Colleen Sloan, PA-C, RDN

Picture your last patient of the day: a 15-year-old girl with declining grades, poor sleep, and fatigue. Her parents are understandably concerned. Before reaching for the prescription pad or referring her to therapy, consider this: What she ate for lunch today might be part of the problem. With 1 in 7 adolescents worldwide diagnosed with mental health disorders, emerging research suggests that diet is a powerful yet often overlooked therapeutic tool.¹

Understanding the nutrition–mental health connection

Adolescence brings a perfect storm of mental health challenges—hormonal shifts, academic pressure, and social media stress. Research shows diet directly influences adolescents’ moods, focus, and emotional regulation.² Poor mental health often manifests through subtle changes in daily functioning: chronic fatigue, difficulty concentrating, irritability, and social withdrawal. These symptoms, which we might attribute to typical teenage struggles, can be exacerbated or even triggered by nutritional deficiencies.

A critical first step

Before passively recommending “eat more vegetables” or “choose whole grains,” pediatricians must first consider food insecurity. It’s critical to find out whether this patient has reliable access to food. Food insecurity is a major but often overlooked factor in adolescent mental health. In 2022, 19% of US children (13.4 million kids) lacked dependable access to adequate food—a rate that has risen nearly 50% since 2021, marking an 8-year high.³ For food-insecure families, affording nutritious foods in sufficient quantities is a daily struggle. This chronic stress elevates cortisol levels and disrupts neurobiological responses, potentially increasing the risk of anxiety, depression, and emotional dysregulation. Food insecurity has been linked to developmental disruptions, school problems, and long-term physical and mental health consequences.

Given these risks, screening for food insecurity should be a routine part of pediatric and mental health visits. The Hunger Vital Sign, a simple 2-question screening tool that takes less than a minute to administer, can help identify at-risk families.⁴ For families struggling with food access, connecting them with local resources should come before dietary recommendations.

Key nutrients for mental well-being

Once food access is addressed, pediatricians can offer practical, teen-friendly nutrition guidance. Research has identified several nutrients essential for brain function, neurotransmitter synthesis, and mood regulation.

· Omega-3 fatty acids: Essential for brain health and neural communication, omega-3 fatty acids play a crucial role in reducing depression and anxiety while improving memory and cognitive function.⁵ Found in: salmon, mackerel, sardines, walnuts, and flaxseeds.

· B-complex vitamins (B6, B9, B12): These vitamins are fundamental to producing mood-regulating neurotransmitters including serotonin, dopamine, and γ-aminobutyric acid. Research shows that B-vitamin deficiencies increase depression risk, and folate deficiency may reduce antidepressant effectiveness.⁶ Found in: leafy greens, eggs, legumes, whole grains, and fortified cereals.

· Magnesium: This mineral influences hundreds of enzymatic reactions and supports optimal nerve transmission and membrane phospholipid formation.⁷ Low magnesium levels have been associated with increased anxiety, irritability, and insomnia, all of which can contribute to poor mental health outcomes.⁸ Found in: leafy greens, almonds, pumpkin seeds, and avocados.

· Vitamin D: Often called the sunshine vitamin, vitamin D supports brain plasticity and mood regulation through its effects on the dopaminergic system. Supplementation has shown promise in reducing adolescent depression, irritability, and fatigue.² Found in: sunlight exposure, fortified foods, fatty fish, and egg yolks.

· Antioxidants: Vitamins C and E protect brain cells from oxidative stress and inflammation—factors linked to anxiety and depression.² Found in: berries, dark chocolate, nuts, and leafy greens.

The gut-brain connection

While individual nutrients play crucial roles in brain health, emerging research reveals an even more exciting connection between diet and mental well-being: the gut-brain axis. This intricate relationship helps explain how the foods we eat influence not just specific nutrient levels, but the very foundation of our mental health. The gut microbiome, home to trillions of microorganisms, produces approximately 95% of the body's serotonin—a neurotransmitter crucial for mood regulation.⁹ This "second brain" communicates directly with our neural networks, influencing everything from anxiety levels to cognitive function. The composition of the gut microbiome is unique to each person and is largely shaped by dietary choices. Fiber, prebiotics, and probiotics support gut health, while processed foods and sugar can disrupt the gut environment, leading to heightened stress responses and emotional dysregulation. Recommending probiotic-rich foods such as yogurt, kimchi, and sauerkraut can be a simple first step in supporting gut health.

Practical implementation strategies

In the United States, 14.7 million youths aged 2 to 19 have obesity, yet their diets often lack the micronutrients needed for optimal nervous system function.¹⁰ When discussing nutrition with adolescents, start with their current habits and build from there. Ask open-ended questions about their typical meals and how different foods may affect their mood and energy. Simple swaps such as a morning smoothie with berries and spinach or trail mix instead of processed snacks, or adding fish to weekly meals can make a significant difference. Connect food-insecure families with local resources first, then work together to identify accessible, nutritious options within their means. Schedule follow-up visits in 4 to 6 weeks or refer them to a registered dietitian to monitor progress and adjust recommendations based on their adherence and response.

By integrating nutrition into our mental health approach, we empower adolescent patients with an evidence-based tool that extends beyond traditional interventions—starting with your very next patient.

References:

1. Mental health of adolescents. World Health Organization. October 10, 2024. Accessed January 30, 2025. https://www.who.int/news-room/fact-sheets/detail/adolescent-mental-health

2. Grajek M, Krupa-Kotara K, Białek-Dratwa A, et al. Nutrition and mental health: a review of current knowledge about the impact of diet on mental health. Front Nutr. 2022;9:943998. doi:10.3389/fnut.2022.943998

3. Child food insecurity in America. The Annie E. Casey Foundation. Updated July 21, 2024. Accessed January 30, 2025. https://www.aecf.org/blog/child-food-insecurity

4. Screen and intervene: a toolkit for pediatricians to address food insecurity. Food Research & Action Center. January 2021. Accessed January 30, 2025. https://frac.org/aaptoolkit

5. DiNicolantonio JJ, O'Keefe JH. The importance of marine omega-3s for brain development and the prevention and treatment of behavior, mood, and other brain disorders. Nutrients. 2020;12(8):2333. doi:10.3390/nu12082333

6. Fava M, Mischoulon D. Folate in depression: efficacy, safety, differences in formulations, and clinical issues. J Clin Psychiatry. 2009;709(suppl 5):12-17. doi:10.4088/JCP.8157su1c.03

7. Botturi A, Ciappolino V, Delvecchio G, Boscutti A, Viscardi B, Brambilla P. The role and the effect of magnesium in mental disorders: a systematic review. Nutrients. 2020;12(6):1661. doi:10.3390/nu12061661

8. Pickering G, Mazur A, Trousselard M, et al. Magnesium status and stress: the vicious circle concept revisited. Nutrients. 2020;12(12):3672. doi:10.3390/nu12123672

9. Appleton J. The gut-brain axis: influence of microbiota on mood and mental health. Integr Med (Encinitas). 2018;17(4):28-32. https://pmc.ncbi.nlm.nih.gov/articles/PMC6469458/

10. Childhood obesity facts. CDC. April 2, 2024. Accessed January 30, 2025. https://www.cdc.gov/obesity/childhood-obesity-facts/childhood-obesity-facts.html