Children who eat a diet rich in healthy foods at the age of three are more likely to have a higher IQ when they are older, according to researchers.
Conversely, youngsters who live on processed foods high in fats and sugars appear to have a lower IQ at the age of eight and a half, regardless of whether their diet has improved later in childhood.
Writing the in the Journal of Epidemiology and Community Health, the authors say that it’s possible that good nutrition in the crucial first three years of life may encourage the brain to grow to its best possible capacity.
The findings are based on the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracks the health and wellbeing of approximately 14,000 children born in 1991 and 1992. Previous ALSPAC research has shown an association between early childhood diet and later behaviour and performance at school.
For this study, the authors, including Dr Kate Northstone at Bristol University’s Department of Social Medicine, looked at questionnaires, which had been completed by parents, listing the types and frequency of the food and drink their children took at ages three, four, seven and 8.5.
The IQ of around 4,000 children, for whom there was complete dietary data, was measured at age 8.5.
The authors identified three dietary patterns. These were “processed”, which was high in fats and sugar intake; “traditional”, which was high in meat and vegetable intake; and “health conscious”, which was high in salad, fruit and vegetables, and rice and pasta. The researchers calculated scores for each pattern for each child.
Even after potentially confounding factors were taken into account, the authors found that a predominantly processed food diet at age three was associated with a lower IQ at age 8.5, irrespective of whether the diet had improved after three. Every one point increase in the dietary pattern score was associated with a 1.67 fall in IQ.
There also appeared to be a positive, if modest, effect in eating a healthy diet, with every one point increase in that dietary pattern being associated with a 1.2 increase in IQ, while dietary patterns between ages four and seven did not appear to have an impact.
The authors say that the brain grows at its fastest rate during the first three years of life, which could explain the findings. The results also chime with other research which shows that head growth in the early years is also linked to intellectual ability.
“This suggests that any cognitive/behavioural effects relating to eating habits in early childhood may well persist into later childhood, despite any subsequent changes (including improvements) to dietary intake,” they say.
“It is possible that good nutrition during this period may encourage optimal brain growth,” they suggest, adding that there should be further research to determine the extent of the effect early diet has on intelligence.