Attention Deficit/Hyperactivity Disorder (ADHD)
Environmental And Dietary Considerations
Considerable controversy continues to surround the question of to what degree environmental toxins and dietary factors contribute to ADHD (Kidd 2000). Overt toxicity from contaminants and pollutants such as mercury and polychlorinated biphenyls (PCBs) are known to cause a wide spectrum of behavioral disorders (Rice 2000), although the effects of more subtle exposures are less clear.
Similarly, several theories have advanced regarding the association between dietary components (e.g., simple sugars) and ADHD, but again, convincing evidence is lacking (Chaves-Carballo 2003). Dietary manipulations such as the Feingold elimination diet (in which one or several categories of food is carefully excluded) have been tried, but with no success in treating ADHD (Krummel 1996).
Likewise, although allergies to foods or food additives have been proposed as a cause of ADHD (Boris 1994; Rowe 1994), there is little scientific basis for this idea. Oligoantigenic diets aim to reduce the number and variety of food-based allergens that children might be exposed to. A few small trials have shown some benefit in carefully selected groups of children (Egger 1985). Because oligoantigenic diets aim to eliminate large categories of food on which growing children may depend, they should be undertaken only in careful collaboration with a physician. Allergy testing has rarely proved helpful in treating ADHD.
The role of dietary sugar. Despite a great deal of attention in the popular press, there has been no convincing evidence that dietary sugar is causal in ADHD (Krummel 1996). In a 1985 study, children with ADHD were shown to have lower adrenaline levels after sugar intake than control children (Girardi 1995). The implications of this study are not clear. However, other studies have suggested that some children with ADHD may have food sensitivities that include sugar. The authors of these studies conclude that diet modification is an important part of ADHD management (Schnoll 2003). Whatever the outcome of this debate, there is little doubt whether dietary sugar benefits a child’s diets. It is linked to tooth decay, obesity, and other health conditions. Therefore, it is probably wise for all children to limit or completely avoid dietary sugar.