Few diagnoses are more controversial than Attention-Deficit Hyperactivity Disorder (ADHD). Like most psychiatric diagnoses, ADHD is a descriptive label based purely on observed or reported behaviours, as there are no objective tests or biological markers. Longstanding debates therefore continue over whether ADHD is over-diagnosed, under-diagnosed, or even valid as a medical condition at all, rather than being a purely social construct.¹

Like autism, ADHD is not a unitary condition, nor a ‘disease’ in any conventional medical sense. Rather, it is best regarded as a behavioural syndrome defined by extremes of normal individual differences in behaviour and cognition, arising from the interaction of innumerable biological, psychological and social factors that shape both brains and behaviour.

Standard treatment guidelines for ADHD prioritise pharmacological and/or behavioural management, dismissing or downplaying nutritional or dietary interventions or support on the grounds that these lack of good clinical trial evidence. This article outlines some key issues that this narrow approach to the management of ADHD fails to take into account, namely:

(1) the heterogeneity of ‘ADHD’ – owing to both the way this condition is defined and diagnosed, and the many other different conditions with which it co-occurs – or which can mimic it;

(2) the fact that nutrition is absolutely fundamental to brain development and function, and therefore affects mood, behaviour, and cognition, as well as physical health;

(3) clinical trial evidence that some nutritional and dietary interventions can benefit many (if not all) individuals with ADHD-type difficulties.

Diagnosis and Prevalence of ADHD  

Diagnosis of ADHD requires severe and persistent difficulties involving either or both of two main dimensions – ‘Hyperactivity-Impulsivity’ (e.g. excessive running, climbing, fidgeting, difficulty playing quietly, acting without thinking, interrupting others) and ‘Inattention’ (e.g. not seeming to listen, being forgetful, not following through on instructions, ‘daydreaming’, making ‘careless’ mistakes) – so the resulting subgroups include ‘Inattentive-type’ (formerly known as Attention Deficit Disorder or ADD), ‘Hyperactive-Impulsive type’, or ‘Combined-type ADHD.

The difficulties must also be age-inappropriate (although in practice, younger children are more likely to be diagnosed²); evident across at least two situations, such as home and school; and causing ‘functional impairment’ (but judgement of this is subjective, and complicated by co-occurring conditions and/or general ability).

The ADHD diagnosis was first introduced in 1980 by the American Psychiatric Association,³ effectively adding ‘Attention Deficit Disorder’ to the pre-existing ‘Hyperkinetic Disorder’ diagnosis. Successive revisions since then have further expanded eligibility, with the latest version, DSM-5 (released in 2015) receiving particular criticism on this score.^4,5

Prevalence rates have therefore increased over time, but vary widely both between and within countries, ranging from 2-5% in the UK and Europe to around 10% in the US and Canada. ADHD is more common in males than females (although better recognition in females has been reducing this difference) and rates remain higher in children than adults (although the latter have risen steeply following removal of the criterion that difficulties must have been present since early childhood).

Conditions Co-Occurring with, or Mimicking ADHD

Variability within ADHD is hugely compounded by its very high overlap with most other developmental and mental health conditions – including dyslexia, dyspraxia (Developmental Coordination Disorder, or DCD), Autistic Spectrum Disorders (‘dual diagnosis’ of ADHD and ASD was disallowed until 2015, since when overlaps of 30-50% in each direction have been reported), anxiety, depression and other mood disorders, sleep disorders, eating disorders, substance use disorders, personality and conduct disorders, and psychosis, among others.

At least four in five children or adults diagnosed with ADHD also meet criteria for at least one other condition, and two-thirds for two or more additional diagnoses.^6,7 The heterogeneity within ‘ADHD’ from these overlaps not only complicates clinical management, but seriously confounds conclusions from any research focused on the broad diagnosis of ADHD alone.

ADHD is also associated with higher rates of many physical health problems – including allergies and immune disorders, sleep problems, accidental injuries, dental caries, and obesity and related metabolic problems.⁸ Nutrition is relevant to many of these, and co-occuring conditions can sometimes provide important clues to what kinds of dietary changes might help in managing both these, and the associated behavioural issues.

Most important, however, is that some medical conditions can easily be misdiagnosed as ADHD (particularly ‘Inattentive-type’) – and a recent review has called for a medical evaluation to be required before an ADHD diagnosis is made.⁹ These ‘differential diagnoses’ include ‘absence’ seizures (i.e. forms of epilepsy), post-concussion states, thyroid or other hormonal conditions, some autoimmune disorders, and iron deficiency or anaemia, among others.

Deficiencies of other essential nutrients than iron, or Vitamin B12 (lack of which can also cause anaemia, and/or psychiatric and neurological symptoms) can also mimic or exacerbate ADHD-type symptoms.

Evidence that food and diet can affect ADHD-type difficulties

Poor quality diets (rich in ultra-processed foods high in sugar and refined carbohydrates, unhealthy fats and artificial additives) are associated with both nutritional deficiencies and imbalances and ADHD-type difficulties.¹⁰ While such studies can’t demonstrate causality, pilot clinical trial evidence indicates that a ‘heart-healthy’ diet can significantly improve behaviour and mood in children with ADHD.¹¹

Excessive intake of ‘free sugars’ damages health in many different ways, and is particularly common in individuals with ADHD-type difficulties.¹² Contrary to common belief, sugar consumption actually impairs attention, cognition and mood even in the short term, a systematic review of clinical trials found.¹³  Low or unstable blood sugar can also trigger mood swings and irritable or aggressive behaviour; so avoiding foods – and drinks – that release sugar rapidly can help manage these kinds of difficulties in ADHD and related conditions (and will also benefit general health).

Specific nutritional and dietary interventions for ‘ADHD’ supported by clinical trial evidence include:

‘Oligoantigenic’ (‘few foods’) diets

Systematic reviews of clinical trials show many children with ADHD react badly to specific foods or ingredients, and that identifying and excluding these can reduce symptoms (and improve general health).^14–17  .

NICE guidelines for ADHD management do support dietitian referral for adverse food reactions, provided these are well-documented, as professional help is needed to plan a suitable and acceptable diet and avoid nutritional deficiencies or imbalances.

They do not, however, recommend the avoidance of artificial food colourings, despite good evidence from controlled trials that these can negatively affect behaviour in children with or without ADHD.^18–20   

Supplementation with Long-chain Omega-3 fatty acids

Systematic reviews and meta-analyses of clinical trials show that supplementation with the long-chain omega-3 fats found in fish and seafood (EPA and DHA) can reduce ADHD-type symptoms in both clinical and general populations.^21–23 However, reported benefits vary with the populations studied, treatment formulations and dosages, and outcome measures used, as well as baseline omega-3 status; so further research is still needed to clarify these issues.

Strong clinical trial evidence also supports use of these omega-3 (and EPA in particular, at 1-2g/day) as an adjunctive treatment for clinical-level depression and other mood disorders.²⁴

Vitamin and mineral supplementation

With respect to specific micronutrients, deficiencies of iron, zinc, and Vitamin D have often been linked with ADHD and related conditions, and clinical trials have also reported benefits from supplementation with these nutrients,^25,26 although the quality of some studies in these areas is variable.

Other, high-quality clinical trials show that broad spectrum vitamin and mineral supplementation can improve behaviour and attention in both children and adults with ADHD, particularly those with low mood or poor emotional regulation.^27,28

Food and diet are the best way to obtain all essential nutrients, but if this is not possible (and this can present particularly challenges for some individuals with ADHD and related conditions) supplementation is a rationale option – although this should always be discussed with the health professional in charge.

To get further support and advice about dietary changes or supplementation book an appointment with one of our registered nutritionists:

Alternatively view a list of supplements that may benefit mood, behaviour, and sleep issues:

Other articles that may interest you

Additives and preservatives and their impact on sleep in ADD/ADHD children and adults

ADHD, anxiety & depression

The sugar rollercoaster

Further information

Further information can be found at www.fabresearch.org

Books:

• • They Are What You Feed Them – Dr Alex Richardson
  • The Better Brain – Professors Julia Rucklidge and Bonnie Kaplan
  • Smart Foods for ADHD and Brain Health – Dr Rachel Gow

FAB Webinars:

References

1. Te Meerman S, Freedman JE, Batstra L. ADHD and reification: Four ways a psychiatric construct is portrayed as a disease. Front psychiatry. 2022;13:1055328. doi:10.3389/fpsyt.2022.1055328
2. Whitely M, Raven M, Timimi S, et al. Attention deficit hyperactivity disorder late birthdate effect common in both high and low prescribing international jurisdictions: a systematic review. J Child Psychol Psychiatry. 2019;60(4):380-391. doi:10.1111/JCPP.12991
3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition (DSM-III).; 1980.
4. Batstra L, Frances A. DSM-5 further inflates attention deficit hyperactivity disorder. J Nerv Ment Dis. 2012;200(6):486-488. doi:10.1097/NMD.0B013E318257C4B6
5. Frances A. Saving Normal: An Insider’s Revolt Against Out-Of-Control Psychiatric Diagnosis, Dsm-5, Big Pharma, and the Medicalization of Ordinar: An Insider’s … and the Medicalization of Ordinary Life. William Morrow & Co.; 2013.
6. Kadesjo B, Gillberg C. The comorbidity of ADHD in the general population of Swedish school-age children. J Child Psychol Psychiatry Allied Discip. 2001;42(4):487-92. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11383964
7. Sobanski E. Psychiatric comorbidity in adults with attention-deficit/hyperactivity disorder (ADHD). Eur Arch Psychiatry Clin Neurosci. 2006;256(S1):i26-i31. doi:10.1007/s00406-006-1004-4
8. Galéra C, Cortese S, Orri M, et al. Medical conditions and Attention-Deficit/Hyperactivity Disorder symptoms from early childhood to adolescence. Mol Psychiatry. 2022;27(2):976-984. doi:10.1038/S41380-021-01357-X
9. Sadek J. Attention Deficit Hyperactivity Disorder Misdiagnosis: Why Medical Evaluation Should Be a Part of ADHD Assessment. Brain Sci. 2023;13(11):1522. doi:10.3390/brainsci13111522
10. Del-Ponte B, Quinte GC, Cruz S, Grellert M, Santos IS. Dietary patterns and attention deficit/hyperactivity disorder (ADHD): A systematic review and meta-analysis. J Affect Disord. 2019;252:160-173. doi:10.1016/j.jad.2019.04.061
11. Khoshbakht Y, Moghtaderi F, Bidaki R, Hosseinzadeh M, Salehi-Abargouei A. The effect of dietary approaches to stop hypertension (DASH) diet on attention-deficit hyperactivity disorder (ADHD) symptoms: a randomized controlled clinical trial. Eur J Nutr. 2021;60(7):3647-3658. doi:10.1007/s00394-021-02527-x
12. Johnson RJ, Gold MS, Johnson DR, et al. Attention-deficit/hyperactivity disorder:Is it time to reappraise the role of sugar consumption? Postgrad Med. 2011;123(5):39-49. doi:10.3810/pgm.2011.09.2458
13. Mantantzis K, Schlaghecken F, Sünram-Lea SI, Maylor EA. Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood. Neurosci Biobehav Rev. 2019;101:45-67. doi:10.1016/j.neubiorev.2019.03.016
14. Millichap JG, Yee MM. The Diet Factor in Attention-Deficit/Hyperactivity Disorder. Pediatrics. 2012;129(2):330-337. doi:10.1542/peds.2011-2199
15. Stevenson J, Buitelaar J, Cortese S, et al. Research Review: The role of diet in the treatment of attention-deficit/hyperactivity disorder – an appraisal of the evidence on efficacy and recommendations on the design of future studies. J Child Psychol Psychiatry. 2014;55(5):416-427. doi:10.1111/jcpp.12215
16. Taylor MR, Chuang C, Carrasco KD, Nagatomo S, Rucklidge JJ. Dietary and Micronutrient Treatments for Children with Neurodevelopment Disorders. Curr Dev Disord Reports. Published online September 13, 2018:1-10. doi:10.1007/s40474-018-0150-5
17. Pelsser LM, Frankena K, Toorman J, Rodrigues Pereira R. Diet and ADHD, Reviewing the Evidence: A Systematic Review of Meta-Analyses of Double-Blind Placebo-Controlled Trials Evaluating the Efficacy of Diet Interventions on the Behavior of Children with ADHD. PLoS One. 2017;12(1):e0169277. doi:10.1371/journal.pone.0169277
18. Schab DW, Trinh NH. Do artificial food colors promote hyperactivity in children with hyperactive syndromes? A meta-analysis of double-blind placebo-controlled trials. J Dev Behav Pediatr JDBP. 2004;25(6):423-434.
19. Bateman B, Warner JO, Hutchinson E, et al. The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children. Arch Dis Child. 2004;89:506-511.
20. McCann D, Barrett A, Cooper A, et al. Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. Lancet. 2007;370(9598):1560-1567. doi:10.1016/S0140-6736(07)61306-3
21. Bloch MH, Qawasmi A. Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: Systematic review and meta-analysis. J Am Acad Child Adolesc Psychiatry. 2011;50:991-1000. doi:10.1016/j.jaac.2011.06.008
22. Hawkey E, Nigg JT. Omega−3 fatty acid and ADHD: Blood level analysis and meta-analytic extension of supplementation trials. Clin Psychol Rev. 2014;34(6):496-505. doi:10.1016/j.cpr.2014.05.005
23. Chang JCPC, Su KP, Mondelli V, Pariante CM. Omega-3 Polyunsaturated Fatty Acids in Youths with Attention Deficit Hyperactivity Disorder: a Systematic Review and Meta-Analysis of Clinical Trials and Biological Studies. Neuropsychopharmacology. 2018;43(3):534-545. doi:10.1038/npp.2017.160
24. Guu TW, Mischoulon D, Sarris J, et al. International Society for Nutritional Psychiatry Research Practice Guidelines for Omega-3 Fatty Acids in the Treatment of Major Depressive Disorder. Psychother Psychosom. Published online September 3, 2019:1-11. doi:10.1159/000502652
25. Granero R, Pardo-Garrido A, Carpio-Toro IL, Ramírez-Coronel AA, Martínez-Suárez PC, Reivan-Ortiz GG. The role of iron and zinc in the treatment of adhd among children and adolescents: A systematic review of randomized clinical trials. Nutrients. 2021;13(11). doi:10.3390/NU13114059
26. Gan J, Galer P, Ma D, Chen C, Xiong T. The Effect of Vitamin D Supplementation on Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Child Adolesc Psychopharmacol. 2019;29(9):670-687. doi:10.1089/cap.2019.0059
27. Johnstone JM, Hatsu I, Tost G, et al. Micronutrients for Attention-Deficit/Hyperactivity Disorder in Youths: A Placebo-Controlled Randomized Clinical Trial. J Am Acad Child Adolesc Psychiatry. 2022;61(5):647-661. doi:10.1016/J.JAAC.2021.07.005
28. Rucklidge JJ, Frampton CM, Gorman B, Boggis A. Vitamin-mineral treatment of attention-deficit hyperactivity disorder in adults: Double-blind randomised placebo-controlled trial. Br J Psychiatry. 2014;204(4):306-315. doi:10.1192/BJP.BP.113.132126

Disclaimer:  The views and opinions expressed in this blog post are those of the author and do not necessarily reflect the official policy or position of any professional organization or guidelines. The information provided is for educational and informational purposes only and is not intended as a substitute for professional advice, diagnosis, or treatment. Always seek the advice of your therapist or other qualified health provider with any questions you may have regarding a medical or mental health condition.