Can Early Omega-3 Fatty Acid Exposure Reduce Risk of Childhood Allergic Disease?

Abstract

A causal link between increased intake of omega-6 (n-6) polyunsaturated fatty acids (PUFAs) and increased incidence of allergic disease has been suggested. This is supported by biologically plausible mechanisms, related to the roles of eicosanoid mediators produced from the n-6 PUFA arachidonic acid. Fish and fish oils are sources of long chain omega-3 (n-3) PUFAs. These fatty acids act to oppose the actions of n-6 PUFAs particularly with regard to eicosanoid synthesis. Thus, n-3 PUFAs may protect against allergic sensitisation and allergic manifestations. Epidemiological studies investigating the association between maternal fish intake during pregnancy and allergic outcomes in infants/children of those pregnancies suggest protective associations, but the findings are inconsistent. Fish oil provision to pregnant women is associated with immunologic changes in cord blood. Studies performed to date indicate that provision of fish oil during pregnancy may reduce sensitisation to common food allergens and reduce prevalence and severity of atopic eczema in the first year of life, with a possible persistence until adolescence. A recent study reported that fish oil consumption in pregnancy reduces persistent wheeze and asthma in the offspring at ages 3 to 5 years. Eating oily fish or fish oil supplementation in pregnancy may be a strategy to prevent infant and childhood allergic disease.

Keywords: allergy; asthma; early life origins; eczema; eicosanoid; inflammation; omega-3; omega-6; polyunsaturated fatty acid; resolution.

Figure 1

Overview of the pathway of conversion of linoleic and α-linolenic acids to longer chain more unsaturated n-6 and n-3 polyunsaturated fatty acids (PUFAs).

Figure 2

Outline of the pathway of conversion of arachidonic acid to eicosanoids. Abbreviations used: COX, cyclooxygenase; Cyt P450, cytochrome P450; HETE, hydroxyeicosatetraenoic acid; LOX, lipoxygenase.

Figure 3

Proposed relationship between increased linoleic acid exposure and increased allergic disease. Abbreviation used: PG, prostaglandin.

Figure 4

Overview of the pathways of synthesis of specialised pro-resolving mediators from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Abbreviations used: AT, aspirin-triggered; MaR, maresin; PD, protectin D; Rv, resolvin.

Figure 5

Risk of persistent wheeze or asthma in children according to maternal use of fish oil or placebo during pregnanacy. From New England Journal of Medicine, H. Bisgaard, J. Stokholm, B.L. Chawes, N.H. Vissing, E. Bjarnadóttir, A.M. Schoos, H.M. Wolsk, T.M. Pedersen, R.K. Vinding, S. Thorsteinsdóttir, N.V. Følsgaard, N.R. Fink, J. Thorsen, A.G. Pedersen, J. Waage, M.A. Rasmussen, K.D. Stark, S.F. Olsen, K. Bønnelykke, Fish Oil-Derived Fatty Acids in Pregnancy and Wheeze and Asthma in Offspring, Volume 375, Page 2530–2539. Copyright © 2016 Massachusetts Medical Society. Reprinted with permission from Massachusetts Medical Society.