The study, led by researchers from University of Turku in Finland and the University of California San Diego School of Medicine, confirms the findings of an earlier pilot study that suggested a link between HMO concentrations and infant weight and body composition.
Writing in The American Journal of Clinical Nutrition, the team reported that high concentrations a HMO known as 2'-Fucosyllactose (2'FL) and low concentrations of another HMO known as Lacto-N-neotetraose (LNnT) were associated with growth in infancy and early childhood.
The team, led by senior author Professor Lars Bode, the study shows that infant weight can vary depending upon concentrations of HMOs in mother's milk, but independent of the mother's pre-pregnancy body mass index or duration of breastfeeding.
"We were surprised by the magnitude of the association," said Bode, of UC San Diego School of Medicine and director of the Larsson-Rosenquist Foundation Mother-Milk-Infant Center of Research Excellence.
"The impact persisted long after actual exposure to HMOs during breastfeeding. Our analytical platform allows us to measure and associate individual HMOs with specific health and development outcomes."
Human milk is an complex mixture of proteins, fats, minerals and vitamins, and complex sugar molecules known as human milk oligosaccharides (HMOs).
The team noted that there are approximately 150 types of HMOs – adding that like a fingerprint the combination and concentration of HMOs is unique to each nursing mother.
HMOs are natural prebiotics that contribute to the shaping of the infant gut microbiome, which can affect health and disease risk.
However, HMOs can also act independently of the microbiome, protecting the infant from diseases, such as infectious diarrhoea or necrotizing enterocolitis – a serious condition that impacts the intestine of premature infants.
Research has also suggested HMOs may reduce the risk for non-communicable diseases, such as asthma, allergies and obesity later in life.
Mounting evidence for the importance of HMOs in development has led to huge interest in the compounds from manufacturers of infant formula, as companies strive to make formulations that resemble breast milk as closely as possible.
While it has been established that breastfeeding has an impact on infant growth and protects against the development of obesity, it has not yet been established whether maternal variations in HMOs form part of this link.
The new study analysed data from 802 mothers and their children who took part in the longitudinal Steps to Healthy Development of Children (STEPS) study, led by researchers at the University of Turku in Finland. As part of the study, children were monitored from birth to age 5.
Results showed that maternal HMO composition three months after delivery was associated with height and weight during the first five years of life.
Specifically, HMO diversity and the concentration of LNnT were inversely associated with growth, while 2′FL was directly associated with child height and weight scores.
"Our goal is to generate a deep mechanistic understanding of how HMOs in a mom's milk can contribute to infant health and development,” said Bode. “Although we are only at the very beginning, the generated knowledge provides fascinating new opportunities.”
"Some HMOs could help infants who are behind the growth curve; other HMOs could do the opposite and help lower the risk of childhood obesity,” he added.
“We could even imagine applying HMOs as novel therapeutics for adults who either need to gain weight or suffer from overweight and obesity."
According to Bode, the study is an example of how data can help guide the development of HMO blends for different products promoting health.
"We could tailor HMO composition in products based on actual scientific evidence and desired outcomes,” he said. “Much like personalised medicine."
However, the team also noted that association studies do not prove causality – adding that the next steps for their research include bringing the data back to the lab to test whether or not HMOs, either alone or in combination, affect growth and to pinpoint the underlying mechanisms.
Source: American Journal of Clinical Nutrition
Published online, doi: 10.1093/ajcn/nqaa010
“Associations between human milk oligosaccharides and growth in infancy and early childhood”
Authors: Hanna Lagström, et al