Food sensitivities, artificial colours and flavours, and excessive phosphate ingestion seem to be an important causative factor in this disorder. Food sensitivities and food allergy provoke hyperactivity through partially digested food proteins (exorphins) entering the blood stream and scrambling the neuronal communicative system. In eight out of nine studies 86% of hyperactive children had elevated blood eosinophils, indicative of allergy or parasitic infection.
Artificial colours, flavours and preservatives inhibit a number of detoxifying enzymes (e.g. aryl sulphatase, catechol-o-methyl transferase), which increases the toxic effects of certain foods. Studies have linked ingestion of artificial food colourings and behavioural change in children. Irritability, restlessness and sleep disturbance have been specifically linked to food colourings such as tartrazine.
The most common chemicals children react to are amines, salicylates, artificial colours, glutamates and preservatives. Statistically significant improvements in conduct, learning, impulsivity and hyperactivity have been demonstrated if these are removed or minimised in the diet. Data from two double blind studies indicate that 73-76% of ADHD children respond favourably to food elimination diets. Maintenance on low-antigen diets raised the success rate to 82%.
Calcium propionate (preservative code 282) is a colourless, tasteless and odourless preservative used in breads to discourage mould growth. Researchers in Darwin investigated the effects of 282 on behaviour on children with “behavioural problems”. The authors concluded that; the preservative may cause restlessness, inattention, irritability and sleep disturbance in some children.