Early diet may shape how the teenage brain develops

Mark Mansfield

The food children eat in their earliest years could have a lasting impact on their intelligence well into adolescence, according to a major review led by researchers at Swansea University.

The study, published in the journal Advances in Nutrition, analysed findings from 73 studies involving young people aged between eight and 19 to examine the relationship between diet, cognitive performance and academic achievement.

Researchers found evidence that unhealthy dietary patterns during infancy and early childhood may be linked to lower intelligence scores later in adolescence.

The review, supported by the IAFNS Cognitive Health Committee, combined evidence from 48 controlled trials and 25 prospective studies.

Professor Hayley Young, from Swansea University’s School of Psychology and lead author of the study, said the findings suggested the foundations of cognitive health are established at a very early age.

She 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.”

The researchers said adolescence remains an important stage of brain development, with significant structural and functional changes taking place during puberty. However, the evidence for dietary interventions during the teenage years was less conclusive than the findings relating to infancy and early childhood.

The review examined a broad range of nutrients and dietary components, including iron, iodine, vitamin D, fatty acids, grains, polyphenols and multi-nutrient interventions.

Researchers cautioned that differing results across studies should not be interpreted as evidence that diet has little effect on the brain. Instead, they argued that nutritional impacts can vary depending on factors such as age, the type and duration of dietary exposure, and the cognitive abilities being measured.

Priorities

To improve understanding of the relationship between nutrition and brain development, the team has proposed seven priorities for future research, including adopting a life-course approach, using better biological markers, carrying out sex-specific analyses and standardising how cognitive outcomes are measured.

The authors conclude that further high-quality research is needed to establish whether adolescence represents a second key opportunity to support cognitive development through nutritional interventions.

The full study, Diet and the Developing Brain: A Systematic Review of Nutritional Influences on Adolescent Cognitive and Academic Outcomes, is available online.