Published in Advances in Nutrition , the study brings together findings from 73 studies — including 48 controlled trials and 25 prospective studies — to examine how diet affects cognitive performance and academic outcomes in young people aged 8 to 19.
Supported by the IAFNS Cognitive Health Committee , the review found that unhealthy dietary patterns in the early years of life, particularly in infancy, may have lasting consequences for intelligence in adolescence.
Professor Hayley Young, from Swansea University’s School of Psychology and lead author of the study, said: “What stands out most clearly is that the foundations of cognitive health appear to be laid very early. A poorer diet in the first years of life was linked to lower intelligence years later, in adolescence, even after accounting for many other influences. The picture during adolescence itself is more mixed: some interventions show promise, but the evidence is far from settled. That is exactly why we need better-designed studies, so we can establish whether adolescence is a genuine second window of opportunity to support the developing brain through nutrition, rather than assuming it is.”
After infancy, adolescence represents a second key period of neuroplasticity, marked by widespread structural and functional changes driven in part by hormonal and endocrine shifts during puberty.
To reflect how brain development unfolds over time, the review draws on longitudinal studies exploring links between early-life diet and later cognitive and academic performance. This life-course approach recognises that later abilities build on earlier developmental milestones, allowing the team to examine how early nutrition may shape outcomes years later.
The researchers assessed long-term evidence on a wide range of nutrients and dietary components, including iron, iodine, choline, vitamin D, polyphenols, fatty acids, grains and multi-nutrient interventions.
Although findings across the literature can appear inconsistent, the authors caution against interpreting this as evidence that diet has little influence. Instead, they argue that the impact of nutrition depends on several factors — including the timing of dietary exposure during development, the characteristics of the population studied, the duration and type of intervention, and the particular cognitive abilities being measured.
To advance research in this emerging field, the team proposes seven guiding principles for future studies:
The authors conclude that further high‑quality research is needed to determine whether adolescence represents a unique window of opportunity to support cognitive development through nutritional interventions.
Advances in Nutrition
Systematic review
People
Diet and the Developing Brain: A Systematic Review of Nutritional Influences on Adolescent Cognitive and Academic Outcomes
7-May-2026
This work was supported by the Institute for the Advancement of Food and Nutrition Sciences (IAFNS) via grant IAFNS-SWANSEAU-20230111. IAFNS is a nonprofit science organization that pools funding from industry and advances science through the in-kind and financial contributions from private and public sector members.