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

Impact of Climate Change on Dietary Nutritional Quality and Implications for Asthma and Allergy

Asthma and allergic disorders are common in childhood with genetic and environmental determinants of disease that include prenatal nutritional exposures such as long-chain polyunsaturated fatty acids and antioxidants. Global climate change is implicated in asthma and allergic disorder morbidity with potential mechanisms including perturbations of ecosystems. There is support that environmental and climatic changes such as increasing global temperate and carbon dioxide levels affect aquatic and agricultural ecosystems with subsequent alterations in long-chain polyunsaturated fatty acid availability and nutrient quality and antioxidant capacity of certain crops, respectively. This article discusses asthma epidemiology and the influence of global climate change.

Associations between child filaggrin mutations and maternal diet with the development of allergic diseases in children

BACKGROUND

Filaggrin (FLG) loss-of-function mutations in children and maternal diet in pregnancy have been implicated in child allergy outcomes. This paper studies the questions: "do FLG mutations modify the effect of maternal diet on the odds of development of allergic diseases?" and "which factor leads to the highest rate of diagnosis allergic diseases over time, maternal diet, or FLG mutations?".

METHODS

Exact logistic regressions studied effect modification. Cox proportional hazard models compared the rate of allergic disease development in three groups (N = 624): (1) children with FLG mutation, (2) children without FLG mutation whose mothers did not eat an allergy preventive diet, and (3) children without FLG mutation whose mothers ate an allergy preventive diet. Maternal diet was classified using a validated index.

RESULTS

Cox models showed the development of atopic dermatitis, asthma, and wheeze was significantly higher for children in group 1 versus 3 (HR = 2.40 [1.32, 4.37], HR = 2.29 [1.05, 4.97], and HR 2.10 [1.004, 4.38], respectively), but not significantly higher for children in group 1 versus 2 (HR = 1.30 [0.74, 2.29], HR = 1.27 [0.61, 2.63], and HR = 1.29 [0.65, 2.58], respectively). Development of allergic rhinitis was significantly higher for group 1 versus 2 and 3 (1 vs. 2: HR = 2.29 [1.10, 4.76]; 1 vs. 3: HR = 3.21 [1.46, 7.08]). There was no significant effect modification for any outcome.

CONCLUSION

Children with FLG mutation had similar risk of atopic dermatitis, asthma, and wheeze as children without an FLG mutation whose mothers did not eat an allergy preventive diet during pregnancy. Child FLG mutation did not modify the effect of maternal diet. The results suggest that maternal diet in pregnancy, a modifiable risk factor, could be a target for preventive interventions.

Maternal active asthma in pregnancy influences associations between polyunsaturated fatty acid intake and child asthma

BACKGROUND

Studies evaluating effects of prenatal polyunsaturated fatty acid (PUFA) intake on childhood asthma reveal mixed results. Inconsistencies may result from not accounting for important modifying factors such as maternal asthma or child sex.

OBJECTIVE

To evaluate whether associations between prenatal PUFA intake and childhood asthma are modified by prenatal active maternal asthma or child sex in 412 mother-child dyads.

METHODS

Energy-adjusted prenatal dietary and supplement intakes of omega-3 (n-3) and omega-6 (n-6) PUFAs were estimated using the Block98 Food Frequency Questionnaire, administered during pregnancy. Mothers reported asthma in children followed prospectively to 4.0 plus or minus 1.7 years. Generalized additive models with smooth terms for PUFA (n-3, n-6, n-6/n-3 ratio) effects were used to investigate associations between PUFAs and child asthma, without prespecifying the form of these relationships, including effect modification by active maternal asthma or child sex.

RESULTS

Among mothers (40% Black, 31% Hispanic), 22% had active asthma in pregnancy; 17.5% of children developed asthma. Lower maternal n-3 PUFA intake was significantly associated with risk of childhood asthma (P = .03), in particular among children of mothers with active asthma and low n-3 PUFA intake (P = .01). This inverse association was more apparent in girls (P = .01) compared with boys (P = .30), regardless of maternal asthma status. For n-6 PUFA and the n-6/n-3 ratio, there was a lower risk of childhood asthma in the midrange of intake and increased risk at higher intake (n-6 PUFA P = .10, n-6/n-3 ratio P = .13).

CONCLUSION

Consideration of factors that modify effects of prenatal PUFA intake on childhood asthma has implications for designing intervention strategies tailored to impact those at greatest risk.

Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

Association of Maternal Prepregnancy Weight and Gestational Weight Gain With Children's Allergic Diseases

IMPORTANCE

Information on the association between maternal prepregnancy body weight, gestational weight change, and childhood allergies is not consistent. Little is known on whether there is a combined association with comprehensive childhood allergies.

OBJECTIVE

To examine the association of maternal prepregnancy body mass index and gestational weight gain (GWG) with the risk of childhood allergic diseases including asthma and/or wheezing, allergic rhinitis, eczema, and food and/or drug allergy.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted from April 12 to June 1, 2019, using the Shanghai Children Allergy Study (SCAS), a large, population-based survey. A multistage and multistrata sampling approach was applied to conduct the survey in 13 districts across Shanghai, China, with an enrollment of 15 145 mother-child pairs.

EXPOSURES

Reported maternal weight before pregnancy and at the time of delivery were requested in the survey; GWG was examined in absolute terms and with reference to the Institute of Medicine guideline.

MAIN OUTCOMES AND MEASURES

The ascertainment of allergic diseases was based on the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

Among 15 145 children aged 3 to 14 years (7911 [52.2%] boys) within the SCAS, 8877 children (58.6%) were screened for allergic diseases. Multivariable log-binomial regression models suggested that excessive GWG was associated with risks of 19% for asthma/wheezing, 11% for allergic rhinitis, and 10% for eczema in the children. Gestational weight gain extremely above the Institute of Medicine guideline in women who were overweight/obese before pregnancy was associated with the highest risk of childhood asthma/wheezing (adjusted prevalence ratio, 1.42; 95% CI, 1.16-1.74; P = .001), allergic rhinitis (adjusted prevalence ratio, 1.32; 95% CI, 1.12-1.56; P = .001), and eczema (adjusted prevalence ratio, 1.24; 95% CI, 1.08-1.41; P = .002). Gestational weight gain below the Institute of Medicine guideline was associated with an attenuated risk of 13% for childhood asthma/wheezing, 11% for allergic rhinitis, 14% for eczema, and 15% food/drug allergy when mothers were of prepregnancy normal weight; similar associations were observed in underweight mothers, but there was no association in overweight mothers. Generally, the associations were similar in the stratified analysis according to children's age group. Moreover, the results were similar in the allergen test subgroup.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that excessive GWG may be a risk factor for childhood allergic diseases. Further studies on the long-term effects of the intrauterine environment on children's health may take maternal weight management during pregnancy into consideration since GWG could be a controllable and modifiable risk factor.

Maternal dietary inflammatory potential and quality are associated with offspring asthma risk over 10-year follow-up: the Lifeways Cross-Generation Cohort Study

BACKGROUND

Asthma is the most common childhood chronic health condition. Maternal antenatal diet has been associated with offspring asthma risk, but studies investigating maternal whole diet quality and inflammatory potential with long-term offspring follow-up (>5 y) are rare.

OBJECTIVES

We aimed to elucidate these associations in a prospective cohort study in Ireland.

METHODS

Early pregnancy diets were assessed using a validated FFQ from which energy-adjusted Dietary Inflammatory Index (E-DII) and Healthy Eating Index (HEI)-2015 scores were computed. Doctor-diagnosed offspring asthma status (general practitioner or parent reports) for the first 10 y of life was collected at 3-y, 5-y, and 9-y follow-up. A total of 862 mother-child pairs with information on maternal diet and ≥1 offspring asthma data points were included. The longitudinal associations between maternal E-DII and HEI scores and offspring asthma status were assessed using generalized estimating equations.

RESULTS

Cumulative offspring asthma incidence was 21% over the 10-y period. In the main models, adjusted for maternal lifestyle and sociodemographic factors, a higher E-DII score, indicating a more proinflammatory diet, was associated with higher risk of offspring asthma (OR: 1.35; 95% CI: 1.10, 1.65; per 1-SD score increment), whereas a higher HEI-2015 score, indicating better dietary quality, was associated with lower risk (OR: 0.77; 95% CI: 0.64, 0.93) (both P < 0.01). Results persisted with further adjustment for childhood factors (e.g., breastfeeding, diet, and childcare attendance) and parental asthma history. Similar associations were observed when E-DII and HEI-2015 scores were modeled in quartiles (both P-trend < 0.05). Associations for HEI-2015 were attenuated after adjustment for E-DII, suggesting the importance of anti-inflammatory pathways.

CONCLUSIONS

Our results suggest that a proinflammatory and low-quality diet during pregnancy is associated with a higher risk of offspring asthma. Pending confirmation from other studies, optimizing these aspects of maternal diet can be a promising strategy for reducing childhood asthma risk. This prospective observational study was registered at the ISRCTN Registry as ISRCTN16537904.

Effect of omega-3 fatty acids supplementation during childhood in preventing allergic disease: a systematic review and Meta-Analysis

BACKGROUND

Early omega-3 fatty acids exposure can influence early immune development and potentially prevent allergic disease.

OBJECTIVES

To review the effects of omega-3 fatty acids during childhood on allergic disease outcomes.

METHODS

We conducted searches of the PubMed, EMBASE and Cochrane Central Register of Controlled Trials and international trial registers (ClinicalTrials.gov and ISRCTN Registry) to September 30, 2018. We included randomized controlled trials (RCTs) and prospective cohort studies regarding the effect of omega-3 fatty acids during childhood on allergic disease outcomes. A total of 8 publications from 2 prospective cohort studies and 6 reports representing 5 unique RCTs were included.

RESULTS

The results of meta-analysis showed that omega-3 fatty acids during childhood did not appear to significantly alter the risk of any atopy (≤3 years old: RR 0.70, 95% CI 0.47 to 1.04, p = 0.08; > 3 years old: RR 0.98, 95% CI 0.82 to 1.16, p = 0.77), wheeze (≤3 years old: RR 0.82, 95% CI 0.54 to 1.26, p = 0.375; > 3 years old: RR 1.03, 95% CI 0.53 to 2.00, p = 0.929) and eczema (≤3 years old: RR 0.86, 95% CI 0.68 to 1.08, p = 0.20; > 3 years old: RR 0.90, 95% CI 0.60 to 1.35, p = 0.60).

CONCLUSIONS

There is limited evidence to support omega-3 fatty acids during childhood could reduce the risk of allergic disease.

Prenatal polyunsaturated fatty acids and child asthma: Effect modification by maternal asthma and child sex

BACKGROUND

Findings on prenatal polyunsaturated fatty acid (PUFA) intake and child wheeze and asthma have been inconsistent.

OBJECTIVE

We sought to examine associations between prenatal PUFA status and child wheeze/asthma and modifying effects of maternal asthma/atopy, child sex, and maternal race.

METHODS

Analyses included 1019 mother-child dyads with omega-3 (n-3) and omega-3 (n-6) PUFAs measured in second-trimester plasma; n-6/n-3 ratios were calculated. Child wheeze/asthma outcomes ascertained at age 4 to 6 years included ever physician-diagnosed asthma, current wheeze (symptoms past 12 months), current asthma (diagnosis and medication and/or symptoms past 12 months), and current diagnosed asthma. Each PUFA indicator and outcome was analyzed in separate models using modified Poisson regression with interaction terms.

RESULTS

In quartile (Q) analyses, higher n-6 PUFAs were associated with increased risk of ever (risk ratio [RR] high vs low [RR Q4 vs Q1], 1.70; 95% CI, 1.07-2.71) and current (RR Q4 vs Q1, 1.70; 95% CI, 1.07-2.71) diagnosed asthma, whereas n-3 PUFAs were associated with lower risk (RR Q4 vs Q1, 0.59; 95% CI, 0.33-1.03) of current diagnosed asthma (P_trend < .05 for all). Higher n-6 PUFAs were associated with a higher risk of all respiratory outcomes among children born to women with asthma (P_interaction < .05 for all outcomes). A significant 3-way interaction between child sex, maternal asthma, and n-6/n-3 PUFA indicated that male children born to women with asthma and a higher ratio had the highest risk across wheeze/asthma outcomes (P_interaction < .05).

CONCLUSIONS

Associations between prenatal PUFA status and childhood wheeze/asthma were modified by maternal history of asthma and child sex.

Prenatal oxidative balance and risk of asthma and allergic disease in adolescence

BACKGROUND

Fetal oxidative balance (achieved when protective prenatal factors counteract sources of oxidative stress) might be critical for preventing asthma and allergic disease.

OBJECTIVE

We examined prenatal intakes of hypothesized protective nutrients (including antioxidants) in conjunction with potential sources of oxidative stress in models of adolescent asthma and allergic disease.

METHODS

We used data from 996 mother-child pairs in Project Viva. Exposures of interest were maternal prepregnancy body mass index and prenatal nutrients (energy-adjusted intakes of vitamins D, C, and E; β-carotene; folate; choline; and n-3 and n-6 polyunsaturated fatty acids [PUFAs]), air pollutant exposures (residence-specific third-trimester black carbon or particulate matter with a diameter of less than 2.5 μm [PM_2.5]), acetaminophen, and smoking. Outcomes were offspring's current asthma, allergic rhinitis, and allergen sensitization at a median age of 12.9 years. We performed logistic regression. Continuous exposures were log-transformed and modeled as z scores.

RESULTS

We observed protective associations for vitamin D (odds ratio [OR], 0.69 [95% CI, 0.53-0.89] for allergic rhinitis), the sum of the n-3 PUFAs eicosapentaenoic acid and docosahexaenoic acid (OR, 0.81 [95% CI, 0.66-0.99] for current asthma), and the n-3 PUFA α-linolenic acid (OR, 0.78 [95% CI, 0.64-0.95] for allergen sensitization and OR, 0.80 [95% CI 0.65-0.99] for current asthma). Black carbon and PM_2.5 were associated with an approximately 30% increased risk for allergen sensitization. No multiplicative interactions were observed for protective nutrient intakes with sources of oxidative stress.

CONCLUSIONS

We identified potential protective prenatal nutrients (vitamin D and n-3 PUFAs), as well as adverse prenatal pro-oxidant exposures that might alter the risk of asthma and allergic disease into adolescence.