By Inbound Pursuit

70% of Your Immune System Lives in Your Gut

Did you know that roughly 70% of your immune system lives in your gut? More specifically, gut-associated lymphoid tissue (GALT) represents almost 70% of the entire immune system, and 80% of plasma cells [mainly immunoglobulin A (IgA)-bearing cells] reside in GALT. This substantial population is a testament to the critical role of your gastrointestinal system in immune system homeostasis ( Vighi, G, et al., 2008 ).

Translation: Your digestive system, along with everything that passes through it, plays a key role in your immune function and overall health.

Gut Immune Function: What You Need to Know

We've talked before (and frequently!) about the GI tract and the microbiome. Consisting of the stomach and small and large intestines, the gut is home to a vast array of bacteria, often termed the gut microbiome (your body has other microbiomes, too!). The gut microbiome plays a big role in physiological processes of the body, including digestion, nutrient absorption, immune regulation, and metabolism. 

When it comes to the way that the gut microbiome influences the immune system, it's a journey that begins at birth. Newborn's start with a sterile gut that is colonized by bacteria that baby acquires from mom and the surrounding environment. This early exposure to microbes (bacteria!) influences the development of the immune system and its ability to differentiate between harmful and harmless substances. 

The microbiome also helps immune cells mature and helps form the GALT we  talked about earlier. Think of the GALT immune cells as patrolmen, monitoring the gut and initiating responses against potential threats. 

The gut-immune connection is a dynamic one where both your diet and your microbiome can play a role. Studies have determined the gut microbiota metabolizes proteins and complex carbohydrates, synthesizes vitamins, and produces metabolic products, like short-chain fatty acids, that can mediate cross-talk between the two ( Yoo, Ji Youn, et al., 2020 ).

We could dig into the nerdy details about innate and adaptive immunity, but at a high level, it's as simple as gut bacteria communicating with immune cells to control how your body responds to infection. Commensal microorganisms are needed to teach the immune system to differentiate between commensal and pathogenic bacteria ( Lazar, Veronica, et al., 2018 ). Over time, the symbiotic relationship evolves to promote overall health and immune function.

Practical Tips: Harnessing the power of your gut microbiome to support a healthy immune response

Think of your gut microbiome as a gatekeeper to your immune system. If you want to boost your immunity, start with the condition of your gut health. Many factors affect your gut microbes, like the environment, medications, lifestyle choices, and eating habits. While there are many factors we cannot control, the latter of the two can be the easiest to manipulate. And according to experts at UCLA Health, the immune cells housed in the gut are directly influenced by diet and lifestyle. Here are 3 dietary changes you can make now to take control of the power your gut microbiome has:

1. Eat Foods High in Dietary Fiber

The bacteria in your gut is healthiest when you eat foods packed with dietary fiber like fruits, vegetables, nuts, whole grains, and legumes. The bacteria digest the fiber and produce short-chain fatty acids (SCFAs) that, in return, nourish the gut barrier and improve immune function ( Morrison, Douglas J, et al., 2016 ). An added bonus is that fiber helps slow gastric emptying, meaning it will also help keep you feeling full and balance your blood sugar in the process. 

2. Eat Fermented Foods

Eating fermented foods such as yogurt, sauerkraut, kefir, kombucha, and kimchi can help boost the number of beneficial bacteria in your gut. These bacteria, also known as probiotics, are associated with various health benefits like improved immunity and digestion ( King, Sarah, et al., 2014 ).

You can also pickle your own vegetables, like cucumbers, onions, and carrots. This is another great way to get in beneficial probiotics! 

3. Eat Prebiotic-Rich Foods

Prebiotic foods including chicory root, Jerusalem artichoke, garlic, onions, and asparagus promote the growth of beneficial bacteria in your gut. These foods are primarily forms of fiber that human cells cannot digest, so the bacteria ferment them to use for fuel and, in turn, provide several systemic health benefits ( Slavin, Joanne 2013 ). Most people do not eat enough prebiotic-rich foods in their diets. Incorporating more prebiotic-rich foods and supplements is a great way to support the beneficial bacteria in your gut and keep your gut microbiome happy and healthy. 

While every person is different, your body and gut health will likely need more support than diet changes alone, but it is a great start. As always, make sure to discuss any significant changes with your doctor or a qualified medical professional.

Want to support your gut health in other ways?

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resB® is the product of over a decade of research at the intersection of lung health and microbiome science. Our interdisciplinary team is pioneering products that target the gut-lung axis to transform the conversation around lung health.

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*These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.

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