Interaction between Traditional Chinese Medicine constitution and gut microbiota: theoretical framework and future prospects

Abstract

Traditional Chinese medicine (TCM) constitution theory, a foundational framework in TCM, categorizes human constitutions into nine distinct types according to the interplay of congenital endowment and acquired environmental factors: balanced constitution (BC), Yang deficiency constitution (YADC), Yin deficiency constitution (YIDC), Qi deficiency constitution (QDC), Qi stagnation constitution (QSC), phlegm–dampness constitution (PDC), dampness–heat constitution (DHC), blood stasis constitution (BSC), and inherited special constitution (ISC). Rooted in four principles (innate inheritance, life course development, psychosomatic integration, and environmental regulation), the theory addresses three core scientific questions: constitutional typeability, constitution–disease correlation, and constitutional adjustability. This paradigm emphasizes individual variability in physiological and psychological traits, aligning TCM with modern precision medicine by linking constitutional profiles to disease susceptibility, progression, and therapeutic responses. The human gut microbiota, a dynamic ecosystem of trillions of microorganisms, has emerged as a critical mediator of host health that influences nutrient metabolism, immune modulation, and neuroendocrine signaling. Emerging evidence reveals intricate associations between microbiota composition and TCM constitutions, primarily through a “strain–metabolite–signaling pathway” regulatory network. For example, the overproliferation of Clostridium scindens in DHC individuals elevates secondary bile acid (lithocholic acid) levels, which then activate the TGR5 receptor to induce intestinal hypersecretion and inflammatory responses. In PDC individuals, the butyrate produced by Faecalibacterium prausnitzii enhances insulin sensitivity via GPR41/43-mediated GLP-1 secretion, thus mitigating metabolic dysregulation. Geographical and dietary factors further modulate these relationships. High-fat diets increase the Firmicutes/Bacteroidetes ratio, correlated with DHC prevalence through LPS/TLR4 pathway activation. Meanwhile, Prevotella-enriched microbiomes in subtropical regions (e.g., Lingnan) reduce DHC-associated BMI via branched-chain amino acid catabolism. Constitutional imbalances are often mirrored in microbiota dysbiosis. PDC individuals exhibit increased Firmicutes abundance and reduced Bacteroidetes count, both linked to enhanced energy extraction and adipose accumulation. YIDC is characterized by depleted Bifidobacterium and Lactobacillus populations and elevated pathobionts, compromising gut barrier function and immune homeostasis. The “gut–brain axis” adds another dimension: microbiota-derived neurotransmitters (e.g., GABA and 5-HT) influence emotional regulation, which is consistent with TCM’s “body–mind unity” concept. For instance, the reduced Flavonifractor plautii and phytosphingosine levels in PDC correlate with metabolic syndrome and psychological symptoms, highlighting the microbiota’s role in constitutional psychology. TCM interventions offer multifaceted strategies to modulate constitutions and microbiota. Herbal formulas such as Gegen Qinlian Tang promote beneficial bacteria (e.g., Bifidobacterium) while inhibiting pathogens, thereby improving gut microecology and metabolic parameters in DHC. Dietary therapies (e.g., high-fiber diets for QSC) and acupuncture indirectly regulate microbiota via neuroendocrine pathways. Modern microbiome therapies, including fecal microbiota transplantation (FMT) and probiotics, align with TCM’s historical use of microbial interventions (e.g., ancient FMT records) to restore constitutional balance. This bidirectional interaction forms a “genetic-stable/microbial-dynamic” system: core microbiota taxa (e.g., Bacteroides and Firmicutes) maintained across generations support constitutional stability, whereas environmental factors (such as diet, stress, and antibiotics) induce rapid microbiota shifts via short-chain fatty acid and bile acid signaling. Constitutions differ from TCM syndromes in stability: the former reflect long-term physiological patterns, whereas the latter represent dynamic pathological states with immediate microbiota associations. Challenges for future research include clarifying causal mechanisms, standardizing constitutional assessment with microbiota-derived biomarkers, and addressing ethnic/geographical microbiota variations. By leveraging AI and big data analytics, researchers may develop microbiota-based predictive models for constitutional typing to expand or revise the traditional nine-type taxonomy. Integrating TCM’s holistic philosophy with microbiome science could unlock personalized interventions—such as tailored herbal–microbiome cocktails—to optimize constitutional balance, enhance disease prevention, and bridge traditional and modern medicine.