HMOs and allergic sensitization: current evidence

Editor(s): Dr. Carine Blanchard .

Key message

Currently there is scientific evidence linking HMOs and more particularly 2 FL and LNnT
with the prevention of allergic sensitization. The results both from preclinical and clinical
observational data, from the LIFE Child Cohort, demonstrates a positive effect of 2FL and
LNnT in reduction of allergic sensitization.


Background: Human Milk Oligosaccharides (HMOs) represent a family of approximately 200 complex carbohydrates present in human milk. They are the third- largest solid component in breast milk after fat and lactose. HMOs have been shown to strengthen the gut barrier function and to block pathogens. They are also known for their prebiotic effect and for promoting beneficial intestinal microbiota growth and stimulating the immune system.
Aim: Here we aimed at understanding the effect of a HMO on allergy prevention in preclinic and human.
Methods: The role of specific HMO (2’FL and LNnT) on allergic sensitization prevention and tolerance induction was investigated in preclinical experiments (epicutaneous sensitization and mucosal sensitization models). The nutritional intervention was performed with a blend of 2 HMO (2’FL and LNnT) added to the diet at 0.2, 1, 5 and 10% . In the LIFE Child cohort in Leipzig, Germany, allergic sensitization and allergic symptoms were recorded in the infants up to 1 year old. Milk samples were collected
from lactating mothers participating in the LIFE Child cohort in Leipzig, Germany. A total of 25 HMOs were analyzed in 156 breast milk samples, collected at 3 months after birth.
Results: In preclinical models, oral administration of the blend of 2’FL and LNnT at 1 or 5% supplementation in the diet consistently decreased allergic sensitization in the
epicutaneous or mucosal sensitization models respectively. The HMO blend administration also induced modulation of the gut microbiota and SCFA production as well as an increase in regulatory T cell numbers in the mesenteric lymph nodes. From the observational human study, levels of 2’FL ranging from 0.8 to 2.5g/L in the mother breast milk were positively associated with a decreased risk of sensitization in the infants.
Conclusion: Altogether, these data suggest that specific doses of 2’FL and LNnt are associated with decreased allergic sensitization.

1. Holvoet S, Ní Cléirigh, E, Shevlyakova M, Sprenger N, Foata F, Dupuis L, Martin-Paschoud C, Combremont S, Körner A, Vogel M, Nutten S, Kiess, W, Blanchard C. Association of 2’FL and LNnT with the decreased risk to develop allergic sensitization. Abstract presented at EAACI Digital Congress, 6-8 June 2020.
2. Natividad JM, Rytz A, Rochat F and Garcia-Rodenas CL. Microbial Products Derived
From Human Milk Oligosaccharides Fermentation by Infant Microbiota Protect Against
Inflammation-Mediated Intestinal Epithelial Barrier Dysfunction In-Vitro. Abstract n. 1999, accepted at the 6th WCPGHAN, June 2020, Copenhagen, Denmark.
3. Natividad JM, Rytz A, Bergonzelli G and Garcia-Rodenas CL. Human Milk Oligosaccharides Confer Resistance against Inflammation-mediated Intestinal Epithelial Barrier Dysfunction In- Vitro Abstract n. 1993, accepted at the 6th WCPGHAN, June 2020, Copenhagen, Denmark.
4. Michel L, Shevlyakova M, Ní Cléirigh E, Eckhardt E, Holvoet S, Nutten S, Sprenger N, Körner A, Vogel M, Nembrini C, Wieland Kiess W, Blanchard C. Novel Approach to Visualize the Inter- Dependencies Between Maternal Sensitization, Breast Milk Immune Components and Human Milk Oligosaccharides in the LIFE Child Cohort. PLoS One. 2020 Apr 21;15(4):e0230472. doi: 10.1371/journal.pone.0230472. eCollection 2020.