Fish Oil and Surgery

Multiple studies demonstrated that fish oil, typically as an addition to standard nutritional support, reduced complications associated with surgical resection, such as postoperative complications, duration of hospital stay, and postoperative death.13,14 Another study demonstrated that an energy-dense drink that contained omega-3 fatty acids (2.02 g EPA and 0.92 g DHA) resulted in significantly better quality of life (QoL), both in physical and cognitive function (P < .01), social function (P = .04), global health status (P = .04), and Karnofsky performance status (P = .04) compared with the control group.15

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No Effect

Several other studies, however, found no additional improvement with fish oil supplementation.

An RCT of 195 patients undergoing subtotal esophagectomy and total gastrectomy received an enteral immunoenhancing diet containing omega-3 fatty acids or standard enteral nutrition for 7 days prior to surgery or standard diet supplementation postsurgery.16 Morbidity, mortality, and duration of hospital stay were similar among the groups. Another study found no difference in postoperative morbidity or median body weight loss with a standard diet plus EPA (2.2 g) supplement compared with standard diet along.17

A study of 62 patients who had undergone prostatectomy received EPA (2.4 g per day) or no supplement for 2 years.18 Prostate-specific antigen recurrence was similar between both groups with a mean follow-up of 53.8 months.

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Numerous studies have evaluated the effect of fish oil supplementation on cachexia because conventional nutritional support often fails to increase body weight among patients with advanced cancer.19 One study demonstrated that patients with cancer had a greater resting energy expenditure, fat oxidation, and glucose intolerance compared with healthy controls. Fish oil supplementation, however, increased body weight and also returned feeding energy expenditure and fat oxidation to levels similar to that of controls.

A systematic review published in 2011 did not find enough evidence to support a benefit of omega-3 fatty acid supplementation and improvement in cachexia.20 Several studies since then, however, demonstrated that the addition of fish oil as part of a nutritional supplement resulted in increased or stabilized body weight, as well as improved appetite and function.21-23 Fish oil supplementation also resulted in increased muscle mass compared with placebo in one study.22 Another study also showed increased energy and protein intake, and improved fatigue and neuropathy, among patients who received an EPA-containing oral nutritional support compared with an isocaloric diet.23


Fish oil supplementation may improve chemotherapy-related outcomes, such as time to tumor progression, and may be protective against certain toxicities. The data remained mixed as to whether fish oil supplementation can improve nutritional and functional status after tumor surgical resection, though these mixed outcomes may be explained by differences in the supplement. Some negative studies, for example, used an EPA-only supplement rather than fish oil, which contains both EPA and DHA.

The data are also mixed regarding the beneficial effects of fish oil on cachexia, but more recent studies suggest that fish oil as part of standard nutritional support can improve nutritional parameters.


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  8. Ghoreishi Z, Esfahani A, Djazayeri A, et al. Omega-3 fatty acids are protective against paclitaxel-induced peripheral neuropathy: a randomized double-blind placebo controlled trial. BMC Cancer. 2012;12:355-63.
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  10. Hershman DL, Unger JM, Crew KD, et al. Randomized multicenter placebo-controlled trial of omega-3 fatty acids for the control of aromatase inhibitor–induced musculoskeletal pain: SWOG S0927. J Clin Oncol. 2015;33:1910-7. doi: 10.1200/JCO.2014.59.5595
  11. Martin RC 2nd, Agle S, Schlegel M, et al. Efficacy of preoperative immunonutrition in locally advanced pancreatic cancer undergoing irreversible electroporation (IRE). Eur J Surg Oncol. 2017;34:772-9. doi: 10.1016/j.ejso.2017.01.002
  12. Wei Z, Wang W, Chen J, Yang D, Yan R, Cai Q. A prospective, randomized, controlled study of ω-3 fish oil fat emulsion-based parenteral nutrition for patients following surgical resection of gastric tumors. Nutr J. 2014;13:25-31.
  13. Jiang ZM, Wilmore DW, Wang XM, et al. Randomized clinical trial of intravenous soybean oil alone versus soybean oil plus fish oil emulsion after gastrointestinal cancer surgery. Br J Surg. 2010;97:804-9. doi: 10.1002/bjs.6999
  14. Klek S, Scislo L, Walewska E, Choruz R, Galas A. Enriched enteral nutrition may improve short-term survival in stage IV gastric cancer patients: a randomized, controlled trial. Nutrition. 2017;36:46-53. doi: 10.1016/j.nut.2016.03.016
  15. van der Meij BS, Languis JAE, Spreeuwenberg MD, et al. Oral nutritional supplements containing n-3 polyunsaturated fatty acids affect quality of life and functional status in lung cancer patients during multimodality treatment: an RCT. Eur J Clin Nutr. 2012;66:399-404. doi:10.1038/ejcn.2011.214
  16. Sultan J, Griffin SM, Di Franco F, et al. Randomized clinical trial of omega-3 fatty acid-supplemented enteral nutrition versus standard enteral nutrition in patients undergoing oesophagogastric cancer surgery. Br J Surg. 2012;99:346-55. doi: 10.1002/bjs.7799
  17. Ida S, Hiki N, Cho H, et al. Randomized clinical trial comparing standard diet with perioperative oral immunonutrition in total gastrectomy for gastric cancer. Br J Surg. 2017;104:377-83. doi: 10.1002/bjs.10417
  18. Higashihara E, Itomura M, Terachi T, et al. Effects of eicosapentaenoic acid on biochemical failure after radical prostatectomy for prostate cancer. In vivo. 2010;24:561-6.
  19. Barber MD, McMillan DC, Preston T, Ross JA, Fearon KC. Metabolic response to feeding in weight-losing pancreatic cancer patients and its modulation by a fish-oil-enriched nutritional supplement. Clin Sci. 2000;98:389-99.
  20. Ries A, Trottenberg P, Elsner F, et al. A systematic review on the role of fish oil for the treatment of cachexia in advanced cancer: an EPCRC cachexia guidelines project. Palliat Med. 2011;26:294-304. doi: 10.1177/0269216311418709
  21. Fietkau R, Lewitzki V, Kuhnt T, et al. A disease-specific enteral nutrition formula improves nutritional status and functional performance in patients with head and neck and esophageal cancer undergoing chemoradiotherapy: results of a randomized, controlled, multicenter trial. Cancer. 2013;119:3343-53. doi: 10.1002/cncr.28197
  22. Murphy RA, Mourtzakis M, Chu QS, Baracos VE, Reiman T, Mazurak VC. Nutritional intervention with fish oil provides a benefit over standard of care for weight and skeletal muscle mass in patients with nonsmall cell lung cancer receiving chemotherapy. Cancer. 2011;117:1775-82. doi: 10.1002/cncr.25709
  23. Sánchez-Lara K, Turcott JG, Juárez-Hernández E, et al. Effects of an oral nutritional supplement containing eicosapentaenoic acid on nutritional and clinical outcomes in patients with advanced non-small cell lung cancer: randomised trial. Clin Nutr. 2014;33:1017-23. doi: 10.1016/j.clnu.2014.03.006