07/06/2026
The food a child eats in their earliest years may shape far more than their physical growth. A major new review suggests that early diet plays an important role in how the brain develops, with effects that can still be seen years later in adolescence.
Published in Advances in Nutrition and led by Swansea University, the review brought together findings from 73 studies, including 48 controlled trials and 25 long-term prospective studies, examining how diet affects cognitive performance and academic outcomes in young people aged 8 to 19. One of the clearest signals to emerge was that a poorer diet in the first years of life, particularly in infancy, was linked to lower intelligence later in adolescence, even after accounting for many other influences.
According to the lead author, Professor Hayley Young, the foundations of cognitive health appear to be laid very early. The picture during adolescence itself is more mixed. Some nutritional interventions in the teenage years show promise, but the evidence is not yet settled. This matters because adolescence represents a second major period of brain development, driven by the structural and hormonal changes of puberty, raising the question of whether it could be a second window of opportunity to support the developing brain through nutrition.
The researchers looked at a wide range of nutrients and dietary components, including iron, iodine, choline, vitamin D, polyphenols, fatty acids, and grains. They caution that apparent inconsistencies across studies should not be read as evidence that diet has little influence. Rather, the impact of nutrition depends on factors such as the timing of dietary exposure, the population studied, the type and length of any intervention, and which cognitive abilities are being measured.
The practical message for families is encouraging rather than alarming. It reinforces how valuable good nutrition is during pregnancy, infancy, and early childhood, while highlighting that researchers are still working to understand how much can be supported later on. A varied, nourishing diet rich in whole foods remains one of the most worthwhile investments in a child's long term development.
Shared for information purpose only.
Source: Young et al., Advances in Nutrition, 2026.
