“Agnibala as the determinant of koṣṭha: a conceptual review in ayurvedic physiology”

Abstract

Introduction: In classical Ayurvedic physiology, the concept of Koṣṭha (the functional nature of the gastrointestinal tract) is intimately linked with Agnibala (digestive/metabolic strength). While Koṣṭha classification has long guided treatment regimens, the determinant role of Agnibala in defining Koṣṭha remains under-explored in integrative context. Methods: We conducted a narrative review by searching classical Ayurvedic texts (e.g., the Charaka Saṃhitā, Suśruta Saṃhitā, Aṣṭāṅga Hṛdaya) and modern biomedical databases (PubMed, Scopus, Web of Science, AYUSH Research Portal) up to 2025. Inclusion criteria comprised publications addressing Agni, Agnibala, Koṣṭha, and digestive physiology in Ayurveda and allied integrative research; exclusion criteria omitted non-English articles without abstracts, purely phytochemical studies without digestive physiology context, and animal-only studies lacking translational relevance. Results: Thematic synthesis revealed: (i) classical textual descriptions of Koṣṭha types (Sama, Pramādita, Mridu, Kashṭa) and their functional implications; (ii) Agnibala as the underlying quantitative capability of digestive fire, influencing tissue assimilation, excretion, and metabolic homeostasis; (iii) the functional interplay between Agni, Koṣṭha and Bala (strength/vitality) in Ayurvedic pathophysiology; (iv) modern correlates such as gut-motility, microbiome-metabolism axis, digestive enzyme activity and metabolic health markers; and (v) research gaps, notably the lack of standardized Agnibala assessment tools and human interventional studies linking Koṣṭha classification to measurable metabolic or gastrointestinal outcomes. Discussion: The Ayurvedic framework positions Agnibala as the foundational determinant that modulates Koṣṭha, thus influencing digestive, absorptive and excretory capacities and overall health resilience. Modern evidence supports many mechanistic inferences yet lacks direct Ayurveda-based protocols applying Agnibala-Koṣṭha paradigms. Future research should adopt constitution-based dietary and lifestyle interventions derived from Koṣṭha-Agnibala typology, incorporate objective biomarkers of digestive/metabolic function, and validate Agnibala classification tools in clinical populations. Conclusion: Recognising Agnibala as a key determinant of Koṣṭha offers a refined physiological model bridging Ayurvedic and modern perspectives on gastrointestinal and metabolic health. Operationalizing this model may enhance personalised digestive-metabolic care grounded in Ayurvedic wisdom.