Salicylate sensitivity in children reported to respond to salicylate exclusion

ADHD impacted by sulfotransferase (SULT1A) inhibition from artificial food colors and plant-based foods

BACKGROUND

Five recent reviews have analyzed trials on the association between artificial food colors and ADHD; the 50 underlying studies and the reviews in aggregate were inconclusive. Recent work has shown human in vivo SULT1A inhibition leading to incremental catecholamines, and an inverted-U relationship between brain catecholamines and proper functioning of the prefrontal cortex where ADHD behavior can arise.

METHOD

This study re-examined the same underlying trials for evidence that SULT1A inhibitors were in the placebos and other inactive foods, that these "inactive" materials were symptomatic, and that ADHD symptoms exhibited an inverted-U response to SULT1A inhibition.

RESULTS

Nearly all the underlying diets, and many placebos and delivery vehicles, were found to contain SULT1A inhibitors. Eight publications provided evidence of ADHD symptoms caused by the "inactive" materials containing SULT1A inhibitors. Ten studies showed additional SULT1A inhibitors reducing the symptoms of some subjects.

CONCLUSION

SULT1A inhibitors in foods, including natural substances and artificial food colors, have a role in ADHD that can both worsen or improve symptoms. Mechanistically, SULT1A enzymes normally deactivate catecholamines, especially dopamine formed in the intestines; SULT1A inhibition can influence brain catecholamines through the intermediary of plasma tyrosine levels, which are influenced by dopamine inhibition of intestinal tyrosine hydroxylase. Biochemical measurements focused on SULT1A activity and plasma tyrosine concentrations are proposed for future work.

Dietary sensitivities and ADHD symptoms: thirty-five years of research

Artificial food colors (AFCs) have not been established as the main cause of attention-deficit hyperactivity disorder (ADHD), but accumulated evidence suggests that a subgroup shows significant symptom improvement when consuming an AFC-free diet and reacts with ADHD-type symptoms on challenge with AFCs. Of children with suspected sensitivities, 65% to 89% reacted when challenged with at least 100 mg of AFC. Oligoantigenic diet studies suggested that some children in addition to being sensitive to AFCs are also sensitive to common nonsalicylate foods (milk, chocolate, soy, eggs, wheat, corn, legumes) as well as salicylate-containing grapes, tomatoes, and orange. Some studies found "cosensitivity" to be more the rule than the exception. Recently, 2 large studies demonstrated behavioral sensitivity to AFCs and benzoate in children both with and without ADHD. A trial elimination diet is appropriate for children who have not responded satisfactorily to conventional treatment or whose parents wish to pursue a dietary investigation.

Salicylate Consumption and Hyperactive Behavior

Two boys labelled hyperactive who had followed a salicylate-free diet for over a year consumed specially prepared cookies daily for 6-7 weeks. With subject 1 (age 6), salicylates were presented in the cookies on two occasions; on other days the cookies were salicylate-free. On two occasions subject 1 violated his diet and consumed salicylates from other sources. With subject 2 (age 12), salicylates were presented five times. Observers collected daily data on out-of-seat, off-task and physically aggressive behavior in the classroom. Visual inspection of the data suggested that behavior changes were associated with salicylate ingestion for subject 1, although there was some variability, but not for subject 2. A randomization test indicated that for subject 1 differences associated with planned salicylate ingestion were significant at the 0.05 level. No significant differences were noted for subject 2.

The effect of the Feingold diet on 'normal" school children

Approximately 300 children in seven primary (elementary) schools used the Feingold diet for two weeks. Ratings were made by teachers before and after use of the diet on questionnaires developed from Conners' long teacher questionnaire. The questionnaire incorporated Conners' hyperactivity factor items, but related to the normal or average child, by referring to most children. Of the total sample, 8.5% improved by five points or more. The mean before diet scores of children who improved were below the cut off value for hyperactivity, indicating hyperactivity itself is not a necessary condition for improvement. Item by item analysis of the response showed that the behavior problems mostly likely to show improvement were distractability, attention span, fiddling, and demands for attention. Parents provided information on the additive foods being ingested by their children. Those children who were reported to be taking a great deal of additive were found to rate significantly higher in behavioral problems compared with children receiving little additive.