Elimination diets for ADHD: beyond the media hype

March 5, 2015 by  
Filed under Commentary, Tips

I am often asked by parents about whether their child’s diet could be causing their ADHD or worsening it. My answer is that yes, there is some controlled research demonstrating that foods or additives can produce the symptoms of ADHD or exacerbate them, but let’s not jump to an elimination diet.

One of the most well-known studies on diet and ADHD was conducted by Dr. Lidy Pelsser and her colleagues, and was published in Lancet in 2011. That study – and an earlier study by Feingold – are the ones that seem to have attracted a lot of parental interest in the topic.

Dr. Pelsser and her colleagues randomly assigned 100 children aged 4-8 years who were diagnosed with ADHD to either a 5 -weeks restricted elimination diet or to a control group who were simply given instructions for a healthy diet. In the ADHD restricted diet group, 41 of 50 children finished the first phase. In that group of 41 children, 32, or 78%, responded favorably by having fewer symptoms. Overall, 32 of 50, or 64%, had decreased ADHD symptoms while on the diet. Associated symptoms such as oppositional behavior and tantrums also decreased. Most parents hear that over 60% improved on the diet and think, “Wow, that sounds great!” But not so fast, because the methodology was seriously confounded by relying on the reports of parents who were not blind to the child’s experimental condition, which can introduce a bias or placebo effect into their reports of improvement.
Children who showed a significant improvement in their ADHD symptoms while on the restricted elimination diet were then assigned to one of two food-challenge groups based on their individual immunoglobulins (IgG) blood tests. Significantly, two-thirds of the children displayed a relapse in their symptoms when challenge foods were re-introduced to their diet.

More recently, Joel T. Nigg, PhD and  Kathleen Holton, PhD, MPH reviewed the literature on research on foods and additives. Their full article is well worth attempting to read if you are considering undertaking an elimination diet for your child, as they point out that adequately controlled experiments generally do not provide evidence of dramatic effects in symptom reduction for the majority of children with ADHD:

The best estimate on the small literature is about a 25% rate of at least some symptom improvement. For some children, perhaps a minority of 10% of children with ADHD, response can include a full remission of symptoms equivalent to a successful medication trial. In short, the literature suggests that an elimination diet should be considered a possible treatment for ADHD, but one that will work partially or fully, and only in a potentially small subset of children.

Of course, every parent hopes their child will be in that subset who do respond to diet changes, but if you are not sure whether foods or additives are causing or exacerbating your child’s ADHD-like symptoms, speak with your pediatrician about whether an elimination diet might be in order as a 5-week trial or test. Maintaining a restricted diet is difficult, time-consuming, costly, and unlikely to work if you do not have pretty much total control over what your child eats both outside of the home and in your home. It is also important to ensure that the elimination diet does not deprive the child of important nutrients, so don’t just start removing everything from your child’s diet. Reading Drs. Nigg and Holton’s detailed review of studies may help you understand what to consider and what to ask your child’s physician.

Comments are closed.