In a new twist in the long-running debate on whether breastfeeding boosts childhood intelligence, scientists have found that breast milk increases the levels of certain chemicals in babies’ brains that are linked to neurodevelopment.
Breastfeeding has previously been shown to have all kinds of health benefits for babies. It helps to protect them against infections, and it’s been linked to a reduced risk of childhood obesity and leukaemia, as well as cardiovascular disease in adulthood.
Whether or not breastfeeding leads to improved intelligence, however, is a controversial question, and studies have found mixed results. The difficulty lies in teasing apart the effect of breastfeeding from the myriad other factors that can affect intelligence.
Now, research at the Children’s National hospital in Washington, DC has shown that breast milk increases the amount of biochemicals that are important for brain growth and development, which could provide an early marker of improved cognition.
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The scientists focused their study on ‘micro-preemies’ – extremely premature babies born at a gestational age of between 23 and 32 weeks. These were admitted to the hospital’s neonatal intensive care unit in the first week of life, where they continued their development outside the womb.
Using a sophisticated, non-invasive imaging technique known as ‘proton magnetic resonance spectroscopy’, the researchers were able to peer inside the newborns’ brains and detect the chemical signatures of different biomolecules.
“We’re able to capture information about the baby’s brain health at a particular point in time,” said Dr Catherine Limperopoulos, senior author of the study and director of the Developing Brain Research Laboratory at Children’s National.
The researchers focused on the frontal white matter and the cerebellum – two brain regions that are especially vulnerable in premature babies. Developmental issues in these areas have been associated with cognitive and behavioural problems later in life.
They found significantly higher levels of some key biochemicals in breast-fed babies, compared to those who had been fed formula milk. Namely, there were increased amounts of inositol (a molecule similar to glucose) and creatine (a molecule which helps to recycle energy inside cells). The percentage of days that babies were fed breast milk was also linked to higher levels of a vitamin-like nutrient called choline.
“These biochemicals are markers of brain development,” said Limperopoulos. “For example, higher levels of choline in the brain are associated with improved memory and cognition. We can’t make that direct link here – we don’t have information about memory and cognition in newborns – but our hope is that this is an early marker for improved later intelligence. We’d need to confirm that with our follow-up studies.
“We’re excited by these results because they’re helping us to understand not only how premature birth can have adverse effects on the developing brain, but also how our caregiving can help to protect the brains of these high-risk infants.”