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The Gut-Immune Connection: How Our Gut Health Influences Our Immune System

Written by Portland Clinic of Natural Health on April 11, 2023

The human gut, also known as the gastrointestinal tract, is a complex and fascinating system that plays a critical role in our overall health. It is responsible for digesting food, absorbing nutrients, and eliminating waste. However, the gut also houses a significant portion of our immune system – almost two-thirds of it, to be precise. This intricate connection between our gut and immune system is crucial for maintaining our health and well-being. In this blog post, we will explore the evidence behind this gut-immune connection and discuss how nurturing our gut health can positively impact our immune system. (1)

The Gut and the Immune System: A Symbiotic Relationship

Our gut is lined with a single layer of cells known as the intestinal epithelium, which acts as a barrier between the outside world and our internal environment. Underneath this layer lies the gut-associated lymphoid tissue (GALT), which is a crucial component of our immune system. The GALT contains various immune cells, including T and B cells, macrophages, and dendritic cells, that actively protect our body from harmful pathogens and maintain immune homeostasis. (2)

The gut is also home to trillions of microorganisms collectively referred to as the gut microbiota. These microorganisms play a vital role in maintaining the balance of our immune system. A healthy and diverse gut microbiota contributes to the proper functioning of the immune system by:

  1. Enhancing the Gut Barrier Function

The gut microbiota helps reinforce the intestinal barrier by producing substances like short-chain fatty acids (SCFAs) that promote the integrity of the gut lining. SCFAs, such as butyrate, propionate, and acetate, strengthen the tight junctions between gut epithelial cells, preventing harmful substances and pathogens from entering the bloodstream. (3)

  1. Regulating the Immune Response

The gut microbiota communicates with immune cells, modulating their activity and ensuring a balanced immune response. For instance, certain gut bacteria can stimulate the production of anti-inflammatory cytokines, like interleukin-10 (IL-10), and suppress the production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α).

  1. Competing with Pathogens

Beneficial gut bacteria compete with pathogens for nutrients and space, preventing harmful microorganisms from colonizing the gut and causing infections.

Promoting Gut Health for a Stronger Immune System

Given the crucial role our gut plays in supporting our immune system, it is essential to maintain a healthy gut to ensure optimal immune function. Here are some evidence-based strategies to promote gut health:

  1. Consume a Diverse and Nutrient-Rich Diet

A diet rich in fruits, vegetables, whole grains, legumes, and fermented foods provides essential nutrients and prebiotics that support a diverse and balanced gut microbiota.

  1. Include Probiotic-Rich Foods or Supplements

Probiotics are beneficial live bacteria and yeasts that can help maintain and restore a healthy gut microbiota. Foods rich in probiotics include yogurt, kefir, sauerkraut, kimchi, and kombucha. Probiotic supplements can also be considered after consulting with a healthcare professional.

  1. Manage Stress

Chronic stress can negatively impact gut health by disrupting the balance of the gut microbiota and weakening the gut barrier. Incorporate stress management techniques, such as meditation, yoga, or deep breathing exercises, into your daily routine.

  1. Prioritize Sleep

Adequate and restorative sleep is essential for maintaining gut health and a balanced immune system. Aim for 7-9 hours of quality sleep per night.


The gut-immune connection is a fascinating and complex relationship that plays a significant role in our overall health. By understanding the importance of this connection and taking steps to promote gut health, we can support a strong and resilient immune system. Embracing a nutrient-rich and diverse diet, including probiotic-rich foods, managing stress, and prioritizing sleep are all evidence-based strategies that can contribute to a healthier gut and, consequently, a stronger immune system. By nurturing our gut health, we can build a solid foundation for lifelong well-being and disease prevention.


  1. Wiertsema SP, van Bergenhenegouwen J, Garssen J, Knippels LMJ. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients. 2021 Mar 9;13(3):886. doi: 10.3390/nu13030886. PMID: 33803407; PMCID: PMC8001875.
  2. Mörbe UM, Jørgensen PB, Fenton TM, von Burg N, Riis LB, Spencer J, Agace WW. Human gut-associated lymphoid tissues (GALT); diversity, structure, and function. Mucosal Immunol. 2021 Jul;14(4):793-802. doi: 10.1038/s41385-021-00389-4. Epub 2021 Mar 22. PMID: 33753873.
  3. Vancamelbeke M, Vermeire S. The intestinal barrier: a fundamental role in health and disease. Expert Rev Gastroenterol Hepatol. 2017 Sep;11(9):821-834. doi: 10.1080/17474124.2017.1343143. Epub 2017 Jun 26. PMID: 28650209; PMCID: PMC6104804.

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