Food and Behaviour Research

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A randomized double-blind, placebo-controlled study of the effects of supplementation with highly unsaturated fatty acids on ADHD-related symptoms in children with specific learning difficulties

Richardson, A. J. and Puri, B.K.  (2002) Prog Neuropsychopharmacol Biol Psychiatry 26(2) 233-9 

Web URL: View this and related abstracts via PubMed here


(1) The authors tested the prediction that relative deficiencies in highly unsaturated fatty acids (HUFAs) may underlie some of the behavioral and learning problems associated with attention- deficit/hyperactivity disorder (ADHD) by studying the effects of HUFA supplementation on ADHD-related symptoms in children with specific learning difficulties (mainly dyslexia) who also showed ADHD features.

(2) Forty-one children aged 8-12 years with both specific learning difficulties and above-average ADHD ratings were randomly allocated to HUFA supplementation or placebo for 12 weeks.

(3) At both baseline and follow-up, a range of behavioral and learning problems associated with ADHD was assessed using standardized parent rating scales.

(4) At baseline, the groups did not differ, but after 12 weeks mean scores for cognitive problems and general behavior problems were significantly lower for the group treated with HUFA than for the placebo group; there were significant improvements from baseline on 7 out of 14 scales for active treatment, compared with none for placebo. Group differences in change scores all favored HUFA, reaching conventional significance levels for 3 out of 14 scales.

(5) HUFA supplementation appears to reduce ADHD-related symptoms in children with specific learning difficulties. Given the safety and tolerability of this simple treatment, results from this pilot study strongly support the case for further investigations.


Existing evidence suggested that a lack of certain fatty acids in the diet might contribute to some features of attention deficit/hyperactivity disorder (ADHD). Fatty acid deficiencies have also been suggested in dyslexia, which often overlaps with ADHD. We therefore studied the effects of fatty acid supplements on ADHD-related symptoms in 41 dyslexic children (aged 8-12 years) who also showed features of ADHD.

The supplement we tested contained mainly omega-3 highly unsaturated fatty acids (HUFA)from fish oil, with some omega-6 HUFA from evening primrose oil. This was a 'randomised controlled trial' - meaning that half the children (selected at random) received identical-looking capsules containing olive oil as a 'dummy' or placebo treatment, and no-one knew until after the trial had finished which children had received which treatment. (This kind of study design is essential to control for expectations and ensure that any effects really are due to the ingredients of the so-called 'active' supplement.)

After 12 weeks, the children who had received the fatty acid treatment showed clear improvements compared with those on placebo according to parents' ratings of their ADHD-related symptoms. Particular improvements were found for 'cognitive problems' (difficulties in attention, concentration and short-term memory), general behaviour problems and anxiety.

This study shows that HUFA supplements can reduce ADHD-related symptoms in children with specific learning difficulties. Larger studies are now needed to confirm the benefits shown here, as this simple nutritional treatment is both very safe and well-tolerated.


This study was widely reported in the media, although the focus tended to be on ADHD rather than dyslexia. One of the typical news articles can be viewed via the link below.

13 February 2002 - BBC Website: Diet can ease problem behaviours