American-style football (referred to as “football” throughout this article) is the most popular team sport in the United States. Many young athletes dream of playing under the lights and fantasize about the glamorous lifestyles often portrayed by the football athletes they idolize growing up. Yet, one thing often overlooked in many of these young athletes’ dreams is the increased health risks and possible long-term injuries that may come with playing the sport.
Although football athletes are often considered healthy and vital, the short and long-term health impacts of playing football have recently come into question. Specifically, cardiovascular and neurocognitive health concerns have generated controversy and debates among scientists, sporting governing bodies, and mainstream media.
Cardiovascular and Neurocognitive Risks of the Sport
In addition to the occasional musculoskeletal injury, health issues common to football athletes include an increased risk of developing cardiovascular disease (CVD), despite high amounts of physical activity. Factors such as high loads of static hemodynamic stress and psychological stress common in the sport carry potential implications for cardiovascular health.
Moreover, while increased body mass may help players excel on the field, a growing body of evidence describes unfavorable cardiovascular risk factors that come with higher body mass in the football athlete population, including hypertension, dyslipidemia, and inflammation, all of which contribute to CVD. The increased risk for CVD seems to follow players off the field, too. Although results have been mixed, some evidence suggests that retired football players have higher cardiovascular risk than the average age-matched population.
Football is also associated with a high incidence of mild traumatic brain injury (mTBI or concussion). Yet, newer evidence demonstrates that a football player does not need a concussion diagnosis to experience neurocognitive decline. Regular exposure to repetitive sub-concussive head impact (RSHI), which is common on the football field, is enough to cause cognitive damage.
RSHI, in the absence of a clinically discernible injury, is linked to harmful neurological changes within the brain, both structural and functional, and may have long-term implications on neurological health over time. For example, a 2018 study by Alosco et al. found that former NFL players have an increased volume of white matter signal abnormalities when compared with same-age controls, which is a possible reflection of long-term injuries from RSHIs that negatively impact cognition.
Furthermore, studies in soccer and football participants have reported higher levels of serum neurofilament light (NfL), a biomarker for axonal injury and an indicator of RSHI, as well as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a), biomarkers of acute systemic inflammation.
Omega-3s Might Play a Protective Role for Football Athletes
Omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) demonstrate a wide array of biological functions and may play a role in protecting football athletes from increased cardiovascular and neurocognitive risks. Regarding cardiovascular health, research indicates that plasma red blood cell levels of EPA and DHA attenuate CVD risk factors, such as high blood pressure, hyperlipidemia, vascular function, inflammation, and oxidative stress.
A small but relevant study conducted on professional football players in 2009 found that supplementing with 2.5g/day of mixed EPA/DHA led to dramatic improvements in blood lipid profiles. Furthermore, the omega-3 index (O3i), a measure of the amount of EPA + DHA in red blood cell membranes, has been correlated with cardiovascular health risk. Evidence indicates that an O3i >8% is associated with the greatest cardioprotection, and an O3i <4% is associated with the lowest.
Concerning cognition, the brain is highly enriched in polyunsaturated fatty acids. DHA, specifically, is a primary structural and functional component of neuronal cell membranes and regulates neurological processes involved in brain development and repair. DHA + EPA studies in animal models have demonstrated neuroprotection after RSHIs and, more recently, researchers have been studying this effect in the athletic population.
In 2016, Oliver et al. examined the potential prophylactic use of different doses (2, 4, or 6 g/day) of DHA on plasma fatty acids and serum NfL as a surrogate marker of head trauma in football athletes. The study revealed that a season of football is associated with some level of subconcussive injury, demonstrated by the observed increases of serum NfL in starting players over the course of the season. For the first time, the study also reported that supplemental DHA, irrespective of dose, can attenuate elevations in serum NfL and therefore, potentially provide neuroprotection.
In 2021, Heileson et al. studied the effect of supplemental omega-3s (560mg EPA + 320mg DPA + 2,000mg DHA) on plasma fatty acids, cardiovascular health markers, and serum NfL over a season compared to a non-supplemented control group. The researchers reported that the quantity of omega-3s provided was sufficient to increase plasma DHA and EPA and that supplementation attenuated NfL levels associated with RSHI as it occurs throughout a football season. The control group experienced a significant 1.5-fold increase in NfL over baseline values, indicating axonal injury. At the same time, there was no significant increase in NfL in the treatment group, indicating neural protection.
Concerning CVD risk, the athletes tested in this study had a baseline O3i of 4.29%, and no athlete had an O3i >8%. However, O3i increased by 71.6% in the treatment group, while the O3i fell to 3.5% in the control group throughout the season. Furthermore, the researchers found a 32% decline in the omega-6: omega-3 ratio and a 155% increase in the EPA: AA ratio in the supplementation group, both of which are believed to decrease inflammation and improve cardiovascular outcomes.
Although the evidence is encouraging, not all research has been as clear. In 2022, Mullins et al. conducted a study similar to that of Oliver et al., but added EPA to evaluate the effects of 3.5 g/day of DHA + EPA on NfL and other inflammatory biomarkers in football athletes over a season. No significant changes were observed in inflammatory markers, IL-6, or TNF-a over time or between treatment groups. However, although not statistically significant, an inverse correlation between plasma DHA + EPA concentrations and serum NfL concentrations was observed.
Another study published last month, showed that DHA supplements given to football players can significantly increase their Omega-3 Index. For this study, a total of 69 football players were assigned either a placebo of corn oil or 2, 4 or 6-gram doses of DHA. Blood samples were collected 8 times over the following 27 weeks.
All players who supplemented with DHA had significantly higher blood levels of this fatty acid compared to the placebo group, with the greatest increase occurring in the 6-gram group. The researchers noted the importance of this study was demonstrating a dose-response incorporation of DHA in the blood in as little as 8 weeks.
Are Football Players Getting Enough Omega-3s?
According to recent evidence, football athletes are not getting enough omega-3s from food alone. A 2019 study aimed to determine the O3i in NCAA Division I football athletes and the distribution across the O3i zones established for cardiovascular disease risk. The researchers found that out of 138 players tested, 34% were considered high risk (O3i <4%), 66% were considered intermediate risk (O3i between 4-8%), and no players tested had an O3i that fell in the low-risk category (O3i >8%).
A similar study conducted on NCAA Division I athletes from across the U.S found that out of nearly 300 athletes tested that 38% were in the high-risk category (O3i <4%), 62% were in the moderate-risk category (O3i between 4-8%), and 0 were in the low-risk category (O3i >8%). While there is limited data on professional football athletes, a 2018 study conducted on professional football players did observe a decrease in omega-3 levels throughout a football season suggesting higher intakes are likely necessary in this population as well.
Applying the Evidence on and off the Field
The available evidence in collegiate and professional football players reveals progressive increases in NfL and decreases in O3i throughout a football season, which may indicate increased neurocognitive damage and cardiovascular risk. However, studies in this population are finding that omega-3 supplementation provided in adequate amounts can attenuate NfL levels and increase O3i values over the season, potentially providing advanced protection for athletes’ cognitive and cardiovascular health.
Given the pattern of inadequate omega-3 intake among American Football athletes and the possible associated health risks, medical support staff may consider implementing testing for cardiovascular risk indicators and O3i pre, during, and post-season and apply strategies year-round to encourage adequate omega-3 intake.
One of the simplest ways to increase omega-3 intake is to increase the consumption of fish and other seafood high in EPA + DHA. This can be accomplished through increasing athlete education, increasing seafood accessibility by including it in team meals, and providing athletes with cooking classes to encourage increased intake on their own. If testing indicates that dietary strategies are still insufficient to maintain optimal omega-3 levels throughout a season, nutritional supplementation may be required. Evidence from the literature suggests that football players may require higher doses (at least 2g) of DHA than the average population (250mg).
Data suggest that those in contact sports like football may benefit from increased levels of omega-3 fatty acids due to the potential cardiovascular and neuroprotective effects. Given that most athletes do not obtain enough omega-3s through their diet, and needs may be higher in athletes playing contact sports than in the general population, supplementation may be necessary to reach optimal omega-3 levels. Regular testing is encouraged to ensure optimal levels are being met and athletes are provided the greatest chance of cardio- and neuro- protection.