PURPOSE OF THE STUDY.
To review the effect of fish intake during pregnancy or infancy on allergic outcomes.
This was a meta-analysis of 1 randomized controlled trial (RCT) and 13 prospective cohort studies. The researchers conducting the RCT enrolled infants at risk for atopy (at least 1 first-degree relative affected by atopy, asthma, or allergy by self-report). The researchers conducting the cohort studies enrolled healthy pregnant women or infants without selection for atopic disease. Studies were conducted in North America, Europe, and Asia.
PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched for records reporting the effect of dietary fish intake during pregnancy or infancy on clinical outcomes of allergic disease or sensitization in children. In all studies, the primary intervention was high versus low or no fish intake during pregnancy or infancy. Outcomes of interest were atopic dermatitis (AD), allergic rhinitis (AR), wheezing, asthma, and food allergy defined by parental report of symptoms or physician diagnosis (direct or by parental report), and sensitization (positive skin prick test result or elevated specific immunoglobulin E) to any food or inhalant allergen. Statistical analysis was performed with attempts to control for confounding factors, family history of allergic disease, and early signs of atopy.
In 1 RCT, researchers enrolled 123 mother-child pairs to receive 300 g of farmed salmon per week or a habitual diet low in oily fish starting at 20 weeks’ gestation. Eighty-six infants were evaluated at 6 months, with no significant differences in immunoglobulin E, AD, wheeze, or sensitization to food or aeroallergens. The cohort studies of maternal fish intake also found no effect on odds ratios for rates of sensitization, AD, AR, wheeze, or asthma. High fish intake during infancy was associated with a 39% reduction in eczema and a 46% reduction in AR. A borderline association with sensitization was found at 4 years of age but was lost by 8 years. No effect was found on wheeze or asthma. There was no study in which researchers reported an association between fish intake during pregnancy or infancy with food allergy.
Fish intake during infancy is associated with a lower risk of AR and eczema, whereas maternal intake of fish during pregnancy is not.
Oily fish are a rich source of n-3 long-chain polyunsaturated fatty acids such as docosahexaenoic acid and eicosapentaenoic acid, which have been suggested to lower the risk of allergic disease through anti-inflammatory effects. The mechanism underlying the association between fish intake in infancy and lower risk of AR and AD remains unclear. Furthermore, the findings of this meta-analysis are potentially limited by publication bias and reverse causation (avoidance of fish because of early signs of atopy). Current expert recommendations are to introduce solid foods beginning at 4 to 6 months of age without delaying the introduction of highly allergenic foods, such as fish.
- Copyright © 2017 by the American Academy of Pediatrics