- Hywel C Williams, professor of dermatoepidemiology (email@example.com)
- Centre of Evidence-Based Dermatology, University Hospital, Queen's Medical Centre, Nottingham NG7 2UH
Time to say goodnight
With concerns about using topical corticosteroids for atopic dermatitis sometimes reaching phobic proportions,1 the emergence of a natural plant oil extract as a possible alternative treatment was well received in the early 1980s.2 3 Interest was fuelled because evening primrose oil extract (containing 8-10% of gamma linolenic acid (GLA)) appeared to cause few side effects and because there was a very plausible mechanism to explain why supplementation with this essential fatty acid might work in atopic dermatitis.4 The scene was therefore set for a new treatment, and physicians like myself were delighted to have another option to offer patients with this miserable condition.
Since then many studies have evaluated the efficacy of oral gamma linolenic acid supplementation for atopic dermatitis, with conflicting results. Fifteen studies (10 dealing with evening primrose oil, and five with borage oil, which contains even higher concentrations of GLA) were summarised in a systematic review of atopic dermatitis treatments that I and others conducted for the NHS Health Technology Assessment programmes.5 Although we could not pool the data because of differences between study participants, GLA doses, and outcomes (which were often clinically meaningless), we found that the largest and best reported studies did not show convincing evidence of any benefit.6
The last stone to be turned
One “unturned stone” has been the notion that GLA works only when given in very …