Neuropsychic development and autism: Potential effect of casomorphins derived from goat milk

The concept of autism has evolved from being viewed as psychopathological symptom to being recognized as a separate spectrum of neurodevelopmental disorders. One of the potential mechanisms discussed is blood–brain barrier (BBB) dysfunction: an increase in its permeability can promote peripheral cytokine and immune cell trafficking into the central nervous system (CNS), amplifying neuroinflammation and vulnerability of neural networks. In cascade models of autism spectrum disorders (ASD), these changes are attributed to intestinal dysbiosis, increased permeability of epithelial barriers and systemic effects of dietary opioid-like peptides, including β-casomorphin-7. The aim of this review is to summarize 2020–2025 data on the possible impact of casomorphins formed from proteolytic digestion of β-casein in goat milk (including β-casomorphin-7) on neuropsychic development and ASD manifestations. The search was performed in PubMed databases using key terms related to ASD, the gut – brain axis, β-casein A1, β-casomorphin-7, goat milk, microbiome and barrier function; experimental, clinical and survey studies were included. The literature data suggest the biologically plausible mechanisms underlying the associations between dietary opioid peptides and CNS functions via the gut – brain axis, including modulation of the microbiome, inflammatory responses and the gut barrier function. However, clinical evidence for the specific effects of goat milk-associated casomorphins on ASD remains limited and inconsistent.