A mother's breast milk can help premature babies get metabolic boost, according to a study that may lead to better baby formula.
Researchers at Pennsylvania State University in the US compared the breast milk of mothers with babies born prematurely - between 28 and 37 weeks gestation - and at term - after 38 weeks.
They examined whether there were differences in the composition of the breast milks' microRNAs, snippets of RNA that affect gene expression and can be passed to the infant.
"We found that there are differences in these microRNA profiles, and that the majority of the altered microRNAs influence metabolism," said Molly Carney, a medical student at Penn State University.
"If those microRNAs are being transferred to the infant, that could potentially impact how the newborn processes energy and nutrients," Carney added.
Babies born prematurely are at risk for a host of problems, including failure to thrive and neurodevelopmental delays.
They also tend to be born at a lower weight than term infants, because of these issues, premature babies have different nutritional needs than babies born at term.
Previous studies have shown that the macronutrients - fats, sugars and proteins - in the breast milk of mothers with premature babies are customised to meet the unique needs of these infants.
Researchers collected 36 samples of breast milk from mothers with infants born at term and 31 samples from mothers with infants born prematurely.
They then processed the samples in a lab, extracting the microRNAs and comparing them to the human genome to pinpoint the differences between premature and term breast milk.
After analysis, they identified nine microRNAs that were significantly different in the premature breast milk.
They found that these microRNAs target metabolic processes and may help regulate gastrointestinal function and energy use in premature babies.
"We know that babies born prematurely have better health outcomes with breast milk than with formula, and our results may explain some of these health benefits associated with breast-feeding," said Steven Hicks, assistant professor at Penn State.
"The unique microRNA profiles that we found in premature breast milk seem well suited to premature infants, because they target metabolic pathways that could spark catch-up growth," Hicks said.
The findings could lead to opportunities to create better baby formula in the future, researchers said.
"MicroRNAs are an epigenetic material that is made by our bodies and is not present in formula. So even though formula is made to mirror the nutritional components of breast milk - carbohydrates, lipids and proteins - it does not have any of these epigenetic factors," Hicks said.
"It is possible to create microRNAs in a lab and put them in formula. This approach might help bridge the health gap we see between formula - and breast-fed infants," Hicks added.
The study was published in the journal Pediatric Research.