Children breastfed past the six-month mark are better thinkers as teenagers, study finds

Babies who are breastfed for longer are better thinkers as teenagers, research suggests.

A study of more than 7,800 British children looked at those who had their mother’s milk for less than two months, two to four months, four to six months or over a year.

Researchers found those breastfed the longest, above the age of one, did best in vocabulary tests at age 14 compared to children who were not breastfed.

The study, by experts from Oxford University, said the differences in scores were equivalent to three IQ points.

Meanwhile children breastfed for four to six months did the best in a test of memory, reasoning and spatial awareness, compared to children who were never breastfed, at the ages of seven and 11.

Breastfeeding was linked to a ‘modest’ increase in children’s intelligence even when their mother’s intelligence and their socioeconomic circumstances were taken into account.

The World Health Organization advises mothers to exclusively breastfeed their baby for at least six months. 

But only about 48 per cent of British and 52 per cent of American mothers breastfeed for this length of time. 

Dr Reneé Pereyra-Elías, who led the study from the University of Oxford’s Nuffield Department of Population Health, said: ‘These results should not cause concern for women who did not breastfeed, or were unable to breastfeed, because the potential gains in IQ among children breastfed for several months compared to children never breastfed would be equivalent to two to three points.

‘However if many children, on average, increased their IQ by around three points, we could see important differences.

‘Therefore, it is important that women who want to breastfeed are given support to do so.’

Breast milk contains polyunsaturated fatty acids and nutrients like iron which help children’s brains develop.

Experts say it also causes children to have fewer infections and illnesses, which may aid their intelligence because they have fewer days off school.

Researchers looked at the link between breastfeeding duration and thinking skills in children from the UK Millennium Cohort Study, who were recruited as babies between 2000 and 2002 and given cognitive tests aged five, seven, 11 and 14.

Among those in the study, around a third of the children had never been breastfed, but 23 per cent had been breastfed for at least six months.

The strongest link between breastfeeding and vocabulary skills was seen in children aged 14, who were given a list of 20 words, ranging from ‘unique’ to ‘pusillanimous’ and asked to select the word with the most similar meaning from a list.

The 14-year-olds breastfed for at least 12 months had the test result almost three IQ points higher than teenagers of the same age who were never breastfed.

Children’s understanding of words in simpler tests was also better, compared to children who were never breastfed, for seven and 11-year-olds who were breastfed for four months or more.

Duration of breastfeeding was not linked to vocabulary at the age of five.

The researchers set out to ensure the results were not driven by mothers’ intelligence, assessed using a vocabulary test, and children’s socioeconomic status, judged based on their parents’ occupations and mother’s level of education.

Children with more educated mothers, and those from wealthier families, tend to be breastfed for longer and may also benefit from tutoring, extra help with homework or trips to zoos, museums and galleries.

But even when this was taken into account, children breastfed for longer did better in cognitive tests.

Children who were breastfed for four to six months, compared to those never breastfed, did better at the age of seven in a spatial test asking them to fit coloured squares into a shape, and slightly better aged five.

They also made fewer errors, aged 11, when asked to check inside boxes on a computer screen for tokens, and remember which they had already checked after they were covered up.

These tests, done only up to the age of 11, measured spatial awareness and problem-solving skills.

The study, published in the journal Plos ONE, concludes that being breastfed for longer can boost children’s intelligence about as much as having a clever mother or coming from a well-off family and ‘should not be underestimated’.