Scientists have discovered another reason why breast is best. Already associated with increased intelligence, greater social mobility and protection against ill health, breastfeeding may also help babies develop a more sophisticated palate.
Researchers at the University of Copenhagen conducted tests on breast milk to see how the flavour changed with the mother's diet. They found that different foods caused subtle shifts in the flavour of breast milk, which appear to prime babies for the wide range of foods they are likely to encounter once they are weaned.
Helene Hausner, at the Centre for Advanced Food Studies at the University of Copenhagen, decided to investigate the influence of diet on breast milk after reading a study that showed how babies enjoyed a meal of carrot-flavoured cereal more if their mothers drank carrot juice while breastfeeding.
Hausner recruited 18 breastfeeding women and gave each of them edible capsules containing distinctive flavours, including banana, liquorice, caraway seed and menthol. To see if the flavours came through in the mothers' breast milk, she tested samples provided by the women before and up to eight hours after taking the capsules.
Her tests showed only around 1% of the flavour compounds were detectable in the breast milk, although some persisted for longer than others. Banana flavour peaked within the first hour, while menthol persisted for eight hours.
In a second series of experiments, Hausner checked whether breastfed babies were more likely to eat certain meals than babies fed on formula from a bottle. She found breastfed babies were happier eating meals laced with caraway flavouring than babies fed on formula.
"Diet does change the flavouring of the milk, but it's not like if the mother eats apple pie, the infant thinks, 'Mmm, apple pie', and gets to like it," Hausner said. "It seems that breastfed infants get used to small flavour changes and so they become more accepting of a variety of flavours compared to formula-fed infants."
"It seems that breastfeeding itself does prime the infants to be more accepting of new flavours when they start to eat solid food," she added.
Hausner, whose research is reported in New Scientist, also examined the flavours of different formula milks and found that they varied between manufacturers.
"If women are feeding their babies formula, it might be best for them to vary the type of formula to get their babies used to changes in flavours," she said.
Gill Rapley, a nurse with more than 20 years' experience of postnatal care, said the research could help new mothers who find their infants are sometimes reluctant to eat. "Mothers often talk about whether something in their milk may have upset their baby, but within eight hours, most flavours will be gone," she told the magazine.
Last year, researchers at Boston's Beth Israel Deaconess medical centre in the US reported that people who were breastfed as babies went on to have a lower risk of heart disease, while a team at King's College London found that breastfeeding raised the IQ of children by an average of seven points, if they had a particular version of a gene.
The studies followed other research which found breastfed babies had a better chance of climbing the social ladder than those raised on formula.
