The Effect of Dietary Supplementation on Aggressive Behaviour in Australian Adult Male Prisoners: A Feasibility and Pilot Study for a Randomised, Double Blind Placebo Controlled Trial

Abstract

This study aimed to assess the feasibility of conducting a nutrition trial in adult male prisoners. Adult male prisoners were recruited for a 16-week randomised control trial comparing the effect of ingestion of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) and multivitamin supplements versus placebo on aggressive behaviour. The baseline and post-intervention assessments from the participant blood samples were the erythrocyte n-3 LCPUFA levels as well as measures of aggressive behaviour determined through institutional records of misconduct (IRM), the Inmate Behaviour Observation Scale (IBOS), and questionnaires. A total of 136 adult male prisoners consented to the study with a retention rate of 60%, and 93% of blood samples were successfully collected. The IRM and IBOS scores were collected for 100% of participants, whilst 82–97% of participants completed the questionnaires. From the baseline data, the Odds Ratio shows that prisoners are 4.3 times more likely to have an IBOS >2 if they are below the 6% cut off on the omega-3 index. Both groups improved across all outcome measures and, at the current sample size, no significant differences were seen between them. A power calculation suggests a total sample size of 600 participants is required to detect the effects of this dietary supplementation, and that this supplementation study is feasible in a Correctional Centre. Important criteria for the exclusion and consideration of logistics and compliance are presented.

The effect of omega-3 long chain polyunsaturated fatty acids on aggressive behaviour in adult male prisoners: a structured study protocol for a multi-centre, double-blind, randomised placebo-controlled trial and translation into policy and practice

“…Our feasibility study showed that prisoners are 4.3 times more likely to have an IBOS of > 2, if they are below the cutoff of 6% omega-3 index [ 38 ] but this does not show causality. This multi-centre trial is adequately powered to demonstrate the effect of n-3 LCPUFA on aggressive behaviour in adult male prisoners.…”

“…Based on our successful model from the feasibility study [ 38 ], one Correctional Centre Officer per site will be seconded to the research project and they will take on the role of trial coordinator, referred to as Project Officers. Project Officers will be trained at the University of Wollongong prior to the commencement of the trial.…”

“…We conducted a feasibility/pilot study at the South Coast Correctional Centre (SCCC) in Nowra, NSW, in 2013 in adult male prisoners [ 38 ]. The sample was restricted to male prisoners for both pragmatic and scientific reasons.…”

“…Baseline data showed negative correlations between blood n-3 LCPUFA levels and measures of aggressive behaviour [ 7 ]. We have shown that conducting a supplementation trial in a Correctional Centre is feasible [ 38 ] and the study design for the multi-centre trial is based on these recommendations [ 38 ]: (1) to collaborate with, and receive support from the Department of Correctional Services; (2) the need to provide incentives to prisoners to aid in recruitment; (3) having an external pathology provider take the blood samples; (4) a designated Correctional Officer as a Project Officer to ensure compliance; (5) the need to restrict buy-ups of cans of tuna and n-3 LCPUFA supplements to reduce potential confoundings; (6) the Correctional Officers require training on how to score the IBOS and how to complete the questionnaires; and (7) the inclusion and exclusion criteria need to ensure that participants are likely to remain in the study for the study duration, are aggressive at baseline (IBOS of 1 or greater) and have an omega-3 index below 6% [ 38 ].…”

Breaking the Cycle of Violent Crime and Punishment: The Promise of Neuronormalization

“…Two additional studies found aggression‐reducing effects of omega‐3s in prison populations. One exception was an Australian prison study that showed null results (Cortie et al., 2020). In another study, 221 Dutch prisoners received either a dietary supplement that contained omega‐3s and vitamins and minerals or a placebo (Zaalberg et al., 2010).…”