An adverse association was observed between omega-6 polyunsaturated fatty acid (PUFA) intake and morbidity from chronic obstructive pulmonary disease (COPD), according to the results of a cross-sectional analysis published in the Annals of the American Thoracic Society.
Recognizing that the PUFAs have been able to modulate the inflammatory response and potentially affect respiratory outcomes, investigators sought to explore the relationship between omega-3 PUFA (ie, alpha linoleic acid [ALA], eicosapentaenoic acid [EPA], and docosahexaenoic acid [DHA]) and omega-6 PUFA (ie, linoleic acid [LA] and arachidonic acid [AA]) intake. The researchers took into account the opposing fatty acid and respiratory morbidity in former smokers with moderate to severe COPD.
A total of 112 participants with COPD who resided in Maryland were enrolled into the study between July 2014 and October 2018. Inclusion criteria were age ≥40 years, postbronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) percent predicted <80%, and identification as a former smoker.
Dietary assessments were conducted using the 2007 grid of the Willett Food Frequency Questionnaire to derive the average daily intake of all nutrients through food or supplement intake within the previous year. PUFA intake was classified as follows: (1) total omega-3 intake (EPA+DHA+ALA), (2) total omega-6 intake (LA+AA), and (3) omega-6/omega-3 ratio. Respiratory health outcomes were analyzed using the modified Medical Research Council scale for functional impairment caused by dyspnea, the COPD Assessment Test for the effect of the disease, and the Saint George’s Respiratory Questionnaire and the Clinical COPD Questionnaire to determine respiratory-specific health-related quality of life.
Every 1-gram increase in total omega-3 intake was linked to lower COPD Assessment Test, Saint George’s Respiratory Questionnaire, and Clinical COPD Questionnaire scores, thus indicating the beneficial association with higher omegs-3 intake. Furthermore, higher total omega-3 intake was linked to fewer severe COPD exacerbations and a trend toward higher lung function. In contrast, every 1-gram increase in total omega-6 intake as associated with lower FEV1 percent predicted; higher modified Medical Research Council, COPD Assessment Test, Saint George’s Respiratory Questionnaire, and Clinical COPD Questionnaire scores; and a higher risk for a COPD exacerbation — specifically, a severe exacerbation — in the past 3 months.
In addition, omega-6/omega-3 ratio was also associated with several respiratory outcomes, including higher adverse COPD effect, which was defined by higher COPD Assessment Test scores and worse quality of life, based on higher total Saint George’s Respiratory Questionnaire and Clinical COPD Questionnaire scores, along with lower FEV1 percent predicted and a higher risk for severe COPD exacerbations.
The investigators concluded that the results of this study suggest that nutrition may represent a modifiable risk factor for respiratory morbidity among individuals with COPD, with omega-3 and omega-6 PUFAs potentially playing key roles.
Lemoine C, Brigham E, Woo H, et al. Relationship between omega-3 and omega-6 fatty acid intake and COPD morbidity [published online November 21, 2019]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201910-740RL