Dr. Dwayne Jackson

The Vital Science Blog

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Fishing for fitness

Over the years, research supporting the health benefits of fish oil supplementation has been astounding.  The omega-3 fatty acids found in cold water fish have been shown to reduce inflammation, increase cardiovascular health, increase the efficiency of the heart during exercise, maintain healthy blood lipid profiles, and, more recently, increase fat metabolism and lean mass gain. Herein we present the science supporting the daily use of fish oil to promote fitness, greater muscular gains, and fat loss. 


  1. Fish oil supplements improve exercise efficiency

Scientists from Australia have shown that fish oil supplements decrease the amount of work the heart and muscles have to do during maximal cycling exercise. The researchers reported that fish oil supplements lowered heart rate (including peak heart rate) during incremental exercise to exhaustion. As well, fish oil supplementation lowered steady-state submaximal exercise heart rate, whole-body oxygen consumption, and the oxygen requirements of the heart. In light of these data, it seems that fish oils make the heart and skeletal muscle contract more efficiently during moderate to high intensity exercise.  


Along similar lines, in a more recent study published in Bioscience, Biotechnology, and Biochemistry, Japanese researchers hypothesized that since eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil act as “blood thinners” (i.e., decrease blood viscosity), then it may improve blood flow/oxygen supply to tissues and increase exercise performance. 


In this double-blinded and placebo-controlled study, 20 fit college aged male volunteers were to instructed to take either 3.6 g of fish oil or a placebo split into 3 daily doses, for 56 days. Prior to and after 8 weeks supplementation, subjects completed a series of VO2max (maximum aerobic fitness) tests and submaximal exercise tests. 


As predicted, the researchers found that fish oil supplementation increased red blood cell EPA and DHA content and decreased oxygen consumption during steady-state submaximal exercise. They also reported that subjects who took fish oil had reduced measures of perceived exertion—meaning that the exercise “felt” easier when they took fish oil. The authors concluded that fish oil supplementation improves exercise efficiency, which may also promote greater exercise endurance capacity. 



Peoples GE, McLennan PL, Howe PR, Groeller H. Fish oil reduces heart rate and oxygen consumption during exercise. J Cardiovasc Pharmacol. 2008 Dec;52(6):540-7.


Kawabata F1, Neya M, Hamazaki K, Watanabe Y, Kobayashi S, Tsuji T.

Supplementation with eicosapentaenoic acid-rich fish oil improves exercise economy and reduces perceived exertion during submaximal steady-state exercise in normal healthy untrained men. Biosci Biotechnol Biochem. 2014 Dec;78(12):2081-8.


  1. Fish oil promotes anabolism

Important for bodybuilders, recent evidence has shown that taking omega-3 fatty acids (like those found in fish oil) in the face of hyperaminoacidemia (which occurs when you drink a whey protein isolate shake) and hyperinsulinemia (which occurs when you ingest fast digesting carbohydrates like dextrose) leads to a considerable increase in anabolism. 


In a study published in Clinical Science, scientists from the Washington University School of Medicine evaluated the anabolic effects of taking an omega-3 fatty acid supplement under conditions of hyperaminoacidemia and hyperinsulinemia. In the study, 9 healthy men and women aged 25-45 years old were subjected to stable-isotope tracer infusions and muscle biopsies before and after 8 weeks of omega-3 fatty acid supplementation. The infusions were used to evaluate the rate of muscle protein synthesis and anabolic signaling under baseline conditions and during insulin and amino acid infusion. Interestingly, omega-3 supplementation alone did not affect anabolism, however when it was combined with hyperaminoacidemia and hyperinsulinemia there was a 34% increase in the muscle protein fractional synthesis rate and a 50% increase in the major anabolic signaling factors mTOR and p70S6K. Furthermore, muscle biopsies revealed that there was an increase in muscle protein concentration and muscle cell size. 



Smith GI, Atherton P, Reeds DN, Mohammed BS, Rankin D, Rennie MJ, Mittendorfer B.

Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia-hyperaminoacidaemia in healthy young and middle-aged men and women. Clin Sci (Lond). 2011 Sep 1;121(6):267-78.


  1. Fish oil improves body composition

Scientists from Gettysburg College conducted research that looked at the effects of fish oil supplementation on resting metabolic rate (RMR), body composition, and cortisol levels in healthy men and women. In this doubled blinded study, baseline (pre-supplementation) measures of RMR, body composition (using a Bod Pod®), and cortisol (from saliva) were completed after fasting. Subjects were randomly put into two groups and received 4 capsules (4 grams) per day of either safflower oil (containing only omega-6 fatty acid) or fish oil (containing only omega-3 fatty acid). They were then instructed to take 2 capsules with breakfast and 2 capsules with dinner for 6 weeks; diet was not manipulated or controlled during this time.  After 6 weeks of supplementation, subjects returned to the lab to be tested again for RMR, body composition, and cortisol levels. 


The researchers reported that those who took the fish oil supplement had over 1lb increase in lean mass and a 1lb loss in fat mass, where as the safflower oil group saw no changes. Interestingly, the authors reported no change in RMR or body mass in either group, but cortisol levels tended to be lower in the fish oil group. The tendency for lower cortisol in the fish oil group correlated with their increase in lean mass and decrease in fat mass. 


This is an interesting study and the data suggests that changes in body composition with supplemental fish oil are (at least partially) due to the positive impact of omega-3 fatty acids on cortisol levels. However, given the significant changes in body composition in the fish oil group, it is perplexing that there was no change in RMR. Regardless, the data generated from this study are intriguing and provide solid support for the use of fish oil in those who are looking to maximize muscular gains while keeping lean. 



Noreen EE, Sass MJ, Crowe ML, Pabon VA, Brandauer J, Averill LK. Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults. J Int Soc Sports Nutr. 2010 Oct 8;7:31.



Muscle and Fishiness 

To reap all the health and exercise benefits of fish oil, take 1 to 3 grams of high DHA and EPA fish oil with breakfast, lunch, and dinner. On training days, take 1 dose with your postworkout protein (25-50g) and dextrose shake (25-50g).

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