Review Suggests Benefits of DHA/EPA in Maternal Diet on Childhood Allergic Disease
Best, K. P. et al., Am. J. Clinical Nutrition, in press, 2016
Women’s and Children’s Health Research Institute, Univ. of Adelaide, Adelaide, Australia
Atopic eczema is quite common in children with a lifetime prevalence of approximately 20 % in North America. It arises from sensitivity to certain allergens which may come from environmental exposures, certain foods, or other factors. The skin of those afflicted often becomes itchy, red, dry, and cracked. The present study aimed to conduct a systematic review and meta-analysis of the various and sometimes conflicting observational studies and randomized controlled trials wherein the relationship of maternal intakes of long-chain (LC) omega-3 fatty acids (DHA/EPA) to outcomes of allergic disease or sensitization (response to immunological testing regimens) in the offspring were assessed.
Of the previous observational studies, 9 of 13 (68 %) reported a protective effect of increased prenatal LC omega-3 or fish intakes on the incidence of allergic disease symptoms in the child. Of the previous randomized controlled trials, 5 of 7 (71 %) indicated a corresponding beneficial effect. Of the latter trials, testing of the offspring within the first 12 months of life from mothers who supplemented with LC omega-3 fatty acids during pregnancy revealed a significant reduction by 32-46 % overall in the incidence of a positive skin prick test (to any allergen extract or hen’s egg or any food extract) as compared to offspring from those mothers who received only a placebo supplement (lacking DHA/EPA). Furthermore, a significant reduction (of 47 %) in the incidence of atopic eczema was found in the offspring of the mothers supplementing with LC omega-3 fatty acids. The authors indicate that since diet is easily modifiable, this simple and low-cost approach of increasing LC omega-3 intake during pregnancy ‘may offer the best opportunity for a primary prevention strategy, decreasing the burden of allergic disease for future generations’.
Dr. Holub's Comments:
The present extensive review and meta-analysis provides overall support to the benefits of increased intakes of LC omega-3 fatty acids during pregnancy and outcomes of childhood allergic disease. The studies as reviewed had wide differences amongst them with respect to the intakes of fish (amount, type, frequency and duration of consumption) and omega-3 fatty acid intakes as well. While not the goal of the present study, specific information would be of considerable interest regarding the specific amounts of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) from dietary or supplemental sources that may be optimal for maternal ingestion to maximize the reduction of allergic disorders in the offspring. Of course, maternal advice on omega-3 intakes must also consider the other health benefits to both the mother and offspring from LC omega-3 fatty acids as DHA/EPA.