Journal of the American Academy of Child and Adolescent Psychiatry. 2012 Jan; 51(1): 86–97.e8.
This meta-analysis of 24 published studies on food colors, plus 10 more on dietary restriction, concluded that a restriction diet (e.g., the Feingold diet or an oligoantigenic diet) affects some children.
QUOTE: “Effects of food colors were notable but were susceptible to publication bias or were derived from small, nongeneralizable samples. Renewed investigation of diet and ADHD is warranted.”
NOTE: It is regrettable that most of the studies available to Nigg for analysis were the same old (OLD) studies; of the 24 studies included, 17 of them used 50 mg or less of food dyes. In fact, 3 of them used 15 mg or less of food dyes for their “challenge” materials. Of the remaining 7 studies, one (Rapp 1978) didn’t report how much was used, and one (David 1987) used a relatively high dosage but was challenging children whose parents had come to him for help because their response to the diet was unstable. This doesn’t leave a lot of useful studies for analysis.
email comment from Dr. Nigg, with permission to post:
Thank you for posting the article and for your comments. I agree with you that the literature here is very weak and so it’s difficult to draw strong conclusions. Also agree that today’s kids are exposed to much higher additive levels than at the time most studies were conducted. In spite of that, it’s interesting that there seems to be some kind of signal there. Our impression was that food colors per se might be only one small part of the puzzle, but that dietary factors overall play a bigger role than usually appreciated.