Durham, NC—Fish oil supplements often are purchased at drugstores in hopes of helping adolescents and young adults control their asthma.

A new study published online by Annals of the American Thoracic Society suggests the remedy might not work, however. Although omega-3 fatty acid (n3PUFA) supplementation has been proposed as a promising antiasthma strategy, the research found that fish oil does not appear to improve asthma 
control in adolescents and young adults who are overweight or obese.

Duke University Hospital–led researchers report that asthma control showed no improvement with 4 grams of fish oil a day for 6 months. Results were measured by a standard asthma-control questionnaire, breathing tests, urgent care visits, and severe asthma exacerbations.

“We don’t know why asthma control in obese patients is more difficult, but there is growing evidence that obesity causes systemic inflammation,” pointed out lead author Jason E. Lang, MD, MPH. “Because the omega-3 fatty acids in fish oil have anti-inflammatory properties, we wanted to test whether fish oil would have therapeutic benefits for these patients.”

The study included 98 overweight/obese participants, about half African-American, who ranged in age from 12 to 25 years; all had an asthma diagnoses but had poor asthma control, despite using a daily inhaled corticosteroid to control their asthma. For every three participants assigned to take fish oil for 25 weeks, one was assigned to take the soy oil placebo.

Also part of the study was an examination of whether a variant in the gene ALOX5 had any influence on the results. While the ALOX5 variant appeared to be linked to leukotriene production, it did not seem to play a role in the effectiveness of fish oil in providing asthma control, according to the results.

Results indicate that n3PUFA treatment increased n3-to-n6PUFA ratio in granulocytes (P = .003) and monocytes (P = .002) but did not affect mean (95% CI) ACQ change at 6 months (n3PUFA: -0.09 (-.09, .10) versus the control group: -0.18 (-.42, .06), P = .58), with similar rates of exacerbations.

“We did not find evidence that n3PUFA use improves most asthma-related outcomes and cannot recommend it as a prevention strategy for overweight/obese patients with asthma,” study authors conclude, although they suggest that larger doses of fish oil over a longer period of time might produce a different result.

Based on the current study, however, Lang added that “there is insufficient evidence for clinicians to suggest to patients with uncontrolled asthma that they should take daily fish oil supplements to help their asthma.”

 « Click here to return to Weekly News Update.