title: Lack of effects of fish oil supplementation for 12 weeks on resting metabolic rate and substrate oxidation in healthy young men: A randomized controlled trial.
abstract: Fish oil (FO) has been shown to have beneficial effects in the body via incorporation into the membranes of many tissues. It has been proposed that omega-3 fatty acids in FO may increase whole body resting metabolic rate (RMR) and fatty acid (FA) oxidation in human subjects, but the results to date are equivocal. The purpose of this study was to investigate the effects of a 12 week FO supplementation period on RMR and substrate oxidation, in comparison to an olive oil (OO) control group, in young healthy males (n = 26; 22.8 ± 2.6 yr). Subjects were matched for age, RMR, physical activity, VO2max and body mass, and were randomly separated into a group supplemented with either OO (3 g/d) or FO containing 2 g/d eicosapentaenoic acid (EPA) and 1 g/d docosahexaenoic acid (DHA). Participants visited the lab for RMR and substrate oxidation measurements after an overnight fast (10-12 hr) at weeks 0, 6 and 12. Fasted blood samples were taken at baseline and after 12 weeks of supplementation. There were significant increases in the EPA (413%) and DHA (59%) levels in red blood cells after FO supplementation, with no change of these fatty acids in the OO group. RMR and substrate oxidation did not change after supplementation with OO or FO after 6 and 12 weeks. Since there was no effect of supplementation on metabolic measures, we pooled the two treatment groups to determine whether there was a seasonal effect on RMR and substrate oxidation. During the winter season, there was an increase in FA oxidation (36%) with a concomitant decrease (34%) in carbohydrate (CHO) oxidation (p < 0.01), with no change in RMR. These measures were unaffected during the summer season. In conclusion, FO supplementation had no effect on RMR and substrate oxidation in healthy young males. Resting FA oxidation was increased and CHO oxidation reduced over a 12 week period in the winter, with no change in RMR.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT02092649.
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Jannas-Vela
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Kaitlin
authors.initials: K
authors.lastname: Roke
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Boville
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: David M
authors.initials: DM
authors.lastname: Mutch
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Spriet
mesh_terms: D000328:Adult; D001481:Basal Metabolism / Q000187:drug effects*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000097:blood / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000097:blood / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood; D005395:Fish Oils / Q000494:pharmacology*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D000069463:Olive Oil / Q000494:pharmacology; D010084:Oxidation-Reduction; D012621:Seasons
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D000069463:Olive Oil; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid