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

A systematic review of the effect of dietary and nutritional interventions on the behaviours and mental health of prisoners

Prisoners experience a higher burden of poor health, aggressive behaviours and worsening mental health than the general population. This systematic review aimed to identify research that used nutrition-based interventions in prisons, focusing on outcomes of mental health and behaviours. The systematic review was registered with Prospective Register of Systematic Reviews on 26 January 2022: CRD42022293370. Inclusion criteria comprised of current prisoners with no limit on time, location, age, sex or ethnicity. Only quantitative research in the English language was included. PubMed/Medline, Web of Science, EMBASE, PsycINFO and CINAHL were searched, retrieving 933 results, with 11 included for qualitative synthesis. Studies were checked for quality using the revised tool to assess risk of bias in randomised trials or risk of bias in non-randomised studies of interventions tool. Of the included studies, seven used nutritional supplements, three included diet changes, and one used education. Of the seven supplement-based studies, six included rule violations as an outcome, and only three demonstrated significant improvements. One study included mental health as an outcome; however, results did not reach significance. Of the three diet change studies, two investigated cognitive function as an outcome, with both reaching significance. Anxiety was included in one diet change study, which found a significant improvement through consuming oily fish. One study using diet education did not find a significant improvement in overall mental resilience. Overall, results are mixed, with the included studies presenting several limitations and heterogeneity. Future research should aim to consider increased homogeneity in research design, allowing for a higher quality of evidence to assess the role nutrition can play in improving the health of prisoners.

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

BACKGROUND

Interventions to better manage aggressive behaviour and reduce recidivism are a primary concern for corrective services. Nutritional interventions to correct prisoner behaviour have been largely overlooked in the literature. Emerging evidence suggests that dietary intake influences aggressive behaviours and that nutritional supplementation with omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) could attenuate both the severity and frequency of aggressive behaviour.

METHODS

Adult male prisoners who have a history of aggressive behaviour (n = 600) will be recruited from at least 6 Correctional Centres and randomised to receive either n-3 LCPUFA or placebo supplementation for a 16-week duration. Treatment will be with either 1 g/day of n-3 LCPUFA (694 mg DHA and 397 mg EPA) or placebo capsules, which are a corn/soy oil blend and are identical in size and colour. The primary outcome measure is the Inmate Behavioural Observation Scale (IBOS): an objective measure of aggressive behaviour. Secondary outcome measures include questionnaires (including aggression, attention deficit disorder, impulsivity, depression/anxiety/stress scales), engagement in programmes, recidivism and quality of life. Baseline and post-intervention assessments include the IBOS, questionnaires and blood to measure the levels of n-3 LCPUFA.

DISCUSSION

To conclusively test the potential that increasing n-3 LCPUFA intakes can improve rates of prisoner aggression and associated mental health and violence-related social system management costs, we propose an adequately powered multi-centre, double-blind, randomised controlled trial, examining the effects of n-3 LCPUFA supplementation on aggressive behaviour in adult male prisoners. If successful, this study will inform prisoner policy with respect to nutrition and by inference contribute to a broader community approach to preventative mental health practices.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry (ANZCTR) ACTRN12618001665224 . Registered on 10 October 2018.

Nutritional supplementation in the treatment of violent and aggressive behavior: A systematic review

Aggression in correctional and psychiatric settings is relatively common and has a negative effect on physical and mental health both among inmates/clients and staff, as well as organizational-level functioning. The aim of the present study was to critically review the evidence on the effectiveness of nutritional supplements in reducing aggression and violence to contribute to a better understanding of options available for managing aggressive behaviors in adults. The EMBASE, MEDLINE, PsycINFO, Cochrane Library, and PubMed databases were searched for effectiveness studies published in English anytime up until March 2020. Study quality was assessed using the Mixed Methods Appraisal Tool. Altogether, 14 studies met inclusion criteria; 2 investigated micronutrients, 10 examined macronutrients, while further 2 examined a combination of micro and macronutrients. Out of the 14 studies, 5 reported a beneficial effect of nutritional supplementation (omega-3 fatty acids, vitamins/minerals, S-adenosyl-l-methionine, or tryptophan). Five studies did not report a significant beneficial effect of nutritional supplementation (omega-3 fatty acids, folic acid, tryptophan, broad range supplement containing vitamins and fatty acids, and fatty acids in augmentation with valproic acid), while four studies reported mixed effects (on l-tryptophan, broad-range micronutrient formula, folic acid, and omega-3 fatty acids). The results overall indicated that research in this area is in its infancy: very few studies examined the same composition of nutritional supplementation and when they did so the results were contradictory. The methodological shortcoming of existing studies and directions for future research are discussed to facilitate high-quality research in this evolving area of nutritional psychiatry.