms underlying the allergic development. Indeed, the modification and identification of the methylation levels of specific genetic loci have gained increasing attention for therapeutic and diagnostic application in combating food allergy. In this review, we summarize and discuss the recent developments of DNA methylation in food allergy, including the pathogenesis, therapy, and diagnosis. This review will also summarize and discuss the environmental factors that affect DNA methylation levels in food allergy.

Human Milk and Allergic Diseases: An Unsolved Puzzle

There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

Pre-birth origins of allergy and asthma

Allergy is a chronic disease that can develop as early as infancy, suggesting that early life factors are important in its aetiology. Variable associations between size at birth, a crude marker of the fetal environment, and allergy have been reported in humans and require comprehensive review. Associations between birth weight and allergy are however confounded in humans, and we and others have therefore begun exploring the effects of early life events on allergy in experimental models. In particular, we are using ovine models to investigate whether and how a restricted environment before birth protects against allergy, whether methyl donor availability contributes to allergic protection in IUGR, and why maternal asthma during pregnancy is associated with increased risks of allergic disease in children. We found that experimental intrauterine growth restriction (IUGR) in sheep reduced cutaneous responses to antigens in progeny, despite normal or elevated IgE responses. Furthermore, maternal methyl donor supplementation in late pregnancy partially reversed effects of experimental IUGR, consistent with the proposal that epigenetic pathways underlie some but not all effects of IUGR on allergic susceptibility. Ovine experimental allergic asthma with exacerbations reduces relative fetal size in late gestation, with some changes in immune populations in fetal thymus suggestive of increased activation. Maternal allergic asthma in mice also predisposes progeny to allergy development. In conclusion, these findings in experimental models provide direct evidence that a perturbed environment before birth alters immune system development and postnatal function, and provide opportunities to investigate underlying mechanisms and develop and evaluate interventions.

The Role of Vitamin D in the Immune System as a Pro-survival Molecule

PURPOSE

Vitamin D is a fascinating and attractive molecule that has gained particular attention in medicine in recent years. Its immunomodulatory and anti-inflammatory potential might resemble the activity of many nature-derived molecules (eg, flavonoids), but its role in biology was selected during a long evolutionary pathway to dampen the damaging effect of cell stress response and of the immune reaction. In this sense, this molecule can be considered an ancient hormone that serves, in its primary role, as a pro-survival agent. The goal of this review was to elucidate this topic.

METHODS

The article reviews current literature on the field, focusing on issues regarding the role of vitamin D in immunity.

FINDINGS

Vitamin D participates in the survival machinery used by the cell, and in particular it plays a major role in synchronizing calcium oscillatory signaling to allow cell autophagy or apoptosis during a stress response.

IMPLICATIONS

Vitamin D should be better highlighted in its molecular action and vitamin D receptor genomics to conceive a more suited therapeutic supplementation protocol in clinics.

Maternal Folic Acid Supplementation during Pregnancy and Childhood Allergic Disease Outcomes: A Question of Timing?

Since the early 1990s, maternal folic acid supplementation has been recommended prior to and during the first trimester of pregnancy, to reduce the risk of infant neural tube defects. In addition, many countries have also implemented the folic acid fortification of staple foods, in order to promote sufficient intakes amongst women of a childbearing age, based on concerns surrounding variable dietary and supplementation practices. As many women continue to take folic acid supplements beyond the recommended first trimester, there has been an overall increase in folate intakes, particularly in countries with mandatory fortification. This has raised questions on the consequences for the developing fetus, given that folic acid, a methyl donor, has the potential to epigenetically modify gene expression. In animal studies, folic acid has been shown to promote an allergic phenotype in the offspring, through changes in DNA methylation. Human population studies have also described associations between folate status in pregnancy and the risk of subsequent childhood allergic disease. In this review, we address the question of whether ongoing maternal folic acid supplementation after neural tube closure, could be contributing to the rise in early life allergic diseases.