The supplementation regimen also increased VO2 max for the runners without conferring any performance in 1,500 metre run times, report scientists from the Gdansk University of Physical Education and Sport in Poland and the University of Southampton in England.
“12 weeks with omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily during endurance training increased O3I in all but one participant in OMEGA group to mean of 11.4%, which is considered to be well within the O3I target range,” wrote Tomczyk et al. in Medicine & Science in Sports & Exercise.
“Moreover, an increase in O3I correlated with an increase in running economy at velocity 12 km/h.”
The Omega-3 Index measures the level of long-chain omega-3 fatty acids, EPA+DHA, in red blood cell membranes expressed as a percent of total fatty acids.
An Omega-3 Index in the range of 8-12% is one indicator of better overall health. As a part of an overall healthy lifestyle, an Omega-3 Index of 8% or higher may help to maintain heart, brain, eye and joint health. An intermediate Omega-3 Index is between 4% and 8%, and a low Omega-3 Index is 4% and below. Most Americans have an Omega-3 Index below 4%.
Commenting independently on the study’s findings, Kaitlin Roke, PhD, Director of Scientific Communication and Outreach, Global Organization for EPA and DHA Omega-3 (GOED), told us: “As Tomczyk et al. stated, unfortunately, most people including athletes don't consume enough EPA+DHA omega-3s in their diet. From an exercise performance perspective, everyone is looking for an edge - from performance to recovery. There is a lot of hype around EPA+DHA omega-3 supplementation/intake. Scientifically, there seems to be some interesting results from skeletal muscle and molecular signalling studies. However, there haven't been a lot of studies to date on more tangible exercise outcomes, as measured in the study by Tomcyzk et al. and this work is welcomed.
Dr Roke added that well designed studies with clear methodology like this paper by Tomczyk et al. are important for the field of nutritional and exercise science.
“Tomczyk et al. set out to address a specific question, and the study design and statistics were understandable and repeatable. After reading this article, I am curious to see if there would be an impact over other running distances (the test length of a 1,500m race was chosen in this study).
“The authors measured VO2 max, which is a common and regular measurement in exercise physiology studies. However, this measurement is subject to a lot of variability - including temperature and humidity of the room (which was controlled for by Tomczyk et al.).
“This exemplifies one of the challenges in measuring changes and outcomes related to supplementation and exercise studies - some of these "objective" markers have a lot of variability making it hard to detect meaningful changes. And, a lot of the important cellular changes can't be seen, or felt!”
The new study included 26 amateur male long-distance runners 29 years of age or older who were randomly assigned to receive either the omega-3 supplement (Omega-3 double plus, NAMED SPORT, Italy), whereas the M) or medium chain triglycerides capsules as placebo during 12 weeks of endurance training.
Results at the end of the study showed that the average omega-3 index increased in the omega-3 group from 5.8% to 11.6%, with no changes recorded in the placebo group.
VO2peak was found to significantly increase in omega-3 group, from 54 ml.kg-1.min-1 at week 0 to 56 ml.kg-1.min-1, after 12 weeks. Again, no significant changes were observed in the placebo group.
“This may suggest better adaptation to endurance training in response to omega-3 fatty acid supplementation, as has been observed with several other dietary supplements,” wrote the researchers. “Still, neither our nor previous reports support the hypothesis that long-term supplementation with omega-3 fatty acids enhances exercise performance.”
Indeed, the researchers did not observe any performance benefits, with 1,500 metre run times unaffected.
The researchers also reported that the change in the Omega-3 Index was positively correlated with changes in running economy when data from both groups were combined (but no effects were seen when only the data from the omega-3 group was used).
“Compared to previous studies in which performance indicators were assessed, our supplementation protocol (2234 mg of EPA and 916 mg of DHA daily for 12 weeks) was a higher dose over a longer supplementation period,” they added. “However, what values of O3I are sufficient for amateur and competitive athletes to optimize athletic performance remains a question to be answered in future studies.”
Commenting on potential follow-on studies, GOED’s Dr Roke told us: “From a statistical perspective, the sample size calculation recommended 40 people in the study to detect significant differences in groups, however only 26 participants completed the study. Therefore, future work with more participants, other ages, and genders would be important for further clarification/determination of an effect.
“Given the clear methods in this paper by Tomczyk et al., it would be possible for this experiment to be repeated in a different population group, with the potential for pooled results to increase statistical power.”
Source: Medicine & Science in Sports & Exercise
Published online ahead of print, doi: 10.1249/MSS.0000000000003038
“Effects of 12 Weeks of Omega-3 Fatty Acid Supplementation in Long-distance Runners”
Authors: M. Tomczyk, et al.