This study highlights that the type of β-casein in milk, particularly the presence or absence of A1 β-casein and its byproduct BCM-7, significantly influences brain, gut, and immune function via the gut-brain axis, with potential implications for cognitive health, inflammation, and personalized nutrition.
Gastrointestinal Function
One of the biggest differences between A1 and A2 milk lies in how they affect the gut.
A1 β-casein: When digested, A1 releases a peptide called beta-casomorphin-7 (BCM-7). This compound can slow down gut transit and trigger inflammation, often resulting in discomfort like bloating or irregular bowel movements.
A2 β-casein: In contrast, milk with only A2 β-casein doesn’t produce BCM-7 and is associated with smoother digestion, reduced inflammation, and improved bowel habits.
Immune System Modulation
Milk proteins also affect immune signaling in different ways.
A1 β-casein: Has been linked to higher levels of immune markers suggesting a heightened, and possibly inflammatory, immune response.
A2 β-casein: Appears to modulate the immune system more gently, possibly enhancing immune function without driving inflammation.
Gut Microbiota Composition
The type of milk protein consumed may shape the gut’s microbial landscape.
A1 β-casein: May alter the microbiota in ways that favor bacteria associated with inflammation.
A2 β-casein: Is linked to healthier microbiota profiles, including higher levels of Lactobacillus and Bifidobacteria, which are known for their gut-supporting and anti-inflammatory roles.
Cognitive Function
Emerging evidence shows that milk proteins may even influence how we think and process information.
A1 β-casein: Some studies report slower response times and reduced accuracy in cognitive tasks, possibly due to the systemic effects of BCM-7.
A2 β-casein: Has not been shown to impair cognitive function, and in some cases may even support better performance on memory and processing tasks.
