Surprising benefit of smaller breasts: 'high lactose' breastmilk that's better for babies, study reveals

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The benefits of having a small bust include no back pain and the ability to sleep on your front.

But experts have discovered another potential upside – as women with smaller breasts appear to produce milk with a higher lactose concentration.

A team from the University of Warsaw recruited 137 women who were exclusively breastfeeding, and collected detailed data on each mother and infant.

Breast size was measured, while breastmilk samples were collected and analysed in a lab.

They discovered women with smaller breasts had higher levels of lactose in their milk compared to those with larger breasts.

Small busts have a potential upside – as women with smaller breasts appear to produce milk with a higher lactose concentration

Lactose is an essential component of breast milk, providing around 40 per cent of the energy required by infants and supporting the development of their central nervous system.

It also helps babies absorb calcium and iron.

No link, however, was found between breast size and the milk's energy density, protein or fat content.

The researchers said hormonal factors might explain their findings, which were published in the American Journal of Human Biology.

Larger breast size has previously been linked with higher levels of the hormones oestradiol and progesterone, which can decrease overall milk production and inhibit lactose formation.

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'This is the first study to report a negative relationship between lactose concentration in breast milk and maternal breast size during fully established lactation,' the scientists wrote.

'The demonstrated association indicates that women with larger breasts size may, via hormonal control, produce milk with lower lactose concentration than women with smaller breasts.'

It is recommended that babies should consume only breast milk for the fist six months of their lives.

After this, advice is that they continue to be breastfed, alongside eating other foods, for two years and beyond.

A previous study found that women with larger cup sizes tend to have lower levels of satisfaction with their breasts.

Research involving 345 adult women revealed those with big busts were more likely to report they were dissatisfied with them – and therefore felt less attractive and had less sexual confidence.

On the other hand those who were more content with their breasts were found to do more exercise and report a better quality of life.

The team, from the University of Canberra in Australia, said: 'Our finding conflicts with societal standards and beliefs that suggest large breasts are congruent with femininity, beauty and sexual attractiveness.'