Fish Oil Supplements in Athletes: No Performance Boost from Latest Reviews

The most recent edition of Advances in Nutrition features two noteworthy articles that merit detailed examination, particularly for those interested in nutritional supplements. The first, and arguably the more relevant to performance-oriented readers, originates from researchers at the University of

The most recent edition of Advances in Nutrition features two noteworthy articles that merit detailed examination, particularly for those interested in nutritional supplements. The first, and arguably the more relevant to performance-oriented readers, originates from researchers at the University of Bath. This study stands out as the inaugural systematic review specifically evaluating fish oil supplements in athletes throughout the extensive history spanning over 25 years of such supplementation research. This review meticulously analyzes the evidence, while a companion umbrella review explores broader implications of fish consumption, providing a comprehensive overview of omega-3 fatty acids' roles.

Examining the Evidence from Systematic Review on Fish Oil in Athletes

Contrary to widespread assumptions that fish oil functions more like an essential nutrient than a mere supplement, the question arises: do athletes truly gain performance advantages from it? A more precise inquiry would be, "In what specific areas of health and athletic performance might athletes experience benefits?" The findings reveal a blend of encouraging and sobering insights: no direct enhancements in athletic performance across any of the examined studies, yet promising trends emerge in areas such as the central nervous system, cardiovascular health, reductions in proinflammatory cytokines, and select physiological aspects of skeletal muscle function.

The review incorporated 32 randomized controlled trials (RCTs) that met stringent inclusion criteria. These trials were generally modest in scale, with an average of just 27 participants per study, ranging from 15 to 81 athletes. This selection came from an initial pool of 137 identified papers, after excluding 115 that either inadequately detailed their methodology and statistical methods or involved participants not classified as competitive athletes—such as recreational exercisers or those merely resistance-trained.

Concerns regarding potential bias are noteworthy. The authors noted that seven RCTs openly disclosed sponsorship or funding from the fish oil industry. When paired with inadequate blinding by researchers, this raises valid questions. Notably, single-blind studies comprised only 20% of the total, and removing them did not substantially alter the overall conclusions.

The review took a broad approach by including studies across diverse athlete groups, varying by sport and participant gender, without mandating specific fish oil dosages, supplementation durations, or whether the supplements focused solely on EPA or DHA. Additionally, many studies overlooked baseline assessments of participants' n-3 fatty acid status, and some combined fish oil with other supplements, such as antioxidants, which the reviewers generously permitted.

Importantly, no RCTs to date have shown any detrimental effects of fish oil supplementation on athletic performance.

This absence of negative impacts is reassuring. However, the lack of confirmed performance improvements does not render fish oil entirely without value; it simply lacks acute ergogenic properties—a conclusion consistent with prior analyses conducted several years ago. Visual representations from earlier research, like those from 2016, highlight established health benefits alongside the consistent absence of boosts to maximal aerobic capacity or sport-specific performance metrics.

The sports covered in these investigations are extensive, encompassing cycling, judo, soccer, basketball, swimming, paddling, marathon running, track and field events, rugby, wrestling, American football, and more. Researchers emphasized that the dosages of DHA and EPA used in most trials mirror levels attainable through regular intake of oily fish varieties. Excellent sources include mackerel (approximately 5,134 mg of omega-3 per 100g), salmon (2,260 mg per 100g), and herring (2,366 mg total n-3 per 100g). These fish not only deliver ample omega-3s but also provide high-quality protein and other vital nutrients, with minimal risks from heavy metal contamination compared to some supplements.

Health Advantages of Fish Consumption Over Supplements

Recent umbrella meta-analyses reinforce the value of fish intake. For instance, each additional 20 grams per day of fish consumption correlates with a 2% to 7% decreased risk across various health outcomes. Complementary evidence from 2020 shows that increasing fish intake by 100 grams daily links to an 8% reduction in all-cause mortality, a 25% drop in cardiovascular mortality, a 22% lower risk of coronary heart disease, and additional protective effects against other conditions, as illustrated in detailed risk reduction charts.

Among athletes, inflammation reduction stood out as the most commonly assessed outcome, with EPA doses from 300 to 2,400 mg daily and DHA from 400 to 1,500 mg daily. Responses varied by inflammatory marker, but tumor necrosis factor-alpha (TNF-α) showed significant reductions in four out of five studies. While TNF-α suppression may not directly enhance training adaptations, other findings are compelling:

• Limited evidence suggests a lower incidence of upper respiratory tract infections (URTIs).
• Improved muscle recovery appeared in 4 of 7 RCTs, gauged by metrics like muscle soreness, countermovement jump height, and creatine kinase levels.
• Consistent positive impacts on cardiovascular function and oxygen utilization kinetics in cyclists, including enhanced cycling efficiency and maximal oxygen uptake (VO2max).

Although no ergolytic effects were identified, increased lipid peroxidation—a potential downside—warrants attention. Three RCTs reported elevated biomarkers like malondialdehyde and F2-isoprostanes at rest with various EPA and DHA doses, while four noted this post-exercise.

Emerging data hints at cognitive advantages and DHA's protective role against neuronal injury biomarkers, though studies remain sparse. Thus, adhering to guidelines for two weekly servings of fatty fish emerges as a prudent strategy, sidestepping risks associated with low-quality, oxidized supplements.

Practical Recommendations: Prioritize Whole Fish Sources

Achieving two servings of fatty fish weekly is feasible, affordable, and straightforward—even canned options qualify. Research indicates canned bluefin tuna serves as a cardioprotective functional food, potentially safer than many commercial fish oil products. Each 50-gram serving delivers over 1 gram of DHA and EPA, often surpassing typical supplement capsules. Key nutrient degradation happens primarily during pre-canning processes like chilling, freezing, and cooking—steps applicable to fresh fish as well.

In summary, while fish oil supplements do not deliver performance enhancements for athletes, their broader health benefits, particularly from whole food sources like fish, support inclusion in a balanced diet. This nuanced perspective from the latest systematic reviews and umbrella analyses guides informed supplementation and dietary choices.

Key Studies and References

• Aubourg, Santiago P. "Loss of quality during the manufacture of canned fish products." Food Science and Technology International 7.3 (2001): 199-215.
• Jayedi, Ahmad, and Sakineh Shab-Bidar. "Fish Consumption and the Risk of Chronic Disease: An Umbrella Review of Meta-Analyses of Prospective Cohort Studies." Advances in Nutrition (2020).
• Lewis, Nathan A., et al. "Are there benefits from the use of fish oil supplements in athletes? A systematic review." Advances in Nutrition (2020).
• Li, Ni, et al. "Fish consumption and multiple health outcomes: Umbrella review." Trends in Food Science & Technology (2020).
• Peoples, Gregory E., and Peter L. McLennan. "Fish oil for physical performance in athletes." Fish and Fish Oil in Health and Disease Prevention. Academic Press, 2016. 119-136.
• Tenore, Gian Carlo, et al. "Canned bluefin tuna, an in vitro cardioprotective functional food potentially safer than commercial fish oil based pharmaceutical formulations." Food and Chemical Toxicology 71 (2014): 231-235.