“The etiology of ADHD is generally acknowledged to be complex and multifactorial. Suggested contributory factors have been diet, nutrition, and in particular abnormalities in the metabolism of the long chain polyunsaturated fatty acids.”[1]
Omega-3 and omega-6 long chain polyunsaturated fatty acids (“LCPUFA”) are of critical importance for normal brain development and function. During fetal life, large amounts of omega-3 and omega-6 LCPUFA, especially docosahexaenoic acid (“DHA”) and arachidonic acid (“AA”) are deposited in the central nervous system. LCPUFAs have a number of effects: as facilitators of neurotransmitter release, membrane structure and stability i.e. fluidity within different cellular compartments which are essential for neuronal maturation and metabolic function as well as for advanced, integrated central nervous system activities such as attention, alertness, and motor coordination.
The most abundant LCPUFA in the brain is DHA from the omega-3 series, which is concentrated at nerve cell synapses and is important for neural cell signaling and neurotransmitter processes.
The ratio of omega-3 to omega-6 fatty acids, particularly the DHA/AA ratio seems to be important for membrane fluidity. Recently, the importance of these LCPUFA for glia cells has been demonstrated. Deficient intake of omega-3 or excessive intake of omega-6 fatty acids have been shown to affect the metabolism to favor omega-6 fatty acids and thus further decrease the availability of both DHA and EPA in the brain.
There is increasing evidence that omega-3 LCPUFA play a part in many neurodevelopmental and psychiatric disorders including ADHD. Various studies of ADHD individuals using a large proportion of EPA in the supplementation showed improvement in symptoms.
Double-blind studies have shown two subgroups of children with ADHD, characterized by oppositional behavior and less hyperactivity/impulsivity, responded with significant reduction of the ADHD symptoms by supplementation with EPA. More research is warranted.