A few weeks back, a feature recently ran in the Shelby Star in which a reader wrote in asking about whether the Feingold Diet might work for her son’s ADHD.  The columnist, John Rosemond, replied that while many mental health professionals believe that the diet is ineffective because of, you know, insufficient evidence.  But, [...]]]>

A few weeks back, a feature recently ran in the Shelby Star in which a reader wrote in asking about whether the Feingold Diet might work for her son’s ADHD.  The columnist, John Rosemond, replied that while many mental health professionals believe that the diet is ineffective because of, you know, insufficient evidence.  But, he says, that’s only “true as far as it goes” — because studies address averages, and even if the participants didn’t improve “on average”, the study might not report that some of the participants did improve.

Well, actually, studies usually do contain that information.  In order to be worth anything, a scientific study must publish all of its data — this is so that readers of that study can evaluate it properly, and so that the study can be replicated by other researchers.  This is a core underpinning of the scientific method.  Any reputable study of the efficacy of the Feingold diet for ADHD treatment would need to indicate how many subjects participated, how many of those participants were diagnosed with ADHD, and how that diagnosis was reached.  The participants with ADHD would be divided into two groups, one using the diet, and one not (to be even more rigorous, the study might then compare these two groups to non-ADHD control groups both on and off the diet).  Finally, the published results would need to indicate exactly how many of the ADHD participants — both on the diet and off — experienced alleviation of their symptoms, and how many did not.

But even more concerning is that the columnist asserts that “perhaps the most convincing evidence” for the efficacy of the Feingold Diet is the testimony of parents.  Sure, the “ADHD Establishment” likes to “dismiss these claims as unscientific”, but “the issue boils down to one fundamental question: Why would these parents say their kids’ behavior improved if it didn’t?”

Mr Rosemond, meet the placebo effect.

For whatever reason, the human brain is subject to “expectancy”, which basically means that it’s prone to producing the results it expects.  In other words, if someone gives you a sugar pill for a head cold, and tells you it will make you feel better, there’s a decent chance your sniffles will clear up.  This person has set you up to expect that you will feel better, and you do.

In fact, human beings are so sensitive to expectancy that if the person giving you the sugar pill believes it will make you feel better, there’s a good chance that you will pick up on this intuitively, in fact you may feel better because of what someone else expects.

This is why clinical trials are required to be double-blind.  A certain number of patients are on the real medication, and a certain number are on the placebo.  The clinicians administering the pills have no idea who is getting what medication.  The only people who know are the researchers, who at the end of the study compare the efficacy of the medication to the efficacy of the placebo.

In the case of the Feingold parents, there are a couple of why the parents in question might report improved behavior.  The first is that they are expecting to see improved behavior, and they interpret their child’s behavior as improving whether it actually is or not.  The second is that the children themselves have been told that this new diet will improve their behavior.  The expectancy has been set up — and their behavior really does improve.

I’m not saying any of this to bash the Feingold diet.  There may not be a lot of scientific validity to back it up, but that could in part be due to the complications of studying something like diet and psychological symptoms.  I certainly support anyone who wants to eliminate synthetic additives from their food.  Furthermore, there’s along and proud history of physicians using the placebo effect to help their patients — in the days before modern pharmacology, it was often the only thing that could.  The Feingold Diet won’t hurt you, or your child, and if it genuinely makes your family’s life better, scientific validity might not be your top concern.

However, before you try Feingold, you may want to make sure that it doesn’t lead to behaviors that do cause harm.  Check out Stephen Barrett’s article on the potential pitfalls.