Elimination diet relieves ADHD, IgG blood tests are not helpful
A study just published in the prestigious medical journal The Lancet finds a clear relationship between diet and behavior in ADHD when investigated by a supervised elimination diet but not by IgG (immunoglobulin G antibody) blood tests. The authors state:
"The effects of a restricted elimination diet in children with attention-deficit hyperactivity disorder (ADHD) have mainly been investigated in selected subgroups of patients. We aimed to investigate whether there is a connection between diet and behaviour in an unselected group of children."
They conducted a randomised controlled trial in which children aged 4-8 years who were diagnosed with ADHD were randomly assigned to either a 5 week restricted elimination diet or instructions for a healthy diet in the first phase.
"Thereafter, the clinical responders (those with an improvement of at least 40% on the ADHD rating scale [ARS]) from the diet group proceeded with a 4-week double-blind crossover food challenge phase (second phase), in which high-IgG or low-IgG foods (classified on the basis of every child's individual IgG blood test results) were added to the diet."
Pediatricians and others involved were masked to group and challenge allocation. Changes in the ARS score in both phases and correlations between food-specific IgG levels related and behavior were the endpoints. What did their data show?
"Between baseline and the end of the first phase, the difference between the diet group and the control group in the mean ARS total score was 23·7 according to the masked ratings... The ARS total score increased in clinical responders after the challenge by 20·8... In the challenge phase, after challenges with either high-IgG or low-IgG foods, relapse of ADHD symptoms occurred in 19 of 30 (63%) children, independent of the IgG blood levels."
This significant study offers three very important points here for clinicians and parents:
- Foods can trigger ADHD behavior.
- Supervised elimination diets can identify the offending foods.
- IgG blood tests do not identify them.
Parents and practitioners should appreciate the authors' conclusion:
"A strictly supervised restricted elimination diet is a valuable instrument to assess whether ADHD is induced by food. The prescription of diets on the basis of IgG blood tests should be discouraged."