June 10, 2026, 12:10 pm | Read time: 7 minutes
The early years of life are considered a crucial phase for brain development. But what role does nutrition play in this? A large new review has evaluated 73 studies to examine whether eating habits in childhood and adolescence are linked to later cognitive abilities and academic performance. The findings suggest that the impact of nutrition may be significantly greater than previously thought.
Why the Early Years Could Be So Important for the Brain
The research team led by Hayley A. Young from Swansea University investigated the influence of nutrition on the cognitive development and academic success of children and adolescents. The scientists analyzed whether dietary habits and interventions from ages eight to 19 are linked to cognitive abilities, intelligence, and academic performance.1 The most striking result: In several long-term studies, children who were better nourished in their early years often performed better on intelligence tests and in school later on.
The Background: Adolescence is a critical developmental phase for the brain. Areas responsible for attention, planning, learning, and problem-solving continue to develop during this time. At the same time, adolescents are susceptible to nutrient deficiencies and diets high in heavily processed foods.2
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How the Analysis Was Conducted
The work is a systematic review. Scientific studies are searched, evaluated, and summarized according to set criteria. The researchers searched four major scientific databases. After a detailed review, 73 studies met the inclusion criteria.
Overview of 73 Studies from Various Countries
The analysis included 48 studies that specifically tested dietary interventions, as well as 25 long-term studies. “Long-term study” means that participants were followed over many years to examine how early dietary habits affect later development.
In the dietary studies, researchers examined the effects of iron, iodine, vitamin D, and omega-3 fatty acids, among other things. They also looked at choline, polyphenols (natural plant compounds found in fruits, vegetables, and herbs), multivitamin supplements, whole grains, fish, walnuts, the so-called new Nordic diet, and school breakfast programs.
The long-term studies primarily focused on nutrition during infancy and early childhood, as well as early adolescence, and later compared these with results from intelligence tests, cognitive tasks, or academic performance.
Additionally, the authors assessed the quality of the individual studies. It was found that many long-term studies were methodologically more robust than some of the dietary studies.
What Children Eat Early On Could Matter Years Later
The Most Significant Links Were Found in the Early Years
The strongest and most consistent evidence was found in the long-term studies. Several investigations showed that diets rich in fruits, vegetables, whole grains, and dairy products were more often associated with better results in later intelligence tests and academic performance. Diets high in heavily processed foods, soft drinks, and sugary products, on the other hand, were more often linked to poorer outcomes.
Particularly notable was that the links were strongest in several studies for nutrition in the first year of life. The authors see this as an indication that this early life phase could be especially important for later cognitive development.
Of particular interest is the type of intelligence: Early nutrition primarily shapes verbal IQ–the knowledge acquired from the environment. Nutrient intake during adolescence, on the other hand, seems to support nonverbal IQ, which reflects pure biological thinking potential.
Iron Deficiency in Infancy Could Have Long-Lasting Effects
Moreover, several long-term studies found evidence that iron deficiency in early childhood can be associated with disadvantages in attention, memory, and other cognitive abilities years later–even if the deficiency was treated later.
However, the researchers emphasize that adolescence opens a “second window of neuroplasticity.” In this massive remodeling phase, the brain is once again particularly receptive to good nutrient supply–but also more susceptible to harmful influences.
Results for Adolescents Were Much More Inconsistent
The intervention studies, on the other hand, presented a mixed picture.
Benefits Were Mainly Seen with Existing Nutrient Deficiencies
Iron supplements were able to improve certain cognitive abilities in several studies, especially in adolescents with iron deficiency or iron deficiency anemia, a type of anemia caused by iron deficiency. Some studies also found benefits for iodine in adolescents with iodine deficiency.
These results suggest that adolescents with inadequate nutrient supply might benefit the most from targeted dietary interventions.
A Clear Picture Is Lacking for Many Other Measures
For omega-3 fatty acids, improvements in attention, processing speed, or specific cognitive tasks were occasionally observed. Other studies, however, found no measurable effects.
Similarly contradictory were the results for choline, vitamin D, whole grains, polyphenol-rich plant compounds, the new Nordic diet, school breakfast programs, or multivitamin supplements.
Overall, the authors conclude that there is currently no single dietary intervention that reliably and demonstrably improves the cognitive performance of all adolescents. However, the data suggest that nutrition generally plays a role in the development of thinking, learning, and academic performance.
What Do the Results Mean for Parents and Adolescents?
The analysis suggests that nutrition could have long-term effects on cognitive development. The early years seem particularly relevant. During this phase, the brain grows rapidly and forms numerous new connections between nerve cells.
The results indicate that the quality of nutrition in early childhood could be linked to later cognitive abilities. However, this does not mean that individual foods determine later intelligence. Rather, the data suggest that long-term dietary habits might be more important than individual meals or short-term dietary interventions.
For adolescents, the results also show that existing nutrient deficiencies can be relevant. Especially for iron and iodine deficiencies, several studies observed benefits from improved supply.
What the Results Do Not Mean
The review shows correlations but does not prove a cause-and-effect relationship. Other factors also influence cognitive development, including education, family environment, sleep, exercise, and social conditions.
Large Analysis, but Not Without Weaknesses
With 73 included studies, the work offers one of the most comprehensive overviews to date of the relationship between nutrition, cognitive performance, and academic success in adolescence. The long-term studies, which followed participants over many years, are particularly informative.
Nevertheless, the results should be interpreted with caution. Children with an overall healthier diet often also grow up under more favorable social conditions. Although many studies considered factors such as parental income or education level, such influences cannot be completely ruled out.
The intervention studies also had limitations. The measures varied significantly in terms of duration, dosage, participant groups, and test procedures, making direct comparisons difficult. Additionally, many studies had methodological weaknesses, including small sample sizes, incomplete data, or issues with implementing the interventions.
Another drawback: In some studies, academic performance was recorded through self-reported grades. Such information can be less accurate than official school data or standardized performance tests. The authors emphasize that further high-quality studies are needed.
There is also an important aspect regarding funding. As a potential conflict of interest, it should be noted that the work was supported by a grant from the Institute for the Advancement of Food and Nutrition Sciences (IAFNS). The organization receives financial support from public and private sources, including the food industry.
A Roadmap for the Future of Research
The authors did not limit themselves to evaluating the current state of research but also formulated seven recommendations for future research. Nutrition should be considered more across the entire lifespan rather than examining individual life phases in isolation. Additionally, the scientists advocate focusing less on individual nutrients and more on complete dietary patterns.
It is also important to use biological markers such as blood levels for iron or omega-3 fatty acids. This would allow for better verification of whether nutrients were actually absorbed and whether observed effects are biologically plausible.
Furthermore, the authors recommend systematically recording pubertal status, considering differences between boys and girls more, standardizing cognitive and academic performance tests, and including social and cultural factors.
In the future, disadvantaged population groups should also be studied more intensively, as they may particularly benefit from nutritional programs and health policy measures. Additionally, long-term studies should more frequently consider important influencing factors such as the family environment, current diet, or the mother’s intelligence.
Conclusion: Early Nutrition Could Have Long-Lasting Effects
The analysis suggests that the quality of nutrition in the early years could be linked to later cognitive abilities and academic performance. The evidence for dietary interventions in adolescence is significantly weaker. According to the authors, further high-quality studies are needed to derive reliable recommendations.