ADHD and Nutrition
Dr Shelley Hyman
Attention-deficit hyperactivity disorder is multi-determined and complex, requiring a multifaceted treatment approach, however, nutritional management is important for patients with ADHD.
Throughout the years, many studies have investigated the role of food, or food components, in influencing the symptoms of ADHD. It is now confirmed that artificial food colouring and the preservative benzoate promote hyperactivity in children and that patients with ADHD can noticeably improve on a diet without artificial food colouring.
However, besides from restricting and eliminating certain foods, dietary supplementation is an intervention with potentially beneficial outcomes in ADHD. There is evidence to suggest that deficiencies in polyunsaturated fatty acids could be related to ADHD, as they are considered to be essential fats, and must be obtained from the diet. The essential fatty acids are important for brain development and function.
Especially low levels of omega-3 polyunsaturated fatty acids have been shown in children and adolescents in ADHD, and thus, supplementing polyunsaturated fatty acids, in the form of fish oil tablets, may alleviate the behavioural and attentional problems associated with ADHD. However, further research is needed to confirm this. Likewise, iron deficiency is commonly presented in children with ADHD, and improvements have been reported following iron supplementation.
There is an emerging theory that, at least in some children, hyperactivity may be caused by a form of food allergy by contributing to neurologic inflammation. This theory explains the fact that ADHD has a high comorbidity with eczema, asthma and gastrointestinal disturbances. There are suggestions that certain foods can have negative physiological effects (impacting organs such as the skin, GI tract and the respiratory system) as well as negative neural effects (resulting in adverse behaviour).
As such, the “few food diet” aims to eliminate the most commonly sensitising allergens from the diet, such as cow’s milk, wheat, eggs and nuts. Only a few double blind studies with small sample sizes have evaluated the effects of this diet on behaviour, but results have shown a consistent and significant benefit among ADHD patients. We can therefore conclude, that at least among specific subgroups, diet is likely to contribute to an individual’s level of hyperactivity. Thus, Annelies et al justifies a 2-3 week restricted elimination diet for those willing and committed to make the effort.
However, it is important to note that nutritional interventions should be used as support for a treatment, not as a replacement for treatment.
- Annelies A. J. Verlaet , Daniela Briceno Noriega, Nina Hermans,Huub F. J. Savelkoul (2014). Nutrition, immunological mechanisms and dietary immunomodulation in ADHD, Eur Child Adolesc Psychiatry. 23:519–529