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Nutritional interventions to reduce symptoms in children and adults with attention deficit hyperactivity disorder: a scoping review protocol

Pedersen, Preben1; Bjerrum, Merete2; Larsen, Palle1; Bjerrum, Stefan3; Pedersen, Jette4; Peters, Micah5

JBI Database of Systematic Reviews and Implementation Reports: September 2017 - Volume 15 - Issue 9 - p 2265–2269
doi: 10.11124/JBISRIR-2016-003134

Review question/objective: : The objective of this scoping review is to examine and map reported nutritional interventions and their outcomes in relieving symptoms of attention deficit hyperactivity disorder (ADHD) in the daily lives of children and adults. A further objective is to determine if experiences of people diagnosed with ADHD, their relatives or staff in being on a diet or having to eat or avoid eating specific food items have been reported in the existing literature.

Specifically the scoping review questions are:

  1. What nutritional interventions have been tested in children or adults with ADHD in order to reduce ADHD symptoms?
  2. Have any experiences of people with ADHD, their relatives and/or staff in changing or sticking to a strict diet been reported?

1Danish Center of Systematic Review, a Joanna Briggs Institute Center of Excellence, Danish Centre of Clinical Guidelines, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark

2Department of Nursing Science, Institute of Public Health, Aarhus University, Aarhus, Denmark

3Psychiatric Clinic, Knudrisgade, Aarhus, Denmark

4AAU Libraries, Aalborg University, Aalborg, Denmark

5Joanna Briggs Institute, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia

Correspondence: Preben Pedersen,

Conflicts of interest: Micah Peters is an associate editor of the JBI Database of Systematic Reviews and Implementation Reports and he will take no part in the editorial or review processes for the present manuscript.

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Attention deficit hyperactivity disorder is the most common neuro-developmental childhood disorder and comprises a range of behavioral problems including inattention, impulsivity and hyperactivity.1 Attention deficit hyperactivity disorder is noted in 3–9% of children and adolescents with a male-to-female ratio ranging from 3:1 to 5:12-4 and 3–5% of adults with an equal male to female ratio, based on the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) criteria.5-7

At this point most researchers agree that ADHD is a problem of complex etiology that needs to be investigated as a function of complex interactions.8-10 The exact etiologies of ADHD have not been conclusively determined; however, lower brain volume or weight,8 and potential brain damage during perinatal insult at preterm birth9 have been proposed as possible reasons for poor maturation of the brain which may result in the development of ADHD during pre-school age.10 Attention deficit hyperactivity disorder is familial and heritable,11,12 and no single risk factor explains ADHD; both inherited and non-inherited factors contribute to the condition and their effects are interdependent. Research into the inherited and molecular genetic contributions to ADHD suggests an important overlap with other neurodevelopmental problems, notably autism spectrum disorders.11,12 Having a biological relative with ADHD, pre- and post-natal exposure, low birth weight or prematurity have been consistently found as risk factors, but none have yet been known to be definitely causal.11,12 There is vast literature documenting associations between ADHD and a wide variety of putative environmental risks that at present can only be regarded as correlates.11-12 Findings from research designs that go beyond simply testing for associations are beginning to contest the robustness of some environmental exposures previously thought to be ADHD risk factors.11,12 As information regarding etiologies of ADHD are missing or unclear, evaluating the effectiveness of interventions may be compromised.

Many studies have indicated that behavioral therapy and medication may at least be partially helpful in the treatment of children with ADHD.13-17 Research on the effect of diet or nutritional supplements on reducing ADHD symptoms has been increasing in the past two decades, particularly, on their effectiveness in reducing symptoms of hyperactivity and attention.1 The role of diet and dietary supplements in the cause and treatment of symptoms of ADHD is controversial but the topic continues to interest parents and physicians who prefer an alternative to stimulant medication or seek complementary therapy.13

Nutritional interventions have been seen as a way to supply the brain with the necessary nutrients to mature. Most parents are enthusiastic about trying diets or supplements as there has been reported anxiety among parents about the side effects of long-term pharmacotherapy, including effects on brain development and the subsequent risk of substance abuse and inhibited growth.13,14 Changing or sticking to a strict diet, however, is often time consuming, requires patience, perseverance and access to and help from a dietician.13 These demands may be beyond the capacity of already busy parents, so it is important to understand whether there is any merit in pursuing dietary or nutritional management options in this area.

The effect of increased intake of polyunsaturated fatty acids (PUFA), supplements of iron, zinc or other minerals, additive and salicylate free diets (Feingold diet) as well as reduction of sugar, aspartame, food additives and coloring, and others have been tested.13 There has been a particular focus on the role of food additives, refined sugar, food allergies and fatty acid metabolism.1 The intense focus on some nutritional interventions in systematic reviews could have resulted in the exclusion or oversight of other relevant and potentially effective interventions. Furthermore, it has been reported that interventions that were recommended 20–30 years ago have lately received renewed interest, for example, the Feingold diet.13

Reviews which have been published within the last ten years draw different conclusions on the overall effect on reduction of ADHD symptoms of nutritional interventions, especially on the effectiveness of PUFA.14 These different conclusions could be a result of unclear etiology of ADHD, due to different doses or follow-up period, unclear diagnostic criteria for ADHD or having a heterogeneous population with the same symptoms but unclear etiology or diagnoses.1,14-17 Interventions that aim at supplying the brain with the necessary nutrients require sufficient time to have the intended effect, therefore we need to map the doses and the period of giving nutritional interventions. On the other hand, nutritional interventions may have little or no effect if the etiology is connected to social causes. Therefore differentiating between etiologies is key when evaluating the effect of interventions. If the etiology of ADHD is not clearly defined, one may draw erroneous conclusions on the effect of specific interventions.

To best support people with ADHD or parents caring for children with ADHD, it is necessary for healthcare staff to both acquire knowledge of effective interventions and develop a comprehensive understanding of interventions that have been tested and studied with limited or no effect. This is necessary in order to prioritize, develop and offer interventions to help people with ADHD to reduce symptoms of ADHD and be better able to overcome the challenges caused by them.18

The intention is to develop one or more clinical guidelines recommending or not recommending nutritional interventions for the reduction of ADHD symptoms. The guidelines must be based on the evidence on nutritional interventions for people with ADHD. Clinical guidelines should be based on a recently published systematic review of the literature aggregating evidence from available research. Therefore, we need to have insight into what intervention studies that have been published about any type of nutritional interventions, their outcomes and whether all interventions or only some interventions have been summarized in systematic reviews within the last 10 years. A scoping review has been chosen as the most appropriate and rigorous methodology to carry out this preliminary stage. The Joanna Briggs Institute guidance for the conduct and reporting of scoping reviews has been adhered to in the preparation of the present protocol and will be followed throughout the ensuing review.19 When primary research and systematic reviews have been identified, the following will be considered:

  1. Will it be appropriate to develop an umbrella review?
  2. Will we need to develop systematic reviews on interventions not included in the published systematic reviews and/or will the published systematic reviews need to be updated?
  3. Will it be reasonable to develop a systematic review of experiences of people with ADHD, their relatives or staff on changing or sticking to a strict diet?

An initial search in the MEDLINE (PubMed), CINAHL, JBI COnNECT+, DARE, PROSPERO, Cochrane Library and PsycINFO indicated that no scoping review on this topic is available or currently under development.

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Inclusion criteria

Type of participants

In this scoping review there are two types of participants: children and adults with ADHD, and relatives or staff involved with persons with ADHD. People of any age with a confirmed ADHD diagnose will be included. The diagnosis of ADHD should be based on the criteria outlined by ICD-10: F90 (Diagnostic and Statistical Manual of Mental Disorders by the World Health Organization) or DSM-V (Diagnostic and Statistical Manual of Mental Disorders by The American Psychiatric Association).20,21

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The core concept examined by this scoping review is the content, nature and outcomes of any nutritional interventions including the use of nutritional supplements or a prescribed diet that have been tested with the intention to reduce ADHD symptoms experienced in everyday life. Further, this scoping review will identify any reported experiences of changing or adhering to a strict diet reported by people with ADHD or people related to a person with ADHD.

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The context elements of this scoping review are any setting where interventions or experiences of such nutritional interventions have occurred (e.g. at home, educational institutions, kindergartens, hospitals or other care facilities).

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The sources of information include both quantitative and qualitative data from any existing literature e.g. primary research studies and systematic reviews The scoping review will consider both systematic reviews (including any experimental and observational study design), including randomized controlled trials, non-randomized controlled trials, quasi-experimental studies, before and after studies, prospective and retrospective cohort studies, case control studies and analytical and descriptive cross sectional studies.

The qualitative part of this review will consider studies that focus on qualitative data including, but not limited to, designs such as phenomenological, grounded theory, ethnography, actions research and feminist research.

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Search strategy

The search strategy aims to find both published and unpublished studies (gray literature). A three-step search strategy will be utilized in this review. The initial search strategy and terms will be chosen in discussion with a research librarian with the aim of establishing a maximum number of articles. An initial limited search of MEDLINE (via PubMed) and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases, and citation searches will also be carried out. Third, the reference lists of all identified reports and articles will be searched for additional studies. Studies published in English, German, Danish, Swedish and Norwegian will be considered for inclusion in this review.

Databases will be searched from their inception to September 2016. If relevant, the reviewers intend to contact authors of primary studies or reviews for further information.

The databases to be searched include: MEDLINE (via PubMed), CINAHL, Embase, Scopus, Swemed+, MedNar, PsycINFO, Turning Research Into Practice (TRIP), ProQuest Dissertations and Theses.

Additional searching for published literature will include: searching of reference lists and bibliographies of included articles.

Initial keywords/search terms to be used will be:

  • ADHD, adult, young adult, children
  • Nutritional intervention, nutrients, diets, vitamins minerals, fatty acids
  • Experience, perception
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Data extraction

Data extraction of both quantitative and qualitative data will be carried out using a data extraction tools developed by the authors; one for systematic reviews and one for primary research. See Appendix I.

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Presenting the data

Data extracted from each of the studies will be mapped and presented in a form that logically reflects the objectives of this scoping review. Tabular and graphical representations of the data may be used to illustrate the identified results and will be supported by narrative descriptions of the data. The data from the studies will be presented and discussed in terms of overall concept/components that can be related to nutritional/diet interventions used among people with ADHD as well as their experiences of these interventions.

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Appendix I: Extraction of findings

Extraction of findings from systematic reviews



Extraction of findings form primary research



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ADHD; adults; children; experience; nutritional intervention

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