Fish Oil Supplementation in Overweight/Obese Patients with Uncontrolled Asthma. A Randomized Trial

Ann Am Thorac Soc. 2019 May;16(5):554-562. doi: 10.1513/AnnalsATS.201807-446OC.


Rationale: Omega-3 fatty acid (n3PUFA) supplementation has been proposed as a promising antiasthma strategy. The rs59439148 ALOX5 polymorphism affects leukotriene production and possibly inflammatory responses to n3PUFA. Objectives: Assess the effects of n3PUFA supplementation and ALOX5 genotype on asthma control in patients with obesity and uncontrolled asthma. Methods: This multicenter trial among 12- to 25-year-olds with overweight/obesity and uncontrolled asthma randomized subjects in a 3:1 allotment to n3PUFA (4 g/d) or soy oil control for 24 weeks. Asthma Control Questionnaire was the primary outcome; secondary outcomes included blood leukocyte n3PUFA levels, urinary leukotriene-E4, spirometry, and asthma-related events. The number of SP1 tandem repeats in rs59439148 determined ALOX5 genotype status. Simple and multivariable generalized linear models assessed effects on outcomes. Results: Ninety-eight participants were randomized (77 to PUFA, 21 to control), and more than 86% completed all visits. Asthma and demographic characteristics were similar among treatment groups. n3PUFA treatment increased the n3-to-n6 PUFA ratio in circulating granulocytes (P = 0.029) and monocytes (P = 0.004) but did not affect mean Asthma Control Questionnaire change at 6 months (n3PUFA: mean, -0.09; 95% confidence interval [CI], 0.09 to 0.10; vs. control: mean, -0.18; 95% CI, -0.42 to 0.06; P = 0.58). Changes in urinary leukotriene-E4 (P = 0.24), forced expiratory volume in 1 second % predicted (P = 0.88), and exacerbations (relative risk [RR], 0.92; 95% CI, 0.30-2.89) at 6 months were similar in both groups. n3PUFA treatment was associated with reduced asthma-related phone contacts (RR, 0.34; 95% CI, 0.13-0.86; P = 0.02). ALOX5 genotype did not affect n3PUFA treatment responses. Conclusions: 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. Clinical trial registered with (NCT01027143).

Keywords: EPA; asthma; fish oil; obesity; omega-3 fatty acids.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Asthma / complications
  • Asthma / drug therapy*
  • Asthma / physiopathology
  • Child
  • Dietary Supplements
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Fatty Acids, Omega-3 / administration & dosage*
  • Female
  • Fish Oils / administration & dosage*
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Humans
  • Male
  • Obesity / complications*
  • Overweight / complications*
  • Treatment Outcome
  • Young Adult


  • Fatty Acids, Omega-3
  • Fish Oils

Associated data