Rationale: Allergic diseases are an increasing public health concern. Early life environments appear critical to immune development, and maternal dietary intake in pregnancy maysbe important influencing factors that could be modifiable as allergy prevention strategies. In this systematic review we focus on maternal diet in pregnancy alone and relate the amount of nutrients/food/food patterns studied to US dietary guidelines. Studies in allergen intake were excluded from this review. Methods: We have undertaken a systematic review on maternal diet, excluding food allergens, in pregnancy alone and its association with allergy outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis, food allergies) in offspring. We have searched 3 bibliographic databases (Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica dataBASE (EMBASE), Web of Science, Central Register of Controlled Trials (CENTRAL), up to February 28, 2019. The risk of bias of each study was critically appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: We identified 95 papers: 17 RCTs and 78 observational. Observational studies varied in design and dietary exposures with contradicting findings. RCTs showed that vitamin D supplementation (OR: 0.73; 95% CI: 0.56 – 0.92) may prevent wheeze/asthma and omega-3 supplementation (OR; 0.74; 95% CI: 0.59 – 0.92) may prevent allergic rhinitis in offspring; meta-analysis was based on <4 outcomes. Conclusions: No clear recommendations regarding maternal diet in pregnancy can be made at present. Vitamin D and omega-3 supplementation needs further studies. We suggest studies should focus on diet patterns/indices on allergy outcomes in the offspring, rather than single nutrients/foods.
RATIONALE: Allergic diseases are an increasing public health concern, and early life environment is critical to immune development. Maternal diet during pregnancy has been linked to offspring allergy risk. In turn, maternal diet is a potentially modifiable factor, which could be targeted as an allergy prevention strategy. In this systematic review, we focused on non-allergen-specific modifying factors of the maternal diet in pregnancy on allergy outcomes in their offspring.
METHODS: We undertook a systematic review of studies investigating the association between maternal diet during pregnancy and allergic outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis (AD), food allergies, and allergic sensitization) in offspring. Studies evaluating the effect of food allergen intake were excluded. We searched three bibliographic databases (MEDLINE, EMBASE, and Web of Science) through February 26, 2019. Evidence was critically appraised using modified versions of the Cochrane Collaboration Risk of Bias tool for intervention trials and the National Institute for Clinical Excellence methodological checklist for cohort and case-control studies and meta-analysis performed from RCTs.
RESULTS: We identified 95 papers: 17 RCTs and 78 observational (case-control, cross-sectional, and cohort) studies. Observational studies varied in design and dietary intakes and often had contradictory findings. Based on our meta-analysis, RCTs showed that vitamin D supplementation (OR: 0.72; 95% CI: 0.56-0.92) is associated with a reduced risk of wheeze/asthma. A positive trend for omega-3 fatty acids was observed for asthma/wheeze, but this did not reach statistical significance (OR: 0.70; 95% CI: 0.45-1.08). Omega-3 supplementation was also associated with a non-significant decreased risk of allergic rhinitis (OR: 0.76; 95% CI: 0.56-1.04). Neither vitamin D nor omega-3 fatty acids were associated with an altered risk of AD or food allergy.
CONCLUSIONS: Prenatal supplementation with vitamin D may have beneficial effects for prevention of asthma. Additional nutritional factors seem to be required for modulating the risk of skin and gastrointestinal outcomes. We found no consistent evidence regarding other dietary factors, perhaps due to differences in study design and host features that were not considered. While confirmatory studies are required, there is also a need for performing RCTs beyond single nutrients/foods.
Rationale: Allergic diseases are an increasing public health concern. Early life environments appear critical to immune development, and maternal dietary intake in pregnancy maysbe important influencing factors that could be modifiable as allergy prevention strategies. In this systematic review we focus on maternal diet in pregnancy alone and relate the amount of nutrients/food/food patterns studied to US dietary guidelines. Studies in allergen intake were excluded from this review. Methods: We have undertaken a systematic review on maternal diet, excluding food allergens, in pregnancy alone and its association with allergy outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis, food allergies) in offspring. We have searched 3 bibliographic databases (Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica dataBASE (EMBASE), Web of Science, Central Register of Controlled Trials (CENTRAL), up to February 28, 2019. The risk of bias of each study was critically appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: We identified 95 papers: 17 RCTs and 78 observational. Observational studies varied in design and dietary exposures with contradicting findings. RCTs showed that vitamin D supplementation (OR: 0.73; 95% CI.: 0.56 – 0.92) may prevent wheeze/asthma and omega-3 supplementation (OR; 0.74; 95% CI.: 0.59 – 0.92) may prevent allergic rhinitis in offspring; meta-analysis was based on <4 outcomes. Conclusions: No clear recommendations regarding maternal diet in pregnancy can be made at present. Vitamin D and omega-3 supplementation needs further studies. We suggest studies should focus on diet patterns/indices on allergy outcomes in the offspring, rather than single nutrients/foods.
