Dietary fatty acid composition during pregnancy and the risk of asthma in the offspring

Fatty acids (FA) modulate the immune system, and it has been proposed that they affect the incidence of IgE-mediated allergic diseases. We explored the association of maternal dietary FA composition during pregnancy with the risk of asthma in the offspring. We analyzed data from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study. Maternal dietary intake during pregnancy (8th month) was assessed by a validated 181 item food frequency questionnaire. The occurrence of asthma was assessed at the age of 5 yr with a questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC). Cox proportional hazards regression was used for the statistical analyses. Low maternal intakes of alpha-linolenic acid (18:3n3) [lowest quarter vs. mid half HR 1.67 (95% CI 1.12 to 2.48)] and total n3 polyunsaturated fatty acids (PUFA) [HR 1.66 (95% CI 1.11 to 2.48)] during pregnancy were associated with an increased risk of asthma in the offspring, while a low intake of arachidonic acid (20:4n6) [HR 0.52 (95% CI 0.32 to 0.84)] and high intake of total saturated fatty acids [highest quarter vs. mid-half HR 0.55 (95% CI 0.34�0.90)] and palmitic acid (16:0) [HR 0.51 (95% CI 0.31 to 0.83)] were associated with a decreased risk of asthma. The ratios of n6 to n3 PUFA and 18:2n6 to 18:3n3, and the maternal intake of oils, fish and fish products, showed no association with the risk of asthma. The associations found were independent of several perinatal and clinical confounders. Maternal intake of FA during pregnancy was associated with childhood asthma. Maternal ALA, total n3 PUFA and palmitic acid intake may decrease, while arachidonic acid intake may increase the risk of asthma in the offspring. (Authors abstract)
Epidemiological studies suggest that the increasing rate of asthma and allergic diseases in Western societies are partly related to the changes in dietary habits that have taken place over the recent decades. In particular, few mothers use fish oil containing supplements. Using food consumption data the results provide evidence that a low maternal intake of alpha-linolenic acid (ALA) during pregnancy is associated with an increased risk of asthma in the offspring. Also a low intake of arachidonic acid (20:4n6) and a high intake of SAFAs, especially palmitic acid (16:0), are associated with a decreased risk of asthma in the offspring at the age of 5 yr.
The strength of the present study is that the collection of dietary data before the development of asthma excludes the selection of subjects according to the end-point. The study population is comprehensive, and the end-point is based on a standardized, validated questionnaire designed specifically for epidemiological studies. The FFQ used in the study was validated and found suitable to measure the food consumption of pregnant Finnish women. High maternal ALA, total n3 PUFA and palmitic acid may decrease, while high arachidonic acid may increase the risk of asthma in the offspring. (Editors comments)