Dyslexia in adults is associated with clinical signs of fatty acid deficiency.

Developmental dyslexia is a complex syndrome whose exact cause remains unknown. It has been suggested that a problem with fatty acid metabolism may play a role, particularly in relation to the visual symptoms exhibited by many dyslexics. We explored this possibility using two self-report questionnaires, designed on the basis of clinical experience, to assess (1) clinical signs of fatty acid deficiency; and (2) symptoms associated with dyslexia in known dyslexic and non-dyslexic subjects. Dyslexic signs and symptoms included the auditory-linguistic and spoken language difficulties traditionally associated with the disorder, as well as visual problems (both with reading and more generally) and motor problems. Fatty acid deficiency signs were significantly elevated in dyslexic subjects relative to controls, particularly within males (P<0.001). In addition, the severity of these clinical signs of fatty acid deficiency was strongly correlated with the severity of dyslexic signs and symptoms not only in the visual domain, but also with respect to auditory, linguistic and motor problems. The pattern of relationships differed somewhat between dyslexic and control groups, and sex differences were also observed. Our findings support the hypothesis that fatty acid metabolism may be abnormal in developmental dyslexia, and indicate the need for further studies using more objective measures.

Fatty acid deficiency signs predict the severity of reading and related difficulties in dyslexic children.

It has been proposed that developmental dyslexia may be associated with relative deficiencies in certain highly unsaturated fatty acids (HUFA). In children with attention-deficit/hyperactivity disorder, minor physical signs of fatty acid deficiency have been shown to correlate with blood biochemical measures of HUFA deficiency. These clinical signs of fatty acid deficiency were therefore examined in 97 dyslexic children in relation to reading and related skills, and possible sex differences were explored. Children with high fatty acid deficiency ratings showed poorer reading (P<0.02) and lower general ability (P<0.04) than children with few such clinical signs. Within males (n=72) these relationships were stronger, and fatty acid deficiency signs were also associated with poorer spelling and auditory working memory (P<0.05, P<0.005 respectively). Within females (n=25) no associations were significant. These results support the hypothesis that fatty acid deficiency may contribute to the severity of dyslexic problems, although sex differences merit further investigation.