A substantial body of epidemiological evidence has implicated diet early in the life course in the aetiology of asthma and other allergic diseases. In a study, researchers have found that higher intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish in childhood is linked with a lower risk for childhood asthma among children with a common fatty acid desaturase (FADS) variant. The research has been published in the European Respiratory Journal on January 28, 2021.
Fish intake has attracted particular interest, as fish is a rich source of the n-3 (omega-3) very long-chain polyunsaturated fatty acids (VLC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have anti-inflammatory effects. Other nutrients in fish, such as vitamin D and selenium, may also protect against asthma risk. However, longitudinal studies on the relation between dietary intake of n-3 (omega-3) very long-chain polyunsaturated fatty acids, EPA and DHA, in mid-childhood and asthma risk is rare. Therefore, Dr Mohammad Talaei and his team conducted a study to investigate whether a higher intake of EPA and DHA from fish in childhood is associated with a lower risk of incident asthma.
The researchers used data from a large UK birth cohort (Avon Longitudinal Study of Parents and Children), Children of the 90s, which recruited mothers who were pregnant in the early 1990s and has been following up their offspring ever since. They assessed the dietary intakes of EPA and DHA from fish using a food frequency questionnaire at 7 years of age. They also used logistic regression, controlling for confounders, to analyse associations between intake of EPA and DHA (quartiles) and incidence of doctor-diagnosed asthma at age 11 or 14 years, and explored potential effect modification by a fatty acid desaturase (FADS) polymorphism (rs1535). Replication was sought in the Swedish BAMSE birth cohort.
Key findings of the study were:
Upon analysis, they found no association between intake of EPA plus DHA from fish and incident asthma overall (n=4543).
However, on stratification by FADS genotype, they found that higher dietary intake of long-chain omega-3 fatty acids was associated with a lower risk of asthma.
They noted that the risk was 51 per cent lower, comparing those in the top quartile of long-chain omega-3 intake with those in the bottom quartile.
They further replicated the interaction in the Swedish BAMSE birth cohort.
The authors concluded, "In children with a common FADS variant, higher intake of EPA and DHA from fish in childhood was strongly associated with a lower risk of incident asthma up to mid-adolescence."
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DOI: 10.1183/13993003.03633-2020