This is due to fatty acids that are found in fish and fish oil – eicosapentaenic acid (EPA) and docosahexaenic acid (DHA). These long-chain unsaturated fatty acids inhibit inflammation, including asthma.

However, the fatty acids do not have the same effect in all children. They are only protective in children with a specific gene variant called rs1535. These children can only produce a limited amount of unsaturated fatty acids. They therefore need to absorb the protective fatty acids directly with food in the form of fish or fish oil.

Children without this gene variant do not have to do so, because they produce the protective fatty acids themselves – an enzyme in the body simply converts vegetable fats.

The source of these results is the Avon Longitudinal Study of Parents and Children (ALSPAC), in which nearly half of the children were carriers of rs1535 gene variant, or 2,025 out of the 4,542 children who took part in the study. The study also revealed that these children, aged between 11 and 14 years, had asthma more frequently if they had not eaten much fish in their childhood years. A questionnaire provided information on the nutritional habits of the children: The parents had completed a questionnaire on what the children were eating when they were seven years old.

It is not yet possible to conclude from the study that eating more fish prevents asthma in children. For the UK, however, the main scientist responsible for the study, Seif Shaheen, recommends that children eat more fish, because few children there eat the recommended amount of fish for their age.

It is still unclear how asthma can be prevented, but unhealthy eating may increase the risk of asthma. “Most studies so far have taken ‘snapshots’ to measure diet and asthma in a short period of time. Instead, we measured their diet and tracked children over the years to find out who developed asthma and who did not”, says Shaheen. The asthma expert is a professor at Queen Mary University in London, UK. He conducted the study together with colleagues in the UK and Sweden.

Sources

Consuming omega-3 fatty acids could prevent asthma. Press release of the Queen Mary University of London, 28 January 2021. Last retrieved on 29 January 2021

Talaei M et al. Intake of n-3 polyunsaturated fatty acids in childhood, FADS genotype, and incident asthma. Eur Respir J. 2021 Jan 28:2003633. Online ahead of print,