A comprehensive systematic review of the impact of dietary factors during pregnancy on childhood atopic outcomes

Abstract

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. 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. 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 . 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.