America - and most of the industrialized world - is getting fatter every year. In the U.S., 20-35% of the population is now obese, and related conditions (e.g., heart conditions, diabetes, and cancer) are now major causes of preventable deaths. According to research research, the toxic diet that contributes to this epidemic could also be harming our intellect. Indeed, it appears that childhood nutrition has longstanding effects on IQ, even when we take into account previous intelligence and socio-economic status (SES).
The research, by Dr. Sophie von Stumm (a Lecturer in Psychology at Goldsmiths, University of London), examined the longitudinal effects of type of diet on IQ in a sample of about 4,000 Scottish children, aged 3 to 5. Although the idea that food affects brain development is commonsensical, prior to Dr. von Stumm's study, research had examined only specific types of food groups (fish, margarine, omega 3 oils, etc.). In her study, Dr. von Stumm compared the effects of two more generic or over-arching types of diet, namely fast versus "slow" food (food that is freshly cooked).
The results indicated that food partly mediated the effects of SES on intellectual development: wealthier parents tended to cook fresh food more frequently for their children, which positively affected their IQ. In other words, one of the reasons why SES positively impacted on IQ gains was that it increased the probability of providing a healthier diet for children. Conversely, lower socio-economic resources caused intellectual decline, partly because they increased the frequency of children's fast-food consumption.
These findings provide compelling support for interventions, such as Jamie Oliver's, designed to improve children's nutritional habits and educate them about the importance of slow food. Although upgrading one's diet from fast to slow food may seem expensive, the costs of not doing so cannot be under-estimated. In particular, children from lower SES could benefit enormously from a healthier diet: IQ affects academic performance and (to a lesser degree) employment success. A better diet should therefore improve individual's career success.
An interesting, yet unaddressed, question, is to what extend fast and slow food may impact on an individual's personality development. For instance, fast food tends to be less varied than slow food - could a diet based on repetitive take-aways and microwaved dinners make people less adventorous and open-minded? Conversely, valuing healthy food may increase people's sense of responsibility and make them more conscientious.
What is clear is that parents should be made aware of the potential consequences of habituating their children to toxic diets. Adult food habits are no doubt influenced by childhood experiences, and if a package of Pringles or a bottle of Coke can induce nostalgia, it will be much harder to resist them. If parents want smarter kids, they should stop spending money on Baby Einstein and spend more time in the kitchen.
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