3-Sialyllactose Sodium Salt – HMO in Infant Formula

What is 3-Sialyllactose Sodium Salt?

3-Sialyllactose sodium salt (abbreviated 3SL-Na) is a biotechnologically produced human milk oligosaccharide (HMO). It is the sodium salt form of 3-sialyllactose, a carbohydrate that occurs naturally in human breast milk. HMOs are among the most abundant components of human milk and play a vital role in early infant development. The sodium salt form is used as a stabilized version to improve solubility and shelf life in food and dietary supplement applications.

Chemical Structure and Properties

3-Sialyllactose consists of a lactose backbone (galactose + glucose) to which a sialic acid residue (N-acetylneuraminic acid, Neu5Ac) is attached via an alpha-2,3-glycosidic bond at the galactose moiety. In the sodium salt form, the free carboxyl group of the sialic acid is stabilized as a sodium carboxylate. This structure confers characteristic biological properties, particularly the ability to bind to specific lectins and pathogen receptors.

Biological Functions

Prebiotic Effect

3-Sialyllactose sodium salt acts as a prebiotic in the infant gut. It selectively promotes the growth of beneficial gut bacteria, especially Bifidobacterium species, thereby contributing to the establishment of a healthy gut microbiome.

Protection Against Infections

Sialylated HMOs like 3SL function as so-called decoy receptors: they mimic the binding sites on the intestinal mucosa, thereby preventing pathogens such as Helicobacter pylori, rotaviruses, and certain Enterobacteriaceae from attaching to the gut wall and causing infection.

Immune Modulation

Studies indicate that 3-sialyllactose supports the maturation of the immune system in infants. It influences the differentiation of immune cells and can promote anti-inflammatory processes, which may contribute to a reduced risk of allergies.

Brain and Nervous System Development

Sialic acid is an essential building block of gangliosides and other glycoconjugates in the brain. Adequate intake of sialylated HMOs may support cognitive development and nerve growth in infants.

Application and Use

3-Sialyllactose sodium salt is primarily used in the following areas:

• Infant formula and follow-on formula: To bring the composition closer to that of breast milk.
• Specialty nutrition for preterm infants: Preterm infants often lack access to breast milk and benefit particularly from HMO supplementation.
• Dietary supplements: For adults in the context of gut health and immune support.

Safety and Tolerability

3-Sialyllactose sodium salt is considered safe and well tolerated. The European Food Safety Authority (EFSA) has authorized biotechnologically produced HMOs, including 3SL, as novel food ingredients and has assessed their safety for use in infant formula. Adverse effects are very rare at recommended doses; mild gastrointestinal discomfort may occasionally occur.

Recommended Intake and Dosage

No uniform official daily dose has been established. In breast milk, the concentration of 3-sialyllactose typically ranges from approximately 10 to 50 mg per liter. Manufacturers of infant formula orient themselves to these natural concentrations when fortifying products. Clinical studies have investigated dosages of 0.1 to 1 g per day without observing adverse effects.

Interactions

No clinically relevant interactions with medications or other nutrients have been described to date. Since HMOs act prebiotically, they may influence the composition of the gut microbiome, which could theoretically lead to modest changes in the absorption of certain nutrients or orally administered medications.

References

1. European Food Safety Authority (EFSA): Scientific Opinion on the safety of 3'-sialyllactose sodium salt as a novel food ingredient. EFSA Journal, 2022.
2. Bode L. - Human milk oligosaccharides: Every baby needs a sugar mama. Glycobiology, 2012; 22(9): 1147-1162.
3. Kunz C. et al. - Oligosaccharides in Human Milk: Structural, Functional, and Metabolic Aspects. Annual Review of Nutrition, 2000; 20: 699-722.