Some research suggests that diet may influence symptoms in a subset of children with ADHD. One early study published in the New Zealand Medical Journal (July 26, 1978;88(616):43–45) examined the effects of a low-allergen, Feingold-type diet in 10 children. The diet eliminated processed foods, food additives, and foods high in salicylates, such as berries, almonds, apples, plums, and tomatoes. Five of the children showed improvement in behavior. When eliminated foods were reintroduced, symptoms returned, suggesting that dietary factors played a role for those individuals.
Another study published in European Child and Adolescent Psychiatry (June 1997;6(2):88–95) evaluated 49 children in a double-blind, placebo-controlled trial. One group followed a low-allergen diet, while the other received the stimulant medication methylphenidate. The medication produced a greater overall response, with 44% of children improving compared with 24% in the diet group. However, the dietary intervention produced no reported side effects. The authors noted that responses to diet varied, raising the possibility that individualized dietary approaches might produce different outcomes.
Additional evidence comes from a study published in the Journal of Pediatrics (November 1994;125(5 Pt 1):691–698), which examined the effects of an additive-free diet. In this six-week open trial, parents of 150 out of 200 children reported improvement in ADHD symptoms while their children were on the diet. Symptoms worsened when food additives were reintroduced. From this group, researchers identified children suspected to be sensitive to additives.
These children were then enrolled in a 21-day double-blind, placebo-controlled, repeated-measures study in which each child served as his or her own control. Participants were randomly given either a placebo or one of six doses (1, 2, 5, 10, 20, or 50 mg) of tartrazine, a commonly used yellow food dye. Parents rated behavior daily. Twenty-four children were identified as clear “reactors,” exhibiting symptoms such as irritability, restlessness, and sleep disturbance. Reactions occurred at all dose levels, with greater severity and longer duration at higher doses. These findings indicate that artificial food dyes can affect behavior in some children with ADHD.
Further research published in Archives of Disease in Childhood (June 2004;89:506–511) also reported associations between food additives and ADHD-related symptoms.
Other studies have explored the role of refined carbohydrates and diets low in essential nutrients, suggesting that overall diet quality may influence attention and behavior. Taken together, this body of research indicates that diet is not the sole cause of ADHD, but it may be an important contributing factor for some children. Dietary approaches are relatively low-risk and inexpensive, and for certain individuals, they may represent a meaningful part of a broader, multifaceted approach to understanding ADHD.
