Meta-analysis Reports Mild Association Between Junk Food and ADHD in Children and Adolescents

Children with ADHD often face challenges in social interactions, leading to long-term consequences if not properly addressed. While various interventions exist, many fail to consider the broader social context in which these children interact. A recent study conducted in Bergen, Norway, explored how primary school teachers perceive their role in supporting children with ADHD who struggle socially and the strategies they use to assist them.

Investigating Teacher Perspectives

Researchers conducted semi-structured interviews with five focus groups of primary school teachers. Using reflexive thematic analysis, they identified two major themes:

1. Understanding Individual Needs in Context – Teachers emphasized that every child is unique, and ADHD should not define a student's social struggles. They highlighted the importance of considering the child’s specific social challenges within their broader environment.
2. Adapting Strategies Through Continuous Assessment – Teachers described their work as a dynamic and flexible process, adjusting their approaches based on the child's evolving needs. This included providing subtle background support as well as direct guidance in social interactions.

A Personalized Approach to Social Support

Rather than relying on standardized interventions, teachers tailored their strategies to foster an inclusive and supportive social environment. Their methods included both active participation in social situations and behind-the-scenes efforts to encourage peer inclusion and understanding.

Rethinking ADHD and Social Development

This study underscores the need to move beyond labels and recognize children with ADHD as individuals with distinct social needs. Teachers play a crucial role in shaping these children’s experiences, using flexible and personalized approaches to promote positive social interactions. By integrating social context and individualized support, educators can help children with ADHD build meaningful connections and navigate their social world more effectively.

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Background:

“Junk food” is a shorthand for highly processed foods and beverages with low nutritional value and dietary fiber that are typically high in added sugars, starches, and additives intended to boost flavor, color, texture, and shelf life. 

Previous studies examining such an association have yielded contradictory or inconclusive results. 

Method:

An Iranian research team therefore conducted a systematic search of the peer-reviewed medical literature to run a meta-analysis of data from studies published to date. 

Meta-analysis of nine studies, with a combined total of over 58,000 persons, found that children and adolescents who consumed more junk foods were about 25% more likely to exhibit ADHD symptoms. Restricting this to the seven studies rated good or high quality (7+ out of 10 on the Newcastle–Ottawa Quality Assessment Scale) produced the same exact outcome.  

The result was consistent across individual studies, with low heterogeneity. There was no sign of publication bias. 

Breaking this down by subtype of junk food: 

• Combining six studies with over 52,000 total participants, sugary beverages including soft drinks were associated with the same 25% increase in ADHD symptoms. Heterogeneity was moderate. 

• Combining three studies with over 1,600 total participants, solid sweets and candies were associated with a greater than one-third increase in ADHD symptoms. There was no variation in outcome among the three studies. 

• Combining three studies with over 22,000 total participants, other heavily processed foods were associated with a 17% increase in ADHD symptoms. Again, there was no variation in outcome among the three studies. 

The team used data adjusted for confounders: “We used … adjusted OR [odds ratios] for the meta-analysis.” 

This outcome, while suggestive, should be interpreted cautiously due to limitations: 

• ADHD symptoms were rated by parents or caregivers using standardized questionnaires. ADHD diagnoses by qualified medical professionals are the gold standard, and were not used. 

• Junk food consumption was likewise estimated by parents or caregivers through answers to questionnaires. There was no direct measurement of consumption. Answers were categorical, making it impossible to look for dose-response relationships. 

• Even if the association holds with further study, it is unclear whether impulsivity associated with ADHD leads to greater consumption of junk foods, or junk food consumption somehow harms development of the nervous system, or the relationship is due to unmeasured confounding by other variables.   

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Conclusion:

The team concluded, “This meta-analysis of observational studies adds strong evidence linking the consumption of junk foods, particularly, sweetened beverages/soft drinks and sweets/candies, with ADHD symptoms in children and adolescents. However, the study did not evaluate the causality of the relationship. So, to identify causality and the dose–response effects of junk food consumption on the development of ADHD, further studies are warranted.” 

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A research team based in London (U.K.) has just released the first meta-analysis to explore whether young people with ADHD experience greater loneliness compared to young people without ADHD.  

There has been a lot of research into social-emotional functioning in ADHD focusing on social networks and peer functioning problems, with little inquiry into young people’s experience of and satisfaction with their relationships.  

The team noted, “This is an important distinction as loneliness, or perceived social isolation, is the subjective feeling of distress due to a perceived deficit in the quantity and quality of one’s social relationships. An individual may be objectively socially isolated but may not have a negative perception of their relationships and equally, someone may find their social relationships lacking despite having a large social network … As loneliness and social isolation (e.g., number of friends or size of social network) have been found to be weakly correlated, it is important to capture the loneliness experience of the young person rather than relying on just the objective measures of social isolation.” 

Loneliness is a public health concern, as it predicts increases in depression, anxiety, self-harm, and suicidal ideation. 

The team performed a systematic search of the peer-reviewed medical literature to identify quantitative studies that compared loneliness among young people under 25 diagnosed with ADHD with non-ADHD matched controls. The search excluded studies in which participants had intellectual disabilities and/or other neurodevelopmental conditions such as autism spectrum disorder. 

Meta-analysis of 15 studies with a combined 6,281 participants found that young people with ADHD experienced greater loneliness than their non-ADHD peers with a small-to-medium effect size. There was no sign of publication bias, but very high variation (heterogeneity) in outcomes across the studies.  

Removing one small outlier study, the remaining 14 studies with 6,099 participants brought heterogeneity down to moderate levels, and yielded a medium effect size increase in perceived loneliness among young people with ADHD.  

Conclusion: 

“The findings in this study highlight the importance of understanding loneliness in this population as young people with ADHD report significantly higher levels of loneliness compared to their non-ADHD peers, and loneliness in young people with ADHD is associated with a range of mental health difficulties,” the researchers stated. “More resources should be focused on loneliness as a separate construct from social isolation and peer difficulties.” 

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