Diet and ADHD

Parents often come to my office after several years of both social and academic failure relating to ADHD, and they still are stuck on the idea that diet, and diet alone, will be a cure all. After all, if you look up diet and ADHD on the web it seems very, very clear. Right? Well the story is a little more complicated than that and a recent review of research can help explain the ins and outs of diet as an intervention for ADHD.

According to two researchers from Children's Memorial Hospital in Chicago, a relatively simple diet low in fats and high in whole grains, fruits, and vegetables is one of the best alternatives to drug therapy for ADHD. Yes, they also note that Omega-3 and omega-6 fatty acid supplements have also been shown to help in some controlled studies. In some studies, and in some limited ways, and you need to be aware of what those limitations are before you put all your eggs into the Omega-3 basket.

Writing online in Pediatrics Drs J. Gordon Millichap and Michelle M. Yee, CPNP, reviewed nearly 70 publications on diet-based interventions in ADHD, emphasizing recent research and better controlled trials. They noted that diet is one established contributor to ADHD that parents can modify.

They note that one of the most provocative findings in recent years came from the Australian Raine study, which was a prospective cohort study that followed children from birth to age 14. It found that development of ADHD was significantly associated with so-called "Western diets" rich in saturated fats and sugar, compared with a "healthy" diet of proteins derived from low-fat fish and dairy products and with a high proportion of vegetables (including tomatoes), fruits, and whole grains. This is a popular study noted on the web as a reason to skip medication ...and behavioural therapy .... and go directly to dietary interventions. But you need to note that their review indicated that controlled trials had failed to show significant benefits for such intensive modifications as oligoantigenic, elimination, or additive-free Feingold-type diets except in small subgroups. Such diets also "are complicated, disruptive to the household, and often impractical," they wrote. And again, worked only in a "small subgroup."

Many parents still rely on some form or another of the  Feingold diet for treating ADHD with diet. The Feingold diet and others are based on the idea that artificial colors and salicylates contribute to ADHD, which became a popular idea in the 1970s. The problem is that extensive and well controlled US federally funded trials showed that most ADHD children did not improve significantly on such diets.  Again, some children with genuine sensitivities to additives and preservatives have been identified and did improve, but these were kids with special and specific sensitivities, often unrelated to ADHD. A good way to think of this is to think some children with ADHD, as with all children, also have food allergies or at least "sensitivities." Children with ADHD ( or autism, Aspergers and other disorders) don't tolerate these sensitivities as another child might, and react to a greater degree than the average child. The improvement isn't one of ADHD, but of less sensitivity, less agitation and improved behaviour. Some children, still, "might benefit from their (food colouring) elimination."

Elimination diets that avoid common allergens such as nuts, dairy, and chocolate, as well as citrus fruits, "have provided mixed opinions of efficacy," they noted.

In another finding Millichap and Yee concluded that only weak evidence supports the widespread belief that refined sugar promotes hyperactivity. But this is a well know fact, in spite of what you hear in schools or read on the web. Some effects on brain electrical activity have been documented, and reactive hypoglycemia following big jolts of sugary foods may account for behavioral changes seen in some ADHD children. But studies linking sugar consumption to ADHD have also been compromised by methodological problems. For example, one trial gave children sugar or placebo at breakfast with a high-carbohydrate cereal, which may have contributed to subsequent reactions to the sugar. The researchers cited a separate study that demonstrated when children ate a protein meal before or simultaneously with sugar, no hyperactivity reaction occurred.

"No controlled study or physician counsel is likely to change this perception (that sugar causes hyperactivity). Parents will continue to restrict the allowance of candy for their hyperactive child at Halloween in the belief that this will curb the level of exuberant activity, an example of the Hawthorne effect. The specific type of therapy or discipline may be less important than the attention provided by the treatment," Millichap and Yee wrote.

The researchers also explored the potential roles of zinc and iron deficiency in ADHD. Their finding was that there is "little indication that such deficiencies explain more than a small minority of ADHD cases. Children with confirmed deficiencies should receive supplements or appropriate dietary adjustments regardless of their ADHD status."

What about polyunsaturated fatty acid supplements? Research has found that "several ADHD symptoms were significantly improved in children receiving omega-3 and omega-6 fatty acid supplements, an effect duplicated in other ... supplement trials." Not all studies have confirmed the result, and recent studies have used too many different methodologies to yield firm conclusions. Nevertheless, these researchers "recommend it to parents of their patients, though not as the sole treatment approach." As they write: "In almost all cases, for treatment to be managed effectively, medication is also required," they wrote. "The beneficial effects of omega-3 and omega-6 supplements are not clearly demonstrated."

When do these researchers recommend using diet as an intervention with ADHD? "They suggested that diet-based interventions in ADHD are most appropriate when any of the following apply:

Children suffer medication reactions or treatment failure.
Parents or children want to try dietary modifications.
Mineral deficiencies are evident."

For a complete reading of this review, go to MedPage.

If your thinking about diet as an intervention, speak to your medical doctor first, and speak with a psychologist about parent education, behavioural therapy and school based supports that have been shown to be effective with children with ADHD.