Higher omega-3 intake in childhood may lower asthma risk in children with common variant

Higher omega-3 fatty acid intake in childhood was associated with lower risk for incident asthma up to mid-adolescence in children with a fatty acid desaturase polymorphism variant, researchers reported in the European Respiratory Journal.

Mohammad Talaei, MD, MPH, PhD, postdoctoral researcher with the Institute of Population Health Sciences at Barts and The London School of Medicine and Dentistry at Queen Mary University of London, and colleagues analyzed data from the Avon Longitudinal Study of Parents and Children (ALSPAC), which followed 4,543 pregnancies from birth to age 7 years and tracked dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid. The mother of each child completed a dietary questionnaire, including questions about the consumption of different food groups and drinks. Omega-3 fatty acid intake through fish consumption was defined as the consumption of shellfish, white fish in breadcrumbs or batter, white fish alone, tuna and oily fish.

Researchers evaluated the associations between omega-3 fatty acid intake and incidence of physician-diagnosed asthma by age 11 and 14 years and analyzed the potential effect modification through a fatty acid desaturase polymorphism (rs1535).

The most common intake was white fish in 74.6% of children, followed by tuna in 18.4%. The median intake of fish was 24.3 g per day.

There was no evidence of an association between omega-3 fatty acid intake from fish and incident asthma overall, but the researchers observed an association when stratified by fatty acid desaturase polymorphism among the 2,025 minor G allele carriers (OR = 0.49; 95% CI, 0.31-0.79; P for trend = .006). There was no inverse association in the homozygous major A allele group (OR = 1.43; 95% CI, 0.83-2.46; P for interaction = .19).

These results were then assessed in a replication analysis of 2,138 children (50.5% boys). The total intake of fish in this cohort was lower compared with the ALSPAC cohort (median, 1.9 vs. 2.5 times per week), but omega-3 fatty acid intake from fish was higher for both EPA and DHA (median, 41 mg and 104 mg per day vs. 11.2 mg and 17.6 mg per day, respectively). The replication analysis cohort also confirmed the association between mid-childhood omega-3atty acid intake, and incident asthma was modified by the fatty acid desaturase polymorphism.

“Replication of these gene-nutrient interactions on incident asthma in the BAMSE birth cohort confirmed that the main findings are unlikely to have arisen by chance,” the researchers wrote. “To our knowledge, these are novel findings which were robust to various sensitivity analyses.”

The researchers cautioned that this was an observational study and further research is required to determine whether higher intake of long-chain omega-3 fatty acids in childhood can prevent subsequent development of asthma. Further research will also evaluate whether higher intake is associated with lower risk for exacerbations in children already diagnosed with asthma, according to a press release.