Does oligoantigenic diet influence hyperactive/conduct-disordered children--a controlled trial

Trialling a microbiome-targeted dietary intervention in children with ADHD-the rationale and a non-randomised feasibility study

Background

Dietary interventions have been previously explored in children with ADHD. Elimination diets and supplementation can produce beneficial behaviour changes, but little is known about the mechanisms mediating change. We propose that these interventions may work, in part, by causing changes in the gut microbiota. A microbiome-targeted dietary intervention was developed, and its feasibility assessed.

Methods

A non-randomised feasibility study was conducted on nine non-medicated children with ADHD, aged 8–13 years (mean 10.39 years), using a prospective one-group pre-test/post-test design. Participants were recruited from ADHD support groups in London and took part in the 6-week microbiome-targeted dietary intervention, which was specifically designed to impact the composition of gut bacteria. Children were assessed pre- and post-intervention on measures of ADHD symptomatology, cognition, sleep, gut function and stool-sample microbiome analysis. The primary aim was to assess the study completion rate, with secondary aims assessing adherence, adverse events (aiming for no severe and minimal), acceptability and suitability of outcome measures.

Results

Recruitment proved to be challenging and despite targeting 230 participants directly through support groups, and many more through social media, nine families (of the planned 10) signed up for the trial. The completion rate for the study was excellent at 100%. Exploration of secondary aims revealed that (1) adherence to each aspect of the dietary protocol was very good; (2) two mild adverse events were reported; (3) parents rated the treatment as having good acceptability; (4) data collection and outcome measures were broadly feasible for use in an RCT with a few suggestions recommended; (5) descriptive data for outcome measures is presented and suggests that further exploration of gut microbiota, ADHD symptoms and sleep would be helpful in future research.

Conclusions

This study provides preliminary evidence for the feasibility of a microbiome-targeted dietary intervention in children with ADHD. Recruitment was challenging, but the diet itself was well-tolerated and adherence was very good. Families wishing to trial this diet may find it an acceptable intervention. However, recruitment, even for this small pilot study, was challenging. Because of the difficulty experienced recruiting participants, future randomised controlled trials may wish to adopt a simpler dietary approach which requires less parental time and engagement, in order to recruit the number of participants required to make meaningful statistical interpretations of efficacy.

Trial registration

ClinicalTrials.gov Identifier: NCT03737877. Registered 13 November 2018—retrospectively registered, within 2 days of the first participant being recruited.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01058-4.

The use of diet interventions to treat symptoms of ADHD in children and adolescents - a systematic review of randomized controlled trials

Background: For over forty years diet interventions have been investigated as a treatment of ADHD in children and adolescents and, with the new discoveries of the microbiota-gut-brain axis, this research becomes more relevant than ever. The aim of this systematic review was therefore to investigate the current knowledge of diet interventions as a treatment of ADHD in children and adolescentsMethods: A systematic literature search in PubMed was conducted, identifying randomized controlled trials investigating diet interventions to treat ADHD in children and adolescents.Results: The study populations were generally small and the studies varied in duration and nature of the exposure. Overall 10 out of 12 studies spoke in favour of an elimination diet, 2 out of 6 of eliminating artificial food colourings from the diet and none in favour of eliminating sucrose or aspartame from the diet to treat ADHD.Conclusion: The current evidence is not enough to recommend treating ADHD with diet interventions, but a subgroup of children and adolescents might warrant from elimination of certain food-items. Further investigations of the mechanism and effect of diet interventions to treat ADHD is needed.

Oligoantigenic Diet Improves Children's ADHD Rating Scale Scores Reliably in Added Video-Rating

OBJECTIVES

The influence of food intake on behavioural disorders was already described in the early 20th century. Elimination of individually allergenic food items from individual diets ["oligoantigenic diet" (OD)] showed promise to improve attention-deficit/hyperactivity disorder (ADHD) symptoms. However, only few of the positive results were evaluated by blinded symptom rating. Therefore the present study's purpose was to evaluate the reliability of a non-blinded rating of the ADHD Rating Scale IV (ARS) for the assessment of OD effects in comparison to a blinded rating of the ARS based on pseudonymized video recordings.

METHODS

Ten children (8m/2f) aged 8 to 14 with ADHD according to ICD-10 participated in an uncontrolled, open-label dietary intervention study. Food items, commonly related to intolerances, were eliminated for four weeks. Participants with > 40% improvement in the ARS between T1 (before the diet) and T2 (after the diet) were defined as responders. Nutrients with individual relevance to ADHD symptoms were identified in a following reintroduction phase (T3-T4) lasting 8-16 weeks. The ARS was completed by a non-blinded child and adolescent psychiatrist (T0-T4). Sessions were recorded on video, pseudonymized, and evaluated by three blinded raters. Complete data were captured for eight children. The inter-rater reliability between the non-blinded therapist and every blinded rater was determined by the intra-class correlation coefficient (ICC). Correlations according to Pearson and Spearman between the non-blinded and blinded rating were calculated for each rater.

RESULTS

Two blinded raters and the non-blinded rater considered 5 of 8 (62.5%) children as responders, whereas one blinded rater disagreed as to the success of one case thus considering only 4 of 8 children as responders to the diet. Inter-rater reliability was assessed after each rater having scored 33 videos: The intra-class coefficients were >.9 for all raters (rater 1: ICC=.997, rater 2: ICC=.996, rater 3: ICC=.996) and the Spearman rho between the raters were high (n=33; rater 1: rho =.989, p<.0001, rater 2: rho=.987, p<.0001, rater 3: rho=.984, p<.0001), respectively.

DISCUSSION

As both, blinded and non-blinded ratings of the ARS, revealed relevant significant improvement of ADHD scores in children following an OD in this uncontrolled trial, Randomized controlled trials appear as highly desirable in order to replicate these improvements and to establish reliable and unbiased effect sizes thereby fostering further more objective confirmatory measurements.

Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) - study protocol of an open-label trial to investigate the mechanisms underlying the effects of a few-foods diet on ADHD symptoms in children

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is the most common childhood behavioural disorder, causing significant impediment to a child's development. It is a complex disorder with numerous contributing (epi)genetic and environmental factors. Currently, treatment consists of behavioural and pharmacological therapy. However, ADHD medication is associated with several side effects, and concerns about long-term effects and efficacy exist. Therefore, there is considerable interest in the development of alternative treatment options. Double-blind research investigating the effects of a few-foods diet (FFD) has demonstrated a significant decrease in ADHD symptoms following an FFD. However, an FFD requires a considerable effort of both child and parents, limiting its applicability as a general ADHD treatment. To make FFD intervention less challenging or potentially obsolete, we need to understand how, and in which children, an FFD affects ADHD behaviour and, consequently, the child's well-being. We hypothesise that an FFD affects brain function, and that the nutritional impact on ADHD is effectuated by a complex interplay between the microbiota, gut and brain, that is, the microbiota-gut-brain axis.

METHODS AND ANALYSIS

The Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) study is an open-label trial with researchers blinded to changes in ADHD symptoms during sample processing and initial data analyses.

ETHICS AND DISSEMINATION

The Medical Research and Ethics Committee of Wageningen University has approved this study (NL63851.081.17, application 17/24). Results will be disseminated through peer-reviewed journal publications, conference presentations, (social) media and the BRAIN study website. A summary of the findings will be provided to the participants.

TRIAL REGISTRATION NUMBER

NCT03440346.

STUDY DATES

Collection of primary outcome data started in March 2018 and will be ongoing until 100 children have participated in the study. Sample data analysis will start after all samples have been collected.

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

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a debilitating mental health problem hampering the child's development. The underlying causes include both genetic and environmental factors and may differ between individuals. The efficacy of diet treatments in ADHD was recently evaluated in three reviews, reporting divergent and confusing conclusions based on heterogeneous studies and subjects. To address this inconsistency we conducted a systematic review of meta-analyses of double-blind placebo-controlled trials evaluating the effect of diet interventions (elimination and supplementation) on ADHD.

METHODS

Our literature search resulted in 14 meta-analyses, six of which confined to double-blind placebo-controlled trials applying homogeneous diet interventions, i.e. artificial food color (AFC) elimination, a few-foods diet (FFD) and poly-unsaturated fatty acid (PUFA) supplementation. Effect sizes (ES) and Confidence intervals (CI) of study outcomes were depicted in a forest plot. I2 was calculated to assess heterogeneity if necessary and additional random effects subgroup meta-regression was conducted if substantial heterogeneity was present.

RESULTS

The AFC ESs were 0.44 (95% CI: 0.16-0.72, I2 = 11%) and 0.21 (95% CI: -0.02-0.43, I2 = 68%) [parent ratings], 0.08 (95% CI: -0.07-0.24, I2 = 0%) [teacher ratings] and 0.11 (95% CI: -0.13-0.34, I2 = 12%) [observer ratings]. The FFD ESs were 0.80 (95% CI: 0.41-1.19, I2 = 61%) [parent ratings] and 0.51 (95% CI: -0.02-1.04, I2 = 72%) [other ratings], while the PUFA ESs were 0.17 (95% CI: -0.03-0.38, I2 = 38%) [parent ratings], -0.05 (95% CI: -0.27-0.18, I2 = 0%) [teacher ratings] and 0.16 (95% CI: 0.01-0.31, I2 = 0%) [parent and teacher ratings]. Three meta-analyses (two FFD and one AFC) resulted in high I2 without presenting subgroup results. The FFD meta-analyses provided sufficient data to perform subgroup analyses on intervention type, resulting in a decrease of heterogeneity to 0% (diet design) and 37.8% (challenge design).

CONCLUSION

Considering the small average ESs PUFA supplementation is unlikely to provide a tangible contribution to ADHD treatment, while further research is required for AFC elimination before advising this intervention as ADHD treatment. The average FFD ES is substantial, offering treatment opportunities in subgroups of children with ADHD not responding to or too young for medication. Further FFD research should focus on establishing the underlying mechanisms of food (e.g. incrimination of gut microbiota) to simplify the FFD approach in children with ADHD.

Restriction and Elimination Diets in ADHD Treatment

Food elimination diets are defined and the history of their investigation in relation to attention-deficit/hyperactivity disorder (ADHD) is reviewed. After noting that a consensus has emerged that an elimination diet produces a small but reliable aggregate effect, the present review provides updated quantitative estimates of effect size and clinical response rates to elimination diets. It then highlights key issues that require research attention, in particular characterization of dietary responders. Finally, because some children may benefit, clinical guidelines at the present state of knowledge are summarized. It is concluded that updated trials of elimination diets are sorely needed for ADHD.

Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives

OBJECTIVE

The role of diet and of food colors in attention-deficit/hyperactivity disorder (ADHD) or its symptoms warrants updated quantitative meta-analysis, in light of recent divergent policy in Europe and the United States.

METHOD

Studies were identified through a literature search using the PubMed, Cochrane Library, and PsycNET databases through February 2011. Twenty-four publications met inclusion criteria for synthetic food colors; 10 additional studies informed analysis of dietary restriction. A random-effects meta-analytic model generated summary effect sizes.

RESULTS

Restriction diets reduced ADHD symptoms at an effect of g = 0.29 (95% CI, 0.07-0.53). For food colors, parent reports yielded an effect size of g = 0.18 (95% CI, 0.08-0.24; p = .0007), which decreased to 0.12 (95% CI, 0.01-0.23; p < .05) after adjustment for possible publication bias. The effect was reliable in studies restricted to food color additives (g = 0.21, 95% CI = 0.06-0.36) but did not survive correction for possible publication bias and was not reliable in studies confined to Food and Drug Administration-approved food colors. Teacher/observer reports yielded a nonsignificant effect of 0.07 (95% CI = -0.03 to 0.18; p = .14). However, high-quality studies confined to color additives yielded a reliable effect (g = 0.22, 95% CI = 0.10-0.41, p = .030) that survived correction. In psychometric tests of attention, the summary effect size was 0.27 (95% CI = 0.07-0.47; p = .007) and survived correction. An estimated 8% of children with ADHD may have symptoms related to synthetic food colors.

CONCLUSIONS

A restriction diet benefits some children with ADHD. Effects of food colors were notable were but susceptible to publication bias or were derived from small, nongeneralizable samples. Renewed investigation of diet and ADHD is warranted.

Effects of food on physical and sleep complaints in children with ADHD: a randomised controlled pilot study

Attention deficit/hyperactivity disorder (ADHD), a common behavioural disorder in children, may be associated with comorbid physical and sleep complaints. Dietary intervention studies have shown convincing evidence of efficacy in reducing ADHD symptoms in children. In this pilot study, we investigated the effects of an elimination diet on physical and sleep complaints in children with ADHD. A group of 27 children (3.8-8.5 years old), who all met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for ADHD, were assigned randomly to either a diet group (15/27) or a control group (12/27). The diet group followed a 5-week elimination diet; the control group adhered to their normal diet. Parents of both groups had to keep an extended diary and had to monitor the behaviour and the physical and sleep complaints of their child conscientiously. The primary endpoint was the clinical response, i.e. a decrease of physical and sleep complaints, at the end of the trial, based on parent ratings on a Physical Complaints Questionnaire. The number of physical and sleep complaints was significantly decreased in the diet group compared to the control group (p < 0.001), with a reduction in the diet group of 77% (p < 0.001, effect size = 2.0) and in the control group of 17% (p = 0.08, effect size = 0.2). Specific complaints that were significantly reduced were in three domains: headaches or bellyaches, unusual thirst or unusual perspiration, and sleep complaints. The reduction of complaints seemed to occur independently of the behavioural changes (p = 0.1). However, the power of this comparison was low. A positive correlation existed between the reduction of physical and behavioural symptoms (p < 0.01). The reduction did not differ between children with or without an atopic constitution (p = 0.7). An elimination diet may be an effective instrument to reduce physical complaints in children with ADHD, but more research is needed to determine the effects of food on (functional) somatic symptoms in children with and without ADHD. This trial was registered as an International Standard Randomised Controlled Trial, ISRCTN47247160.