Breastfeeding premature babies improves long-term heart structure and function, an Oxford University study has found.
The hearts of babies born early often develop abnormally. Dr Adam Lewandowski and colleagues at the Oxford Cardiovascular Clinical Research Facility, directed by Professor Paul Leeson, have previously shown that, in adult life, the hearts of people who were born very preterm have smaller chambers, thicker walls and reduced function.
The changes in the heart are thought to emerge in the first few months after birth and therefore the team wanted to explore whether the way the baby was fed during this time might be able to alter how the heart develops. Lewandowski, who led the research, explained: “We already had data on more than 900 individuals who were followed since birth as part of an earlier study, which started in 1982, on the effects of different feeding regimes in preterm infants. We invited individuals who had been followed up throughout life to come to Oxford for a detailed cardiovascular study and used this information to investigate how different feeding regimes could affect the development of the heart in the long term.”
From the original group, now in their early- to mid-twenties, 102 people were able to visit Oxford and take part in the study. A further 102 people of similar age who had not been born prematurely were also recruited.
The study showed that while those who had been born early had reduced heart volumes and function compared to those born at term, the reduction was considerably less in people who had been exclusively fed on breast milk compared to those fed only on formula milk. Furthermore, in those fed a combination of breast milk and formula, the more breast milk consumed in the diet as babies the better their heart structure and function as adults.
After analysing the results to take into account other factors that might have affected heart volume and function, breastfeeding and the amount of breast milk in the diet was still clearly associated with better heart volume and function when compared to formula feeding.
Lewandowski said: “Even the best baby formula lacks some of the growth factors, enzymes and antibodies that breast milk provides to developing babies. These results show that even in people whose premature birth has inevitably affected their development, breastfeeding may be able to improve heart development.”
Background and objectives: Preterm birth relates to long-term alterations in cardiac morphology and function. Understanding whether preterm postnatal life is a tractable period of cardiovascular development that can be positively altered by nutrition is relevant to long-term outcomes. We hypothesized that being fed human breast milk during early postnatal life is beneficial to long-term cardiac structure and function in preterm-born individuals compared with infant formulas.
Methods: A total of 926 preterm-born infants originally took part in a randomized controlled trial of postnatal milk-feeding regimens between 1982 and 1985 across 5 different UK centers. Preterm-born individuals were randomly assigned to either breast milk donated by unrelated lactating women or nutrient-enriched formulas. We followed 102 individuals from this cohort: 30 of whom had been randomized to being fed exclusively human milk and 16 to being fed exclusively formula. As a comparison group, we recruited an additional 102 individuals born term to uncomplicated pregnancies. Cardiac morphology and function were assessed by MRI.
Results: Preterm-born individuals fed exclusively human milk as infants had increased left and right ventricular end-diastolic volume index (+9.73%, P = .04 and +18.2%, P < .001) and stroke volume index (+9.79%, P = .05 and +22.1%, P = .01) compared with preterm-born individuals who were exclusively formula fed as infants.
Conclusions: This study provides the first evidence of a beneficial association between breast milk and cardiac morphology and function in adult life in those born preterm and supports promotion of human milk for the care of preterm infants to reduce long-term cardiovascular risk.
Adam J Lewandowski, Pablo Lamata, Jane M Francis, Stefan K Piechnik, Vanessa M Ferreira, Henry Boardman, Stefan Neubauer, Atul Singhal, Paul Leeson, Alan Lucas