Could Your Gut Be the Key to a Stronger Immune System?

By Dr Pascale Ricci

The gastrointestinal (GI) tract is key to a healthy immune system.
The GI tract contains the largest population of immune cells in the body and plays a central role in regulating immune function. The gut’s immune system, known as gut-associated lymphoid tissue (GALT), works to maintain equilibrium — balancing tolerance to harmless substances like food and friendly bacteria, while defending against harmful pathogens.

The intestinal microbiota (trillions of microbes) plays a central role in shaping immunity by producing key compounds, like short-chain fatty acids (SCFAs) that modulate immune cell development and function, influence the integrity of the intestinal barrier and help control inflammation. 

When the microbial balance of the gut microbiota is disturbed, a state known as dysbiosis, it can increase susceptibility to autoimmune, allergic, and inflammatory diseases. The intestinal lining acts as both a physical and immunological barrier, coordinating crosstalk between microbes and immune cells to preserve equilibrium and prevent abnormal immune activation.
The dynamic interplay between the gut microbiota, epithelial cell structure of the GI tract, and immune cells is essential for maintaining overall immune health.

The biodiversity of your gut microbiome can directly affect inflammation in your body. When your gut microbiome is rich and diverse, meaning it contains a wide variety of beneficial bacteria, it helps regulate your immune system and reduces inflammation. 
Biodiversity in the gut microbiome has a significant impact on energy metabolism as well, where higher microbial diversity is associated with improved metabolic health, including more efficient energy use from the food we eat, better glucose control and reduced risk of obesity and metabolic disorders. Again, the more diverse the microbial communities, the broader the array of compounds they produce, which regulate energy balance by influencing gut hormone secretion involved in appetite and digestion, lipid metabolism and improves how fat tissue stores and uses energy.
Examples of beneficial bacterial associated with enhanced gut barrier integrity and favourable energy metabolism are Akkermansia muciniphila and Bifidobacterium spp..

Greater biodiversity in the gut microbiome enhances immune resilience, ensuring that the immune system is better equipped to stay balanced, allowing the microbiome to maintain or restore its composition after insults like antibiotics or infections and keep inflammation in check. High microbial diversity allows the microbiome to stay functional, even when some microbes are lost, supporting metabolic flexibility, thereby maintaining a healthy immune response, reducing whole-body inflammation, and improved epithelial barrier integrity.

Conversely, reduced microbial diversity (dysbiosis) is consistently, in both human and animal studies, linked to increased inflammation, not only within the gut, but throughout the entire body. It has been associated with inflammatory bowel disease (Crohn’s Disease and Ulcerative Colitis) obesity and metabolic syndrome. In dysbiosis, harmful bacteria, such as Escherichia coli can thrive, whilst protective species such as Faecalibacterium prausnitzii decline. This imbalance disrupts immune regulation, impairs barrier function, and promotes chronic inflammatory signalling. Obese individuals tend to have less diverse gut bacteria and different levels of key bacterial groups. This imbalance can lead to the gut extracting more energy from food than usual, which may contribute to weight gain. It also promotes low-grade inflammation in the body via certain microbial byproducts like lipopolysaccharides.

The latest clinical interventions that have shown to beneficially modulate the gut microbiota and improve immune outcomes include prebiotics, probiotics and targeted dietary modifications.

Prebiotics — such as inulin, galactooligosaccharides (GOS), and fructooligosaccharides (FOS) — help nourish beneficial gut bacteria such as Bifidobacteria. By supporting these microbes, prebiotics boost the production of SCFAs which are key to gut and immune health. Prebiotics have also demonstrated a reduction in infection rates and improvements in mucosal immunity (by increasing protective antibodies like IgA) in healthy populations. These effects are mediated both by microbiota-dependent and direct immunomodulatory mechanisms.

Probiotics, especially strains of Lactobacillus and Bifidobacterium, have been shown to improve gut barrier function, modulate inflammatory responses, and enhance immune cell activity. 

Dietary modifications — Typical Western diets reduce diversity and favour pro-inflammatory microbial profiles. From a dietary perspective, an increased intake of plant-based fibres and fermented foods, have been shown to reduce inflammatory markers and increase microbial diversity. Diets rich in fibre, polyphenols, and unsaturated fats, like the Mediterranean diet, fosters beneficial bacteria and is associated with improved gut barrier integrity and reduced systemic inflammation.

Bonus read: Eat for Your Genes: How Precision Testing Is Redefining Nutrition

By recognising that your gut is playing a central role in immune regulation, you can adopt strategies to support gut health — enhancing microbial diversity, reinforcing gut barrier integrity and modulating immune responses. 

Our team specialises in cutting-edge therapies to help restore gut balance, strengthen barrier function and promote immune resilience. Contact your nearest clinic today to explore how REVIV treatments can help with your gut and immune health.