Systematic review: Mediterranean diet adherence and health outcomes in children and adolescents with ADHD and OCTD

Abstract

Background

Mediterranean diet (MD) is linked to improved health outcomes in children and adolescents. While prior research suggests that individual components of the MD, such as omega-3 fatty acids, may improve cognitive function and behavior in individuals with special educational needs (SEN), it is not known the association between adhering to MD and the symptomatology of SEN.

Aim

To systematically identify and evaluate the association between adherence to the MD and the diagnosis, symptomatology, and/or well-being of children and adolescents diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Tics Disorder (OCTD), conditions classified as SEN.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a literature search was carried out on MEDLINE, Scopus, and Web of Science, from February to June 2024. Studies were included according to the following criteria: studies written in English or Portuguese; participants ≤19 years old; evaluation of MD using specific scores; and SEN diagnosis and/or symptomatology/well-being. This systematic review was also registered at PROSPERO as CRD42024527230.

Results

Six studies were included, investigating two specific conditions within the SEN umbrella: ADHD (five studies) and OCTD (one study). Studies found that higher adherence to the MD was associated with reduced symptoms of OCTD and ADHD. Also, a lower likelihood of ADHD diagnosis or having ADHD was associated with children and adolescents adhering more to MD.

Conclusion

This systematic review suggests that higher adherence to the MD is linked to lower prevalence and symptom severity of ADHD and OCTD in children and adolescents with SEN. However, future research is needed to confirm these results.

Keywords

adolescence childhood Mediterranean diet special educational needs attention deficit hyperactivity disorder systematic review

Introduction

Special Educational Needs (SEN) refer to children and adolescents who experience greater challenges in learning, communication, or behavior due to disabilities, which may hinder their ability to access education and reach their full potential.^1,2 Globally, in 2019, approximately 317 million children and adolescents were affected by health conditions contributing to developmental disabilities.³ Additionally, recent data from the Department for Education in England indicates that, in the 2023/24 academic year, 1.6 million children were identified as having SEN, marking an increase of 101,000 from the previous year.⁴ These trends underscore the growing need for effective support and resources for students with SEN.

Although the definition of SEN may not be consistent between countries, some documents help identify common conditions. The Individuals with Disabilities Education Act (IDEA) program from the United States of America comprises 14 disability categories: autism, deaf-blindness, deafness, developmental delay, emotional disturbance, hearing impairment, intellectual disability, multiple disabilities, orthopedic impairment, other health impairment, specific learning disability, speech or language impairment, traumatic brain injury, and visual impairment.² Apart from that, the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-V), is also a widely used tool to diagnose various conditions that fall under the umbrella of SEN, since the definitions covered in this manual align with the SEN categories in most countries.⁵

Research suggests that dietary interventions play a crucial role in shaping cognitive and behavioral outcomes in children and adolescents with SEN. For instance, it has been reported that consuming omega-3 fatty acids from fish or monounsaturated fats from olive oil may support cognitive function and mood regulation in individuals with autism spectrum disorders (ASD).^6,7 Furthermore, in individuals diagnosed with attention deficit hyperactivity disorder (ADHD), the consumption of nutrient-dense foods, such as fruits, vegetables, and whole grains, in conjunction with a moderate intake of omega-3 fatty acids, has been observed to enhance attention and behavioral control.^8–11

Among dietary patterns, the Mediterranean Diet (MD) has garnered considerable attention as a paradigmatic example of healthy eating, credited for its significant contributions to favorable health outcomes, improved biochemical indices, and heightened quality of life.^12–15 Generally, the MD can be characterized by abundant fruits and vegetables, whole grains, legumes, nuts, and olive oil, and a moderate consumption of fish, white meats, dairy, and wine.^16,17 In children and adolescents, adherence to the MD has been decreasing worldwide due to factors such as the westernization of diets, increased consumption of processed foods, and changes in lifestyle, including more sedentary behavior and greater availability of convenience foods.¹⁸ Despite this decline, the MD has been mainly associated with reduced inflammation, reduced sedentary behaviours, and increased quality of life in this age group.¹⁹

Given the documented benefits of individual MD components, such as omega-3 fatty acids and monounsaturated fats, for managing SEN-related conditions like ADHD and ASD, studying overall MD adherence may offer more comprehensive insights into the potential of this dietary pattern to manage these conditions. While previous research has explored specific foods’ effects on conditions like ADHD and ASD,^20,21 no systematic review has comprehensively examined the impact of overall MD adherence on SEN outcomes in children and adolescents. This systematic review specifically investigates conditions such as ADHD and OCTD, which represent the most studied neurobehavioral conditions in the context of MD adherence. This gap in the literature highlights the need for a focused investigation into MD adherence, which may provide a unique, integrated approach to supporting children and adolescents with SEN, especially as it encompasses a range of nutrients that work synergistically.

This systematic review aims to identify the associations previously reported in the literature between adherence to the MD and (1) the symptomatology and/or well-being of children and adolescents with SEN or (2) the diagnosis of SEN itself.

Method

Study design

This systematic review was based on the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA),²² using PRISMA guidelines²³ and it was registered in the International Prospective Register of Systematic Reviews (PROSPERO), as CRD42024527230.²⁴

Search strategy

This research was conducted from February to June 2024 in three databases namely — MEDLINE (PubMed^®), Scopus, and Web of Science. The search expression was built by one reviewer, while the remaining reviewers confirmed the process. The comprehensive search strategy was constructed as a combination of key terms related to the age of the populations (children and adolescents), the Mediterranean diet context, and disability categories defining SEN (e.g., ADHD, OCTD, and related neurodevelopmental disorders). The full details of the search terms used in the MEDLINE database are provided in Supplementary Table 1. A similar expression was used in Scopus and Web of Science.

To help refine the terms relating to SEN included in the search expression, the DSM-V⁵ was used based on the terms about neurodevelopmental disorders and referenced in the IDEA program.² The IDEA program categorizes students based on their disabilities and the special education they may need.

Eligibility criteria

The eligibility criteria are shown in Table 1, according to the PICOS (Population, Intervention, Comparator, Outcome, Study type) criteria. In addition, only articles in English and Portuguese were considered.

Table 1.

Eligibility criteria of the studies selected according to population, intervention, comparator, outcomes, and study design (PICOS) format.

PICOS	Inclusion criteria	Exclusion criteria
Population	Children and adolescents <19 years old, including those with a diagnosed SEN and/or neurotypical controls used for comparison.	Population >19 years old or with a prior diagnosis of special dietary needs.
Intervention/Exposure	Adherence to the Mediterranean Diet as assessed using validated scoring instruments (e.g., KIDMED, Mediterranean Diet Score, Mediterranean Adequacy Index).	Mediterranean Diet presented but not associated with a special educational need; other dietary patterns evaluated; only specific food groups evaluated.
Comparator	Low adherence to the Mediterranean Diet, or comparison of individuals with SEN to neurotypical control participants, or comparisons between different adherence categories (e.g., high vs. medium vs. low).	Studies without a relevant comparator group. Comparisons based on other dietary patterns or interventions.
Outcome	Measures related to the diagnosis, symptom severity (e.g., impulsivity, inattention), or well-being (e.g., quality of life) in children and adolescents with SEN.	Diagnosis, symptomatology and/or well-being of children and adolescents with special educational needs without considering the influence of their diet.
Study Design	Original research studies.	Reviews, abstracts only, single-case studies, books, and conference papers.

Study selection and data extraction

To address the study aims, data extraction focused on two primary categories of outcomes related to the participants’ conditions:

Diagnosis/Prevalence: Data pertaining to the likelihood or prevalence of a SEN diagnosis (specifically ADHD and OCTD) in relation to adherence levels to the MD.

Symptomatology and Well-being: Data quantifying the severity of SEN symptoms and measures of well-being. Specific symptom domains extracted included:

ADHD Symptoms: Impulsivity (e.g., measured by the Barratt Impulsivity Scale), inattention, and hyperactivity scores (e.g., from the Turgay DSM-IV Based Child and Adolescent Behavior Disorders Screening and Rating Scale).

OCTD Symptoms: Tic severity and obsessive-compulsive traits (e.g., measured by the Yale Global Tic Severity Scale and Yale-Brown Obsessive-Compulsive Scale).

Well-being: Any reported measures of mental health, quality of life, or neurobehavioral function associated with MD adherence.

Two reviewers applied the eligibility criteria and selected the studies for inclusion in this systematic review through title and abstract reading. In cases of disagreement, a third reviewer confirmed the selection. Then, two reviewers thoroughly evaluated the full-text studies to determine which ones should be included in this systematic review. When disagreements arose, a third reviewer assisted in the decision-making process, relying on the support of literature to find coherence.

Following the establishment of exclusion and inclusion criteria, all selected article references underwent thorough examination to uncover additional pertinent information, employing the snowballing technique procedure.²⁵

The entire process of reviewing the articles and the reason for those that were excluded are shown in the PRISMA flowchart (Figure 1).

Figure 1.

Preferred reporting items for systematic reviews and meta-analyses (PRISMA) fluxogram.

All the necessary information to answer the study objectives has already been published within the papers, so no contact with authors was needed. There was no minimum number of studies to include in this systematic review.

Table 2 presents the eligible studies included in this systematic review. The following topics are described: author, year; country; type of study; sample size, age, and sex; Mediterranean Diet (instrument and adherence level); SEN (identification, prevalence and method for symptomatology); association found between MD and SEN; and the quality assessment score. Table 3 summarizes the instruments used to assess the adherence to MD and its characterization.

Table 2.

Characteristics of the included studies assessing adherence to the Mediterranean diet and related outcomes in children and adolescents with special educational needs.

Author, year (reference)	Country	Type of study	Sample size, age, and sex	Mediterranean diet (MD)		Special education needs (SEN)			Association between MD and SEN	Quality assessment score
Author, year (reference)	Country	Type of study	Sample size, age, and sex	Instrument	Adherence level	Identification	Prevalence	Method for symptomatology	Association between MD and SEN	Quality assessment score
Darabi Z et al., 2022	Iran	Case-control	n = 360 6-13 years old 76% male	Mediterranean Diet Score	The sample was divided by tertiles.	Diagnostic and Text Revision of Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV TR)	33% of the individuals diagnosed with Attention Deficit Hyperactivity Disorder (ADHD)	——–	Negative association was found between adherence to MD and ADHD diagnosis.	6^a
Briguglio M et al., 2019	Italy	Cohort	n = 9 11-18 years old 100% male	KIDMED	Mean (SD): 3.0 (1.7)	Yale Global Tic Severity Scale and Yale-Brown Obsessive-Compulsive Scale	100% of the individuals diagnosed with Obsessive-Compulsive Tics Disorder (OCTD)	——–	Negative association was found between adherence to MD and OCTD traits.	7^b
Martin IS et al., 2021	Spain	Cross sectional	n = 57 6–16 years old 68% male	KIDMED	Poor adherence: Mean (SD): 49.9 (11.7) Medium adherence: Mean (SD): 45.0 (9.4) High adherence: Mean (SD): 41.6 (16.5)	Previously diagnosed with ADHD	100% of the individuals diagnosed with ADHD	Barratt Impulsivity Scale version 11c	Negative association was found between adherence to MD and impulsivity symptoms.	7^c
Ríos-Hernández A et al., 2017	Spain	Case-control	n = 120 6–16 years old 57% male	KIDMED	ADHD Cases: Mean (SD): 6.2 (2.0) Poor adherence: 11.7% Medium adherence: 58.3% High adherence: 30.0% Controls: Mean (SD): 8.1 (1.8) Poor adherence: 0.0% Medium adherence: 36.7% High adherence: 63.3%	DSM-IV TR, ADHD Rating-Scale-IV and Kiddie Schedule for Affective Disorders and Schizophrenia–Present and Lifetime version	50% of the individuals diagnosed with ADHD	——–	Negative association was found between adherence to MD and ADHD diagnosis.	8^a

Author, year (reference)	Country	Type of study	Sample size, age, and sex	Mediterranean diet (MD)		Special education needs (SEN)			Association between MD and SEN	Quality assessment score
Author, year (reference)	Country	Type of study	Sample size, age, and sex	Instrument	Adherence level	Identification	Prevalence	Method for symptomatology	Association between MD and SEN	Quality assessment score
Besenek M et al., 2022	Turkey	Case-control	n = 233 Aged 6–18 63% male	KIDMED	ADHD Cases: Mean (SD): 4.5 (2.5) Low adherence: 37.5% Medium adherence: 49.2% High adherence: 13.3% Controls: Mean (SD): 6.1(2.3) Poor adherence: 15.9% Medium adherence: 54.0% High adherence: 30.1%	Schedule for Affective Disorders and Schizophrenia for School Aged Children Kiddie-SADS-lifetime Version	48% of the individuals diagnosed with ADHD	Turgay DSM-IV Based Child and Adolescent Behavior Disorders Screening and Rating Scale – Parent form	Negative association was found between adherence to MD and ADHD diagnosis and inattention symptoms.	7^a
Martín IS et al., 2018	Spain	Cross-sectional	n = 89 8–16 years old 57% male	KIDMED	With ADHD: Mean (SD): 6.4 (2.7) ≥7 points: 53.7% <7 points: 46.3% Without ADHD: Mean (SD): 7.9 (2.0). ≥7 points: 72.3% <7 points: 27.7%	DSM-IV TR	46% of the individuals had ADHD	——–	Negative association was found between adherence to MD and having ADHD.	7^c

^aThe NOS for case–control studies (ranging from 0 to 9 stars), ^bThe NOS for cohort studies (ranging from 0 to 9 stars), ^cThe NOS for cross-sectional studies (ranging from 0 to 8 stars).

Table 3.

Overview of the tools mentioned in the literature and the comprehensive methods used to evaluate the Mediterranean diet pattern in children and adolescents.

Instrument	Method for food assessment	Components in analysis	Scoring methods	Score range	Adherence level	References
Mediterranean Diet Score	Food-Frequency Questionnaire	1) Vegetables, 2) legumes, 3) fruits and nuts, 4) grains, 5) fish, 6) meat, 7) poultry, 8) dairy products, 9) alcohol.	Each food group is assigned 0 or 1 points. (1) to (6) components: score 0 for intake lower than the median consumption; score 1 for intake equal or higher than the median consumption. (7) to (9) components: score 0 for intake equal or higher than the median consumption; and score 1 for intake lower than the median consumption.	Sum of the components ranging from 0 to 9.	Higher values indicate higher adherence.	²⁶
KIDMED	16 items of ‘yes’ or ‘no’ questions	1) Fruit, 2) vegetables, 3) fish, 4) fast-food restaurants, 5) legumes grains, 6) pasta or rice, 7) cereal or grains for breakfast, 8) nuts, 9) olive oil, 10) breakfast, 11) dairy products for breakfast, 12) commercially baked goods or pastries for breakfast, 13) yogurts or cheese, 14) sweets and candy.	Concerning the Mediterranean diet, questions denoting a negative connotation (n = 4) were assigned a value of −1, and those with a positive aspect (n = 12) were scored +1.	Sum of the components ranging from −4 to 12.	High adherence: ≥8. Medium adherence: 4–7. Poor adherence: ≤3.	^{27,28,29–31}

Identified records were de-duplicated using Systematic Review Assistant De-duplication³² followed by a manual search in EndNote.³³ Starting from 441 articles, 13 were selected after abstract screening and, of those, six were included in the qualitative synthesis (Figure 1).

Quality assessment

To assess the quality of all included cohort and case-control studies, the Newcastle-Ottawa Scale (NOS)³⁴ was applied, which provides an overall quality score ranging from 0 to 9 points. For cross-sectional studies, an adapted version of the NOS³⁵ was used, ranging from 0 to 8 points. This adapted version has been previously applied in the quality evaluation of other systematic reviews.^36,37

Results

Six studies were examined and summarized in Tables 2 and 3, which included two cross-sectional studies,^27,28 three case-control studies,^26–30 and one cohort study.³¹ Collectively, the studies involved 868 participants aged between six and 18 years old. Two of the studies were published between 2017 and 2018,^28,29 while the remaining four were published between 2019 and 2022.^26,27,30,31 Geographically, four studies were conducted in Europe^27–29^,31 and two in Asia.^26,30 One article provided data about children²⁶ and five articles included data on both children and adolescents^{27,28,29–31} (Table 2).

For quality assessment, both the two cross-sectional articles and the one cohort article scored 7.00 points. The three case-control studies included had a mean score of 7.00 ± 0.82 (ranging from 6.00 to 8.00 points) (Table 2).

This systematic review identified that the included studies used two specific instruments to measure the adherence to the MD principles, as shown in Table 3. Among the instruments used, five articles employed the Mediterranean Diet Quality Index for Children and Adolescents (KIDMED), making it the most used tool in this systematic review to assess adherence to the MD.^{27,28,29–31}

The selected studies explored the relationship between adherence to the MD with ADHD in five studies^27–30 and with Obsessive-Compulsive Tics Disorder (OCTD) in one study.³¹ The outcomes of the studies diverge into the symptomatology of the SEN, which was studied in three studies,^27,30,31 and the diagnosis itself in three studies^28–29 (Table 2).

For identification of ADHD, it was mostly used the Diagnostic and Text Revision of Statistical Manual of Mental Disorders-Fourth Edition (three out of six studies^28–29), and for OCTD it was used the Yale Global Tic Severity Scale and Yale-Brown Obsessive Compulsive Scale.³¹ Additionally, in the studies examining ADHD, the sample included 33%²⁶ to 100%²⁷ individuals with the SEN, with the remaining participants in these studies not diagnosed with any disabilities. In contrast, the one study on OCTD included 100%³¹ individuals with the SEN (Table 2).

Regarding ADHD diagnosis, two case-control studies^26,29 found that higher adherence to the MD was linked to a lower likelihood of ADHD diagnosis. Also, one cross-sectional study²⁸ found a negative association between adherence to the MD and having ADHD. On the other hand, considering the symptomatology of ADHD, one study²⁷ reported that higher adherence to the MD may be related to fewer impulsivity symptoms in children diagnosed with ADHD, whereas one study³⁰ found that higher adherence to the MD may result in lower prevalence of ADHD and fewer inattention symptoms (Table 2).

Regarding OCTD, one study³¹ suggested that higher adherence to the MD was associated with fewer symptoms of this SEN (Table 2).

Discussion

This systematic review suggests a focused potential relationship between adherence to the MD and outcomes in children and adolescents with ADHD and OCTD. A key finding from the studies reviewed is the predominant use of the KIDMED index for assessing adherence to the MD in Mediterranean countries,^{27,28,29–31} while a study outside of this region used the MDS.²⁶ The KIDMED index, specifically designed for children and adolescents, was the most used tool in this systematic review, appearing in five out of six studies, highlighting its relevance in pediatric populations.

Several studies explored the potential benefits of the MD for both OCTD and ADHD. For OCTD, one study found that higher adherence to the MD led to improvements in symptomatology.³¹ For ADHD, the findings suggest that higher adherence to the MD may positively affect specific outcomes, including decreased impulsivity,²⁷ reduced likelihood of ADHD diagnosis^26,29 or having ADHD altogether,²⁸ and a decrease in inattentive symptoms.³⁰ These findings indicate a possible beneficial role for the MD in managing ADHD symptoms, with the specific components of the diet, such as omega-3 fatty acids and antioxidants, aligning with previous research on the potential benefits of certain foods for ADHD.

ADHD emerged as the most studied SEN in the systematic review, with five out of six articles focused on it, often employing a case-control design. This design often compares the dietary adherence of children diagnosed with ADHD against a group of neurotypical controls. This methodological approach explains the participant prevalence of individuals with SEN ranging from 33% to 50% in the full sample of case-control studies, contrasting with 100% prevalence in single-group or cohort studies. The condition's high visibility in research may also be attributed to its worldwide prevalence of approximately 8.0%,³⁸ affecting over 84.8 million people globally in 2021.³⁹ A large body of literature has examined the association between specific foods, dietary patterns, and ADHD symptoms,^40,41 underscoring the relevance of understanding how dietary interventions may support the management of ADHD in children and adolescents.

The studies included in this review suggest that promoting adherence to the MD could potentially reduce the risk or severity of ADHD symptoms in children and adolescents.^27–30 Notably, research has shown that following a healthy dietary pattern characterized by high consumption of plant-based vitamins and minerals (e.g., fruits, vegetables) and low consumption of processed foods may provide a protective effect against hyperactivity or ADHD occurrence in children.⁴² This aligns with the principles of the MD, which also emphasizes these types of foods. Contrarily, other studies have shown that higher sugar intake, particularly from sugar-sweetened beverages, is linked to increased ADHD symptoms, particularly hyperactivity,⁴⁰ and increased odds of ADHD.⁴³ These findings indirectly corroborate the conclusions of this systematic review by indicating that the MD, which promotes low sugar intake, could potentially mitigate these symptoms.

Omega-3 polyunsaturated fatty acids, particularly those from fish, have been widely researched for their role in reducing ADHD symptoms^41,44,45 and in improving attention and behavior.^46,47 The data from this systematic review suggests that the MD, rich in omega-3 fatty acids from fish, could be a valuable dietary approach for managing ADHD symptoms in children and adolescents,^27,30 providing additional support for the efficacy of dietary interventions in ADHD treatment.

Research has also identified a link between oxidative stress and OCTD, with individuals diagnosed with this condition exhibiting systemic imbalances marked by elevated oxidative stress markers.^48,49 This finding has prompted researchers to investigate the potential of antioxidants as a supportive treatment for OCTD. Their studies suggest that the anti-inflammatory and free radical-scavenging properties of antioxidants may counteract the effects of oxidative stress and potentially improve OCTD symptoms.⁵⁰ The antioxidant-rich MD, including fruits, vegetables, and whole grains, which are natural sources of antioxidants, could play a role in influencing oxidative stress mechanisms. This finding strengthens the connection between diet and OCTD symptom management, suggesting that dietary interventions, like MD, could help improve OCTD symptoms by counteracting oxidative stress.

Moreover, studies examining the role of vitamins B12 and folate in mental health, particularly their influence on neurotransmitter synthesis like serotonin, offer additional support for the potential role of diet in managing OCTD symptoms.⁵¹ Foods rich in B12 (milk, fish, poultry, and eggs)⁵² and folate (legumes, leafy vegetables and dairy products)⁵³ align with the MD's emphasis on nutrient-dense, minimally processed foods. This connection highlights the potential for MD to not only promote mental health through its nutrient content but also support the synthesis of neurotransmitters that are crucial for neuropsychiatric health, including in those with OCTD. However, it's worth noting that only one study in this systematic review found evidence of the MD alleviating OCTD symptoms,³¹ pointing to the need for further studies to confirm the diet's effectiveness as a mainstream treatment for this condition.

While research on the impact of diet on SEN is ongoing, there is currently limited research specifically on the MD and its influence on outcomes for specific SEN, which this systematic review couldn’t find evidence for, such as autism spectrum disorders (ASD). However, research in ASD offers some compelling evidence regarding how the consumption of certain foods and the adherence to specific dietary patterns may influence the symptomatology of individuals with this condition.^54,55 Studies have indicated that children with ASD often experience higher levels of inflammation and gastrointestinal issues related to alterations in the gut-brain axis.^56–58 The MD, which has been linked to improved brain function, reduced inflammation, and better gut health,^59,60 could be beneficial in addressing some of these symptoms by promoting a more balanced gut microbiome and reducing systemic inflammation. However, given the paucity of research on the MD's direct impact on ASD, more studies are needed to determine whether this dietary pattern could be effective in managing ASD symptoms.

Although current evidence does not support the use of vitamin D supplementation as a monotherapy for children with ASD, considering its long-term tolerability, and critical role in brain function and development, vitamin D might be a valuable complementary treatment for ASD.⁶¹ Particularly, supplementation has shown benefits in reducing hyperactivity and irritability symptoms in children with ASD.^62,63 Natural sources of vitamin D include fatty fish, meat, egg yolks, and dairy products,⁶⁴ all of which are emphasized in the MD. Accordingly, MD could provide a foundation for future dietary interventions aimed at managing ASD symptoms through nutritional support. Still, even though it seems that integrating a Mediterranean dietary approach might offer a valuable strategy for managing ASD symptoms, further studies specifically focusing on the effects of the MD on ASD are needed to confirm these potential benefits.

The findings of this systematic review support the notion that nutritional interventions, such as promoting a balanced diet like the MD, can be especially beneficial for children and adolescents with SEN who are either too young for medication or do not respond well to medication. This is consistent with the growing body of evidence showing that dietary patterns, as opposed to individual food items, have a more significant and lasting effect on overall health.^65–67 While dietary changes should not be viewed as a replacement for medication, they may serve as a valuable complementary approach to managing symptoms of SEN. Collaborating with healthcare professionals, such as nutritionists, to develop personalized dietary plans could help optimize outcomes for these children. Further investigation is necessary to refine and validate nutritional interventions, ensuring they are evidence-based and useful for diverse types of SEN.

This systematic review represents an important contribution to the field of pediatric nutrition, as it is the first comprehensive attempt to assess the relationship between MD adherence and various health outcomes in children and adolescents with SEN. A key strength of the systematic review lies in the rigorous quality assessment process employed to evaluate all the included studies, as well as the detailed follow-up of the entire PRISMA methodology. However, the heterogeneity of the studies, which employed diverse methodologies, populations, interventions, and outcome measures, restricts our ability to draw definitive conclusions. While the systematic review provides valuable insights, the small number of studies calls for further research to confirm these findings and establish their generalizability. Additionally, the inclusion of three cross-sectional studies further limits the ability to establish causal relationships.

This systematic review suggests that adherence to the Mediterranean Diet may offer benefits for children and adolescents with ADHD and OCTD. However, several important gaps in the research need to be addressed. There is a need for long-term prospective studies that could track the sustained effects of MD adherence over time, as most studies included were cross-sectional, preventing the establishment of causal relationships between the MD and symptom improvement.

While studies on ADHD and OCTD are promising, there is a notable absence of studies examining the impact of the MD, as assessed by validated scoring systems, on other SEN, such as ASD, where preliminary evidence suggests an association between its symptomatology and specific MD components. Notably, there is limited evidence outside Mediterranean regions, with no studies in the systematic review focused on US populations, which further limits the generalizability of the findings and overlooks cultural, dietary, and healthcare differences.

Further, there is limited understanding of the practical barriers to adopting the MD, such as socio-economic constraints, accessibility to Mediterranean foods, and cultural differences, especially in non-Mediterranean regions. Addressing these gaps could provide a more comprehensive understanding of the role of the MD in managing SEN and help develop more effective, culturally sensitive dietary recommendations tailored to diverse cultural and healthcare contexts.

Conclusion

In conclusion, this systematic review suggests that higher adherence to the MD is associated with a lower prevalence and reduced symptom severity of ADHD and OCTD in children and adolescents. While MD offers a promising, complementary nutritional approach for these neurobehavioral conditions, the current body of evidence is limited by its predominantly cross-sectional design. Future research must prioritize robust, long-term prospective studies to establish causality and should broaden the scope to investigate the effects of MD adherence on other SEN, such as ASD.

Supplemental Material

sj-docx-1-mnm-10.1177_1973798X261422446 - Supplemental material for Systematic review: Mediterranean diet adherence and health outcomes in children and adolescents with ADHD and OCTD

Supplemental material, sj-docx-1-mnm-10.1177_1973798X261422446 for Systematic review: Mediterranean diet adherence and health outcomes in children and adolescents with ADHD and OCTD by Nuno Silva, Nuno Gomes and Beatriz Teixeira in Mediterranean Journal of Nutrition and Metabolism

Footnotes

ORCID iDs

Nuno Silva

Nuno Gomes

Beatriz Teixeira

Authors’ contributions

Nuno Silva (NS), Nuno Gomes (NG) and Beatriz Teixeira (BT) designed the research and drafted the manuscript;

NS, NG and BT conducted the research;

NS, NG and BT analysed data;

NS wrote this paper and had primary responsibility for final content;

NG and BT reviewed and edited the paper.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Availability of data and materials

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

Supplemental material

Supplemental material for this article is available online.

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