Cognitive development is influenced by many factors, including nutrition. There is an increasing body of literature that suggests a connection between improved nutrition and optimal brain function. Nutrients provide building blocks that play a critical role in cell proliferation, DNA synthesis, neurotransmitter and hormone metabolism, and are important constituents of enzyme systems in the brain1. Cognitive performance is a predictor of academic achievement. Higher educational attainment is associated with better jobs, higher income, higher socio-economic status, better health care access and housing, better lifestyle, nutrition and physical activity and is therefore of broad benefit for society as a whole².

The focus of these studies was to investigate the relationships between multiple dimension of dietary intakes, a comprehensive overall score and food components in early life (ages one, two and three), and various cognitive and educational outcomes at different developmental stages (cognitive development at ages 10 and 17; educational outcomes at grades five and seven) in a cohort of Western Australian children.

Diet in the early years of life influences cognitive outcomes at 10 years

Early childhood is believed to be a sensitive period for brain development. The main finding was that a higher diet score at age one was positively associated with cognitive outcomes (higher verbal and non-verbal skills) at age ten after adjusting for a range of sociodemographic characteristics. This association was attenuated at age two and three after adjustment for sociodemographic factors, suggesting a stronger influence of diet in the first year of life. Examining the components of the diet score, it was found that increased fruit consumption at age one was positively associated with cognitive performance at age ten, while increased soft drink consumption at age one was negatively associated with cognitive performance at age ten years. At two and three years of age, increased dairy consumption showed positive associations with later cognitive outcomes. These findings suggest that the promotion of a nutrient-dense diet for children during the early years is beneficial for cognitive development.

The relationship between nutrition in infancy and cognitive performance during adolescence

Much of the work previously published has focused on short-term associations between dietary factors and cognitive performance¹. Therefore, this study represented a major progression in the field, as it was possible to extend the previous study by exploring whether the association between early diet and cognitive performance exists in the longer term, specifically in 17 year-old adolescents. In addition, in this study we investigated the long lasting effect of breastfeeding on the cognitive performance of adolescents. It was found that boys who had been breastfed for 4 months or longer performed better with respect to their psychomotor speed. However, there was no association between breastfeeding and cognitive performance in girls. A better quality diet at age one was also associated with a faster reaction time across the whole cohort (i.e. boys and girls combined). This study supports and strengthens previous findings concerning the importance of a high quality diet and breastfeeding during infancy in brain development.

Good quality diet in the early years may have a positive effect on academic achievement

Cognitive capacity is strongly associated with academic achievement; however, little attention has been paid to the direct influence of diet on academic performance. Associations between quality of diet and cognitive performance were identified in the previously presented studies. In this study, it was explored whether associations also exist with respect to the relationship between diet and academic attainment. More specifically, the aim of this study was to examine the associations between diet during the sensitive early years of life and academic performance with respect to mathematics, reading, writing  and spelling scores in ten (grade five) and 12 year old (grade seven) children. It was found that a higher (i.e. better quality) diet score at age one was an independent predictor for higher scores in mathematics, reading, writing and spelling at grades five and seven. Significant associations were also found between a higher diet score at age two years and academic scores for mathematics, writing and spelling at grade seven. Regarding specific food groups, higher fruit consumption at age one year and higher dairy consumption at ages one, two and three years were consistently associated with higher academic scores. These findings are consistent with the findings of the previous studies presented in this thesis and support the view that a good quality diet during the early years of life is important with respect to both cognitive and academic performance in childhood and adolescence.

Possible Mechanism

During the early years, significant and rapid brain growth occurs and by the age of two years the brain reaches 80% of its adult weight and 50% of its synaptic density, indicating a sensitive periods of neurocognitive development in the early years of life³.
The studies showed that a better quality diet (reflected by a higher diet score) and some specific ‘healthy food’ components of the diet such as dairy products and fruit are associated with better cognitive and academic performance. The relatively high micronutrient content of these foods is likely to play a role in improved brain development and subsequently cognition. Micronutrients that have been linked to cognitive performance include B12 vitamin, folate, zinc, iron, iodine and omega-3 fatty acids¹.

Based on: Nyaradi A, Li J, Hickling S, Whitehouse AJO, Foster JK, Oddy WH. Diet in the early years of life influences cognitive outcomes at ten years: a prospective cohort study. Acta
Paediatrica. 2013;102(12):1165-73.
Nyaradi A, Li J, Foster JK, Hickling S, Oddy WH. The relationship between nutrition during infancy and cognitive performance during adolescence. Frontiers in Nutrition: Neuroenergetics,
Nutrition and Brain Health. 2015;2.
Nyaradi A, Li J, Foster JK, Hickling S, Jacques A; O’Sullivan T, Oddy WH. Good quality diet in the early years may have a positive effect on academic achievement. Acta Paediatrica.
2016:105: e209–e218.