Date Published: February 28, 2018
Publisher: Public Library of Science
Author(s): Vanessa Garcia-Larsen, Despo Ierodiakonou, Katharine Jarrold, Sergio Cunha, Jennifer Chivinge, Zoe Robinson, Natalie Geoghegan, Alisha Ruparelia, Pooja Devani, Marialena Trivella, Jo Leonardi-Bee, Robert J. Boyle, Sanjay Basu
Abstract: BackgroundThere 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 findingsTwo 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.ConclusionsOur 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.
Partial Text: Immune-mediated health conditions such as allergic and autoimmune diseases appear to have increased in prevalence in many countries and are leading causes of chronic illness in young people . There is evidence that early dietary exposures may influence the development of these diseases, but a comprehensive analysis of the relationship between all dietary exposures during pregnancy, lactation, or the first year of life and risk of allergic or autoimmune disease has not been undertaken . Relevant dietary exposures may include intake of individual foods or food groups, nutrients or nutrient groups, dietary supplements, avoidance of specific allergenic foods, timing of introduction of specific foods or food groups to the infant diet, overall dietary pattern, and duration of breastfeeding. A recent World Allergy Organization guideline recommended probiotic and prebiotic supplements for eczema prevention [2,3], but European, North American, and Australasian guidelines do not support this [4–6]. Several guidelines recommend exclusive breastfeeding for at least 4 to 6 months to reduce risk of eczema, food allergy, and wheezing [4,5,7], and a recent Australasian guideline recommends oily fish or omega-3 fatty acid supplements during pregnancy to reduce eczema . Recent focused systematic reviews support a relationship between breastfeeding and reduced asthma risk [8,9] and between probiotics and prebiotics and reduced eczema risk [2,10,11]. In order to inform United Kingdom dietary recommendations for infants and their pregnant or lactating mothers, we undertook an updated and comprehensive systematic review of diet during pregnancy and infancy and risk of allergic sensitisation, allergic disease, or autoimmune disease.
This review is reported in accordance with PRISMA guidance. The review is part of a series of systematic reviews commissioned by the UK Food Standards Agency in order to inform UK dietary recommendations for infants and their pregnant or lactating mothers, under the title ‘Review of scientific published literature on infant feeding and development of atopic and autoimmune disease’. The protocols for the systematic reviews were registered with the International Prospective Register of Systematic Reviews (PROSPERO CRD42013003802 ‘Review A:milk feeding’; CRD42013004239 ‘Review B:timing of allergenic food introduction’; CRD42013004252 ‘Review C:maternal and infant diet’) on 5 August 2013, prior to title screening or selecting any studies from the search results. This manuscript reports findings from the majority of the project, comprising Reviews A and C, ‘milk feeding’ and ‘maternal and infant diet’. Review B, regarding timing of introduction of allergenic foods, and one part of Review C, regarding use of hydrolysed infant formula, have been published separately [12,13]. Thus, this manuscript describes outcomes for maternal or infant intake of individual foods or food groups, nutrients or nutrient groups, dietary supplements, maternal allergenic food avoidance, timing of introduction of solid foods or nonallergenic foods to the infant diet, overall dietary pattern and duration of breastfeeding. This manuscript does not include timing of introduction of allergenic foods (milk, soya, egg, peanuts, tree nuts, fish, seafood, wheat) to the infant diet or use of hydrolysed formula in infants. Measures of dietary diversity and objective measures of nutritional status (with the exception of blood vitamin D level) were not included in these systematic reviews. These measures were considered to be too indirect as indicators of dietary intake to be used to inform public health guidance in the UK. As part of this project, we also searched for other systematic reviews covering the same topic published since 1 January 2011.
Our original search identified 16,289 original titles. Title, abstract, and full text screening yielded a total of 343 titles (260 original studies; 964,143 participants) of milk feeding and 281 titles (173 original studies; 542,672 participants) of maternal and infant diet, including 80 trials of maternal (n = 26), infant (n = 32), or combined (n = 22) interventions. Full details of the search results are shown in Fig 1 (PRISMA flow chart), and characteristics of included studies and risk of bias are summarised in S1 Appendix. Risk of bias was high in 125 (48%) studies of milk feeding and 44 (25%) studies of maternal and infant diet (most commonly due to attrition bias in intervention studies and confounding bias in observational studies). Key findings are shown in Table 1, which includes a GRADE assessment of certainty for each finding , and in Figs 2–9. The full report, with a detailed description of the methodology used and all review findings, is available on the Food Standards Agency website (https://www.food.gov.uk/science/research/allergy-research/fs305005ac). Summary reports to the Food Standards Agency for studies of milk feeding and studies of maternal and infant diet are in S2 Text and S3 Text, respectively. Detailed appraisal of findings underlying the 2 reports are in S1 Data and S2 Data, respectively, and all data used for meta-analyses are in S3 Data. An associated statement by the Committee on Toxicity is available on the Food Standards Agency website (https://cot.food.gov.uk/cotstatements/cotstatementsyrs/cot-statements-2017/statementonrevsaandc).