1-2 February 2004 - London - Optimum Nutrition for the Mind

Please visit the conference website for full details of this two-day meeting, which includes presentations from leading experts on the role that nutrition can play in mental health.

Among them, Dr Alex Richardson of Mansfield College and the University Lab of Physiology, Oxford will be speaking on: The role of fatty acids in behavioural and learning difficulties such as ADHD, Dyslexia, Dyspraxia and Autistic Spectrum Disorders

Abstract

Increasing evidence implicates functional deficiencies or imbalances in certain highly unsaturated fatty acids (HUFA) of the omega-3 and omega-6 series in ADHD, dyslexia, dyspraxia and autism spectrum disorders (ASD. Omega-3 and omega-6 fats are essential for normal brain development and function, and both must be provided by the diet. The omega-3 HUFA (EPA and DHA) are often relatively scarce in modern diets, however, as they are provided directly only by fish and seafood. Although they can be synthesised in vivo from simpler omega-3 (from green vegetables and some nuts and seeds), these too may be lacking from diets high in packaged or processed foods. Furthermore, this conversion process is inefficient and involves competition with more plentiful omega-6 fats for the necessary enzymes.

Many features associated with ADHD, dyslexia, dyspraxia and ASD are consistent with mild HUFA deficiencies. These include the excess of males affected, the links with various minor neurodevelopmental anomalies, and an apparent elevation of atopic or auto-immune disorders in affected individuals and their relatives. Fatty acid abnormalities could also help to explain some of the key cognitive and behavioural features of these conditions - such as anomalous visual, motor, attentional or language processing - as well as associated difficulties with mood, appetite or digestion, temperature regulation and sleep. Direct evidence from clinical and experimental studies also supports this proposal. Thus physical signs associated with fatty acid deficiency are unusually common in ADHD, dyslexia and ASD; and reduced blood concentrations of HUFA in these conditions have also been reported.

Definitive evidence of a causal contribution, however, can only come from intervention studies in the form of randomised controlled trials. Published studies of this kind remain fairly few in number, and have only involved the diagnostic categories of ADHD and dyslexia, although other trials with a focus on dyspraxia or ASD are in progress. In ADHD, two studies found no benefits from treatment with omega-6 alone (from evening primrose oil), and one trial of pure DHA also gave negative results. By contrast, treatment with an omega-3/omega-6 combination (80% fish oil and 20% evening primrose) has been associated with improved attention, concentration and conduct both in a US study involving ADHD-type children, and a UK study of children with dyslexia and ADHD tendencies. These findings suggest that the omega-3 EPA may be the most effective fatty acid in the treatment of these conditions, as appears to be the case in depression and schizophrenia from the results of other studies, although this hypothesis now needs to be tested.

The available evidence therefore suggests that fatty acid treatment may benefit some individuals with these conditions, at least in the short-term. Further research is still needed, however, to establish this with certainty, to assess the durability of such treatment effects, to determine optimal treatment compositions and dosages (which may vary between conditions or individuals), and to develop reliable ways to identify those individuals most likely to benefit from this kind of treatment approach.