Oiling the Brain: A Review of Randomized Controlled Trials of Omega-3 Fatty Acids in Psychopathology across the Lifespan

Abstract

Around one in four people suffer from mental illness at some stage in their lifetime. There is increasing awareness of the importance of nutrition, particularly omega-3 polyunsaturated fatty acids (n-3 PUFA), for optimal brain development and function. Hence in recent decades, researchers have explored effects of n-3 PUFA on mental health problems over the lifespan, from developmental disorders in childhood, to depression, aggression, and schizophrenia in adulthood, and cognitive decline, dementia and Alzheimer’s disease in late adulthood. This review provides an updated overview of the published and the registered clinical trials that investigate effects of n-3 PUFA supplementation on mental health and behavior, highlighting methodological differences and issues.

People with schizophrenia and depression have a low omega-3 index

“…As outlined earlier, a number of mechanisms have been identified for the roles of n-3 LCPUFA in the brain [18,21] that include potentially vascular mechanisms which may underlie both cardiovascular and mental health [19]. Further supportive of this, Canadian researchers investigated n-3 PUFA levels in people who had suffered an acute myocardial infarction and found that those who suffered major depression had notably lower n-3 PUFA levels and omega-3 index (4.46%) than those without depression (5.05%) [46].…”

“…The role of EPA and DHA in improving endothelial function via production of antiinflammatory eicosanoids, reducing adhesion of substances to the endothelial wall and influence on nitric oxide production (and therefore vasodilation and blood flow) may contribute to common underlying mechanisms for their protective role in cardiovascular and mental health [19]. A growing body of work has investigated the role of n-3 LCPUFAs in mental health with indications of benefit across the lifespan including developmental disorders, depression, schizophrenia and cognitive decline [20,21]. Following the latter studies reviewed, a robust multi-centre trial reported that n-3 LCPUFA supplementation for 12 weeks was able to significantly reduce transition to psychosis at 12 month follow-up compared to placebo in young people at high risk for psychosis [22].…”

The effect of school meals with fatty fish on adolescents’ self-reported symptoms for mental health: FINS-TEENS - a randomized controlled intervention trial

“…Fish is rich in n-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) and other important nutrients, such as vitamin D, selenium, iodine and high-quality protein [11,12]. Especially the n-3 LCPUFAs have received considerable interest, and there is growing evidence that suboptimal intakes of n-3 LCPUFAs may be associated with mental health over the lifespan [13,14]. The most prominent findings have been revealed for depression [15], but there is also some support for an effect of n-3 LCPUFAs in subgroups of children with attention-deficit hyperactivity disorder (ADHD) [16].…”

“…The most prominent findings have been revealed for depression [15], but there is also some support for an effect of n-3 LCPUFAs in subgroups of children with attention-deficit hyperactivity disorder (ADHD) [16]. Still, findings from randomized controlled trials (RCT) with clinical populations remain inconclusive [14] and no benefits on mental health were seen in a sample of typically developing children after supplementation with n-3 LCPUFAs for 16 weeks [17]. However, long-term effects were found for both externalizing and internalizing problems, after 6 months supplementation with n-3 LCPUFAs in a community-residing sample of children (8–16 y), suggesting a delayed effect of n-3 LCPUFAs [18].…”

A 6-month randomised controlled trial investigating effects of Mediterranean-style diet and fish oil supplementation on dietary behaviour change, mental and cardiometabolic health and health-related quality of life in adults with depression (HELFIMED): study protocol

“…In particular, considerable research has in recent decades investigated benefits of omega-3 polyunsaturated fatty acids (n-3 PUFAs) for mental health across the lifespan including attention deficit hyperactivity disorder (ADHD) and learning difficulties, uni-and bipolar depression, schizophrenia and mild cognitive impairment [15,16]. However, a range of nutrients and other food components (e.g.…”