Results from a small randomized control trial suggest that the inflammation of the airways associated with asthma may be reduced by eating a diet rich in omega-3 fatty acids.
The research, published in the Journal of Human Nutrition and Dietetics, examined differences in asthma severity among 31 Greek children eating a Mediterranean diet with at least two meals of fatty fish per week and 33 children who were instructed to follow their normal diet for six months.
At the endpoint, there were no statistically significant differences between the Mediterranean and control groups in regards to lung function – as measured by spirometry – or change from baseline scores on an asthma control and quality of life questionnaire. Similarly, the proportion of children who stopped taking a daily asthma medication during the six-month period was similar between the two groups.
The high-fish diet did, however, appear to have an effect on children’s lung function as measured by fractional exhaled nitrous oxide (FeNO) analysis. This well-known and widely used test is used to diagnose and monitor asthma. It is based on the findings that cells in the bronchioles of asthmatics release more nitric oxide (NO) gas than those without the disease, and that the level of exhaled NO corresponds to inflammation severity. The Mediterranean group’s average FeNO decreased by 18.6 percent, a change that the authors say corresponds to a reduction of 14.15 parts per billion (ppb) from baseline levels after adjusting for age, sex, BMI, and regular physical activity.
On the flipside, kids in the control group showed an average 78.2 percent increase in FeNO after six months. According to guidelines from the American Thoracic Society, a reduction in FeNO by at least 10 units (for a final value lower than 50 ppb) is considered an indicator of a potent response to anti-inflammatory therapy.
"We already know that a diet high in fat, sugar, and salt can influence the development and progression of asthma in children and now we have evidence that it's also possible to manage asthma symptoms through healthy eating," lead author Maria Papamichael, of La Trobe University, Australia, said in a statement.
And because the children in this trial didn’t even do that good of a job adhering to the fish-heavy diet, per the results of food intake questionnaires given to the subjects’ parents, the researchers speculate that this study might underrepresent the full benefit of omega-3 fatty acids for asthma.
“[O]ur findings suggest that a Mediterranean diet supplemented with fatty fish might be a potential nonpharmacological strategy to combat airway inflammation,” wrote the authors. “This has important public health implications because dietary interventions are easily applied in ‘real-life’ situations, are of low cost, have multiple health benefits, and might assist in reducing asthma burden in children. Given that there are no adverse effects of regular fish consumption, a healthy diet incorporating two fatty fish meals per week provides overall health benefits and well-being.
“Future robust clinical trials are warranted to replicate and corroborate the promising findings documented,” they concluded.