SOURCES: Paul Leeson, Ph.D., F.R.C.P., professor of cardiovascular medicine, University of Oxford, and clinical director, Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, England; Jennifer Wu, M.D., obstetrician/gynecologist, Lenox Hill Hospital, New York City; June 14, 2016, Pediatrics
TUESDAY, June 14, 2016 (HealthDay News) -- Breast-feeding premature babies appears to increase the likelihood that those infants will have healthier hearts in young adulthood, new research suggests.
The finding was based on an analysis involving just over 200 men and women in their early- to mid-20s. It suggests that premature infants fed just breast milk during infancy ultimately have better heart volume and overall function compared to preemies raised on formula or a mixture of formula and breast milk.
"It was completely unknown that breast milk would provide this particular protective effect on the development of the heart in babies born preterm," said study author Paul Leeson. He's the clinical director of the Cardiovascular Medicine Division of the Cardiovascular Clinical Research Facility at the University of Oxford, in England.
"We suspected it might, but were surprised by the size of the effect," he added.
The study authors pointed out that premature babies often go on to develop long-term heart abnormalities. Those can include small heart chambers, thicker heart walls and impaired heart function. The first few months of life are considered a critical period in terms of development of the heart, the researchers said.
To see what effect breast-feeding during infancy might have, the researchers followed 102 people born preterm in the 1980s who were part of a larger study on feeding regimens. At the time, half of that group was assigned to receive breast milk, while the other half was given formula. Ultimately, 30 were fed solely breast milk, while 16 were were given "nutrient-enriched" formula only during early postnatal life.
They were compared with another 102 people born full-term from the same time period.
The researchers conducted heart testing when all the participants were between 23 and 28 years old.
As expected, participants who were born premature had reduced heart volume and function compared with those carried to term. But those born premature and fed exclusively with breast milk had greater heart volume than preemies fed only formula.
The study only found an association between heart health and breast milk. And, the impact of breast milk appeared to be incremental. That meant that those whose feeding mix included more breast milk than formula ended up with greater heart volume and better functioning hearts than those whose diets included more formula.
"What we have now found is that, although exclusive breast milk does not alter the wall thickness, it does mean the hearts of adults who were born preterm get closer in size to those of adults born at term and the function of their hearts is better," Leeson said.
Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City, said "the benefits [of breast milk] for premature infants are enormous." Wu was not involved with the study.
"In the short term, there are protective antibodies and the production of important gut flora," she said. "In the long term, breast-feeding improves heart structure and function."
But at the same time, Wu added that "breast-feeding can be a challenge for moms with premature infants."
"Due to Newborn and Infant Critical Care Unit admissions and longer hospital stays, breast-feeding can be difficult to initiate and maintain," she said. "Extra support and lactation consultations are needed."
The study was published online June 14 in Pediatrics.
There's more information on the benefits of breast-feeding at WomensHealth.gov.