Postbiotic Interventions via Hydrocolloid-Enhanced Delivery for Modulating the Gut-Brain Axis in Psychiatric Disorders: A Dietary Strategy Review

There is increasing evidence that the gut-brain axis (GBAx)—the bidirectional communication network connecting the gastrointestinal tract and the central nervous system—is a vital component of mental health. Historically, probiotics and prebiotics have been recognized for their ability to restore microbial balance, but postbiotics (POS)—comprising non-viable microbial cells or their metabolic by-products are now being more closely examined as a more stable and safer alternative for utilization in research and therapy settings. Hydrocolloid encapsulation emerges as a dietary strategy for stable POS delivery. This review consolidates the current understanding of POS interventions in the regulation of crucial components of GBAx, such as neuroinflammation, neurotransmitter synthesis, immune system, and epigenetic processes; all of which are pertinent to various psychiatric disorders e.g, depression, anxiety, autism spectrum disorder, bipolar disorder, and schizophrenia. Clinical trials have demonstrated that POSs can diminish symptom severity by regulating the immune pathways, balancing cortisol levels, and enhancing neurotransmitter balance and can provide adjunctive effects with conventional treatments. Despite these promising findings, the field faces with significant challenges, most notably the absence of standardized manufacturing protocols and the need for more long-term randomized controlled trials to establish efficacy across populations. In addition, regulatory and quality-control frameworks for POSs are being developed, indicating the need for concerted efforts among researchers, health practitioners, and policymakers. As research on supplement formulations continues, as well as the application of functional foods and personalized approaches to nutrition, POSs will be well placed to support expanded therapeutic offerings for psychiatric illnesses and move toward an integrated strategy for mental health.