Dietary interventions

Elimination diets — We generally do not suggest elimination diets for children with ADHD, but decisions regarding trials of dietary interventions for ADHD must be made on a case-by-case basis. Some experts suggest that a short (no more than five-week) trial of an elimination diet may be warranted for certain children (eg, those whose caregivers are concerned about the use of and potential side effects of pharmacologic agents and are motivated to comply with the diet) [49-51]. If the decision is made to try an elimination diet, the diet should be supervised by the child’s healthcare provider and a dietician to ensure adequate nutritional intake. If behavior improves during the elimination diet, restricted foods can be added back weekly, one component at a time, to identify problematic foods that should be excluded from a less restrictive permanent diet.

The influence of diet on attention, hyperactivity, and behavior is controversial. Dietary factors (eg, food additives, food allergy or intolerance, etc) generally do not impact behavior to a clinically significant level and do not account for the majority of cases of ADHD. However, a small subset of children may demonstrate mild adverse behavioral effects in response to particular dietary components and improvements in behavior when these components are eliminated. (See "Attention deficit hyperactivity disorder in children and adolescents: Epidemiology and pathogenesis", section on 'Dietary influences'.)

Systematic reviews and meta-analyses of randomized trials with methodologic limitations suggest that some children with ADHD respond favorably to elimination diets [52-57]. In a 2012 meta-analysis of five randomized crossover studies, restriction diets reduced ADHD symptoms in children (effect size 0.29, 95% CI 0.16-0.52) [54]. Masked challenge with specific food colors had a small effect on parent-reported ADHD symptoms (20 studies, 794 participants, effect size 0.18, 95% CI 0.08-0.29), and a non-significant effect on teacher-reported symptoms (10 studies, 323 participants effect size 0.07, 95% CI -0.03-0.18). This discrepancy between parent and health professional/teacher report of symptoms has been noted in other studies [53,58]. The long-term effects of dietary elimination on nutritional status are unknown [49].

Clinical guidelines and practice parameters from the American Academy of Pediatrics, the American Academy of Allergy, Asthma & Immunology, and the United Kingdom’s National Institute for Health and Care Excellence (NICE) do not routinely recommend elimination diets for the treatment of ADHD [2,4,59]. However, the NICE guidelines indicate that referral to a dietician may be warranted if perceived links between specific foods or beverages and behavior are corroborated with a food diary [4]. 

Essential fatty acid supplementation — We do not suggest essential fatty acid supplementation for children with ADHD. Some studies have noted decreased fatty acid concentrations in the serum of children with ADHD [60-63]. However, evidence that fatty acid supplementation improves core symptoms in children with ADHD is limited [57,64-66].

In a 2012 meta-analysis of randomized and quasi-randomized trials comparing omega-3 and/or omega-6 fatty acid with placebo supplementation in children with ADHD (diagnosed with validated criteria), there were no differences in parent- or teacher-rated ADHD symptoms (overall), inattention, or hyperactivity/impulsivity [64]. Pooled analysis of two small trials (97 participants) found some evidence of improvement in overall ADHD symptoms or parent-rated ADHD symptoms among children supplemented with both omega-3 and omega-6 fatty acids (risk ratio 2.19 95% CI 1.04 to 4.62). Few of the studies included in the meta-analysis were of high quality. Methodologic limitations included small sample size, variable inclusion criteria, variable type and dose of supplement, and short duration of follow-up [64].

In a 2011 meta-analysis of 10 randomized trials (699 participants), omega-3-fatty acid supplementation was associated with improved ADHD symptoms in children with a diagnosis of ADHD or symptoms of ADHD [65]. The effect size was small to moderate compared with that of pharmacologic therapies (0.31 versus approximately 1.0 and 0.7, respectively) [2,65,67]. Possible explanations for the variable findings in the two meta-analyses include differences in population (children diagnosed with ADHD versus children with ADHD diagnosis or symptoms) and outcome measures (separate versus pooled parent- and teacher-reported symptoms).

Other alternative therapies — Complementary and alternative medicine (CAM) therapies may be considered or employed by as many as 64 percent of patients with ADHD [68]. CAM therapies often are used by patients without the explicit knowledge of the primary care provider [69-71]. It is important for primary care providers to ask their patients whether they have tried any CAM therapies for ADHD so that the risks and benefits of such therapies can be discussed [72].

In addition to elimination diets and fatty acid supplementation, other complementary and alternative (CAM) therapies that have been suggested in the management of ADHD include vision training, megavitamins, herbal and mineral supplements (eg, St. John's wort), neurofeedback/biofeedback, chelation, and applied kinesiology, among others. Most of these interventions have not been proven efficacious in blinded randomized controlled trials