A new study has found that babies who are breast-fed or bottle-fed to a schedule do not tend to perform as well academically, as their demand-fed counterparts. However, researchers from the Universities of Essex and Oxford who conducted the analyses have urged caution in the interpretation of their results.
The study, published in the European Journal of Public Health
, was based on the results of children's IQ tests and school-based SATs tests carried out between the ages of five and 14. The team found that the IQ scores of eight-year-old pupils who had been demand-fed as babies tended to be four to five points higher than those of children who had been schedule-fed.
"At this stage, we must be very cautious about claiming a causal link between feeding patterns and IQ," warned Dr Maria Iacovou, senior research fellow at the University of Essex's Institute for Social and Economic Research (ISER), who led the study. "We cannot definitively say why these differences occur, although we do have a range of hypotheses. This is the first study to explore this area and more research is needed to understand the processes involved."
Dr Iacovou and her colleagues accounted for a wide range of background factors, including parents' educational levels, family income, the age and sex of children, maternal health and parenting styles. In addition to identifying associations between demand-feeding and higher IQ scores in eight-year-olds, the researchers found evidence of this difference in SATs results at ages five, seven, 11 and 14. On the other hand, researchers found that scheduled feeding resulted in certain benefits for mothers, including feelings of confidence and high levels of wellbeing.
"The difference in IQ levels of around four to five points, though statistically highly significant, would not make a child at the bottom of the class move to the top, but it would be noticeable," said Dr Iacovou. "To give a sense of the kind of difference that four or five higher IQ points might make, in a class of 30 children, for example, a child who is right in the middle of the class, ranked at 15th
, might be, with an improvement of four or five IQ points, ranked higher, at about 11th
in the class."
The research was funded by the Economic and Social Research Council (ESRC), and is based on data taken from the Avon Longitudinal Study of Parents and Children (ALSPAC), a study of more than 10,000 children born in the Bristol area during the early 1990s. Researchers divided the mother and baby pairs into three categories: those where the baby was fed to a schedule at four weeks of age, those where the mother tried but did not manage to feed to a schedule, and those that fed on demand. The results showed that the children of mothers who had tried to feed to a schedule, but had not succeeded, tended to have similar levels of attainment as demand-fed babies.
"This is significant because the mothers who tried but did not manage to feed to a schedule are similar to schedule-feeding mothers in that they tend to be younger, more likely to be single, more likely to be social tenants and likely to be less-well educated or to read to their child," explained Dr Iacovou. "These social characteristics are all understood to increase a child's likelihood of performing less well at school.
"It seems that it is actually having been fed to a schedule, rather than having the type of mother who attempted to feed to a schedule (successfully or not) which makes the difference," she added. "This is research based on large-scale data and we are confident that there is a very low risk that the results arose by chance. Nonetheless, this is the first and only study of its kind, and further research is needed before we can say categorically that how you feed your baby has a long-term impact on his or her IQ and academic attainment, and before we can say definitively what the mechanisms are by which this relationship comes about."