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PHILADELPHIA — Can a common dietary supplement for heart health also calm aggression in the brain? Researchers have found compelling evidence that omega-3 fatty acids actually can.
Commonly found in fish and fish oil supplements, a team from the University of Pennsylvania says omega-3 can significantly reduce aggressive behavior. Their study, published in the journal Aggression and Violent Behavior, analyzed data from 29 randomized controlled trials involving nearly 4,000 participants worldwide to make this conclusion.
The study suggests that omega-3 supplementation leads to a modest but substantial 30% reduction in aggression levels, regardless of factors like age, gender, diagnosis, treatment duration, or dosage. Interestingly, the beneficial effects were observed for both reactive aggression (impulsive responses to provocation) and proactive aggression (premeditated violent behavior).
Penn neurocriminologist Adrian Raine believes these results provide strong evidence for using omega-3 supplements as a complement to other interventions aimed at reducing aggression in various settings, including communities, clinics, and the criminal justice system. While it's not a magic cure-all, researchers believe omega-3 supplements could be a safe, inexpensive, and effective addition to existing treatments for violent behavior.
“At the very least, we would argue that omega-3 supplementation should be considered as an adjunct to other interventions, whether they be psychological (e.g. CBT) or pharmacological (e.g. risperidone) in nature, and that caregivers are informed of the potential benefits of omega-3 supplementation,” Raine's team writes in a media release.
To arrive at these groundbreaking findings, the researchers conducted a comprehensive meta-analysis, a statistical technique that combines data from multiple studies to draw stronger conclusions. They scoured scientific literature to identify 29 random trials conducted between 1996 and 2024. Importantly, the study found statistically significant reductions in aggression levels, regardless of whether the researchers averaged the effect sizes by study, independent sample, or laboratory.
Paper Summary
Methodology
The researchers, led by Adrian Raine at the University of Pennsylvania, conducted a systematic review to identify all randomized controlled trials that examined the effect of omega-3 supplementation on aggressive behavior. They found 29 eligible studies with a combined 3,918 participants.
To analyze the data, they used three different approaches. In the first, they calculated an overall effect size by treating each independent sample from the studies as a separate data point. In the second approach, they averaged the results when one publication reported on multiple independent samples, so each study contributed just one effect size. In the third approach, they averaged results at the lab level, so studies from the same research group were combined into one data point.
Across these three meta-analytic approaches, the results showed omega-3 significantly reduced aggression compared to placebo, with modest average effect sizes ranging from 0.16 to 0.28 depending on the analysis method.
Results
The effects remained significant even after adjusting the results through statistical methods to account for potential publication bias. Omega-3 supplements reduced both reactive, impulsive aggression as well as proactive, premeditated aggression, based on a subset of studies examining these subtypes. The benefits were seen across children and adults, males and females, community samples and those with clinical disorders.
There was little evidence that factors like treatment duration, omega-3 dosage level, recruitment source, or the type of aggression measure used (self-reports vs. observer ratings) influenced how well omega-3 worked.
Study Limitations
Most studies were short-term, so the long-term effects of omega-3 supplementation are unclear. The overall effect size was modest, around 0.22, so omega-3 is unlikely to be a game-changing treatment for aggressive individuals but could provide a small boost, especially when combined with other interventions.
Additionally, some of the studies had small sample sizes and did not use intent-to-treat analyses, which can produce biased results. The meta-analysis also could not account for potential differences in factors like the ratio of EPA to DHA in the supplements used across studies.
Key Takeaways
Despite the limitations, the authors argue there is now sufficient evidence from well-designed randomized trials to consider implementing omega-3 supplementation programs to help reduce aggression, alongside other evidence-based interventions.
While not a “magic bullet,” omega-3 could be an easy-to-implement nutritional supplement to include as part of a broader strategy for curbing aggressive and violent behavior in schools, prisons, psychiatric facilities, and the broader community.
“We believe the time has come both to execute omega-3 supplementation in practice and also to continue scientifically investigating its longer-term efficacy,” the team concludes.
