Can Fish Oil Make You a Better Runner?

Last updated: 16-Aug-18

By Andrew Mobbs

A recent study published by the Stanford University School of Medicine and the University of California found ultra runners to be an extremely healthy bunch of people. The study conducted on 1200 ultra runners over the course of a year found that they suffered fewer serious illnesses or injuries, had less sick days off per year and visited the doctor less frequently than the general population1. Another study by The Federation University in Australia found that ultra runners had on average a biological age that was 16 years younger than their real age2.

So there you have it ultra running is clearly good for you. Well yes, but there was also a problem, the studies also highlighted that ultra runners were far more likely to suffer from joint pain, stress fractures, asthma and allergies, and the source of these issues was inflammation.

The dangers of inflammation

The many hours and miles spent on roads and trails doing what we love to do can cause increased levels of inflammation and muscle damage throughout the body. A Greek study published in the European Journal of Clinical Investigation on participants in the 2006 Spartathlon found that the runners had significantly raised markers of inflammation called cytokines. An inflammatory cytokine is a molecule released by the immune system that stimulates other cells to cause an inflammatory response.

The release of cytokines is absolutely necessary to help the body deal with acute inflammation, but when that inflammation becomes chronic it can cause real problems in the body. The specific cytokines that were found to be raised in the Spartathlon study included C-reactive protein (CRP), Interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha).

IL-6 has long been associated with the development of asthma3, and all 3 are associated with heart disease and an increased risk of heart attack. In fact, a 2009 study at Liverpool John Moores University tested competitors in the Lakeland Ultra and found that 12% showed signs of significant heart muscle damage4.

So what has this got to do with fish oil? Well Omega 3 is nature’s natural anti-inflammatory. So as ultra runners if we can hit that balanced sweet spot between getting all the physiological and psychological benefits from running, and also keeping inflammation to a minimum, we are in a win win situation.

What benefits can Omega 3 bring to runners?

The general health benefits of Omega 3 have been known for a long time, but its ability to help athletes is just starting to be studied in depth. Studies have shown that Omega 3 supplementation can significantly reduce levels of CRP, IL-6 and TNF-alpha5 6.

Omega 3 has been shown to reduce DOMS (delayed onset muscle soreness)7, as well as increasing blood flow to the muscles during exercise. It does this by simultaneously widening arteries8 and making red blood cells more flexible so they squeeze through capillaries9 10. Normally they would become stiffer as exercise progresses due to free radical production11. Omega 3 also turns on the body’s muscle building switch known as mTor, which means it helps to build muscle and prevent its breakdown, which is especially important towards the end of long runs12 14.

How much fish oil to take?

Studies have shown that to benefit from the anti-inflammatory effects of Omega 3 we need to take at least 2.7 grams of the main Omega 3 fatty acids found in fish oil – EPA and DHA per day15. It was initially thought that EPA was the more powerful anti-inflammatory fatty acid, but new research published in the American Journal of Clinical Nutrition in June of this year shows that DHA is actually more effective at reducing inflammatory markers16.

The natural ratio of EPA to DHA found in fish is 3:2, however, most fish oil manufacturers pack much more EPA into their supplements because it is cheaper to produce, often going as high as 4 or 5:1. However, the best fish oils use a natural 3:2 ratio, so we recommend aiming for at least 2.7 grams a day of omega 3 in a 3:2 EPA to DHA ratio. 

Why take fish oil and not vegetarian sources of omega 3 like flax seed?

Flax seed and other vegetarian sources of omega 3 are rich in ALA (alpha linoleic acid), this is the shortest Omega 3 fatty acid made up of 18 carbon molecules, and is a largely inactive molecule in the body. To help with inflammation ALA has to be turned into EPA and DHA. EPA and DHA are both longer molecules at 20 and 22 carbon molecules, however, unfortunately this conversion process is very inefficient.

A 2007 study in the Journal of Applied Physiology, Nutrition and Metabolism showed that only 5% of ALA could be converted to EPA and less than 0.5% of AlA made it into DHA. The conversion is made even more difficult when people eat a diet high in Omega 6 fatty acids which compete for the same conversion enzymes as Omega 3 fatty acids, that’s why we need specific sources of EPA and DHA17.

Not all fish oils are the same

Omega 3 fatty acids are found in nature in a triglyceride form, however, the majority of Omega 3 fish oils on the market are sold in an ethyl ester form, which is artificially created in a lab. The ethyl ester form allows companies to concentrate their Omega 3 EPA and DHA content, but it significantly reduced the absorption and effectiveness of the omega 3.

Studies have shown that triglycerides are between 70% and 400% better absorbed than ethyl ester fish oils and more effective at reducing inflammation once they have been absorbed into the body18 19. To effectively deal with inflammation make sure to only choose a triglyceride omega 3.

I recommend Intelligent Labs Omega 3, a ultra pure triglyceride Omega 3, with the natural 3:2 EPA and DHA ratio. It’s also the strongest triglyceride Omega 3 on the market with 3 grams of EPA and DHA per 4 capsules.

We use affiliate links in some of our reviews and articles. This means that if you purchase an item through one of these links we will earn a commission. You will not pay more when buying a product through our links but the income will help us to keep bringing you our free training guides, reviews and other content to enjoy. Thank you in advance for your support.

1 Martin D. Hoffman , Eswar Krishnan, Health and Exercise-Related Medical Issues among 1,212 Ultramarathon Runners: Baseline Findings from the Ultrarunners Longitudinal TRAcking (ULTRA) Study, Plos One, January 8, 2014.

2 Joshua Denham, Christopher P. Nelson, Brendan J. O’Brien, Scott A. Nankervis, Matthew Denniff, Jack T. Harvey, Francine Z. Marques, Veryan Codd, Ewa Zukowska-Szczechowska, Nilesh J. Samani, Maciej Tomaszewski, and Fadi J. Charchar, Longer Leukocyte Telomeres Are Associated with Ultra-Endurance Exercise Independent of Cardiovascular Risk Factors, PLoS One. 2013; 8(7)

3Mercedes Rincon, and Charles G. Irvin, Role of IL-6 in Asthma and Other Inflammatory Pulmonary Diseases, Int J Biol Sci. 2012; 8(9): 1281–1290.

4European Society of Cardiology (ESC). “Ultra-endurance running may not be good for the heart, study suggests.” ScienceDaily. ScienceDaily, 31 August 2010,

5Rasic-Milutinovic Z, Perunicic G, Pljesa S, et al. Effects of N-3 PUFAs supplementation on insulin resistance and inflammatory biomarkers in hemodialysis patients. Ren Fail 2007;29: 321-9.

6Hamid Tayyebi-Khosroshahi1, Jalil Houshyar1, Reza Dehgan-Hesari1, Hosein Alikhah2, Amir-Mansour Vatankhah3, Abdol-Rasoul Safaeian4, Neda Razzagi, Effect of treatment with Omega-3 fatty acids on C-reactive protein and tumor necrosis factor-alfa in hemodialysis patients Zonouz, 2012, Volume:23, Issue:3,500-506.

7Tartibian, Bakhtiar; Maleki, Behzad Hajizadeh; Abbasi, Asghar. The Effects of Ingestion of Omega-3 Fatty Acids on Perceived Pain and External Symptoms of Delayed Onset Muscle Soreness in Untrained Men. Clinical Journal of Sports Medicine, March 2009

8Hill A.M., J.D.Buckley, K.J.Murphy, P.R.C.Howe (2007) Combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors. Am.J.Clin.Nutr. 85:1267-1274.

9Cartwright I. J., A.G.Pockley, J.H.Galloway, M.Greaves, F.E.Preston (1985) The effects of dietary ω-3 polyunsaturated fatty acids on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity in healthy volunteers. Atherosclerosis 55:267-281.

10Terano T., A.Hirai, T.Hamazaki, S.Kobayashi, T.Fujita, Y.Tamura, A.Kumagai (1983) Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects. Atherosclerosis 46:321-331.

11Szygula Z. (1990) Erythrocytic system under the influence of physical exercise and training. Sports Med. 10:181-197.

12Gordon I. Smith, Philip Atherton, Dominic N. Reeds, B. Selma Mohammed, Debbie Rankin, Michael J. Rennie, and Bettina Mittendorfer. Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperaminoacidemia-hyperinsulinemia in healthy young and middle aged men and women. Clin Sci (Lond). 2011 Sep; 121(6): 267–278.

13Di Girolamo FG1, Situlin R, Mazzucco S, Valentini R, Toigo G, Biolo G. Omega-3 fatty acids and protein metabolism: enhancement of anabolic interventions for sarcopenia. Curr Opin Clin Nutr Metab Care. 2014 Mar;17(2):145-50.

14McDonald C1, Bauer J, Capra S. Omega-3 fatty acids and changes in LBM: alone or in synergy for better muscle health? Can J Physiol Pharmacol 2013 Jun;91(6):459-68.

15Fish oil: what the prescriber needs to know, Leslie G Cleland, Michael J James and Susanna M Proudman, Arthritis Res Ther. 2006; 8(1): 202.

16Janie Allaire, Patrick Couture, Myriam Leclerc, Amélie Charest, Johanne Marin4, Marie-Claude Lépine, Denis Talbot, André Tchernof, and Benoît Lamarche, Randomized, crossover, head-to-head comparison of EPA and DHA supplementation to reduce inflammation markers in men and women: the Comparing EPA to DHA Study, Am J Clin Nutr, June 8, 2016.

17Mélanie Plourde, Stephen C. Cunnane, Extremely limited synthesis of long chain polyunsaturates in adults: implications for their dietary essentiality and use as supplements, Applied Physiology, Nutrition, and Metabolism, 2007, 32(4): 619-634.

18Dyerberg, J., Madsen, P., Møller, J., Aardestrup, I., & Schmidt, E. (2010). Bioavailability of marine n-3 fatty acid formulations. Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA), 83(3), 137-141.

19Davidson MH, Johnson J, Rooney MW, Kyle ML, Kling DF. A novel omega-3 free fatty cid formulation has dramatically improved bioavailability during a low fat diet compared with omega-3-acid ethyl ester: The ECLIPSE (Epanova compared to Lovaza in a pharmacokinetic single dose evaluation) study. J coin Lipidol 2012;6:573-84.

"ultra runners are far more likely to suffer from joint pain, stress fractures, asthma and allergies, and the source of these issues is inflammation"

Like what you read?

Click here to sign up for more

Related news

Latest news

MIUT 85k Race Report

MIUT 85k Race Report I want to share my experience of the MIUT 85k as a novice Ultra-Runner – what my background is, how I prepared, how

Read More »



Distance - slider
Entry Fee
Entry Fee - slider


Date Range

Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for

For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

Endurance - Multi-activity


An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

Suitable for

Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

Suitable for

Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

Suitable for

Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.