By Krista Forand, M.Ed.
If you look online, there is a lot of information about ADHD and diet. It can be hard for parents to make sense of all of this information, as much of it is conflicting. For parents who are considering dietary approaches to treating their child’s ADHD, it can be overwhelming, costly and time consuming to sift through all of this information and put their trust into a particular dietary approach.
One major piece of advice that I share is to watch out for dietary approaches that make sweeping general claims (e.g., “this will cure ADHD!) and that cost a lot of money. Also, if you are concerned about your child’s diet/nutrition or possible allergies speak with your family doctor about this and seek assistance from a registered dietician. Making drastic changes to your child’s diet or using mega doses of vitamins can actually cause serious health problems (e.g., mega doses of certain vitamins can cause liver problems). Lastly, don’t be fooled by product labels that say “natural” and assume that these products cannot be harmful, particularly in large doses. For example, ginger is considered a “natural” aid for stomach upset and inflammation, but it interacts with other things (e.g., ibuprofen, blood thinners), making it dangerous if taken in combination.
If you are considering dietary treatments for your child with ADHD, consider the research that has been conducted in this area and the limitations of this research. The first meta-analysis (i.e., a study of studies) that was conducted in this area was in 1983 and it focused on the Feingold diet (i.e., a diet that eliminates certain colorings and preservatives). They found a very small effect size that was not significant, meaning that this diet did not significantly help to improve ADHD symptoms (specifically hyperactivity).
In 2012, another meta-analysis was conducted that looked at both diet and food colors. These researchers found that about 8% of children with ADHD may have symptoms related to synthetic food colors. They also concluded that about 30% of children in the studies were responsive to the diets. However, they noted that the research in this area is very outdated and they recommended a renewed investigation into the influence that diet may have on ADHD symptoms.
A recent review (2014) noted several limitations of the ADHD-diet research. Out of all the dietary approaches that they reviewed (e.g., sugar and artificial sweeteners, elimination diets, amino acids, vitamins, essential fatty acids and minerals) they concluded that most of them do not have enough evidence to recommend their use in clinical practice. They did find some positive effects for fish oil supplementation and the Few Foods Diets, but noted that both of these approaches need more evidence before they can be recommended. It is also important to understand that the Few Foods Diet is a short-term restriction of foods for determining if a person has specific food sensitivities and was not recommended by these authors as a long-term treatment for ADHD. Restrictive diets can have negative consequences particularly for growing children who need a variety of foods for nutritional balance. Few Foods Diets typically take at least a year, while the longest treatment time in the studies that were reviewed was only 9 weeks.
Other issues with the ADHD-diet research include many studies that were not blinded, meaning parents knew that their child was on the special diet, which can contribute to false positive effects due to the parents’ expectation that it will work. Another criticism is that some of the studies involved parents who had a bias towards dietary approaches to treating ADHD and they weren’t blind. This is recipe for false positive effects and is not considered good research.
Another issue to consider is the effort that it takes parents to implement certain diets. The more restrictive “rules” you have about what can and cannot be eaten, the more that parents need to look for specific foods or products, find ways to cook differently and hope that their child will eat what is “allowed” according to the diet. Many families will struggle to maintain consistency with such “high needs diets”.
At this point, it is a good idea for everyone to keep a balanced perspective about the research that has been done in this area so far. Since the 1983 meta-analysis, which showed no benefits, there has been some inkling of benefit for some diets and perhaps fish oils. However, it is clear right now, that we need more research that is of higher quality. In the meantime, it is recommended that parents understand where diet may play a role in their child’s overall health, rather than seeking a dietary approach to cure their ADHD. Diet is just one of many areas of our lives (e.g., sleep, exercise, social support, education etc.) that can affect how we feel and function in everyday life. Parents may want to consider making very small changes (e.g., increasing vegetables) in these areas to help their child before seeking out more intense diet approaches that may or may not work.
Krista Forand, M.Ed.
Krista has worked in various roles with the CanLearn Society (formerly Calgary Learning Centre) since 2009. She is currently working with the clinical team as a registered psychologist, providing assessments and group interventions for individuals with learning and attention difficulties. In 2014, Krista obtained her graduate degree from the University of Calgary where she cultivated her interest in learning disabilities and attention disorders. She believes in the therapeutic effect of psychoeducational assessment and how this process can empower individuals and families to take control of their lives, by understanding their unique way of being in the world.
Kavale, K.A., & Forness, S.R. (1983). Hyperactivity and diet treatment: A meta-analysis of the Feingold hypothesis. Journal of Learning Disabilities, 16, 324-330.
Nigg, J.T., Lewis, K. Edlinger, T., & Falk, M. (2012). Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. Journal of the American Academy of Child and Adolescent Psychiatry, 51, 86-97. DOI: 10.1016/j.jaac.2011.10.015
Heilskov Rytter, M.J., Beltoft Borup Andersen, L., Houman, T, Bilenberg, N., Hvolby, A., & Molgaard, C. (2014). Diet in the treatment of ADHD in children-A systematic review of the literature. Nordic Journal of Psychiatry, 69(1), 1-18. DOI: 10.3109/08039488.2014.921933