Whereas fish oil may have a host of benefits as a dietary supplement in the general population, a new study reveals that supplementation did little to improve outcomes for overweight or obese children with uncontrolled asthma.
The study, published in the Annals of the American Thoracic Society, found no improvement in severe asthma exacerbations or emergency care visits in children who were given 4 grams of fish oil daily for 6 months compared with those who were given a placebo.1 Improvement was measured based on self-reported outcomes and breathing tests, according to the report.
Jason E. Lang, MD, MPH, associate professor of Allergy, Immunology, and Pulmonary Medicine at the Duke University School of Medicine, Durham, North Carolina, director of the Duke Clinical Research Institute, and lead author of the study, says at this point the study was not able to justify a recommendation for clinicians to use omega-3 fatty acid supplements for the purpose of improving asthma.
“The evidence at this point for omega-3 fatty acids improving asthma is scant and mainly theoretical. It is possible that future research will find that certain subgroups of patients with asthma will respond, but that is speculation,” Lang says. “Our study demonstrated that among patients who took fish oil and had increases in their blood omega-3 fatty acid levels, asthma did not improve. Furthermore, a proposed mechanism has been that omega-3 fatty acids will help patients by reducing arachidonic acid pathway inflammation, specifically leukotrienes. Unfortunately, we did not see any reductions in leukotrienes in patients taking the supplements.”
Some studies have linked the omega-3 fatty acids found in fish oil to lower incidence of asthma, and the study team sought to test the theory in overweight and obese children—a population particularly at risk for poor asthma control. Lang’s trial was the largest to evaluate the effect of fish oil supplementation in asthma patients, with 98 patients aged 12 to 25 years enrolled in the study. Participants who were given fish oil supplements throughout the study showed elevated levels of omega-3 in their blood, but there were no improvements in asthma control and lung function measures or on the participants’ Asthma Control Questionnaire (ACQ) at 3 or 6 months into the study, according to the report. The only improvement noted over the study period was a decrease in the number of calls participants made to their physicians related to asthma symptoms. John La Puma, MD, FACP, founder of Chef Clinic and co-founder of ChefMD, Santa Barbara, California, has discussed the benefits of fish oil supplements for patients with asthma on his professional blog, and says he thinks the participants in Lang’s study may have had benefits obscured by other physiologic conditions, including obesity. He isn’t ready to discount the benefits of supplementation just yet, despite Lang’s findings.
“The finding that they made fewer calls to their physician may well be simply because they were asked to take a medication and the psychological effect of so doing helped them,” La Puma says, “but their lung function was no better and, although obesity is likely a cause of chronic inflammation, there are many better ways to get the benefits of both omega-3s—such as eating fish—and reducing inflammation by eating foods that are very high in anti-inflammatory agents.”