The potential role of synbiotics in the management of CMA is becoming increasingly clear. In this article, we discuss what synbiotics are, the connection between the gut microbiota and the immune system, and how this science may shape the future of cow’s milk allergy management.

Synbiotics combine prebiotics and probiotics¹⁻². Although the two are sometimes confused, they have distinct functions:

• Prebiotics are non‑digestible food ingredients that stimulate the growth or activity of beneficial gut bacteria³.
• Probiotics are beneficial bacteria that can help rebalance gut microbiota when consumed in adequate amounts⁴⁻⁵.

The goal of combining prebiotics and probiotics is to produce a synergistic effect, offering greater benefits together than either component alone⁶.

With 70–80% of immune cells located in the gut⁷, the gut microbiota and immune system are closely interconnected.

From the moment we’re born, gut microbiota play a very important role when it comes to immune system development and its responses^8-9. At birth, the gut is essentially sterile and not yet populated with the diverse microbiota required for a healthy microbiome⁶. Colonisation begins immediately after birth, diversifies with the introduction of solid foods, and typically matures by around age three⁸⁻⁹.

The immune system is also immature at birth and continues to develop as it learns to distinguish harmful threats from beneficial exposures. Working together, the gut microbiota and immune system help:

• Defend against harmful pathogens
• Maintain immune tolerance to antigens¹⁰
• Strengthen overall immune defences¹¹

In infants and young children, maintaining a healthy balance between gut microbiota and immune function is particularly important, as it influences lifelong health trajectories¹².

Gut dysbiosis refers to an imbalance in the gut microbiota¹³ and is associated with a range of conditions, including inflammatory bowel disease, obesity, type 1 diabetes, and allergic disorders¹⁴⁻¹⁵.

Many factors can contribute to dysbiosis, such as diet, antibiotic use, complementary feeding, and physical or psychological stress¹⁶. Early life is a particularly vulnerable period, with key risk factors including¹⁷⁻¹⁸:

• Premature birth
• Caesarean delivery
• Antibiotic exposure

Healthy breastfed infants typically have higher levels of Bifidobacteria, a beneficial probiotic passed on during birth and through breast milk¹⁹⁻²⁰. Breast milk also contains non‑digestible oligosaccharides—complex carbohydrates readily consumed by Bifidobacteria²¹.

Infants with cow’s milk allergy often show gut dysbiosis, characterised by significantly reduced Bifidobacteria and increased levels of more adult‑like bacteria²²⁻²³.

This imbalance can trigger abnormal immune responses, which in turn can potentially contribute to the development of food allergies, including Cow’s Milk Allergy¹⁵,²².

Cow’s Milk Allergy occurs when the immune system reacts abnormally to cow’s milk protein²⁶. It typically develops within the first few months of life and affects 2–3% of infants under one year²⁷.

Some studies suggest synbiotics may help regulate the gut microbiota and immune responses—both directly and indirectly²⁴. They may also help manage and reduce the severity of CMA symptoms^25,29.

Current management primarily involves removing cow’s milk protein from the infant’s diet. For symptomatic breastfed infants, mothers are usually advised to follow a dairy‑free diet to avoid transferring cow’s milk protein through breast milk^27-28. For formula fed or mixed fed infants, hypoallergenic formula are recommended. ^1,26,27

While this approach is effective at reducing symptoms, synbiotics may play a valuable role in future management strategies. By helping to rebalance the gut microbiota, synbiotics may address the underlying dysbiosis that contributes to abnormal immune responses and allergy development¹.