What Are HMOs? (And Why They Matter in Our Synbiotic)

When you think about breast milk, you might picture nourishment, immunity, and comfort. One of its lesser-known, yet powerful components is a group of complex sugars called human milk oligosaccharides (HMOs). Unlike lactose or fat (which are used directly by the baby), HMOs aren’t digested—they work behind the scenes to support gut, immune, and microbial health.

HMOs are the third most abundant solid component after lactose and lipids. There are more than 200 structurally different HMOs identified to date.¹ Although they don’t nourish the baby directly, they interact with receptors in the gut² and feed beneficial gut bacteria. This generates key metabolites that support digestion, immunity, and gut health.  

At Persephone, we’ve designed our synbiotic to take advantage of this natural pairing, combining clinically studied probiotic strains with a blend of four key HMOs to specifically feed our probiotics. These HMOs mirror those found in breast milk and help the probiotics grow and do their job effectively. 

The four HMOs in our blend represent three different classes of HMOs:

1. Fucosylated HMOs (2’-Fucosyllactose)

• Most abundant class in breast milk and our blend

• Not produced by ~20% of mothers due to normal genetic variation

2. Sialylated HMOs (6’-Sialyllactose and 3’-Sialyllactose)

• Associated with brain development

3. Undecorated HMOs (Lacto-N-tetraose)

• Simpler structure accessible by a greater number of microbes 

The Bottom Line

Persephone’s synbiotic is not just a probiotic, it’s a system designed to reflect how nature supports early life microbiome development. The inclusion of HMOs means the beneficial strains have the specialized support they need to establish themselves in the gut.

In other words: it’s not just about adding bacteria—it’s about setting up the right environment for those bacteria to do their job.

*Medical Disclaimer

The information provided on this blog is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Every baby is unique, and health decisions should always be made in partnership with a qualified healthcare professional. If you have questions or concerns about your child’s health, diet, or development, please consult your pediatrician or another trusted healthcare provider before making changes.

References:

1. Soyyılmaz B, Mikš MH, Röhrig CH, Matwiejuk M, Meszaros-Matwiejuk A, Vigsnæs LK. The Mean of Milk: A Review of Human Milk Oligosaccharide Concentrations throughout Lactation. Nutrients. 2021 Aug 9;13(8):2737. https://pmc.ncbi.nlm.nih.gov/articles/PMC8398195/. 

2. Rousseaux, A., Brosseau, C., Le Gall, S., Piloquet, H., Barbarot, S., & Bodinier, M. (2021). Human milk oligosaccharides: Their effects on the host and their potential as therapeutic agents. Frontiers in Immunology, 12, 680911. https://doi.org/10.3389/fimmu.2021.680911.