We have been unable to identify any studies into the effects of the Feingold diet for people on the autism spectrum published in English-language, peer-reviewed journals.
We found a number of research reviews which looked at the Feingold diet for people with other conditions, particularly attention deficit hyperactive disorder. In general, these reviews concluded that the Feingold diet is unlikely to provide any significant benefits.
The Food Standards Authority website reported that there is some research to suggest that certain artificial food colours and the preservative sodium benzoate could be linked to increased hyperactivity in some children.
Determining if the Feingold diet has any significant benefits for individuals on the autism spectrum is therefore not currently possible. We must wait until further research of sufficiently high quality has been completed.
There is a need for small scale pilot studies which use scientifically robust, experimental methodologies to determine if the Feingold diet provides any benefits for people on the autism spectrum.
These studies should investigate if there are different subsets of individuals on the autism spectrum (such as those with gastrointestinal problems or those with intolerance to additives or salicylates) who might benefit most from the diet.
These studies should also investigate which parts of the diet (exclusion of additives, or salicylates or both) provide the most benefits to which groups of people.
It may then be possible to determine if further, large-scale trials into the diet are justified.