The study, published in the journal Allergy, analysed milk samples and data from 421 infants and mothers participating in the CHILD Study, a longitudinal study tracking nearly 3,500 Canadian mothers and children from pregnancy to school age.
Led by Lars Bode, PhD, at UC San Diego School of Medicine, and Meghan Azad, PhD, from the Rady Faculty of Health Sciences at University of Manitoba, the team reported that the ‘unique composition’ of HMOs found in breast milk was linked to a significantly lower incidence of food sensitisation in infants at one year of age.
While no individual HMO was associated with food sensitisation, the team noted that the overall HMO composition appeared to play a role in the protection.
"Our research has identified a 'beneficial' HMO profile that was associated with a lower rate of food sensitization in children at one year," commented Bode. "To our knowledge, this is the largest study to examine the association of HMOs and allergy development in infants, and the first to evaluate overall HMO profiles."
The researchers noted that in general, composition of HMOs in breast milk is variable and determined by factors like lactation stage, gestational age, maternal health, ethnicity, geographic location and breastfeeding exclusivity.
What are HMOs?
HMOs are structurally complicated sugar molecules unique to human breast milk. They are the third most abundant solid component in human milk after lactose and fat.
They are not actually digestible by infants, but act as a prebiotic, helping to guide development of the infant gut microbiota, which previous research suggests is a key influencer of allergic disease.
Past research has also shown that breastfed infants have a lower risk for a variety of medical conditions, such as wheezing, infections, asthma and obesity – many of which are believed to be related to the infl;uence of HMOs.
As such, HMOs have been generating a huge level of interest both from academic researchers and from the infant formula industry – which has been quick to begin development and bringing to market of a variety of HMO molecules for use in infant formula products.
The new study analysed data from the CHILD study, which was launched in 2008 by the Canadian Institutes of Health Research and the AllerGen Network of Centres of Excellence – a consortium of researchers, industry partners, policymakers, health care providers and patient advocates supporting improved understanding and treatment of allergic diseases.
Breast milk samples taken three-to-four months after birth were analysed at the Larsson-Rosenquist Foundation Mother-Milk-Infant Center of Research Excellence at UC San Diego, directed by Bode.
At one year of age, infants were given skin prick tests to check for allergic sensitisation to common allergens, including certain foods.
"A positive test is not necessarily proof of an allergy, but does indicate a heightened sensitivity," said Azad. "Sensitisations during infancy don't always persist into later childhood, but they are important clinical indicators and strong predictors of future allergic disease."
The team found that 14% of the infant (59 of 421) displayed sensitisation to one or more food allergens at age one.
While no individual HMO was associated with food sensitisation risk, the team reported that overall HMO composition appeared to play a role.
The authors said the findings underscore the potential for HMOs, which are still not widely found in infant formula, to be used for therapeutic interventions or in the development of new and improved products.
Bode and colleagues added that their findings demonstrate the link between HMO composition and prevention of food sensitisation and underscore the need for further research to explore the underlying biological mechanisms involved, establish long-term consequences of HMO composition on confirmed allergic disease in later childhood, and begin to assess how HMOs might be used therapeutically.
Published online ahead of print, doi: 10.1111/all.13476
“Human milk oligosaccharide profiles and food sensitization among infants in the CHILD Study”
Authors: Kozeta Miliku, et al