New research suggests that eating more long-chain omega-3 fatty acids in childhood may reduce the risk of developing subsequent asthma, but only in children with a common gene variant. The study, led by Queen Mary University of London, is in collaboration with the Bristol University and University of Southampton, UK, and Karolinska Institutet, Sweden.
In the UK, 1.1 million children (1 in 11) are currently being treated for asthma, and most adult asthma begins in childhood. The NHS spends around £ 1 billion annually on treating and caring for people with asthma.
Senior author, Professor Seif Shaheen of Queen Mary University in London, said, “Asthma is the most common chronic disease in childhood and we don’t currently know how to prevent it. It is possible that poor diet increases your risk of asthma. So far, however, most studies have taken “snapshots” of diet and asthma measured over a short period of time. Instead, we measured diet and then watched children over many years to see who developed asthma and who did not.
“While we cannot say with certainty that eating more fish will prevent asthma in children, what we have found is that it would make sense for children in the UK to consume more fish as few are currently reaching the recommended intake.”
Fish is of particular interest as it is a rich source of the long-chain omega-3 fatty acids eicosapentaenoic acid acid (EPA) and docosahexaenoic acid (given) that have anti-inflammatory properties.
The study, published in the European Respiratory Journal, used data from a large UK birth cohort, Children of the 90s, which recruited mothers who were pregnant in the early 1990s and have been tracking their offspring ever since. They analyzed the association between the intake of EPA and DHA from fish at the age of 7 (estimated from food frequency questionnaires) and the incidence of new cases of asthma diagnosed by a doctor at the age of 11-14.
Long-chain omega-3 intake by fish was not associated with asthma in the entire cohort (4,543 persons). However, the team delved deeper into children with a specific genetic makeup. More than half of the children carried a common variant of the FADS gene (fatty acid desaturase), which is associated with lower levels of long-chain omega-3 fatty acids in the blood. In these children, a higher diet of long-chain omega-3 fatty acids was associated with a lower risk of asthma. The risk was 51 percent lower compared to those in the upper quartile of long-chain omega-3 intake with those in the lower quartile.
This finding was also found in an independent birth cohort study in Sweden (BAMSE).
Since they found only one observation, the researchers warn that they cannot say with certainty that a higher intake of long-chain omega-3 fatty acids in childhood can prevent the later development of asthma. The next step is to determine whether a higher intake is also linked to a lower risk of exacerbations in children who already have asthma.
Reference: “Uptake of polyunsaturated n-3 fatty acids in childhood, FADS genotype and asthma” Mohammad Talaei, Emmanouela Sdona, Philip C. Calder, Louise R. Jones, Pauline M. Emmett, Raquel Granell, Anna Bergström, Erik Melén and Seif O. Shaheen, Jan. 27, 2021, European Respiratory Journal.
DOI 10.1183 / 13993003.03633-2020
The project was funded by the Rosetrees Trust and the Bloom Foundation. The UK Medical Research Council, Wellcome and the University of Bristol provide key support for children of the 1990s.