A common dietary supplement reduces aggression by 30%

Fish oil supplements containing omega-3 have long been touted as good for heart health. A new study has found they also reduce aggression. Researchers say the safe, common supplements should be used everywhere from the playground to the prison system.

Overt acts of aggression include verbal and physical violence and bullying. Then, there are covert signs like vandalism and property damage, fire-setting, and theft. Both can negatively affect relationships and have legal consequences. It goes without saying that, on many levels, society would be better off if aggressive behaviors were reduced. A new study may have discovered a way of doing that.

The study by researchers from the University of Pennsylvania (Penn) found that commonplace omega-3 supplements reduced aggression, regardless of age or gender.

“I think the time has come to implement omega-3 supplementation to reduce aggression, irrespective of whether the setting is the community, the clinic, or the criminal justice system,” said Adrian Raine, a Penn neurocriminologist and the lead and corresponding author of the study. “Omega-3 is not a magic bullet that is going to solve the problem of violence in society. But can it help? Based on these findings, we firmly believe it can, and we should start to act on the new knowledge we have.

Omega-3 has enjoyed a strange association with violent behavior for a while. Back in 2001, Dr Joseph Hibbeln, a senior clinical investigator at the US National Institutes of Health (NIH), published a study finding a correlation between the consumption of high amounts of fish (a rich source of omega-3) and lower homicide rates. The following year, the University of Oxford in the UK led a study where British prisoners were given nutritional supplements that included vitamins, minerals and essential fatty acids. The researchers found that prisoners given supplements were less violent and antisocial.

In addition to examining the effect of omega-3 supplements on aggression, the researchers in the current study particularly wanted to ascertain whether omega-3 was effective for all forms of aggression. In psychology, a distinction is made between ‘reactive’ aggression, an in-the-moment response to a perceived threat or provocation, and ‘proactive’ aggression, which requires planning.

The researchers conducted a meta-analysis of 29 randomized controlled trials that explicitly measured aggression in people who’d been given omega-3 supplements. They specifically focused on aggressive behavior and not broader traits like anger, which is viewed more as a feeling or emotion, and hostility, which is more of an attitude. Studies where additional nutritional supplements, such as calcium and vitamin D, were included, but the researchers examined them as a potential moderator.

A modest short-term effect linked to omega-3 supplementation, which the researchers say equates to a 30% reduction in aggression, was seen across age, gender, baseline diagnosis, treatment duration and dosage. Notably, omega-3 was found to reduce both reactive and proactive aggression. The researchers were limited to short-term data because only one out of the 19 laboratories conducting the studies followed up with participants after supplementation ended

The researchers explain how they think omega-3 exerts its effects. Previous studies have pointed to aggressive and violent behavior having a cognitive and neurochemical basis. And, omega-3 is known to play a critical role in brain structure and function, including regulating neurotransmitters and gene expression, and reduces brain inflammation.

“As such, given the undeniable fact that omega-3 is pervasively involved in multiple facets of neuronal biology, it is reasonable to believe that omega-3 supplementation could play a causal role in reducing aggression by upregulating brain mechanisms that may be dysfunctional in … individuals, given the assumption that there is, in part, a neurobiological basis to aggression,” said the researchers.

Further studies are needed to assess the long-term effectiveness of omega-3 supplementation on reducing aggression. Other research avenues would be using MRI scans to determine whether omega-3 enhances brain functioning and examining whether genetics affects omega-3 treatment. In the meantime, the researchers say there is little harm in people, including children, taking this widely available, safe and inexpensive dietary supplement.

“At the very least, parents seeking treatment for an aggressive child should know that in addition to any other treatment that their child receives, an extra portion or two of fish each week could also help,” Raine said.

And the researchers say omega-3 should be used in conjunction with existing psychological and psychiatric treatments.

“[W]e would argue that omega-3 supplementation should be considered as an adjunct to other interventions, whether they be psychological (e.g. CBT [cognitive behavioral therapy]) or pharmacological (e.g. [the antipsychotic drug] risperidone) in nature, and that caregivers are informed of the potential benefits of omega-3 supplementation,” the researchers said.