Human Milk Oligosaccharides

Human Milk Oligosaccharides (HMOs) are complex sugars that are available in human milk. They are the 3rd largest solid component in breast milk after fat and lactose and have no nutritive function. HMOs are responsible for directly stimulating the immune system by promoting good gut bacteria, strengthening the gut barrier function and blocking pathogens.

In this brochure several experts explain the role of gut microbiota in health and disease. In the chapter by Clements Kunz special attention is given to milk carbohydrate fractions and how HMOs differ from other Oligosaccharides.

Since around 1900, concomitant with the discovery of lactobacilli and bifidobacteria and their relevance for health and disease, pediatricians have already realized that the microbial composition of stool samples from breast-fed and bottle-fed infants differed. Observations indicated that this difference is particularly linked to the milk carbohydrate fraction. This was the starting point of research on human milk carbohydrates – HMOs. There are around 150-200 types of HMOs identified so far.

HMOs have also been shown to provide benefits to formula-fed infants by influencing the establishment of the gut microbiota. A randomized controlled trial showed that infants fed formulas fortified with a type of HMO, 2’-fucosyllactose (2’FL), had similar growth as breastfed infants. Another randomized controlled trial showed that use of term infant formula supplemented with two HMOs, 2’FL and lacto-N-neotetraose (LNnT), shifts stool microbiota and metabolic signatures closer to that of breastfed infants

Oligosaccharides differ greatly between one another. “The short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides used in infant formula are very different structurally from human milk oligosaccharides (HMOs).”


In this presentation Norbert Sprenger presents the composition and diversity of HMOs. HMOs have a composition and structural diversity not seen with generic prebiotics such as plant-derived fructo-oligosaccharides (FOS). Individual synthetic HMOs are now becoming available, and are allowing the progression from basic research to clinical studies. Safety of synthetic HMOs is established in preclinical safety toxicity studies. Clinical data demonstrate that synthetic HMOs (2’FL and LNnT) are safe and well tolerated. Initial clinical studies show that infant formula with 2 above HMOs shift gut microbiota towards those seen in breast-fed infants and reduce low respiratory tract morbidity and antibiotic use during first year of life.

Oligosaccharides are sugars found in breast milk that are not digested by babies, but rather feed healthy bacteria in the child's intestines as their gut microbiome, the collection of bacteria which play a role in a range of basic functions of the body, develops.
Breast milk has been shown by many studies to prevent allergy and sickness, and researchers say the sugars may also prevent infection by other bad bacteria, assisting the undeveloped immune systems of newborns.
Early-stage research demonstrates the complexity of breast milk, and the benefits it gives for the baby. Increasingly, research is suggesting these breast milk sugars (Human Milk Oligosaccharides - HMO) may protect against infections in the newborn, such as rotavirus and Group B streptococcus, as well as boosting a child's 'friendly' gut bacteria.

In this interview David Mills talks about Human Milk Oligosaccharides.

What are they?
Complex sugars that the mother produces in very large quantities in her breast milk.

How do they work?
HMOs are essentially fiber, and travels through the infant without being absorbed.

What is the purpose of HMO?
They affect the infant’s gut bacteria.

What are they good for?
- Direct stimulation for the immune system in a positive way
- They help to promote good gut bacteria in the infant’s colon
- Block pathogenic bacteria



An interactive learning environment for healthcare professionals developed from more than a decade of research on Human Milk Oligosaccharides.


HMO Academy

Developed from more than a decade of research on Human Milk Oligosaccharides