Dietary omega-3 polyunsaturated fatty acids prevent impaired social behaviour and prefrontal dopamine metabolism in food allergic mice

Background: It is suggested that allergic immune activation, combined with a genetic predisposition, may contribute to the expression of aberrant social behaviour relevant to autism. We have previously shown that a food allergic response reduced social behaviour in mice, which was associated with altered dopaminergic activity in brain regions relevant for social and emotional behaviour. Dietary fatty acid composition has been shown to affect both the immune system and neurological processes and may therefore contribute to the prevention of food allergy-induced abnormalities in social behaviour. Method: The aim of this study was to assess whether dietary supplementation with fish oil rich in long chain omega-3 polyunsaturated fatty acids (n-3 LCPUFA) prevents food allergy-induced abnormalities in social behaviour and associated deficits of the dopaminergic system in the prefrontal cortex of whey-sensitised mice. Results: The n-3 LCPUFA-enriched fish oil diet decreased the acute allergic skin response and was able to prevent the disturbance in social behaviour of whey-sensitised mice. N-3 LCPUFA supplementation increased docosahexaenoic acid (DHA) incorporation in the brain and restored levels of dopamine and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3-MT) and homovanillic acid (HVA) in the prefrontal cortex of allergic mice. Moreover, reduced levels of 5-HIAA, metabolite of serotonin, in intestines of allergic mice was also restored by the n-3 LCPUFA-enriched diet. Conclusion: In addition to its effects on the allergic skin response, n-3 LCPUFA restored allergy-induced deficits in social behaviour and in prefrontal dopamine and metabolite levels. Therefore, n-3 LCPUFA may exert its beneficial effect on behaviour via modulation of the dopaminergic system in the prefrontal cortex and may therefore be an interesting target in the use of dietary interventions for immune-mediated psychiatric disorders such as ASD.