New Information on Fish Oil Safety and Health Benefits

By: Mark Lange, PhD


A systematic review of scientific literature reveals that concerns of fish oil supplements possibly increasing bleeding risk are unfounded, according to a paper from the Danish Medical Journal.[i]

Data collected from 16 studies of people undergoing surgery found that fish oil supplementation did not, in fact, increase bleeding risk.  Fish oil supplementation is associated with a reduction in platelet aggregation in healthy individuals, but that does not appear to translate into an increase in bleeding risk during surgery.

Three other studies[ii] [iii] [iv] found the following:

  1. 10 weeks supplementation with 2.7 grams of DHA produced greater reduction in triglyceride levels more than the same amount of EPA.
  2. EPA and DHA have similar effect on expression of genes involved in regulating the anti-inflammatory and pro-inflammatory processes.
  3. DHA supplementation increases the Omega-3 Index more than EPA supplementation. The Omega-3 Index is a measure of omega-3 fatty acids in red blood cells, which relates to risk for heart disease.

Since the concern about fish oil’s potential to increase bleeding during surgery has not been supported, discontinuation of the supplement leading up to surgery and other invasive procedures is not recommended.



[i] K. Munk Begtrup, et al.  No impact of fish oil supplements on bleeding risk: a systematic review.  Danish Medical Journal 2017, Vol 64, No. 5, A5366

[ii] C. Vors, et al.  Inflammatory gene expression in whole blood cells after EPA vs DHA supplementation: Results from the ComparED study.  Atherosclerosis, Feb 2017, Vol 257, pp 116-122

[iii] J. Allaire, et al.  A randomized, crossover, head-to-head comparison of EPA and DHA supplementation to reduce inflammation marker in men and women.  American J of Clin Nutr.  Aug 2016, Vol 104, No 2 pp 280-287

[iv] J. Allaire, et al.  Supplementation with high-dose DHA increases the omega-3 Index more than high-dose EPA.  Prostaglandins, Leukotrienes and Essential Fatty Acids,  May 2017, Vol. 120, pp 8-14