Babies and children * Healthy living * Mental wellbeing

Childhood diet high in processed foods may lower IQ

Childhood diet high in processed foods  may lower IQ Healthy food means healthy mind, study suggests

They say you are what you eat, and now a new study suggests that a childhood diet high in "junk" food may result in a lower IQ.

But a diet high in vitamins and nutrients may have the opposite effect, resulting in a higher IQ - and the healthier the diet, the greater the effect.

The study looked at data collected by the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracked the food and drink habits of around 14,000 children born in 1991 and 1992.

Three dietary patterns were identified: "processed" high in fats and sugar intake; "traditional" high in meat and vegetable intake; and "health conscious" high in salad, fruit and vegetables, rice and pasta. Scores were calculated for each pattern for each child.

Once other possible factors had been accounted for, the researchers found that a predominantly processed food diet at the age of 3 was associated with a lower IQ at the age of 8.5, irrespective of whether the diet improved after that age - in fact each 1 point reduction in the diet "score" was associated with a drop in IQ of 1.67 points.

Health diets resulted in a higher IQ, with each 1 point increase in diet score linked to an increase in IQ of 1.2 points.

But diet between the ages of 4 and 7 had no effect on subsequent IQ scores. The study obtained complete scores for over 4,000 participants in ALSPAC.

These results echo previous ALSPAC research showing an association between early childhood diet and later behaviour and school performance, and the authors note that "it is possible that good nutrition during this period may encourage optimal brain growth."

Full details of the study are published online in the Journal of Epidemiology and Community Health.

This article was published on Tue 8 February 2011

Image © Ivonne Wierink -

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