The gut microbiome consists of beneficial bacteria that are essential for digestion, immune function, and overall health.

Microbiome

The human gut flora is a complex system of about 1000 known bacterial species, with over 90% belonging to the phyla Firmicutes, Bacteroidetes, and Actinobacteria. The human gut contains a variety of microbes that influence many aspects of human biology.

The gut microbiota is crucial for intestinal health, immune and nervous system regulation, nutrient synthesis, and pathogen defense.

Humans are composed of roughly 10% human cells and 90% microbial cells, primarily located in the gut.

Genetic factors, dietary habits, and environmental conditions contribute to the diversity and specificity of human intestinal flora. In turn, human intestinal flora play important roles in host physiological functions such as metabolism, energy intake, and immune regulation.

Ideally, the intestinal flora is balanced. However, factors such as environment and drugs can disrupt this balance, leading to dysbiosis, which affects health. There is substantial evidence that the gut microbiome is crucial in many chronic diseases.

Understanding and improving your gut health is a complex process that involves a combination of dietary, lifestyle, and behavioral changes. By adopting a balanced diet rich in fiber, prebiotics, and probiotics; staying hydrated; managing stress; exercising regularly; and getting adequate sleep, you can significantly improve the health of your gut microbiome. These changes can lead to better digestion, enhanced immune function, and improved mental health, ultimately contributing to overall well-being.

Studies indicate that a healthy gut microbiome can reduce anxiety and depression by influencing neurotransmitters like serotonin and dopamine.

Obesity affects nearly 12% of the global population. Dietary changes can impact the gut microbiome, leading to weight loss, enhanced intestinal barrier integrity, reduced antigenic load in the bloodstream, and improved inflammatory and metabolic profiles.

Gut health in TCM

In Chinese medicine, the microbiome is often linked to the concept of the gut as the center of health, where the spleen and stomach are crucial for digestion and the production of Qi and blood. When the microbiome is balanced, it supports overall health and immunity.

Several Chinese herbs are known for their beneficial effects on the gut and microbiome. For example, Huang Qi (Astragalus) is often used to boost the immune system and support gut health. Dang Shen (Codonopsis) helps to strengthen the spleen and stomach, enhancing digestion and nutrient absorption. Gan Cao (licorice root) is another popular herb known for its harmonizing properties and its ability to soothe the gut lining. Sheng Jiang (fresh ginger) can help with digestion and reduce inflammation, which positively influences the microbiome.

These herbs, often combined in formulas, aim to restore balance and improve gut health, which in turn nurtures a healthy microbiome.

The regulatory effects of TCM on gut microbial communities are mainly reflected in the treatment of dysbiosis to restore homeostasis of the intestinal flora.

  • Ganoderma lucidum (Chin. Ling Zhi) is used for health and therapy. Its water extract has anti-obesity effects by altering gut microbiome composition, reversing high-fat diet-induced gut issues, maintaining intestinal integrity, reducing endotoxemia, and improving glucose tolerance and insulin sensitivity.

  • Licorice (Chin. Gan Cao) is commonly used for sore throats and gastrointestinal issues. Studies show that licorice aqueous extracts decrease Bacteroides gates and increase Firmicutes, enhancing food calorie absorption. Licorice may aid intestinal absorption, reduce inflammation, and treat abdominal pain. Diammonium glycyrrhizinate (DG), found in licorice root, protects against nonalcoholic fatty liver disease (NAFLD) by reducing the Firmicutes-to-Bacteroidetes ratio, lowering endotoxin-producing bacteria like Desulfovibrio, and increasing probiotics like Proteobacteria and Lactobacillus. Licorice helps maintain gut barrier function, reducing “leaky gut,” a concept similar to Spleen Qi deficiency in TCM.

  • Astragalus (Chin. Huang Qi) is known for boosting immune function and gut integrity; studies show it enhances Akkermansia, a bacterium linked to a healthy gut lining.

  • Berberine (Chin. Huang Lian). Known for its antimicrobial properties, it reduces harmful bacteria (e.g., E. coli, Clostridium) while promoting beneficial species like Bifidobacterium. Modern studies show berberine improves metabolic disorders like diabetes by modifying gut microbiota.

  • Ginseng (Chin. Ren Shen). Enhances the growth of Lactobacillus and Bifidobacterium, key probiotics for gut health. Helps regulate immune responses, aligning with TCM’s concept of strengthening Qi.

  • Rhubarb (Chin. Da Huang). A strong purgative in TCM, it reduces the Firmicutes/Bacteroidetes ratio, a key marker in obesity and metabolic disorders.

  • Vitamin D is an important pro-hormone for optimal intestinal calcium absorption for mineralization of bone, which is common in high-fat foods such as cream and salmon. Vitamin D is essential for the homeostasis of intestinal flora.

  • Acetate is commonly found in nature, including in fruits and vegetable oils. Recent research indicates that acetate produced by protective Bifidobacteria can enhance intestinal defense mechanisms mediated by epithelial cells, thereby offering protection against harmful infections. Furthermore, moderate consumption of wine has demonstrated potential benefits in delaying the onset of neurodegenerative diseases. Post-consumption, microbial metabolites may provide effective protection for neuroblastoma cells from nitrosative stress injury.

With the common use of synthetic and semisynthetic antibiotics, the problem of bacterial resistance has become increasingly serious. The intestinal flora affects anticancer activity, toxicity, and pharmacokinetics of drugs at various levels.

Regulation of microbiome in TCM and modern science

Gut microbiotas regulate digestion, immunity, and metabolism, akin to the spleen's role in TCM. Microbial dysbiosis, or imbalanced gut flora, can cause symptoms like fatigue, loose stools, and bloating similar to Spleen Qi deficiency in TCM.

TCM views emotional health as deeply connected to digestive function. The liver controls the flow of Qi, and its dysfunction leads to “liver attacking the spleen,” causing stress-induced gut issues. While modern science translates this relation as “the gut-brain axis” communication system where gut microbes influence mood, cognition, and stress response. Lactobacillus and Bifidobacterium produce GABA and serotonin, mirroring TCM’s view of Qi harmonization in emotional well-being.

TCM emphasizes balance, similar to microbiome stability. A balanced gut microbiome maintains homeostasis between pro-inflammatory and anti-inflammatory bacteria, akin to Yin-Yang in TCM.

  • Yin deficiency, characterized by heat, dryness, and inflammation, is observed in conditions such as Inflammatory Bowel Disease (IBD), which is associated with excessive inflammation and an imbalance of microbiota.

  • Yang deficiency, which involves cold and sluggish digestion, can be associated with conditions such as small intestinal bacterial overgrowth (SIBO), where motility is reduced and digestion is impaired.

Numerous herbs, foods, and dietary practices have been demonstrated to support a healthy gut microbiome. Specifically, herbs such as peppermint, ginger, and chamomile are known to reduce inflammation and soothe the digestive tract. Foods rich in prebiotics, including garlic, onions, and bananas, serve as nourishment for beneficial gut bacteria. Probiotic foods, like yogurt, kefir, and fermented vegetables such as sauerkraut and kimchi, introduce healthy bacteria into the gut. A diet high in fiber, encompassing whole grains, legumes, and diverse fruits and vegetables, is also essential for maintaining a balanced microbiome. Additionally, polyphenol-rich foods, including green tea, berries, and olive oil, can promote the growth of beneficial microbes.

Ideal timing for eating to restore gut health

  • Consume food within an 8–10-hour window. Time-restricted eating provides your gut with opportunities to rest and repair.

  • Ensure you do not skip breakfast. A balanced morning meal initiates digestion and stabilizes blood sugar levels.

  • Schedule your main meal at midday when digestive enzymes are most active, making this the optimal time for your largest meal.

  • Opt for a light dinner, consumed 3-4 hours before bedtime. This practice prevents overnight fermentation and enhances sleep quality.

  • Avoid constant snacking. Allow intervals of 3-5 hours between meals to enable the "migrating motor complex" to cleanse your gut.