Do Some Foods Cause ADHD? Does Dieting Help?

If we are to read what we believe on the Internet, dieting can cure many of the ills faced by humans.  Much of what is written is true. Changes in dieting can be good for heart disease, diabetes, high blood pressure and kidney stones to name just a few examples. But what about ADHD?  Food elimination diets have been extensively studied for their ability to treat ADHD.  They are based on the very reasonable idea that allergies or toxic reactions to foods can have effects on the brain and could lead to ADHD symptoms.

Although the idea is reasonable, it is not such an easy task to figure out what foods might cause allergic reactions that could lead to ADHD symptoms.   Some proponents of elimination diets have proposed eliminating a single food, others include multiple foods and some go as far to allow only a few foods to be eaten so as to avoid all potential allergies.  Most readers will wonder if such restrictive diets, even if they did work, are feasible.  That is certainly a concern for very restrictive diets.

Perhaps the most well-known ADHD diet is the Feingold diet (named after its creator).  This diet eliminates artificial food colorings and preservatives that have become so common in the western diet.   Some have claimed that the increasing use of colorings and preservatives explains why the prevalence of ADHD is greater in Western countries and has been increasing over time.   But those people have it wrong.  The prevalence of ADHD is similar around the world and has not been increasing over time.   That has been well documented but details must wait for another blog.

The Feingold and other elimination diets have been studied by meta-analysis.  This means that someone analyzed several well controlled trials published by other people.  Passing the test of meta-analysis is the strongest test of any treatment effect.    When this test is applied to the best studies available, there is evidence that exclusion of fool colorings helps reduce ADHD symptoms.  But more restrictive diets are not effective.  So removing artificial food colors seems like a good idea that will help reduce ADHD symptoms.   But although such diets ‘work’, they don’t work very well.  On a scale of one to 10 where 10 is the best effect, drug therapy scores 9 to 10 but eliminating food colorings scores only 3 or 4.   Some patients or parents of patients might want to this diet change first in the hopes that it will work well for them.  That is a possibility, but if that is your choice, you should not delay the more effective drug treatments for too long in the likely event that eliminating food colorings is not sufficient.  You can learn more about elimination diets from: Nigg, J. T. and K. Holton (2014). “Restriction and elimination diets in ADHD treatment.” Child Adolesc Psychiatr Clin N Am 23(4): 937-953.

Keep in mind that the treatment guidelines from professional organization point to ADHD drugs as the first line treatment for ADHD.  The only exception is for preschool children where medication is only the first line treatment for severe ADHD; the guidelines recommend that other preschoolers with ADHD be treated with non-pharmacologic treatments, when available.  You can learn more about non-pharmacologic treatments for ADHD from a book I recently edited: Faraone, S. V. & Antshel, K. M. (2014). ADHD: Non-Pharmacologic Interventions. Child Adolesc Psychiatr Clin N Am 23, xiii-xiv.

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