• A Systematic Review of Evidence on the Triangular Relationship between Nutrition, Mental Health, and Biological Markers in Students and the Development of Innovative School Health Planning Models
  • Mahsa Robatjazi,1,*
    1. Undergraduate Student in School Health, Student Research Committee, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran


  • Introduction: Nutrition is one of the fundamental determinants of students’ physical, psychological, and social development. In recent years, increasing attention has been given to the role of dietary patterns in shaping mental health and cognitive performance in children and adolescents. At the same time, biological markers provide measurable indicators of metabolic, inflammatory, and hormonal status that may explain how nutrition influences mental well-being. Understanding the interplay between these three domains is not only of theoretical importance but also a foundation for designing school-based interventions to improve student health and quality of life. A systematic review of the available evidence can provide a comprehensive perspective and guide the development of innovative school health planning models.
  • Methods: This study was designed as a systematic review. A comprehensive search was conducted across major databases, including PubMed, Scopus, Web of Science, and Google Scholar. The search covered the past two decades to capture recent advances and long-term trends in this field. Eligible studies were those that examined direct or indirect links between dietary patterns, mental health indicators, and biological markers in children and adolescents. Observational, interventional, and review studies providing quantitative or qualitative evidence were included. Articles with weak methodological quality or lacking direct relevance to the topic were excluded. Extracted data were classified based on dietary patterns, mental health outcomes, and biological markers, and findings were synthesized descriptively and analytically.
  • Results: The review highlighted that diet quality is a decisive factor in students’ psychological and cognitive status. Healthy dietary patterns, characterized by regular intake of fruits, vegetables, whole grains, lean protein, and essential micronutrients, were consistently associated with reduced anxiety and depressive symptoms, enhanced concentration, and improved quality of life. Conversely, high-fat, high-sugar, and low-fiber diets were linked to an increased risk of psychological disorders and poorer academic performance. From a biological perspective, multiple biomarkers emerged as mediators of these relationships. Inflammatory markers such as CRP, IL-6, and TNF-α were found at elevated levels among children and adolescents with unhealthy diets, suggesting that chronic low-grade inflammation may underlie diminished mental well-being. Similarly, metabolic hormones including leptin, ghrelin, and adiponectin showed notable changes in relation to dietary habits and psychological outcomes. Salivary biomarkers such as cortisol, alpha-amylase, and sIgA also proved valuable in reflecting stress responses and offered potential for non-invasive monitoring of students’ mental health. School-based intervention studies provided strong evidence for the effectiveness of integrated nutrition and physical activity programs. Such programs not only improved metabolic outcomes, including reduced BMI and healthier lipid profiles, but also enhanced students’ vitality, quality of life, and emotional well-being. Interventions involving family participation and long-term follow-up demonstrated the most sustainable effects. Further evidence indicated that certain biomarkers may serve as predictive tools for psychological and behavioral disorders. Elevated salivary cortisol, for example, was linked to chronic stress and impaired cognitive performance. Alterations in gut microbiota composition and oxidative stress markers such as 8-OHdG were also identified as key pathways bridging nutrition and mental health. Collectively, these findings suggest that the diet–mental health relationship is multidimensional, involving behavioral, psychological, and biological processes.
  • Conclusion: This systematic review underscores the complex triangular relationship between nutrition, mental health, and biological markers. The evidence suggests that healthy dietary habits can improve psychological outcomes while simultaneously reducing adverse inflammatory and metabolic profiles in school-aged populations. Incorporating biomarker assessment into school-based research and practice offers a valuable tool for early detection of disorders, monitoring intervention effectiveness, and designing preventive strategies. Consequently, the development of innovative school health planning models that integrate nutritional, psychological, and biological perspectives may play a vital role in enhancing students’ quality of life, academic achievement, and long-term well-being. It is recommended that policymakers and educators adopt multidimensional, evidence-based approaches when designing school health interventions to ensure a healthier future generation.
  • Keywords: Nutrition, Mental health, Biological markers, Students, School health