Effects of omega-3 supplementation in combination with diet and exercise on weight loss and body composition

Am J Clin Nutr. 2011 Feb;93(2):455-62. doi: 10.3945/ajcn.110.002741. Epub 2010 Dec 15.


Background: In addition to the metabolic and cardiovascular benefits of omega-3 (n-3) fatty acids, several studies have suggested an added weight loss-enhancing benefit to this supplement.

Objective: The objective was to assess whether supplemental omega-3 fatty acids in conjunction with diet and exercise augment weight loss over a 6-mo period.

Design: In a single-institution, placebo-controlled, randomized clinical trial, 128 individuals with a body mass index (in kg/m(2)) between 26 and 40 were assigned to receive 5 omega-3 [3.0 g eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) at a 5:1 ratio (EPA:DHA)] or placebo capsules daily in conjunction with lifestyle modification. The primary endpoint was weight loss; secondary endpoints included metabolic and psychometric variables. Analyses were by intention-to-treat.

Results: Overweight and obese individuals were assigned to the omega-3 arm (n = 64) or to the placebo arm (n = 64). Subjects in both arms received dietary and exercise counseling. Eighty-one individuals completed the 24-wk study, and the dropout rate was 27%. Subjects in both arms lost an average of >5% of their body weight. No significant differences in weight loss were observed between the omega-3 (-5.2 kg; 95% CI: -6.0, -4.4 kg) and placebo (-5.8 kg; 95% CI: -6.7, -5.1 kg) arms. The absolute mean (±SEM) change difference was 0.61 ± 0.58 kg (P = 0.29). In addition, no significant differences in the other factors assessed were observed.

Conclusion: Omega-3 fatty acids were not effective as an adjunct for weight loss in this otherwise healthy, overweight population.

Publication types

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

MeSH terms

  • Adult
  • Body Composition / drug effects
  • Combined Modality Therapy
  • Diet, Reducing*
  • Dietary Fats / administration & dosage
  • Dietary Supplements*
  • Docosahexaenoic Acids / pharmacology
  • Docosahexaenoic Acids / therapeutic use*
  • Eicosapentaenoic Acid / pharmacology
  • Eicosapentaenoic Acid / therapeutic use*
  • Exercise*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / therapy*
  • Overweight / therapy*
  • Weight Loss / drug effects*


  • Dietary Fats
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid