According to new research published in the Annals of the American Thoracic Society, fish oil supplements do not appear to improve asthma control in adolescents and young adults.
Researchers report that four grams of fish oil a day for six months did not improve asthma control in overweight or obese patients, as measured by a standard asthma control questionnaire, breathing tests, urgent care visits and severe asthma exacerbations.
Dr. Jason E. Lang, lead study author and associate professor of paediatrics at Duke University, USA, explains: “We don’t know why asthma control in obese patients is more difficult, but there is growing evidence that obesity causes systemic inflammation.”
“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.”
Details of the study
The 98 overweight/obese participants in the study ranged from 12 to 25 years of age.
All of whom were diagnosed with asthma by a physician 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.
The researchers also looked at whether a variant in the gene ALOX5 affected study findings. It is known that mutations in the gene can decrease responses to anti-leukotriene drugs.
Leukotrienes are inflammatory molecules that play a critical role in triggering asthma attacks. In this study, the ALOX5 variant did appear to be linked to leukotriene production but not to the effectiveness of fish oil in providing asthma control.
“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.” Added Lang.
However, the research authors wrote that the study’s negative findings may not be the last word on fish oil and asthma. They highlighted that larger doses of fish oil over a longer period of time may produce a different result.