Can a protocol of fish oil be effective in reducing markers of inflammation and oxidative stress in athletes?

EFFECT OF 8-WEEK N-3 FATTY-ACID SUPPLEMENTATION ON OXIDATIVE STRESS AND INFLAMMATION IN MIDDLE- AND LONG-DISTANCE RUNNING ATHLETES: A PILOT STUDY

Why is this important?

Strenuous exercise causes oxidative stress and inflammation in the body. This is a normal response and required in order to create an adaptation to the applied demand. When the inflammatory response gets out of control and a lack of recovery occurs then the athlete could be at risk of illness and/or injury as a result of muscle damage. Finding the balance is key to an effective training program. Research focusing on anti-oxidants and in particular high dose anti-oxidants (6-8g/day vitamin C & E) to reduce this effect has been found to be effective in the short term yet blunting skeletal muscle adaptation (1) in the long term (28 days) and being seen as deleterious to performance This study (2) explored a high dose (~4g/day) supplementation program of Omega-3 (EPA: DHA) oils for 8 weeks to 17-30-year-old middle and long-distance runners who were training at least 5 hours per day every day compared to a sedentary group (less than 1hr training twice per week). The investigators were interested to see if there was a difference between exercising individuals and sedentary ones with an identical supplementation program. 
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Conventional Wisdom

Previous research has investigated omega 3 supplementations to assist with reducing inflammation and oxidative stress in athletes. Jouris et al, 2011 (3) investigated the effect of 7 days of 3g/day of omega 3 on delayed onset muscle soreness (DOMS) after eccentric exercise and found ti to be effective in reducing perceived soreness in the participants. Omega 3 supplementation has been found to be effective in chronic inflammatory diseases such as bowel disease and rheumatoid arthritis yet the data on athletes is equivocal with varying results across varying studies. Omega 3’s have the ability to act as anti-oxidants and anti-inflammatory mediators via inhibition of pathways associated with inflammation as well as their direct action on macrophages and neutrophils. 

Tinlane Perspective

This study was very interesting as it investigated a group that is very much in line with or actually performs more training than the athletes that we work with. They measured a multitude of markers including testosterone/cortisol, oxidative damage (TNF-alpha, urine 8-OHdG, MDA, PCc), anti-oxidant ability (GPx, CAT), muscle damage (creatinine, CPK, LDH, IGF-1) and lipids (TAGs, Total cholesterol and HDL). The actual supplementation was 4 capsules contained 600mg DHA and EPA with a total of 950mg of omega 3 fatty acids. So the actual dosage of EPA: DHA was 2.4g/day and not 4g/day of those specific fatty acids. This is actually less than what we typically recommend on a daily basis at Tinlane. What we do not know is whether or not this supplementation protocol had any effect on adaptation to training as measured. It is important to note that diet was not controlled in this study although the baseline PUFA 6:PUFA 3 ratio intake was assessed at baseline to assess the groups habitual intake, The authors did not comment on the ratio’s the groups - so it is unclear of there was a difference at baseline.

Key Takeaways

• Triglycerides decreased in the athlete group only and total cholesterol decreased more markedly in athletes than the sedentary participants
• Creatinine was higher than baseline in athletes. This may be due to higher workloads and increased protein intake during the 8 weeks. So in terms of muscle breakdown, Omega 3s at this dose appears to have little effect.
• MDA, the key lipid peroxidation marker was significantly lower in both groups after 8 weeks and this effect was more pronounced in the athletic group. The main effect of lipid peroxidation on biological membranes is the overall decrease in their fluidity and severe damage to the membrane proteins (4)  It was absent in urine in the athletes! 
• PCc and 8-OHdG did not change indicating that oxidative stress was not completely blunted or knocked out. I read this as being a positive effect.
• TNF-alpha decreased in both groups yet more so in the athlete group indicating a reduction in inflammatory damage markers.
• GPx and CAT (anti-oxidant effect) increased in both groups 
• Cortisol was found to decrease in athletes yet increased in the sedentary group
• Overall, the effect of omega 3 supplementation on the markers investigated was more pronounced in the athletic group. The amount being recommended is not high dose and can be achieved through diet and supplementation very easily.
• Focus on finding good quality omega 3 supplements that contain at least 950-1000mg EPA:DHA per capsule.
• The other alternative in whole food form which Tinlane always recommends first and foremost is herring, mackerel, sardines, kippers on a daily basis!

Reference: 

1. Merry, Troy L, and Michael Ristow. “Do antioxidant supplements interfere with skeletal muscle adaptation to exercise training?.” The Journal of physiology vol. 594,18 (2016): 5135-47. doi:10.1113/JP270654
2. Buonocore, D., Verri, M., Giolitto, A. et al. Effect of 8-week n-3 fatty-acid supplementation on oxidative stress and inflammation in middle- and long-distance running athletes: a pilot study. J Int Soc Sports Nutr 17, 55 (2020). https://doi.org/10.1186/s12970-020-00391-4
3. Jouris, Kelly B et al. “The Effect of Omega-3 Fatty Acid Supplementation on the Inflammatory Response to eccentric strength exercise.” Journal of sports science & medicine vol. 10,3 432-8. 1 Sep. 2011

Richter C. Biophysical consequences of lipid peroxidation in membranes. Chem Phys Lipids. 1987;44:175–89.