Researchers have been granted ethical approval to give Omega-3 to inmates in five Australian prisons to see if the supplement can help curb violence and improve mental health.

Prisoners at Nowra's South Coast Correctional Centre will be invited to participate in the study based on their tendencies towards aggression, impulsivity and levels of Attention Deficit Hyperactivity Disorder (ADHD).

University of Wollongong (UOW) Associate Professor Barbara Meyers said the pilot study, which was carried out at the Nowra facility, yielded positive results in some areas but was not large enough to gauge potential impacts on aggressive behaviour.

"We're about to start recruitment and I'm hoping if it's anything like the pilot study, there are a lot of inmates enthusiastic about it," Associate Professor Meyer said.

"One of the inmates said when he was attending programs at the prison he had a greater attention span.

"He was more interested in learning than looking out the window."

Fatty acids and cognitive health

Inmates from the South Coast Correctional Centre south of Nowra will be given Omega-3 supplements as part of the trial. ( ABC News: Steven White )

Associate Professor Mitchell Byrne from UOW's School of Psychology will be assessing the impact the fatty acids have on the prisoners' behaviour.

"There's been pretty good evidence for a long time that Omega-3 has significant cardiovascular benefits and on general physical health," he said.

"However there's been emerging research over the past decade or so that Omega-3 plays a significant role in cognitive functioning and cognitive health, including mental health disabilities and just the way we process information."

Omega-3 is involved in the cellular structure of all cells and form the cell's membrane and can support inter-cellular communication resulting in faster thought processes and promote the production of neuro-chemicals like serotonin and dopamine.

"So if we don't have sufficient Omega-3 we're not operating on optimum capacity," Associate Professor Byrne said.

"An appropriate level of Omega-3 in the diet and therefore in the cells leads to better functioning of the brain as opposed to not having the appropriate amount.

"Therefore, any sort of condition that might involve cognition or better human functioning is going to be supported by Omega-3."

The trial soon to begin on inmates at the South Coast Correctional Centre will aim to prove this further.

"In the past, from the pilot study, we've identified a relationship between the amount of Omega-3 in a person's blood and the degree to which they express both aggressive symptoms and ADHD symptoms," Associate Professor Byrne said.

"So that relationship has been established and we're now in the process of an intervention study to see if we can support people's development and growth."

Study set to expand to SA

After the trial gets underway in Nowra, it will expand to jails at Lithgow, Wellington and Port Macquarie in mid-July, with inmates at prisons in Port Augusta and Yatala in South Australia to be recruited for the trial in 2020.

Associate Professor Meyer said about 600 inmates from across Australia would take part in the study before the findings were released.

"The outcome of this trial will be published internationally, it's worthwhile doing and the [inmates] are making a valued contribution to this research," she said.

Willing participants will be randomly assigned either Omega-3 a or placebo and monitored over a 16-week period.

"We're also measuring muscle strength, because Omega-3 improves muscle strength," Associate Professor Meyer said.

"Then we'll also measure their blood levels of Omega-3 because if they already have high levels, they're unlikely to benefit from this trial."