title: Supplementation with a blend of krill and salmon oil is associated with increased metabolic risk in overweight men.
abstract: BACKGROUND
  Krill is an increasingly popular source of marine n-3 (ω-3) PUFA that is seen as a premium product. However, to our knowledge, the effect of krill-oil supplementation on insulin sensitivity in humans has not been reported.
  
  
  OBJECTIVE
  We assessed whether supplementation with a blend of krill and salmon (KS) oil [which is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] affects insulin sensitivity in overweight men.
  
  
  METHODS
  The design was a randomized, double-blind, controlled crossover trial. A total of 47 men with a mean ± SD age of 46.5 ± 5.1 y, who were overweight [body mass index (in kg/m(2)) from 25 to 30] but otherwise healthy, received 5 1-g capsules of KS oil or a control (canola oil) for 8 wk and crossed over to another treatment after an 8-wk washout period. The primary outcome was insulin sensitivity assessed by using the Matsuda method from an oral-glucose-tolerance test. Secondary outcomes included lipid profiles, inflammatory markers, 24-h ambulatory blood pressure, and carotid artery intimamedia thickness.
  
  
  RESULTS
  Unexpectedly, insulin sensitivity (per the Matsuda index) was 14% lower with the KS oil than with the control oil (P = 0.049). A mediation analysis showed that, after controlling for the likely positive effects of blood EPA and DHA (i.e., the omega-3 index), the reduction in insulin sensitivity after KS-oil supplementation was more marked [27% lower than with the control oil (P = 0.009)].
  
  
  CONCLUSIONS
  Supplementation with a blend of KS oil is associated with decreased insulin sensitivity. Thus, krill-oil supplementation in overweight adults could exacerbate risk of diabetes and cardiovascular disease. This trial was prospectively registered at the Australian New Zealand Clinical Trials Registry as ACTRN12611000602921.
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Albert
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: José G B
authors.initials: JG
authors.lastname: Derraik
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Brennan
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: Janene B
authors.initials: JB
authors.lastname: Biggs
authors.affiliation: Nutraceuticals Research Group, University of Newcastle, Callaghan, Australia.
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Garg
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: David
authors.initials: D
authors.lastname: Cameron-Smith
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Hofman
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; and w.cutfield@auckland.ac.nz.
authors.forename: Wayne S
authors.initials: WS
authors.lastname: Cutfield
mesh_terms: D000328:Adult; D000818:Animals; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology; D018592:Cross-Over Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000097:blood; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000097:blood; D033201:Euphausiacea; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D005395:Fish Oils / Q000008:administration & dosage / Q000009:adverse effects*; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009520:New Zealand; D050177:Overweight / Q000503:physiopathology*; D000074262:Rapeseed Oil; D012307:Risk Factors; D012474:Salmon; D016896:Treatment Outcome
chemical_list: D005229:Fatty Acids, Monounsaturated; D005395:Fish Oils; D000074262:Rapeseed Oil; D004281:Docosahexaenoic Acids; C030341:salmon oil; D015118:Eicosapentaenoic Acid
keywords: cholesterol; insulin sensitivity; lipids; males; nutraceutical; n–3 PUFA; omega-3