Understanding the evidence for and against the role of breastfeeding in allergy prevention

Science and Faith to Understand Milk Bioactivity for Infants

Milk bioactivity refers to the specific health effects of milk components beyond nutrition. The science of milk bioactivity involves the systematic study of these components and their health effects, as verified by empirical data, controlled experiments, and logical arguments. Conversely, 'faith in milk bioactivity' can be defined as personal opinion, meaning, value, trust, and hope for health effects that are beyond investigation by natural, social, or human sciences. Faith can be strictly secular, but also influenced by spirituality or religion. The aim of this paper is to show that scientific knowledge is frequently supplemented with faith convictions to establish personal and public understanding of milk bioactivity. Mammalian milk is an immensely complex fluid containing myriad proteins, carbohydrates, lipids, and micronutrients with multiple functions across species, genetics, ages, environments, and cultures. Human health includes not only physical health, but also social, mental, and spiritual health, requiring widely different fields of science to prove the relevance, safety, and efficacy of milk interventions. These complex relationships between milk feeding and health outcomes prevent firm conclusions based on science and logic alone. Current beliefs in and understanding of the value of breast milk, colostrum, infant formula, or isolated milk proteins (e.g., immunoglobulins, α-lactalbumin, lactoferrin, and growth factors) show that both science and faith contribute to understand, stimulate, or restrict the use of milk bioactivity. The benefits of breastfeeding for infants are beyond doubt, but the strong beliefs in its health effects rely not only on science, and mechanisms are unclear. Likewise, fear of, or trust in, infant formula may rely on both science and faith. Knowledge from science safeguards individuals and society against 'milk bioactivity superstition'. Conversely, wisdom from faith-based convictions may protect science from unrealistic 'milk bioactivity scientism'. Honesty and transparency about the potentials and limitations of both scientific knowledge and faith convictions are important when informing individuals and society about the nutritious and bioactive qualities of milk.

Timing of introduction to solid food, eczema and wheezing in later childhood: a longitudinal cohort study

BACKGROUND

The timing of introduction to solid food has been associated with eczema and wheezing in childhood. Our aim was to determine whether differences persist within the recommended 4 to 6 month age range.

METHODS

A longitudinal cohort study with repeated measures was conducted among children from birth to 10 years of age who were participating in the TARGet Kids! practice based research network in Toronto, Canada. The primary exposure was the timing of introduction to infant cereal as the first solid food. The primary outcome was eczema and the secondary outcome was wheezing collected by parent report using the validated International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Multinomial generalized estimating equations were used and effect modification by family history of asthma and breastfeeding duration were explored.

RESULTS

Of the 7843 children included, the mean (standard deviation) age of introduction to infant cereal was 5.7 (1.9) months. There was evidence for family history of asthma and breastfeeding duration to be effect modifiers in the eczema (P = 0.04) and wheezing (P = 0.05) models. Introduction to infant cereal at 4 vs. 6 months of age was associated with higher odds of eczema (OR 1.62; 95% CI: 1.12, 2.35; P = 0.01) among children without a family history of asthma who were not breastfeeding when solid foods were introduced. Introduction to infant cereal at 4 vs. 6 months of age was associated with a higher odds of wheezing (OR 1.31; 95% CI: 1.13, 1.52; P < .001) among children without a family history of asthma who were breastfeeding when solid foods were introduced. There was little evidence of an association among the remaining strata for either outcome.

CONCLUSION

The findings of this study support recommendations to introduce solid food around 6 months of age.

Analysis of Multimorbidity of Moderate to Severe Allergic Rhinitis in Children: A Real-World Study

INTRODUCTION

Allergic rhinitis (AR) in children is associated with various comorbidities, posing challenges for treatment and management. There have been few investigations of these multimorbidities in Chinese children with AR. Here, we investigated the prevalence of multimorbidities in children with moderate to severe AR and analyzed the influencing factors using real-world data.

METHODS

In total, 600 children who visited the outpatient clinic of our hospital and were diagnosed with moderate-severe AR were prospectively enrolled. All children underwent allergen detection and electronic nasopharyngoscopy. Parents or guardians completed a questionnaire that included age, sex, mode of delivery, feeding pattern, and familial history of allergy. The multimorbidities investigated included atopic dermatitis (AD), asthma, allergic conjunctivitis (AC), chronic rhinosinusitis (CRS), adenoid hypertrophy (AH), tonsil hypertrophy (TH), recurrent epistaxis, and recurrent respiratory tract infections (RRTIs).

RESULTS

The AR multimorbidities reported in children were as follows: recurrent epistaxis (46.5%), AC (46.3%), AD (40.7%), asthma (22.5%), RRIs (21.3%), CRS (20.5%), AH (19.7%), and TH (12.5%). In univariate logistic regression analysis, age (<6 years), birth mode, familial history of allergy, and single dust mite allergy were associated with AR multimorbidity (p < 0.05). Multivariate logistic regression revealed that a familial history of allergy was an independent risk factor for AC (odds ratio [OR] = 1.539, 95% confidence interval [CI]: 1.104-2.145) and AH (OR = 1.506, 95% CI: 1.000-2.267) (p < 0.05). Age (<6 years) was independently associated with the risk of AD (OR = 1.405, 95% CI: 1.003-1.969) and RRTIs (OR = 1.869, 95% CI: 1.250-2.793) (p < 0.05), cesarean section with AR and CRS risk (OR = 1.678, 95% CI: 1.100-2.561), and single dust mite allergy with asthma (OR = 1.590, 95% CI: 1.040-2.432) and CRS (OR = 1.600, 95% CI: 1.018-2.515) risk (p < 0.05). Further, non-dust mite allergy was independently associated with AR and CRS (OR = 2.056, 95% CI: 1.084-3.899).

CONCLUSION

AR was found to be accompanied by different comorbidities, including both allergic and non-allergic comorbidities, complicating disease treatment. These findings demonstrated that age (<6 years), familial history of allergy, types of allergens, and cesarean section were risk factors for different multimorbidities associated with AR.

The human milk proteome and allergy of mother and child: Exploring associations with protein abundances and protein network connectivity

Background

The human milk proteome comprises a vast number of proteins with immunomodulatory functions, but it is not clear how this relates to allergy of the mother or allergy development in the breastfed infant. This study aimed to explore the relation between the human milk proteome and allergy of both mother and child.

Methods

Proteins were analyzed in milk samples from a subset of 300 mother-child dyads from the Canadian CHILD Cohort Study, selected based on maternal and child allergy phenotypes. For this selection, the definition of "allergy" included food allergy, eczema, allergic rhinitis, and asthma. Proteins were analyzed with non-targeted shotgun proteomics using filter-aided sample preparation (FASP) and nanoLC-Orbitrap-MS/MS. Protein abundances, based on label-free quantification, were compared using multiple statistical approaches, including univariate, multivariate, and network analyses.

Results

Using univariate analysis, we observed a trend that milk for infants who develop an allergy by 3 years of age contains higher abundances of immunoglobulin chains, irrespective of the allergy status of the mother. This observation suggests a difference in the milk's immunological potential, which might be related to the development of the infant's immune system. Furthermore, network analysis showed overall increased connectivity of proteins in the milk of allergic mothers and milk for infants who ultimately develop an allergy. This difference in connectivity was especially noted for proteins involved in the protein translation machinery and may be due to the physiological status of the mother, which is reflected in the interconnectedness of proteins in her milk. In addition, it was shown that network analysis complements the other methods for data analysis by revealing complex associations between the milk proteome and mother-child allergy status.

Conclusion

Together, these findings give new insights into how the human milk proteome, through differences in the abundance of individual proteins and protein-protein associations, relates to the allergy status of mother and child. In addition, these results inspire new research directions into the complex interplay of the mother-milk-infant triad and allergy.

Effects of early life exposure to home environmental factors on childhood allergic rhinitis: Modifications by outdoor air pollution and temperature

BACKGROUND

There is growing evidence that allergic rhinitis (AR) is associated with indoor environmental factors, but their role in childhood AR during early life remains unclear.

OBJECTIVE

To investigate the association of preconceptional, prenatal, early postnatal, and current exposure to home environmental factors with childhood AR, and to further explore whether this association can be interacted by outdoor air pollution and temperature.

METHODS

A retrospective cohort study of 8689 preschool children was conducted during 2019-2020 in Changsha, China. A standard questionnaire was used to collect data on each family's health outcomes and home environments. We considered home environmental exposures during one year before conception, pregnancy, first year of life, and past year. Associations of indoor air pollution and allergens with AR were assessed by multiple logistic regression models.

RESULTS

Pre-birth exposure to indoor air pollution emitted by new furniture or redecoration and dampness related allergen derived from mold/damp stains and mold/damp clothes or bedding during 1 year before conception and pregnancy was significantly associated with increased AR, with adjusted ORs (95% CI) ranging from 1.35 (1.05-1.75) to 1.87 (1.55-2.27). Childhood AR was also significantly related with post-birth exposure to dampness related indoor allergen including mold/damp stains and mold/damp clothes or bedding in first year and past year and pollen allergen including total and nonflowing plants in past year, with a range of ORs (95% CI) from 1.20 (1.01-1.42) to 1.79 (1.42-2.27). We identified that pre-birth, particularly in utero exposure to both indoor air pollution from renovation and dampness related allergens, played a key role in AR development compared to post-birth exposures, and accumulative effect was observed with the highest risk of AR. High exposure to traffic-related air pollution (TRAP) including outdoor PM_2.5, NO₂, CO, and O₃, as well as living near traffic road not only significantly increased adverse effect of home environmental factors but also decreased protective effect of household dogs on childhood AR. Early life exposure to low temperature in pregnancy and high temperature in first year significantly increased AR risk of home environmental exposure. Sensitivity analysis indicated that some sub-groups were more susceptible to AR risk of home environmental exposure.

CONCLUSION

Our study suggests that pre-birth exposure to home environmental factors played an important role in AR development and this effect can be interacted by TRAP and temperature, which supports a hypothesis of "(pre)fetal origin of childhood AR".

Sialic acid, the secret gift for the brain

The human brain grows rapidly in early life which requires adequate nutrition. Human milk provides optimal nutrition for the developing brain, and breastfeeding significantly improves the cognition development of infants. These benefits have been largely attributed to human milk oligosaccharides (HMOS), associated with sialic acid (Sia). Subsequently, sialylated HMOS present a vital source of exogenous Sia to infants. Sialic acid is a key molecule essential for proper development of gangliosides, and therefore critical in brain development and function. Recent pre-clinical studies suggest dietary supplementation with Sia or sialylated oligosaccharides enhances intelligence and cognition performance in early and later life. Furthermore, emerging evidence suggests the involvement of Sia in brain homeostasis and disbalance correlates with common pathologies such as Alzheimer's disease (AD). Therefore, this review will discuss early brain health and development and the role of Sia in this process. Additionally, studies associating breastfeeding and specific HMOS to benefits in cognitive development are critically assessed. Furthermore, the review will assess studies implying the potential role of HMOS and microbiota in brain development via the gut-brain axis. Finally, the review will summarize recent advances regarding the role of Sia in neurodegenerative disease in later life and potential roles of dietary Sia sources.

Levels of Breast Milk MicroRNAs and Other Non-Coding RNAs Are Impacted by Milk Maturity and Maternal Diet

There is emerging evidence that non-coding RNAs (ncRNAs) within maternal breast milk (MBM) impart unique metabolic and immunologic effects on developing infants. Most studies examining ncRNAs in MBM have focused on microRNAs. It remains unclear whether microRNA levels are related to other ncRNAs, or whether they are impacted by maternal characteristics. This longitudinal cohort study examined 503 MBM samples from 192 mothers to: 1) identify the most abundant ncRNAs in MBM; 2) examine the impact of milk maturity on ncRNAs; and 3) determine whether maternal characteristics affect ncRNAs. MBM was collected at 0, 1, and 4 months post-delivery. High throughput sequencing quantified ncRNAs within the lipid fraction. There were 3069 ncRNAs and 238 microRNAs with consistent MBM presence (≥10 reads in ≥10% samples). Levels of 17 ncRNAs and 11 microRNAs accounted for 80% of the total RNA content. Most abundant microRNAs displayed relationships ([R]>0.2, adj p< 0.05) with abundant ncRNAs. A large proportion of ncRNAs (1269/3069; 41%) and microRNAs (206/238; 86%) were affected by MBM maturity. The majority of microRNAs (111/206; 54%) increased from 0-4 months. Few ncRNAs and microRNAs were affected (adj p < 0.05) by maternal age, race, parity, body mass index, gestational diabetes, or collection time. However, nearly half of abundant microRNAs (4/11) were impacted by diet. To our knowledge this is the largest study of MBM ncRNAs, and the first to demonstrate a relationship between MBM microRNAs and maternal diet. Such knowledge could guide nutritional interventions aimed at optimizing metabolic and immunologic microRNA profiles within MBM.

Non-Cholesterol Sterols in Breast Milk and Risk of Allergic Outcomes in the First Two Years of Life

This study aimed to explore associations between non-cholesterol sterol concentrations in breast milk and allergic outcomes in children aged two. Data from the KOALA Birth Cohort Study, the Netherlands, were used. Non-cholesterol sterols were analyzed by gas–liquid chromatography–mass spectrometry in breast milk sampled one-month postpartum (N = 311). Sterols were selected for each allergic outcome, i.e., eczema, wheeze, and allergic sensitization, prior to analyses. Associations between the selected sterols with allergic outcomes were analyzed using multiple logistic regression to calculate odds ratios (ORs). The odds of eczema in the first two years of life were lower with higher concentrations of cholestanol (OR (95%CI): 0.98 (0.95; 1.00), p = 0.04), lanosterol (0.97 (0.95; 1.00), p = 0.02), lathosterol (0.93 (0.87; 0.99), p = 0.02), and stigmasterol (0.51 (0.29; 0.91), p = 0.02) in breast milk sampled one-month postpartum. None of the sterols were associated with wheeze in the first two years of life. The odds of allergic sensitization at age two were lower with higher concentrations of campesterol in breast milk (OR (95%CI): 0.81 (0.70; 0.95), p = 0.01). In conclusion, our data suggest that exposure to higher non-cholesterol sterol concentrations in breast milk may indeed be associated with the prevention of allergic outcomes in the first two years of life.

Allergic Diseases: A Comprehensive Review on Risk Factors, Immunological Mechanisms, Link with COVID-19, Potential Treatments, and Role of Allergen Bioinformatics

The prevalence of allergic diseases is regarded as one of the key challenges in health worldwide. Although the precise mechanisms underlying this rapid increase in prevalence are unknown, emerging evidence suggests that genetic and environmental factors play a significant role. The immune system, microbiota, viruses, and bacteria have all been linked to the onset of allergy disorders in recent years. Avoiding allergen exposure is the best treatment option; however, steroids, antihistamines, and other symptom-relieving drugs are also used. Allergen bioinformatics encompasses both computational tools/methods and allergen-related data resources for managing, archiving, and analyzing allergological data. This study highlights allergy-promoting mechanisms, algorithms, and concepts in allergen bioinformatics, as well as major areas for future research in the field of allergology.

Non-Coding RNAs in Human Breast Milk: A Systematic Review

Breast milk is the primary source of nutrition and hydration for the newborn infant but also plays an important role in the child’s first immune defense. Additionally, several breast milk factors have been implicated in immune-related health outcomes later in life, including immunoglobulins, cytokines, chemokines, growth factors and, more recently, non-coding RNA (ncRNA) species. In this systematic review, we provide a comprehensive summary of the current literature on endogenous ncRNAs found in human breast milk. Thirty (30) relevant studies were identified and, whilst the majority studies focused on microRNAs (miRNAs), there is evidence that breast milk contains high quantities of RNA which also include long-coding RNAs, circular RNAs, as well as other short RNAs and fragmented tRNA and rRNAs. Among studies investigating miRNAs, miR-148a-3p, miR-30a/d-5p, miR-22-3p, miR-146b-5p, miR-200a/c-3p, and the 5p end of the let-7 miRNAs were commonly reported among the top 10 miRNAs in the cell, lipid, and skim milk fractions of breast milk. Methodological difference and small sample sizes limit the possibility of conclusively identifying which maternal and infant characteristics affect the miRNA profile. The highly expressed miRNAs were generally reported to be similar across lactational stage, milk fraction, maternal and infant characteristics, or infant growth and health. All the same, individual studies identify potential differences in miRNA expression levels which should be confirmed by future studies. Stability, uptake, and physiological functions of miRNAs were also considered in several studies. Breast milk miRNAs are relatively resistant to a range of harsh conditions and uptake experiments suggest that extracellular vesicles containing miRNAs and circular RNAs can be taken up by intestinal epithelial cells. Although the evidence regarding the functional effect of breast milk miRNAs is limited, the predicted functions range from metabolic and biosynthetic processes to signaling pathways, cellular adhesion, communication, growth, and differentiation. Finally, this systematic review highlights some of the methodological challenges and knowledge gaps which can help direct future research in this field. In particular, it is important to further investigate the bioavailability of miRNAs in different milk fractions, and to characterize other ncRNAs which are largely unstudied.

Infant Feeding Practices During the First Postnatal Year and Risk of Asthma and Allergic Disease During the First 6 Years of Life

Background: Breastfeeding may protect against childhood asthma and allergic diseases. Studies have not focused on the mode of feeding human milk and followed children to school age although feeding human milk from a bottle rather than the breast may alter the risk of disease. Materials and Methods: At 12 months' postpartum, women in the Moms2Moms study (Columbus, OH) completed a survey assessing sociodemographic and infant feeding behaviors. At 6 years' postpartum, they completed a survey and pediatric medical records were abstracted to assess asthma and allergic disease diagnoses. Logistic regression models were used to estimate associations between infant feeding behaviors and asthma or allergic disease. Results: Of 285 children, 16% had asthma and 44% ever had ≥1 allergy diagnosis. Longer durations of each infant feeding behavior were not clearly associated with increased odds of asthma or allergic disease by age 6. Results suggested that longer durations of breast milk feeding (regardless of the mode of feeding) may be related to a lower risk of food allergy (e.g., odds ratio [OR]1-month, adjusted = 0.96, 95% confidence interval [CI] = 0.87-1.05; OR12-month, adjusted = 0.57, 95% CI = 0.19-1.74), but that the mode of feeding (regardless of the substance fed) may be more meaningful for environmental allergies (e.g., exclusive direct breast milk feeding OR12-month, adjusted = 0.32, 95% CI = 0.06-1.81). However, effect estimates were imprecise and CIs included the null. Conclusions: Although no clear associations between mode of breast milk feeding (breast versus expressed) and asthma and allergy outcomes were observed, future research with larger samples should further evaluate these associations.

Breastfeeding and Allergic Diseases: What's New?

Asthma and other allergic disorders, such as atopic dermatitis and food allergies, are common chronic health problems in childhood. The rapid rise in the prevalence of these conditions registered over the last few decades has stressed the need to identify the modifiable risk factors associated with the development of these diseases. Breast milk, recognized as the gold standard for healthy growth and development of the newborn, is one of the major factors associated with a lower incidence of allergic and infectious diseases in childhood and young adulthood. Although the underlying mechanisms for these effects are not well understood, breastfeeding leads to immune system maturation. In this narrative review, we summarize existing evidence on breastfeeding and human milk composition in relation to allergic disease prevention or development.

Comparative Analysis of Whey Proteins in Human Milk Using a Data-Independent Acquisition Proteomics Approach during the Lactation Period

Human milk (HM) is the primary source of nutrients and bioactive components that supports the growth and development of infants. However, the proteins present in human milk may change depending on the period of lactation. In this light, the objective of the present study was to evaluate the effect of lactation period on HM utilizing a data-independent acquisition (DIA) approach to identify the differences in HM whey protein proteomes. As part of the study, whey proteins of January, February, and June in human milk were studied. The results identified a total of 1563 proteins in HM whey proteins of which 114 groups were subunits of differentially expressed proteins as revealed by cluster analysis. Protein expression was observed to be affected by the period of lactation with expression levels of plasminogen, thrombospondin-1, and tenascin higher during January, keratin, type I cytoskeletal 9 highest in February, and transcobalamin-1 highest in June. The results of this study contribute to expand our understanding of the human whey proteome but also provide strong evidence for the nutritional difference of HM during different lactation periods.

Duration of breastfeeding, age at introduction of complementary foods and allergy-related diseases: a prospective cohort study

Background

The influences of breastfeeding and infant diet in the prevention of allergy-related diseases are uncertain and many of the studies conducted on the topic are limited by methodological challenges. Our aim was to assess whether the duration of breastfeeding and age at complementary food introduction affected the prevalence of asthma, wheeze, allergic rhinoconjunctivitis (ARC) and eczema at two and six years of age.

Methods

We used information gathered between 2000 and 2014 through questionnaires in the Prevention of Allergy among Children in Trondheim (PACT) study, a prospective cohort study in Trondheim, Norway. The current study includes 6802 children who submitted questionnaires detailing breastfeeding duration and or age at introduction to complementary foods, as well as at least one of the child health questionnaires completed at two and six years of age. Adjusted odds ratios (aORs) were calculated for each combination of exposure and outcomes and sensitivity analyses were performed to assess the possible influence of recall bias and reverse causality.

Results

The mean duration of breastfeeding was 11 months (SD 5.6) in this study population and 5695 of 6796 (84%) infants had been breastfed for at least 6 months. We did not find any conclusive preventative effect of longer breastfeeding on parental reported doctor-diagnosed asthma, aOR 0.79 (95% CI 0.51, 1.21). However, at 6 years of age we observed a reduction in the less strictly defined outcome wheeze, aOR 0.71 (95% CI 0.53, 0.95). Longer breastfeeding was associated with a reduced risk of ARC at 2 years, aOR 0.65 (95% CI 0.49, 0.86), with a continued protective trend at 6 years, aOR 0.77 (95% CI 0.58, 1.04).

Conclusions

Longer breastfeeding resulted in a reduced risk of wheeze and a trend towards a protective effect on ARC up until school age. No conclusive associations were seen between the duration of breastfeeding or age at introduction to complementary foods and prevention of asthma, wheeze, ARC and eczema.

Trial registration

The trial is registered in Current Controlled Trials as ISRCTN28090297.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13006-020-00352-2.

Identification of modifiable pre- and postnatal dietary and environmental exposures associated with owner-reported canine atopic dermatitis in Finland using a web-based questionnaire

A cross-sectional hypothesis generating study was performed to investigate modifiable exposures such as whether feeding pattern (a non-processed meat based diet, NPMD, or an ultra-processed carbohydrate based diet, UPCD), certain environmental factors and their timing of exposure might be associated with the development of canine atopic dermatitis (CAD). Also, genetic and demographic factors were tested for associations with CAD. The data was collected from the validated internet-based DogRisk food frequency questionnaire in Finland. A total of 2236 dogs were eligible for the study (the owners reported 406 cases and 1830 controls). Our main interest was to analyze modifiable early risk factors of CAD, focusing on nutritional and environmental factors. We tested four early life periods; prenatal, neonatal, early postnatal and late postnatal periods. Twenty-two variables were tested for associations with CAD using logistic regression analysis. From the final models we identified novel dietary associations with CAD: the NPMD during the prenatal and early postnatal periods had a significant negative association with the incidence of CAD in adult dogs (age above 1 year). Oppositely, UPCD was associated with a significantly higher risk for CAD incidence. Other variables that were associated with a significantly lower risk for CAD were maternal deworming during pregnancy, sunlight exposure during early postnatal period, normal body condition score during the early postnatal period, the puppy being born within the same family that it would stay in, and spending time on a dirt or grass surface from 2 to 6 months. Also, the genetic factors regarding maternal history of CAD, allergy-prone breeds and more than 50% white-colored coat all showed a significant positive association with CAD incidence in agreement with previous findings. Although no causality can be established, feeding NPMD early in life seemed to be protective against CAD, while UPCD could be considered a risk factor. Prospective intervention studies are needed to establish the causal effects of the protective role of NPMD on prevalence of CAD during the fetal and early postnatal life.

Free Amino Acids in Human Milk: A Potential Role for Glutamine and Glutamate in the Protection Against Neonatal Allergies and Infections

Breastfeeding is indicated to support neonatal immune development and to protect against neonatal infections and allergies. Human milk composition is widely studied in relation to these unique abilities, which has led to the identification of various immunomodulating components in human milk, including various bioactive proteins. In addition to proteins, human milk contains free amino acids (FAAs), which have not been well-studied. Of those, the FAAs glutamate and glutamine are by far the most abundant. Levels of these FAAs in human milk sharply increase during the first months of lactation, in contrast to most other FAAs. These unique dynamics are globally consistent, suggesting that their levels in human milk are tightly regulated throughout lactation and, consequently, that they might have specific roles in the developing neonate. Interestingly, free glutamine and glutamate are reported to exhibit immunomodulating capacities, indicating that these FAAs could contribute to neonatal immune development and to the unique protective effects of breastfeeding. This review describes the current understanding of the FAA composition in human milk. Moreover, it provides an overview of the effects of free glutamine and glutamate on immune parameters relevant for allergic sensitization and infections in early life. The data reviewed provide rationale to study the role of free glutamine and glutamate in human milk in the protection against neonatal allergies and infections.

Duration of breastfeeding is associated with leptin (LEP) DNA methylation profiles and BMI in 10-year-old children

BACKGROUND

Breastfeeding is protective against many long-term diseases, yet the mechanisms involved are unknown. Leptin gene (LEP) is reported to be associated with body mass index (BMI). On the other hand, breastfeeding duration has been found to be associated with DNA methylation (DNAm) of the LEP gene. Therefore, epigenetic regulation of LEP may represent the mechanism underlying the protective effect of breastfeeding duration against obesity.

METHODS

In the Isle of Wight Birth Cohort, peripheral blood DNAm at 23 cytosine-phosphate-guanine sites (CpGs) in the LEP locus in 10-year-old (n = 297) samples and 16 CpGs in 18-year-old (n = 305) samples, were generated using the Illumina Infinium MethylationEPIC and HumanMethylation450 Beadchips respectively and tested for association with breastfeeding duration (total and exclusive) using linear regression. To explore the association between breastfeeding durations and genome-wide DNAm, epigenome-wide association studies (EWASs) and differential methylation region (DMR) analyses were performed. BMI trajectories spanning the first 18 years of life were used as the outcome to test the association with breastfeeding duration (exposure) using multi-nominal logistic regression. Mediation analysis was performed for significant CpG sites.

RESULTS

Both total and exclusive breastfeeding duration were associated with DNAm at four LEP CpG sites at 10 years (P value < 0.05), and not at 18 years. Though no association was observed between breastfeeding duration and genome-wide DNAm, DMR analyses identified five significant differentially methylated regions (Sidak adjusted P value < 0.05). Breastfeeding duration was also associated with the early transient overweight trajectory. Furthermore, DNAm of LEP was associated with this trajectory at one CpG site and early persistent obesity at another, though mediation analysis was not significant.

CONCLUSIONS

Breastfeeding duration is associated with LEP methylation at age 10 years and BMI trajectory. LEP DNAm is also significantly associated with BMI trajectories throughout childhood, though sample sizes were small. However, mediation analysis did not demonstrate that DNAm of LEP explained the protective effect of breastfeeding against childhood obesity.

The Functional Power of the Human Milk Proteome

Human milk is the most complete and ideal form of nutrition for the developing infant. The composition of human milk consistently changes throughout lactation to meet the changing functional needs of the infant. The human milk proteome is an essential milk component consisting of proteins, including enzymes/proteases, glycoproteins, and endogenous peptides. These compounds may contribute to the healthy development in a synergistic way by affecting growth, maturation of the immune system, from innate to adaptive immunity, and the gut. A comprehensive overview of the human milk proteome, covering all of its components, is lacking, even though numerous analyses of human milk proteins have been reported. Such data could substantially aid in our understanding of the functionality of each constituent of the proteome. This review will highlight each of the aforementioned components of human milk and emphasize the functionality of the proteome throughout lactation, including nutrient delivery and enhanced bioavailability of nutrients for growth, cognitive development, immune defense, and gut maturation.

[Clinical features of cow's milk protein allergy in infants presenting mainly with gastrointestinal symptoms: an analysis of 280 cases]

OBJECTIVE

To investigate the epidemiological and clinical features of cow's milk protein allergy (CMPA) in infants presenting mainly with gastrointestinal symptoms.

METHODS

A retrospective analysis was performed for the clinical data of 280 hospitalized infants, who were diagnosed with CMPA presenting mainly with gastrointestinal symptoms.

RESULTS

Among the 280 infants, 203 infants(72.5%) were aged of less than 6 months. Major manifestations included diarrhea in 171 infants (61.1%), hematochezia in 149 infants (53.2%), vomiting in 71 infants (25.4%), eczema in 57 infants (20.4%), malnutrition in 42 infants (15%) and constipation in 13 infants (4.6%). Of the 280 infants, 258 (92.1%) had mild-to-moderate CMPA and 22 (7.9%) had severe CMPA. Compared with the mild-to-moderate CMPA group, the severe CMPA group had a significantly higher incidence rate of malnutrition (50.0% vs 12.0%) and a significantly lower incidence rate of hematochezia (22.7% vs 55.8%). The breastfeeding CMPA group had significantly lower incidence rates of malnutrition (10.3% vs 24.6%) and severe CMPA (4.4% vs 18.0%) than the artificial feeding CMPA group, and the artificial feeding CMPA group had a significantly lower incidence rate of hematochezia than the breastfeeding and mixed feeding CMPA groups (37.7% vs 56.6%/59.0%).

CONCLUSIONS

CMPA presenting mainly with gastrointestinal symptoms is more common in infants aged of less than 6 months. Diarrhea and hematochezia are the most common manifestations at the time of onset. Most infants have mild-to-moderate allergy. Compared with breastfeeding, artificial feeding is more likely to cause malnutrition and severe CMPA.

Birth Mode, Breastfeeding, Pet Exposure, and Antibiotic Use: Associations With the Gut Microbiome and Sensitization in Children

PURPOSE OF REVIEW

The infant gut microbiota has become a focus of multiple epidemiologic and cohort studies. This microbiome is derived from the mother (via the vaginal canal, maternal skin contact, breastfeeding, and possibly in utero microbial transfer) and is likely influenced by multiple external factors. It is now believed by some experts that colonization and formation of the newborn and alterations of gut microbiota in children are dependent on earlier alterations of the microbiota of mothers during or perhaps even before pregnancy. This review will focus on specific factors (pet keeping, breastfeeding, antibiotic use, and mode of delivery) that influence the infant gut microbiome and atopy.

RECENT FINDINGS

This is a review of recent literature describing how pet keeping, breastfeeding, antibiotic use, and mode of delivery influences and changes the infant gut microbiome and atopy. General trends in gut microbiota differences have emerged in different birth cohorts when each external factor is analyzed, but consistency between studies is difficult to replicate. The aforementioned factors do not seem to confer an overwhelming risk for development of atopy alone. This review provides a comprehensive review of early life environmental factors and their influence on the infant gut microbiome and atopy.

Discovery and Quantification of Nonhuman Proteins in Human Milk

The question whether and which nonhuman peptides or proteins are present in human milk was raised many decades ago. However, due to cross-reactivity or nonspecific antibody recognition, the accuracy of detection by immunochemical methods has been a concern. Additionally, the relative low-abundance of nonhuman peptides/proteins in the complex milk sample makes them a challenging target to detect. Here, by deep proteome profiling, we detected several nonhuman peptides, which could be grouped as nonhuman proteins. We next estimated their concentration in human milk by combining data-dependent shotgun proteomics and parallel reaction monitoring. First, we fractionated human milk at the protein level and were able to detect 1577 human proteins. Additionally, we identified 109 nonhuman peptides, of which 71 were grouped into 36 nonhuman proteins. In the next step, we targeted 37 nonhuman peptides and nine of them could be repeatedly quantified in human milk samples. Peptides/proteins originating from bovine milk products were the dominant nonhuman proteins observed, notably bovine caseins (α-S1-, α-S2-, β-, κ-caseins) and β-lactoglobulin. The method we present here can be expanded to investigate more about nonhuman peptides and proteins in human milk and give a better understanding of how human milk plays a role in allergy prevention.

Prevalence and risk factors of asthma in mainland China: The CARE study

BACKGROUND

There are limited population based data on the prevalence of asthma in China. The China Asthma and Risk factors Epidemiologic (CARE) survey was designed to understand the prevalence and risk factors for asthma in mainland China.

OBJECTIVES

The CARE survey aims to demonstrate the prevalence and risk factors of asthma in mainland China among adolescents (age >14 years) and adults.

METHODS

The survey was performed between February 2010 and August 2012 in eight provinces/cities of seven areas in mainland China. The inhabitants (age, >14 years) recruited in this survey were through multi-stage cluster random sampling. Asthma diagnosis was based on medical history and lung function tests. Multivariable logistic regression was used to analyzed the risk factors for asthma.

RESULTS

The study included 164 215 subjects (men, 79 692 [48.53%]; women, 84 523 [51.47%]). 2034 (1.24%) were asthmatic patients. Among all asthmatic patients, 521 (25.61%) were newly diagnosed. Univariable regression analysis showed that risk factors for asthma included smoking, first-degree relatives with asthma, allergic rhinitis, chronic bronchitis, COPD, pollinosis, allergic pneumonia, concomitant allergic diseases, BMI and raising pets. Multivariable logistic regression indicated that asthma risk factors included women, age stratification, smoking, first-degree relatives suffering from asthma or pollinosis, combined with allergic rhinitis, eczema or GERD.

CONCLUSIONS

We speculated that the prevalence of asthma is increasing in mainland China among individuals aged >14 years in the past 10 years. A number of risk factors were identified. The risk factors of asthma would be further elucidated in our future work.

CLINICAL IMPLICATIONS

Our CARE study highlights that asthma epidemic in mainland China should be paid more attention.

Immunological Effects of Human Milk Oligosaccharides

Human milk oligosaccharides (HMOs) comprise a group of structurally complex, unconjugated glycans that are highly abundant in human milk. HMOs are minimally digested in the gastrointestinal tract and reach the colon intact, where they shape the microbiota. A small fraction of HMOs is absorbed, reaches the systemic circulation, and is excreted in urine. HMOs can bind to cell surface receptors expressed on epithelial cells and cells of the immune system and thus modulate neonatal immunity in the infant gut, and possibly also sites throughout the body. In addition, they have been shown to act as soluble decoy receptors to block the attachment of various microbial pathogens to cells. This review summarizes the current knowledge of the effects HMOs can have on infections, allergies, auto-immune diseases and inflammation, and will focus on the role of HMOs in altering immune responses through binding to immune-related receptors.

Economic value of using partially hydrolysed infant formula for risk reduction of atopic dermatitis in high-risk, not exclusively breastfed infants in Singapore

INTRODUCTION

Previous trials have demonstrated reductions in atopic dermatitis (AD) incidence when healthy, high-risk, non-exclusively breastfed infants were fed until four months of age with 100% whey-based partially hydrolysed formula (PHF-W) versus standard cow's milk formula (CMF). We assessed the cost-effectiveness of this intervention in Singapore.

METHODS

Modelling techniques were used to simulate, from birth to Month 30, the incidence and clinical/economic burden of AD in high-risk, non-exclusively breastfed infants fed with PHF-W or CMF for up to four months. Epidemiologic and clinical data were from a local comparative trial. Expert opinion informed AD treatment patterns and outcomes. Outcomes included reduction in AD risk, time spent with AD, days without AD flare, quality-adjusted life years (QALYs) and direct/indirect costs. Multivariate probabilistic sensitivity analysis was used to assess model parameter uncertainty.

RESULTS

Over 30 months, with the use of PHF-W instead of CMF, the proportion of children who developed AD and the time spent with AD decreased by 16.0% (28.3% vs. 44.3%) and 6.4 months, respectively, while time without AD flare and QALYs increased by 14.9 days and 0.021 QALYs per patient, respectively. Estimated AD-related discounted costs per child for PHF-W and CMF were SGD 771 and SGD 1,309, respectively (net savings: SGD 538). PHF-W was less expensive and more effective than CMF for 73%, and cost less than SGD 50,000 per QALY for 87% of all multivariate simulations.

CONCLUSION

Early short-term nutritional intervention with PHF-W instead of CMF may reduce AD incidence and costs for healthy, high-risk, non-exclusively breastfed infants in Singapore.

Food allergy and atopic dermatitis: Prediction, progression, and prevention

The rising burden of allergic diseases in childhood requires a compelling need to identify individuals at risk for atopy very early in life or even predict the onset of food allergy and atopic dermatitis since pregnancy. The development and clinical phenotypes of atopic diseases in childhood depend on a complex interaction between genetic and environmental factors, such as allergen exposure, air pollution, and infections. Preventive strategies may include avoidance measures, diet supplements, and early complementary food introduction. Overall, the management of allergic diseases has been improving to date toward a patient's tailored approach. This review will cover the current understanding of risk factors, prediction, and management of food allergy and atopic dermatitis in childhood and discuss how these may contribute to the modification of the natural history of food allergy and atopic dermatitis.

Association between breastfeeding and eczema during childhood and adolescence: A cohort study

Background

Breastfeeding is said to protect children from eczema (atopic dermatitis), but the available evidence is conflicting and subject to the influences of parental atopy and reverse causation (when mothers extended duration of breastfeeding because their children had eczema).

Methods

In the prospective, population-based Leicester Respiratory Cohort study, we assessed duration of breastfeeding in children aged 1–4 years. Prevalence of eczema was determined by questionnaire surveys that were repeated until the children were 17 years old. We investigated the association between having been breastfed and current eczema using generalized estimating equations, adjusting for potential confounders, and tested for effect modification by parental atopy. We also assessed the association between having been breastfed and incident eczema at ages 2, 4, and 6 years using multivariable logistic regression.

Results

Among the 5,676 children in the study, 2,284 (40%) had never been breastfed, while 1,610 (28%), 705 (12%), and 1,077 (19%) had been breastfed for 0–3, 4–6, and >6 months, respectively. Prevalence of current eczema decreased from 36% in 1-year-olds to 18% in children aged 10–17 years. Breastfeeding was not associated with current eczema. Compared with children who had never been breastfed, the adjusted odds ratios for current eczema at any age were 1.02 (95% confidence interval 0.90–1.15) for children who had been breastfed for 0–3 months, 0.97 (0.82–1.13) for children breastfed for 4–6 months, and 0.98 (0.85–1.14) for children breastfed for >6 months. There was no strong evidence for an effect modification by parental atopy (p-value for interaction term was 0.061) and no association between having been breastfed and incident eczema later in childhood.

Conclusions

This population-based cohort study found no evidence for protection of breastfeeding against childhood eczema at any age, from infancy through adolescence.

Breast Milk Transforming Growth Factor β Is Associated With Neonatal Gut Microbial Composition

BACKGROUND AND OBJECTIVES

Breast milk is a complex bioactive fluid that varies across numerous maternal and environmental conditions. Although breast-feeding is known to affect neonatal gut microbiome, the milk components responsible for this effect are not well-characterized. Given the wide range of immunological activity breast milk cytokines engage in, we investigated 3 essential breast milk cytokines and their association with early life gut microbiota.

METHODS

A total of 52 maternal-child pairs were drawn from a racially diverse birth cohort based in Detroit, Michigan. Breast milk and neonatal stool specimens were collected at 1-month postpartum. Breast milk transforming growth factor (TGF)β1, TGFβ2, and IL-10 were assayed using enzyme-linked immunosorbent assays, whereas neonatal gut microbiome was profiled using 16S rRNA sequencing.

RESULTS

Individually, immunomodulators TGFβ1 and TGFβ2 were significantly associated with neonatal gut microbial composition (R = 0.024, P = 0.041; R = 0.026, P = 0.012, respectively) and increased richness, evenness, and diversity, but IL-10 was not. The effects of TGFβ1 and TGFβ2, however, were not independent of one another, and the effect of TGFβ2 was stronger than that of TGFβ1. Higher levels of TGFβ2 were associated with the increased relative abundance of several bacteria, including members of Streptococcaceae and Ruminococcaceae, and lower relative abundance of distinct Staphylococcaceae taxa.

CONCLUSIONS

Breast milk TGFβ concentration explains a portion of variability in gut bacterial microbiota composition among breast-fed neonates. Whether TGFβ acts in isolation or jointly with other bioactive components to alter bacterial composition requires further investigation. These findings contribute to an increased understanding of how breast-feeding affects the gut microbiome-and potentially immune development-in early life.

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.

Maternal History of Childhood Abuse and Risk of Asthma and Allergy in 2-Year-Old Children

OBJECTIVES

Exposure to child abuse (CA) is associated with an increased risk of developing asthma and allergies; it is unknown if that risk is present across generations. This study investigated if 2-year-old children born to mothers with a history of CA were at an increased risk of receiving a diagnosis of asthma or allergies.

METHODS

Data from 1,551 participants were collected as part of the All Our Babies (AOB) study, a prospective pregnancy cohort. During pregnancy, each woman provided information about her own history of CA, and at 24 months postpartum, she provided information about her child's medical diagnoses. Symptoms of maternal depression and anxiety were assessed during pregnancy and at 24 months postpartum.

RESULTS

Unadjusted models showed that compared to children born to mothers without a history of CA, 2-year-old children born to mothers with a history of CA were more likely to have had a diagnosis of asthma (7.4% vs 4.2%, p = .016) or allergy (15.6% vs 9.2%, p < .001). Maternal symptoms of depression assessed in late pregnancy and symptoms of depression and anxiety at 24 months postpartum were significant mediators of the relationship between maternal CA and 2-year-old asthma diagnosis. Maternal symptoms of depression and anxiety assessed in late pregnancy were also significant mediators of the relationship between maternal CA and 2-year-old allergy diagnosis.

CONCLUSIONS

The results indicate that maternal exposure to CA is associated with increased risk of asthma and allergy in their 2-year-old children; symptoms of maternal depression and anxiety were identified as pathways linking the variables.

Nutrition and Allergic Diseases

The development of IgE-mediated allergic diseases is influenced by many factors, including genetic and environmental factors such as pollution and farming, but also by nutrition. In the last decade, substantial progress has been made in our understanding of the impact that nutrition can have on allergic diseases. Many studies have addressed the effect of breastfeeding, pre-, pro- and synbiotics, vitamins and minerals, fiber, fruit and vegetables, cow's milk, and n-3 fatty acids, on the development of allergies. In addition, nutrition can also have indirect effects on allergic sensitization. This includes the diet of pregnant and breastfeeding women, which influences intrauterine development, as well as breastmilk composition. These include the diet of pregnant and breastfeeding women that influences intrauterine development as well as breastmilk composition, effects of food processing that may enhance allergenicity of foods, and effects via modulation of the intestinal microbiota and their metabolites. This editorial review provides a brief overview of recent developments related to nutrition and the development and management of allergic diseases.

Duration of exclusive breastfeeding and wheezing in the first year of life: A longitudinal study

INTRODUCTION

Wheezing is the most common symptom associated with asthma in young children. There is a lack of well-designed prospective studies on the relationship of exclusive breastfeeding with wheezing in infants. This prospective cohort study investigated whether a relationship exists of exclusive breastfeeding with wheezing at 12 months of age.

MATERIALS AND METHODS

A series of 1632 mother-infant pairs were sequentially recruited. Mothers were trained at hospital on breastfeeding practices and how to recognise wheezing. At hospital discharge they received a calendar-diary to record the date at stopping breastfeeding and at onset of wheezing. Data were collected by telephone interviews through 12 months post-delivery. Breastfeeding was in accordance with the World Health Organisation and wheezing with the International Classification of Diseases (ICD-10-CM code R06.2).

RESULTS

At 12 months 1522 mother-infant pairs were participating. Breastfeeding started in 95.9% of them and was exclusive in 86.1%. The incidence of wheezing ever and recurrent wheezing at 12 months of age was 33.7% and 10.0%, respectively. Duration of exclusive breastfeeding was shorter in wheezing than non-wheezing infants (median 2.6 months vs. 4.1 months, P<0.001). After adjustment for confounders each month of exclusive breastfeeding reduced the risk of wheezing ever by 11% and of recurrent wheezing by 15%, at 12 months of age.

CONCLUSION

Longer duration of exclusive breastfeeding reduces the risk of wheezing throughout the first 12 months of life. These findings would be relevant to all healthcare operators and mothers, also to improve their awareness about the best feeding practices for the infant's health.

Mode of Delivery and Asthma at School Age in 9 European Birth Cohorts

Evidence on the association between mode of delivery and asthma at school age is inconclusive. We assessed the associations between specific modes of delivery and asthma in children from 9 European birth cohorts that enrolled participants between 1996 and 2006. Cohort-specific crude and adjusted risk ratios for asthma at ages 5-9 years were calculated using Poisson regression models and pooled. A sensitivity analysis was carried out in children born at term to reduce confounding due to perinatal factors. The study included 67,613 participants. Cohort-specific rates of cesarean delivery varied from 9.4% to 37.5%. Cesarean delivery, as opposed to vaginal delivery, was associated with an increased risk of asthma (adjusted risk ratio (aRR) = 1.22, 95% confidence interval (CI): 1.02, 1.46). Compared with spontaneous vaginal delivery, the adjusted risk ratio was 1.33 (95% CI: 1.02, 1.75) for elective cesarean delivery, 1.07 (95% CI: 0.94, 1.22) for emergency cesarean delivery, and 0.97 (95% CI: 0.84, 1.12) for operative vaginal delivery. In children born at term, the associations were strengthened only for elective cesarean delivery (aRR = 1.49, 95% CI: 1.13, 1.97). The large sample size allowed analysis of the associations between specific modes of delivery and asthma at school age. The increased risk of asthma associated with elective cesarean delivery, especially among children born at term, is relevant in counteracting the increasing use of this procedure, which is often performed without a clear medical indication.

Specific oral tolerance induction in childhood

Food allergy continues to be a significant public health concern for which there are no approved treatments and management strategies primarily include allergen avoidance and pharmacological measures for accidental exposures. Food allergy is thought to result from either a failure to establish oral tolerance or the breakdown of existing oral tolerance, and therefore, experimental preventative and treatment strategies are now aimed at inducing specific oral tolerance. This may occur in infancy prior to the development of food allergy through the optimal timing of dietary exposure (primary oral tolerance induction) or as a treatment for established food allergy through oral immunotherapy (secondary oral tolerance induction). Trials examining the effectiveness of early dietary allergen exposure to prevent food allergy have yielded promising results for peanut allergy but not so for other allergens, although the results of several trials are yet to be published. Although infant feeding guidelines no longer advise to avoid allergenic foods and exposure to food allergens orally is an important step in inducing food tolerance by the immune system, evidence regarding the optimal timing, dose and form of these foods into the infant's diet is lacking. Likewise, oral immunotherapy trials appear promising for inducing desensitization; however, the long-term efficacy in achieving sustained desensitization and optimal protocols to achieve this is unknown. More research is needed in this emerging field.

Serum fatty acids in infants, reflecting family fish consumption, were inversely associated with allergy development but not related to farm residence

AIM

In this study, differences in serum fatty acid patterns between farm and nonfarm infants were investigated and related to subsequent allergy development. We also related allergy-related serum fatty acids to maternal diet and breast milk fatty acids.

METHODS

The FARMFLORA birth cohort included 28 farm and 37 nonfarm infants. Serum was obtained from 21 farm infants and 29 controls at four months post-partum and analysed for phospholipid fatty acids. Allergy was diagnosed by paediatricians at three years of age.

RESULTS

Serum fatty acid patterns were similar in farm and control infants, although farm infants had lower 18:1 omega-7 proportions. Serum proportions of eicosapentaenoic acid (EPA) were unrelated to farming status, but lower in children who subsequently developed allergy, with an odds ratio of 0.47 and 95% confidence interval of 0.27-0.83 (p = 0.01) for every 0.1% EPA increase. The infants' serum EPA proportions correlated with breast milk EPA proportions, which, in turn, correlated with maternal oily fish intake during lactation.

CONCLUSION

The allergy-protective effect of farming was not linked to infant serum fatty acid composition. However, healthy infants had higher proportions of EPA in their sera, probably reflecting a family diet rich in fish, compared to subsequently allergic children.

Colostrum and Mature Human Milk of Women from London, Moscow, and Verona: Determinants of Immune Composition

Cytokines and growth factors in colostrum and mature milk may play an important role in infant immune maturation, and may vary significantly between populations. We aimed to examine associations between environmental and maternal factors, and human milk (HM) cytokine and growth factor levels. We recruited 398 pregnant/lactating women in the United Kingdom, Russia, and Italy. Participants underwent skin prick testing, questionnaire interview, and colostrum and mature milk sampling. HM cytokine and growth factor levels were quantified by electro-chemiluminescence. We found significant geographical variation in growth factor levels, but no evidence of variation between sites in cytokine detectability. There was an inverse correlation between time of milk sampling and growth factor levels in colostrum for Hepatocyte Growth Factor (HGF) and TGFβ1 and TGFβ3, but not TGFβ2, and levels were significantly higher in colostrum than mature milk for all growth factors. The kinetics of decline were different for each growth factor. Cytokines were present at much lower levels than growth factors, and the decline over time was less consistent. HM growth factors and cytokine levels vary between populations for unknown reasons. Levels of HM mediators decline at different rates postpartum, and these findings suggest specific biological roles for HM growth factors and cytokines in early postnatal development.

High levels of omega-3 fatty acids in milk from omega-3 fatty acid-supplemented mothers are related to less immunoglobulin E-associated disease in infancy

AIM

We previously reported a protective effect of maternal omega-3 fatty acid supplements on the development of immunoglobulin E (IgE)-associated disease in infancy. This study assessed omega-3 long-chain polyunsaturated fatty acids (LCPUFA) in maternal milk in relation to omega-3 LCPUFA supplementation and the development of allergic disease in their infants.

METHODS

This study randomised 95 pregnant women at risk of having an allergic infant, to daily supplements of 2.6 g omega-3 LCPUFA or a placebo of 2.7 g soya bean oil from gestational week 25 until 3 months of lactation. Breast milk samples were collected as colostrum, at one and 3 months. Milk fatty acids were related to allergic outcome in the infants at 24 months.

RESULTS

Omega-3 milk fatty acids were higher in women who received omega-3 supplements than the placebo group (p < 0.01). Higher proportions of milk eicosapentaenoic acid and docosahexaenoic acid and a lower arachidonic/eicosapentaenoic acid ratio were associated with an absence of IgE-associated disease in the infants. None of the children developed IgE-associated atopic eczema above a level of 0.83 mol% eicosapentaenoic acid in colostrum. [Correction added on 7 July 2016, after online publication: In the preceding sentence, the correct word should be "above" instead of "below" and this has been amended in this current version.] CONCLUSION: High omega-3 LCPUFA milk levels in mothers who received omega-3 LCPUFA supplements were related to fewer allergies in their children.

Breastfeeding and timing of first dietary introduction in relation to childhood asthma, allergies, and airway diseases: A cross-sectional study

OBJECTIVES

We investigated associations of breastfeeding (BF) durations and patterns and of timing of other dietary introductions with prevalence of asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema among preschool children.

METHODS

During April 2011-April 2012, we conducted a cross-sectional study in 72 kindergartens from five districts of Shanghai, China and obtained 13,335 questionnaires of children 4-6-years-old. We used multiple logistic regression models to evaluate the target associations.

RESULTS

Compared to children who were never BF, children who were exclusively breastfed 3-6 months had the lowest risk of asthma (adjusted odds ratio and 95% confidence interval: 0.81, 0.72-0.91) and wheeze (0.93, 0.87-0.99); and exclusive BF >6 months was significantly associated with a reduced risk of hay fever (0.93, 0.89-0.97), rhinitis (0.97, 0.94-0.99), pneumonia (0.97, 0.94-0.99), and eczema (0.96, 0.93-0.99). No significant associations were found between time when fruits or vegetables were introduced and the studied diseases. Associations were independent of the child's sex and parent's ownership of the current residence. Longer duration BF was only significantly protective when there was no family history of atopy.

CONCLUSIONS

This study suggests that heredity, but not sex and socioeconomic status, may negatively impact the effect of BF on childhood airway and allergic diseases. Our findings support China's national recommendation that mothers provide exclusive BF for the first four months, and continue partial BF for more than 6 months.

Microbiome and its impact on gastrointestinal atopy

The prevalence of allergic conditions has continuously increased in the last few decades in Westernized countries. A dysbiotic gut microbiome may play an important role in the development of allergic diseases. Genetic, environmental, and dietary factors may alter the commensal microbiota leading to inflammatory dysregulation of homeostasis. Murine and human studies have begun to elucidate the role of the microbiota in the pathogenesis of atopic diseases including asthma, atopic dermatitis, and food allergies. However, the role of the microbiome in most eosinophilic gastrointestinal diseases (EGIDs) is not yet known. This review provides an overview of what is currently known about the development of tolerance from both molecular and clinical standpoints. We also look at the gut-specific microbiome and its role in atopic conditions with the hope of applying this knowledge to the understanding, prevention, and treatment of EGIDs, particularly EoE.

Developments in the field of allergy in 2014 through the eyes of Clinical and Experimental Allergy

The pathogenesis of asthma continues to be a major topic of interest to our authors with reviews and original papers on the role of viruses, mechanisms of inflammation, biomarkers, and phenotypes of asthma being major topics. A number of papers described new treatments for asthma focusing on blocking the Th2 response reflecting the fact that two decades of work in this area is finally bearing fruit. The pathogenesis of chronic rhinosinusitis is a growing area of interest, but there has been less on the genetics of airways disease than in previous years possibly reflecting the degree of rigour (and therefore a smaller body of work), with which these sorts of studies are now being undertaken. There continues to be a wide range of papers dealing with mechanisms of allergic disease ranging from clinical-based studies to basic research and the use of in vivo animal models especially mice. As before, mechanisms and new approaches to immunotherapy are common themes. Several were published in the allergens section investigating modification of allergens to increase their effectiveness and reduce the risk of adverse events. Risk factors for allergic disease was a common theme in the epidemiology section and food allergy a common theme in clinical allergy with papers on the development of protocols to induce tolerance and attempts to find biomarkers to distinguish sensitization from allergic disease. This was another exciting year for the editors, and we hope the readers of the journal.

Early weaning is beneficial to prevent atopic dermatitis occurrence in young children

BACKGROUND

Epidemiological data on infant feeding practices and allergic diseases are controversial. The purpose of this study was to explore the association of early weaning with the occurrence of atopic dermatitis (AD).

METHODS

We conducted a matched case-control study on incident physician-diagnosed AD in early childhood including 451 cases and 451 controls. Data on several factors, including feeding practices, were collected through an interviewer-administered questionnaire. Odds ratios (OR) and the corresponding 95% confidence intervals (CIs) were estimated through logistic regression models, conditioned on study center, age, sex, and period of interview, and adjusted for potential confounders.

RESULTS

Early weaning, defined as the introduction of solid foods at 4 or 5 months of age, was inversely related to the risk of AD, with children weaned at 4 months having lower AD risk (OR = 0.41, 95% CI, 0.20-0.87) compared to those exclusively breastfed. Similar results were observed for weaning started at 5 months of age (OR = 0.39, 95% CI, 0.18-0.83). This association persisted when children with and without family history of allergy were considered separately. Prolonged partial breastfeeding (breastmilk plus milk formulas) was not associated with AD. Consistently, the introduction of a high number of different solid foods reduced the risk of AD (P trend = 0.02 at 4 months of age and P trend = 0.04 at 5 months).

CONCLUSION

Our data provide evidence against the preventing role of prolonged exclusive (but not partial) breastfeeding in AD occurrence and confirm recent results indicating a beneficial role of early weaning in AD.

The rise of food allergy: Environmental factors and emerging treatments

Food allergy has rapidly increased in prevalence, suggesting an important role for environmental factors in disease susceptibility. The immune response of food allergy is characterized by IgE production, and new findings from mouse and human studies indicate an important role of the cytokine IL-9, which is derived from both T cells and mast cells, in disease manifestations. Emerging evidence suggests that route of exposure to food, particularly peanut, is important. Exposure through the skin promotes sensitization while early exposure through the gastrointestinal tract promotes tolerance. Evidence from mouse studies indicate a role of the microbiome in development of food allergy, which is supported by correlative human studies showing a dysbiosis in food allergy. There is no approved treatment for food allergy, but emerging therapies are focused on allergen immunotherapy to provide desensitization, while pre-clinical studies are focused on using adjuvants or novel delivery approaches to improve efficacy and safety of immunotherapy.

•

Emerging evidence suggests that route of exposure to food allergens in early life determines sensitization versus tolerance.

•

The microbiota and dietary factors appear to play a key role in susceptibility to food allergy.

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Immunotherapy applied via different routes is currently the most promising form of experimental treatment for food allergy.

Working group reports: evaluation of the evidence to support practice guidelines for nutritional care of preterm infants-the Pre-B Project

The "Evaluation of the Evidence to Support Practice Guidelines for the Nutritional Care of Preterm Infants: The Pre-B Project" is the first phase in a process to present the current state of knowledge and to support the development of evidence-informed guidance for the nutritional care of preterm and high-risk newborn infants. The future systematic reviews that will ultimately provide the underpinning for guideline development will be conducted by the Academy of Nutrition and Dietetics' Evidence Analysis Library (EAL). To accomplish the objectives of this first phase, the Pre-B Project organizers established 4 working groups (WGs) to address the following themes: 1) nutrient specifications for preterm infants, 2) clinical and practical issues in enteral feeding of preterm infants, 3) gastrointestinal and surgical issues, and 4) current standards of infant feeding. Each WG was asked to 1) develop a series of topics relevant to their respective themes, 2) identify questions for which there is sufficient evidence to support a systematic review process conducted by the EAL, and 3) develop a research agenda to address priority gaps in our understanding of the role of nutrition in health and development of preterm/neonatal intensive care unit infants. This article is a summary of the reports from the 4 Pre-B WGs.

Associations of Early Life Exposures and Environmental Factors With Asthma Among Children in Rural and Urban Areas of Guangdong, China

BACKGROUND

Environmental factors may play important roles in asthma, but findings have been inconsistent.

OBJECTIVE

The goal of this study was to determine the associations between early life exposures, environmental factors, and asthma in urban and rural children in southeast China.

METHODS

A screening questionnaire survey was conducted in 7,164 children from urban Guangzhou and 6,087 from rural Conghua. In the second stage, subsamples of 854 children (419 from Guangzhou, 435 from Conghua) were recruited for a case-control study that included a detailed questionnaire enquiring on family history, early life environmental exposures, dietary habits, and laboratory tests (including histamine airway provocation testing, skin prick tests, and serum antibody analyses). House dust samples from 76 Guangzhou families and 80 Conghua families were obtained to analyze levels of endotoxins, house dust mites, and cockroach allergens.

RESULTS

According to the screening survey, the prevalence of physician-diagnosed asthma was lower in children from Conghua (3.4%) than in those from Guangzhou (6.9%) (P < .001). A lower percentage of asthma was reported in rural subjects compared with urban subjects (2.8% vs. 29.4%; P < .001) in the case-control study. Atopy (OR, 1.91 [95% CI, 1.58-2.29]), parental atopy (OR, 2.49 [95% CI, 1.55-4.01]), hospitalization before 3 years of age (OR, 2.54 [95% CI, 1.37-4.70]), high consumption of milk products (OR, 1.68 [95% CI, 1.03-2.73]), and dust Dermatophagoides farinae group 1 allergen (OR, 1.71 [95% CI, 1.34-2.19]) were positively associated with asthma. Living in a crop-farming family at < 1 year of age (OR, 0.15 [95% CI, 0.08-0.32]) and dust endotoxin levels (OR, 0.69 [95% CI, 0.50-0.95]) were negatively associated with asthma.

CONCLUSIONS

Rural children from an agricultural background exhibited a reduced risk of asthma. Early life exposure to crop farming and high environmental endotoxin levels might protect the children from asthma in southern China.

Human Breast Milk miRNA, Maternal Probiotic Supplementation and Atopic Dermatitis in Offspring

Background

Perinatal probiotic ingestion has been shown to prevent atopic dermatitis (AD) in infancy in a number of randomised trials. The Probiotics in the Prevention of Allergy among Children in Trondheim (ProPACT) trial involved a probiotic supplementation regime given solely to mothers in the perinatal period and demonstrated a ~40% relative risk reduction in the cumulative incidence of AD at 2 years of age. However, the mechanisms behind this effect are incompletely understood. Micro-RNAs (miRNA) are abundant in mammalian milk and may influence the developing gastrointestinal and immune systems of newborn infants. The objectives of this study were to describe the miRNA profile of human breast milk, and to investigate breast milk miRNAs as possible mediators of the observed preventative effect of probiotics.

Methods

Small RNA sequencing was conducted on samples collected 3 months postpartum from 54 women participating in the ProPACT trial. Differential expression of miRNA was assessed for the probiotic vs placebo and AD vs non-AD groups. The results were further analysed using functional prediction techniques.

Results

Human breast milk samples contain a relatively stable core group of highly expressed miRNAs, including miR-148a-3p, miR-22-3p, miR-30d-5p, let-7b-5p and miR-200a-3p. Functional analysis of these miRNAs revealed enrichment in a broad range of biological processes and molecular functions. Although several miRNAs were found to be differentially expressed on comparison of the probiotic vs placebo and AD vs non-AD groups, none had an acceptable false discovery rate and their biological significance in the development of AD is not immediately apparent from their predicted functional consequences.

Conclusion

Whilst breast milk miRNAs have the potential to be active in a diverse range of tissues and biological process, individual miRNAs in breast milk 3 months postpartum are unlikely to play a major role in the prevention of atopic dermatitis in infancy by probiotics ingestion in the perinatal period.

Trial Registration

ClinicalTrials.gov NCT00159523