Research at the University of Bristol's School of Social and Community Medicine was based on the Avon Longitudinal Study of Parents and Children, which tracked the long-term health and well-being of 14,000 children born in England in 1991 and 1992.
Parents completed questionnaires on the types and amount of food and drink their children consumed when they were three, four, seven and eight-and-a half.Researchers used this to identify three dietary patterns: processed, traditional (high in meat and vegetables), and health-conscious.
The results show that a diet of predominantly processed foods, high in fat and sugar, at the age of three was associated with a lower IQ at eight-and-a-half, irrespective of whether the diet changed years later. In contrast, children who ate a healthy diet of fruit, vegetables, rice and pasta had a much higher IQ.
The authors of the report said that during the first three years of life the brain grows at its fastest rate, while other research has indicated that head growth during this period is linked to intellectual ability.
'The research 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,' said the authors.
'It is possible that good nutrition during this period may encourage optimal brain growth, but further research is needed to determine the extent of the effect early diet has on intelligence.'
Claire Patmore, manager of Woodlands Day Nursery and Pre-School in Woodford Green, Essex, said, 'We have always believed that it is part of our role to provide children with a healthy diet. Our chef Jason prepares meals using only fresh and locally sourced ingredients, and develops menus with help from senior nutritional advisers.
'The nursery combines good food with educating children about healthy eating, which sets them up with healthy habits for life.'
