What is the theory behind it?

Some scientists have proposed that autism, dyslexia, attention-deficit/hyperactivity disorder (ADHD) and dyspraxia are a related group of neurodevelopmental disorders that are caused by problems in the metabolism of EFAs ^{(3, 12, 13)}. The idea is that, for unknown reasons, the brains and bodies of individuals with autism and related disorders have problems converting the EFAs from foods into the forms that are necessary for many biochemical reactions ⁽⁷⁾. In addition, omega-3 fatty acids seem to be lower in individuals with autism than in others ^{(9, 14)}.

Both of the omega-3 fatty acids DHA and EPA have been found to affect many aspects brain function ^{(1, 3)}. Specifically, changing the amount of DHA and EPA in the diet alters the amounts of certain critical genes in the brain, at least in rats ⁽¹⁵⁾. In addition, one study found that giving animals a diet with a ratio of omega-6 to omega-3 EFAs of about 1:4 improved experimental measures of cognition in the animals ⁽¹⁾. Finally, mood and behavior problems in humans have been linked to a lack of omega-3 EFAs in the diet ^{(2 , 3 , 12 )}.