Fatty acid metabolism in neurodevelopmental disorder: a new perspective on associations between attention-deficit / hyperactivity disorder, dyslexia, dyspraxia and the autistic spectrum

FAB RESEARCH COMMENT:

This introductory review forms part of a Special Issue, arising from the proceedings of a unique multi-disciplinary conference on 'Fatty Acids in Neurodevelopmental Disorders', co-organised by Dr Alex Richardson for the Highland Psychiatric Research Group.

It explains the theory and rationale, and summarises preliminary evidence. for the proposal that deficiences or imbalances of omega-3 and omega-6 long-chain polyunsaturated fatty acids (LC-PUFA) may play a role in childhood neurodevelopmental disorders including ADHD, autism, dyspraxia (developmental co-ordination disorder or DCD) and dyslexia (specific reading difficulties).

All of these conditions show a high degree of both clinical and genetic association not only with each other, but with

• other mental health conditions in which fatty acid abnormalities have already been implicated - including depression, bipolar disorder and schizophrenia, among others; and

• various physical health conditions - most notably allergies and immune disorders - in which deficiencies or imbalances of omega-3 and omega-6 LC-PUFA are also thought to play a role. 

Adequate supplies of both omega-3 and omega-6 fatty acids are essential for normal brain development and function, and must be provided by diet. However, modern diets are relatively lacking in omega-3 - particularly the long chain forms (EPA and DHA) found in fish and seafood; and while they usually provide an excess of short-chain omega-6 (found in vegetable oils), conversion of this within the body to the biologically essentially longer-chain forms (AA and DGLA) is not efficient, and can be imapired by diet and lifestyle as well as genetic factors.

Preliminary evidence indicates that omega-3 (and possibly omega-6) LC-PUFA deficiencies may be unusually common in children and adults with dyslexia, dyspraxia, ADHD and Autism - and may contribute to some of the core symptoms of these conditions, as well as to associated physical health symptoms.

Converging evidence suggests that such deficiencies may reflect abnormalities of fatty acid metabolism that increase dietary needs for these essential fats - and that dietary supplementation may therefore be of benefit in these conditions. 

Futther research, including clinical trials of dietary supplementation with LC-PUFA, is now warranted to investigate these possibilities.

See also:

• FAB Research Factsheet - Physical Signs of Fatty Acid Deficiency

• Richardson & Ross 2000 - Fatty acid metabolism in Neurodevelopmental Disorders: A new perspective on ADHD, dyslexia, dyspraxia and the autistic spectrum

• Richardson et al 2000 - Fatty acid deficiency signs predict the severity of reading and related difficulties in dyslexic children

• Taylor et al 2000 - Dyslexia in adults is associated with clinical signs of fatty acid deficiency

• MacDonell et al 2000 - Increased cytosolic PLA2 in dyslexia

• Richardson & Puri 2000 - The potential role of fatty acids in ADHD 

• Richardson and Puri 2002 - A controlled study of the effects of fatty acid treatment on ADHD symptoms in dyslexic children