Allergy-protective breast milk components not found in infant formulas

Unique human milk oligosaccharides (HMOs) have been associated with reduced food sensitisation in 1-year old infants in a study led by researchers at the University of California San Diego School of Medicine, adding further to the knowledge about breast feeding and food allergy development.

HMOs are structurally complicated sugar molecules only found in human breast milk. The composition of HMOs in breast milk is known to vary according to a number of factors such as lactation stage, gestational age, maternal health, ethnicity, geographic location and breastfeeding exclusivity. Past research has shown that breastfed infants have a lower risk for a variety of medical conditions, such as wheezing, infections, asthma and obesity. However, there is no consistent evidence that breastfeeding is effective for the prevention of allergic disease.

The current study determined the composition of human milk oligosaccharides in milk samples from 421 mothers participating in the CHILD Study, a longitudinal study tracking nearly 3,500 Canadian mothers and children from pregnancy to school age. Breast milk samples were taken three-to-four months after birth, while infants were given skin prick tests to check for allergic sensitisation to common allergens at one year of age. A specific beneficial HMO profile was associated with a lower rate of food sensitisation in the one-year old children.

The importance of gut microbiota in the development of allergic disease has recently come under the spotlight through much other research. Given HMOs are not digestible, but rather act as a prebiotic, the current findings may suggest the beneficial HMO profile promotes healthy gut bacteria which in turn confers allergy protection.

The limitations of using skin prick tests to determine allergic sensitivity were acknowledged, as was the need to further explore the underlying mechanisms by which certain HMOs provide protection against allergies. The researchers also suggest HMO modification as a means for allergy prevention if longitudinal benefits can be proven.

Reference: Miliku et al. 2018. Allergy. DOI: 10.1111/all.13476