The systematic review search process identified 162 relevant articles published, with an English abstract, in peer-reviewed journals since 1st January 1958 until 29th February 2008. A total of 3558 comparisons of content of nutrients and other substances in organically and conventionally produced foodstuffs were extracted for analysis. Articles included in the review were assessed for study quality (satisfactory quality studies provided clear statements on material and nutrients analysed, laboratory and statistical methods and a clear definition of organic agricultural practices), and one third of all studies (n=55; 34%) met the pre-defined satisfactory quality criteria. .
