A researcher in The Netherlands did a study to determine whether diet affected ADHD symptoms in children between the ages of 4 and 8. Fifty children ate regular meals with their families after gettting advice about healthy eating. The other fifty went on a strict elimination diet. All they could eat were meat, vegetables, pears and water, sometimes getting potatoes, fruits and wheat. All the kids were evaluated for ADHD symptoms after 2 weeks. About half of the children on the limited diet did not respond, so the potatoes, fruit and wheat were taken away. After 9 weeks, 64% of the children on restricted diets had improved their ADHD symptoms, while none of the children on regular diets showed any improvement. Then, in a second part of the study, foods were added back one at a time and this caused the ADHD symptoms to come back in 19 out of 30 children who had improved. Interestingly, the types of food that caused relapse had nothing to do with immunologic testing for sensitivity to the food.
This study is interesting, but does not provide a lot of evidence about diet causing ADHD symptoms. For one thing, the researchers, patients and families knew which group each child was in and this can influence results. The study did reveal that IgG testing does not tell which foods are likely to cause ADHD symptoms. For families that are willing to do the hard work of severely restricting their diets, it may be a helpful thing to do. However, this study does not show that the results are necessarily worth the effort.