Ⅰ. Core Digestive & Absorptive Functions

• Nutrient Processing Hub:
  Responsible for 99% of nutrient absorption, including carbohydrates, fats, proteins, and vitamins—providing energy and materials for tissue repair.
  Utilizes specialized structures (e.g., duodenum, jejunum) and enzymatic processes to break down complex nutrients.

• Microbial Collaboration:
  Gut microbiota ferment indigestible fibers to produce short-chain fatty acids (SCFAs), which nourish intestinal cells and regulate metabolism.

Ⅱ. Immune Defense Centrality

• Largest Immune Organ:
  Houses 70–80% of the body’s immune cells (e.g., T cells, NK cells), forming the frontline defense against pathogens.

• Microbial Barrier Function:
  Beneficial bacteria block pathogenic colonization and maintain mucosal integrity, preventing toxin leakage into the bloodstream.

Ⅲ. Metabolic Regulation

• Detoxification Pathway:
  Eliminates 80% of metabolic waste and toxins, preventing systemic toxicity.

• Microbial Metabolic Control:
  Gut microbes regulate fat storage, blood sugar balance, and cholesterol metabolism; dysbiosis may drive obesity and diabetes.

Ⅳ. Neuroendocrine Interactions

• Gut-Brain Axis Communication:
  Bidirectional signaling via the vagus nerve and neurotransmitters (e.g., serotonin) links gut health to mood, cognition, and mental disorders.

Ⅴ. Chronic Disease Prevention

• Anti-Inflammatory Effects:
  A balanced gut microbiome suppresses chronic inflammation, lowering risks of cardiovascular diseases and cancers.

• Aging Delay:
  Healthy microbiota reduce oxidative stress, slowing skin aging and organ decline.

Maintenance Strategies (Evidence-Based)

• Diet: High-fiber foods (vegetables, whole grains) and probiotics (yogurt, fermented foods).

• Lifestyle: Regular exercise, stress management, and avoiding antibiotic overuse.