No impact of fish oil supplements on bleeding risk: a systematic review

Dan Med J. 2017 May;64(5):A5366.


Introduction: Fish oil supplementation may inhibit platelet aggregation and can potentially increase the risk of bleeding. The aim of the present systematic review was to evaluate the effect of fish oil supplements on haemostasis and bleeding risk, and to provide recommendations on whether it is necessary to discontinue fish oil supplementation prior to surgery.

Methods: Studies were identified through PubMed and Embase searches and by reviewing the reference lists of the included papers. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Included in the review were publications including a minimum of 20 healthy subjects and studies on patients who were undergoing surgery and who had fish oil exposure.

Results: In total, 52 publications were included; 32 publications on healthy subjects and 20 publications on patients undergoing surgery. The majority of the included studies were randomised controlled trials or included a control group. Overall, fish oil supplements reduced platelet aggregation in healthy subjects. Fish oil exposure in surgical patients did not increase bleeding or blood transfusions either during or after surgery.

Conclusion: Fish oil supplements reduced platelet aggregation in healthy subjects. This biochemical effect was not reflected in increased bleeding risk during or after surgery evaluated in randomised controlled trials. Consequently, this systematic review does not support the need for discontinuation of fish oil supplements prior to surgery or other invasive procedures.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Blood Loss, Surgical
  • Dietary Supplements / adverse effects*
  • Fish Oils / adverse effects*
  • Humans
  • Postoperative Hemorrhage / chemically induced
  • Postoperative Hemorrhage / diagnosis*
  • Randomized Controlled Trials as Topic
  • Risk Assessment


  • Fish Oils