How can you make a population smarter? Last week, research in the American journal JAMA Pediatrics showed that mothers' milk increases a child's intelligence. The study, from Boston Children's Hospital, found that breastfeeding for six months to a year was associated with better receptive language skills at three years and higher verbal and non-verbal intelligence scores at seven. A year of breastfeeding as a baby gave a seven-year-old 4.2 more IQ points – 0.35 of a point for each month it received its mother's milk.
While the evidence that breastfeeding reduces ear infections and gastroenteritis in infants has been strong for ages, it hasn't convinced women in the UK. Figures released this month show a dip in the number of mothers who continue to feed after six to eight weeks – already less than half. There is also considerable variation, with deprived areas recording rates as low as 20%.
The Department of Health recommends exclusive breastfeeding for six months – advice followed by an estimated 2% of mothers. So, is this why the UK is slipping down the global educational league tables? And should you breastfeed to boost your child's IQ?
The solution
The debate about breastfeeding boosting intelligence has been raging for decades. There are many other factors that influence intelligence test scores, such as socioeconomic status, birthweight, birth order, parental education, the amount of stimulation the child gets, and the intelligence of a baby's mother. According to a paper in the BMJ, there is a "known association of maternal intelligence with both the initiation and duration of breastfeeding".
Some research projects have been better than others at allowing for these factors. But researchers have also measured feeding differently – some defining it by asking if women have ever breastfed (eg for a couple of minutes) versus never breastfed. Most of these studies have found no significant increase in IQ. Others have asked more carefully about the exclusivity and length of feeding. At least one, a randomised controlled trial by the department of paediatrics at McGill University in Montreal that promoted breastfeeding, did find an increase in the IQ of exclusively breastfed babies.
The Boston study has allowed for maternal intelligence, family income and measured breastfeeding duration and exclusivity. It is still unlikely to be the last word. Breastfeeding is not easy for everyone, but it can't be so difficult that less than half of us can do it.
