Children flying off the handle, fighting at school, increasing rates of ADHD, depression and violent offences, perhaps even more global conflicts – a new study suggests that something very simple could be cranking up aggression: not enough omega-3 from seafood.

A study of 4,000 participants over 28 years has found a clear reduction in aggression when children and adults are given either omega-3 supplements or eat more fish.

According to an advisor to the US National Institutes of Health, Dr Joseph Hibbeln, a country’s incidence of homicide, depression, and suicide tracks its seafood consumption.

In Australia, a prisoner’s omega-3 index, measured in a pinprick blood test, predicts anger, aggression and ADHD. A study in UK prisons found that giving omega-3 supplements to inmates, compared to placebos, reduced violent offences by more than a third.

“Based on this evidence our considered opinion is that there is now sufficient evidence to begin to implement omega-3 supplementation to reduce aggression in children and adults, whether the setting is community, the clinic or the criminal justice system,” say the study authors Adrian Raine and Lia Brodrick from the University of Pennsylvania.

“There is now clear evidence that not only are low blood omega-3 levels associated with increased aggressive behaviour, but supplementation with fish oil can reduce aggressive tendencies in adults and children,” says Professor William Harris from the Fatty Acid Research Institute in the US and advisor to UK charity foodforthebrain.org.

Foodforthebrain.org offers a pin prick home test for omega-3 backed up with a free online Cognitive Function Test and diet and lifestyle questionnaire that assesses omega-3 status and other factors that are important to brain function and development.

“Less than 5% of children in the UK achieve the basic recommended levels of fish and omega-3 fatty acid intake,” says Dr Simon Dyall, a nutritional neuroscientist at the University of Roehampton. “Even these recommendations are too low, according to the evidence regarding brain function. Many children and young adults eat no fish at all and have no omega-3 fatty acid supplements. The evidence is more than sufficient to recommend we take action now to protect their brains.”

In the same way that GPs test vitamin D, these scientists believe we need to test both children and adults presenting with ADHD, depression, anxiety and aggression for their omega-3 index.

“In Japan, where they eat a lot of seafood, the average level is 10% on the pinprick omega-3 index, and rates of violence, depression, suicide and Alzheimer’s are a fraction of those in the UK. People in the UK and US average 4% on the pinprick omega-3 index. You need over 8% for a healthy brain. Many offenders test as low as 2%.” says foodforthebrain.org founder Patrick Holford. “You can’t build a healthy brain without omega-3. Our children are suffering. There is more than enough evidence of this.

“Yet there is no government recommendation in the UK for how much omega-3 we need. The advice to eat fish twice a week is neither enough nor heeded. That is why we are helping people help themselves by testing their omega-3 index and advising them accordingly. But we need this done on a national scale, especially in poorer communities. If doctors can test and prescribe vitamin D, why can’t they test and prescribe omega-3?”

The Supporting Science

  • A. Raine, L. Brodrick ‘Omega-3 supplementation reduces aggressive behaviour: A meta-analytic review of randomized controlled trials’Aggression and Violent Behavior, 2024, 101956 doi.org/10.1016/j.avb.2024.101956.
  • Hibbeln JR. Depression, suicide and deficiencies of omega-3 essential fatty acids in modern diets. World Rev Nutr Diet. 2009;99:17-30. doi: 10.1159/000192992.
  • Meyer BJ, Byrne MK, Collier C, Parletta N, Crawford D, Winberg PC, et al. (2015) Baseline Omega-3 Index Correlates with Aggressive and Attention Deficit Disorder Behaviours in Adult Prisoners. PLoS ONE 10(3): e0120220. doi:10.1371/ journal.pone.0120220.
  • Gesch CB, Hammond SM, Hampson SE, Eves A, Crowder MJ. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. A randomised, placebo-controlled trial. Br J Psychiatry. 2002 Jul;181:22-8. Doi: 10.1192/bjp.181.1.22.