Diet during pregnancy and infancy and risk of allergic or autoimmune disease: A systematic review and meta-analysis

PLoS Medicine

Feb 2018

DOI: 10.1371/journal.pmed.1002507

Citations:220

Influential Citations:15

Systematic Reviews / Meta-Analyses

Enhanced Details

Methods

Systematic review and meta-analysis of observational and interventional studies on maternal/infant diet and risk of allergic or autoimmune disease. Included randomized controlled trials (RCTs) and controlled clinical trials (CCTs), and observational cohorts with case-control or cross-sectional designs. Participants included pregnant women during pregnancy or lactation and their offspring from birth through childhood.

Intervention

Probiotic: Lactobacillus rhamnosus; 1-10 billion CFU per day; orally; started around 36–38 weeks gestation and continued through the first 3–6 months of lactation. Omega-3 polyunsaturated fatty acids (fish oil) during pregnancy and lactation; dosage varied across trials; one trial used dietary advice to consume at least 2 servings per week of low-mercury oily fish (e.g., farmed salmon).

Results

Probiotic supplementation during late pregnancy and lactation is associated with a reduced risk of eczema in offspring (RR 0.78; 95% CI 0.68–0.90; absolute risk reduction 44 per 1,000; I2 = 61%). Omega-3 fatty acid (fish oil) supplementation during pregnancy and lactation is associated with reduced allergic sensitisation to egg at 1 year (RR 0.69; 95% CI 0.53–0.90; I2 = 15%); pregnancy-only supplementation showed a stronger effect for egg sensitisation (RR 0.55; 95% CI 0.40–0.76; I2 = 0%), and reduced peanut sensitisation (RR 0.62; 95% CI 0.40–0.96; I2 = 0%). No autoimmune outcomes were reported for these interventions. Some multifaceted interventions and longer breastfeeding duration showed weaker or uncertain effects on other allergic outcomes; overall, maternal diet during pregnancy and lactation may influence child immune development, with probiotics and fish oil showing the most robust perinatal effects.

Limitations

High risk of bias in many studies; substantial heterogeneity in exposures and outcome definitions; potential publication bias in observational analyses; inclusion of abstract-only publications; data not uniformly updated beyond 2017; inconsistent reporting of dosages across probiotic and fish-oil trials; no autoimmune outcomes consistently reported for probiotics or fish oil.

Abstract

Background There is uncertainty about the influence of diet during pregnancy and infancy on a child’s immune development. We assessed whether variations in maternal or infant diet can influence risk of allergic or autoimmune disease. Methods and findings Two authors selected studies, extracted data, and assessed risk of bias. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess certainty of findings. We searched Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica dataBASE (EMBASE), Web of Science, Central Register of Controlled Trials (CENTRAL), and Literatura Latino Americana em Ciências da Saúde (LILACS) between January 1946 and July 2013 for observational studies and until December 2017 for intervention studies that evaluated the relationship between diet during pregnancy, lactation, or the first year of life and future risk of allergic or autoimmune disease. We identified 260 original studies (964,143 participants) of milk feeding, including 1 intervention trial of breastfeeding promotion, and 173 original studies (542,672 participants) of other maternal or infant dietary exposures, including 80 trials of maternal (n = 26), infant (n = 32), or combined (n = 22) interventions. Risk of bias was high in 125 (48%) milk feeding studies and 44 (25%) studies of other dietary exposures. Evidence from 19 intervention trials suggests that oral supplementation with nonpathogenic micro-organisms (probiotics) during late pregnancy and lactation may reduce risk of eczema (Risk Ratio [RR] 0.78; 95% CI 0.68–0.90; I2 = 61%; Absolute Risk Reduction 44 cases per 1,000; 95% CI 20–64), and 6 trials suggest that fish oil supplementation during pregnancy and lactation may reduce risk of allergic sensitisation to egg (RR 0.69, 95% CI 0.53–0.90; I2 = 15%; Absolute Risk Reduction 31 cases per 1,000; 95% CI 10–47). GRADE certainty of these findings was moderate. We found weaker support for the hypotheses that breastfeeding promotion reduces risk of eczema during infancy (1 intervention trial), that longer exclusive breastfeeding is associated with reduced type 1 diabetes mellitus (28 observational studies), and that probiotics reduce risk of allergic sensitisation to cow’s milk (9 intervention trials), where GRADE certainty of findings was low. We did not find that other dietary exposures—including prebiotic supplements, maternal allergenic food avoidance, and vitamin, mineral, fruit, and vegetable intake—influence risk of allergic or autoimmune disease. For many dietary exposures, data were inconclusive or inconsistent, such that we were unable to exclude the possibility of important beneficial or harmful effects. In this comprehensive systematic review, we were not able to include more recent observational studies or verify data via direct contact with authors, and we did not evaluate measures of food diversity during infancy. Conclusions Our findings support a relationship between maternal diet and risk of immune-mediated diseases in the child. Maternal probiotic and fish oil supplementation may reduce risk of eczema and allergic sensitisation to food, respectively. show less