91吃瓜

Human microbiome; Gut health; Probiotics; Dysbiosis; Fecal microbiota transplantation; Microbial diversity; Host-microbe interaction; Inflammatory disease; Metabolic syndrome; Personalized medicine

Introduction

The concept of the human body as a superorganism composed of both human and microbial cells has redefined modern medicine and biology. The human microbiome encompasses bacteria, viruses, fungi, and archaea residing in various body sites, with the gut harboring the largest and most diverse population. These microbial communities are intricately involved in nutrient metabolism, immune system development, pathogen defense, and maintenance of epithelial integrity [1]. Advances in next-generation sequencing and bioinformatics have propelled microbiome research into mainstream science, linking microbial imbalances—dysbiosis—with a wide array of chronic diseases [2].

Description

The gut microbiome has received the most attention due to its vast population and central role in host physiology. Dominated by bacterial phyla such as Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria, the gut microbiota contribute to digestion by fermenting indigestible carbohydrates into short-chain fatty acids (SCFAs) such as butyrate, acetate, and propionate [3]. These SCFAs not only serve as energy sources but also regulate immune responses and maintain gut barrier integrity.

Microbial diversity and composition are shaped by multiple factors including mode of birth (vaginal vs. cesarean), diet, antibiotic use, geography, and age. A diverse microbiome is generally associated with health, while reduced diversity or dominance of pathogenic species is linked to diseases like Clostridioides difficile infection, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), obesity, and type 2 diabetes [4].

Microbiota also influence the brain via the gut-brain axis, a bidirectional communication network involving neural, hormonal, and immunological signaling pathways. Studies have shown that changes in gut microbiota can affect mood, cognition, and behavior, and may play a role in conditions such as autism spectrum disorder, depression, and Parkinson’s disease [5].

Results

Recent clinical and preclinical studies have confirmed the microbiome’s impact on host health and disease. For example, germ-free mice—raised without exposure to microbes—exhibit underdeveloped immune systems and increased susceptibility to infections and inflammation, demonstrating the critical role of microbiota in immune maturation [6]. Human studies have found significant alterations in gut microbiota composition in individuals with metabolic syndrome, characterized by increased Firmicutes/Bacteroidetes ratio and reduced levels of beneficial genera like Bifidobacterium [7].

Fecal microbiota transplantation (FMT) has emerged as a highly effective therapy for recurrent C. difficile infection, with cure rates exceeding 90%. Research is ongoing to evaluate its efficacy in ulcerative colitis, Crohn’s disease, and even neurological conditions [8]. Meanwhile, probiotic and prebiotic interventions are gaining traction as non-invasive approaches to restore microbial balance. While their efficacy varies by strain, dose, and host factors, targeted formulations show promise in improving gastrointestinal and metabolic outcomes [9].

Microbiome-based diagnostics are another burgeoning field. Biomarker signatures derived from fecal or oral samples are being developed to detect diseases such as colorectal cancer, IBD, and even Alzheimer’s disease with high sensitivity and specificity [10]. Personalized microbiome analysis is enabling precision nutrition plans aimed at optimizing metabolic health and weight loss based on an individual’s microbial profile.

Conclusion

The human microbiome represents a vast and largely untapped resource for understanding human physiology and treating disease. As research deepens, the microbiome is increasingly recognized as both a contributor to disease pathogenesis and a potential therapeutic target. Technologies such as metagenomics, metabolomics, and machine learning are accelerating discovery and application. However, challenges remain, including inter-individual variability, causality versus correlation in microbiome-disease links, and the standardization of microbial therapies. With continued interdisciplinary collaboration and ethical oversight, the microbiome is poised to become a cornerstone of next-generation medicine, offering novel pathways to health, prevention, and personalized treatment.