Violence inhibition mechanism functioning mediates the relationship between dietary eicosapentaenoic acid intake and physical aggression

Abstract

Deficiency in long-chain omega-3 polyunsaturated fatty acids, in particular eicosapentaenoic acid (EPA), is implicated in aggression and callous-unemotional (CU) traits. A violence inhibition mechanism (VIM) has been proposed to regulate aggression through responding to expressions of distress. However, it remains unclear whether EPA intake is related to the VIM, and if so, whether this pathway can mediate relationships between EPA intake and deviant personality traits. The current investigation documents two, independently-sampled studies that tested relationships between EPA intake, personality (aggression, CU traits), and electrophysiological indices of the VIM (motor extinction cued by facial expressions of distress). In study one, 98 participants completed a food-frequency questionnaire, the inventory of callous-unemotional traits, and an aggression questionnaire. EPA intake was negatively correlated with physical aggression, even after controlling for age and sex. In study two, 47 participants completed the same measures in addition to having electroencephalography recorded during a novel paradigm assessing the distinct processing stages of the VIM. Stop-P300 (motor extinction) responses to facial expressions of distress mediated the relationship between EPA intake and physical aggression. For the first time, we have evidenced an association between EPA intake and indices of distress-induced motor extinction proficiency. Findings are in line with a proposed role of EPA in regulating aggression, possibly through associations with networks involved in distress-cued executive control over behaviour. Results are discussed in terms of the potential benefit of nutritional supplementation in clinical and forensic arenas. Data and a pre-print of this manuscript are available here: https://osf.io/u3jdc/?view_only=b7f32cd1798344b5a6dffa2892253392