Adolescence is a critical period for brain development and mental health, yet rates of depression and psychological distress among teens continue to rise. A new review suggests that what adolescents eat may be linked to mental health outcomes, though researchers stress that the evidence remains incomplete.
The review, led by researchers at Swansea University, examined findings from 19 studies exploring relationships between diet and mental health in adolescents. Published in Nutrients, the analysis included six randomized controlled trials and 13 prospective cohort studies conducted across different populations and settings.
Across the studies, healthier overall dietary patterns were often associated with fewer depressive symptoms, while poorer diet quality tended to be linked with greater psychological distress. In contrast, evidence supporting the use of individual nutrient supplements was mixed. Vitamin D supplementation showed some emerging signals of benefit, but findings were inconsistent and varied by study design and population.
Rather than pointing to a single nutrient or food, the review found more consistent associations when researchers looked at whole-diet patterns and diet quality scores. These approaches consider how foods are eaten together over time, which may better reflect real-world eating habits.
The authors note that adolescence may represent a window for prevention and early support. Diet is a modifiable factor embedded in daily life, but its relationship with mental health is influenced by many variables, including socioeconomic status, sex and broader lifestyle factors. Because of these complexities, the researchers caution against drawing firm conclusions about cause and effect.
The review also highlights notable gaps in the existing research. Most studies have focused on depression, while other outcomes such as anxiety, stress, self-esteem, aggression and externalizing behaviors remain underexamined. In addition, differences in study design, dietary assessment methods and mental health measures make it difficult to compare results across studies.
To address these limitations, the authors outline a research roadmap aimed at strengthening future evidence. Their recommendations include greater use of exposure-based study designs, incorporation of biological markers, improved standardization of methods and broader mental health outcome measures. They also call for more open science practices to improve transparency and reproducibility.
Lead author Professor Hayley Young said the findings support a shift away from isolated supplementation strategies and toward broader dietary approaches when considering adolescent mental health. At the same time, she emphasized that higher-quality research is needed to identify which dietary patterns may be most helpful and for whom.
The review does not suggest that diet alone can prevent or treat mental health conditions. Instead, it adds to a growing body of research examining how everyday factors, including eating patterns, may interact with mental health during a sensitive stage of development.
This work was supported by the Cognitive Health Committee of the Institute for the Advancement of Food & Nutrition Sciences. Professor Hayley Young has served as a scientific advisor to the committee since 2020 and has received research funding, in-kind support or fees from several food, health and pharmaceutical organizations.