How the Gut Affects Your Immune System

Green Smoothie Napken saying Boost Your Immune SystemHow the Gut Affects Your Immune System, there is a lot of fear right now surrounding the coronavirus. This pandemic has most of us stuck in our homes, snacking and worrying. 

All of these things aren’t good for our guts or our immune health. 

So put down that package of cookies, grab some berries instead, and buckle in. You’re about to learn about how your gut and immune system are connected, and how eating certain foods can help to keep you better equipped to avoid and fight COVID-19.

How the Immune System Works

We’ve all heard about our immune system and we know it’s what keeps us healthy. 

Your immune system has been growing since you were in the womb. Every new thing it gets exposed to helps it to learn to better protect you. It was designed to protect your body from invaders and to attack the ones that slip through the cracks. 

The immune system is built up of different cells that all carry out different important processes to protect you from pathogens (disease-causing organisms). Pathogens have specific signs — called antigens — that allow your immune cells to differentiate them from your body cells.

There are two different responses that your immune system has:

  • Innate Immune Response
  • Adaptive Immune Response

The innate immune response is the initial reaction to pathogens. It happens automatically as it’s triggered. This is a fast-acting response system that allows your body to get a head start on getting back to being healthy.

The adaptive immune response is just as it sounds — it adapts depending on what pathogen is present. The two main superhero cell types in the adaptive immune response are T cells and B cells. T cells help to control the situation while the B cells create specific antibodies (AKA immunoglobulins) to bind to the antigen which alerts the immune cells of more specifically what to kill. 

The adaptive immune response is a bit slower but it is more specific. It also creates a database of sorts so your immune cells easily recognize pathogens it’s already fought. This makes future encounters much easier when you’re exposed to that specific invader because your body already knows how to respond.

Components of the Immune System

We already talked about a few types of important cells in your immune system — B and T cells. But here we will break them down a little bit more so you know exactly what does what. 

B cells

B cells create antibodies, which are otherwise known as an immunoglobulin (Ig). Immunoglobulins are like little sirens. They are proteins that attach themselves to pathogens and then alert the rest of the immune system to come attack. 

In the gut, B cells are mainly found in the Peyer’s patches. Most of these are IgA secreting cells.

T cells

T cells are broken down into several different types. The main ones are:

  • T helper 1 (Th1) — help fight intracellular microbial infections, can be indicators of autoimmune disorders
  • T helper 2 (Th2) — help fight parasitic infections, usually increase with allergic reactions
  • T helper 17 (Th17) — can be an indicator of autoimmune disorders
  • Regulatory T cell (Treg) — extremely important in autoimmune health if they are not regulated properly they can lead to autoimmune disorders, if they are regulated properly then they can help your body to avoid developing autoimmune disorders

In the gut, most T cells are found in the lamina propria of the small intestines. 


Neutrophils are a major impact of the innate immune system. Neutrophils act sort of like Pacman. They go to the area of infection and start consuming the pathogenic cells. Neutrophils are heavily regulated by the gut microbiota, especially intestinal serum amyloid A (SAA).

Dendritic Cells (DCs)

Dendritic cells for your gastrointestinal tract are in your lamina propria of your small intestines. They are one of your body’s first lines of defense against antigens. 

They help with producing retinoic acid (RA) which is crucial to your immune health and growth of T cells.

Mast Cells

Mast cells have a lot of work to do, especially in the gut. Some of their major tasks include:

  • Blood flow control
  • Blood clotting (necessary for injuries and healing them)
  • Smooth muscle peristalsis 
  • Permeability of intestinal epithelial cells (IECs)
  • Electrolyte exchange with IECs

Studies in germ-free mice showed a common trend of low intestinal mast cells with higher blood percentage levels of mast cells. This means that the body is having an immune system response when it shouldn’t be and links the gut to the immune system. 

Intestinal Epithelial Cells (IECs)

The cells that make up a portion of your intestinal wall are IECs. They create a strong bond that doesn’t allow for dangerous cells to make their way in. 

That is, as long as they are healthy cells. Typically, IECs aren’t considered a part of your immune system, however, some of their jobs help the immune system considerably. 

IECs secrete antimicrobial peptides, cytokines, and chemokines which all help with immunoregulation. Germ-free mice tend to have a lower proliferation rate of IECs — proving that there is a high potential that the gut microbiome regulates this part of the immune system. 


The Gut Microbiome Link to Immune Health

You’ve probably heard (more than once) that you can heal yourself through your gut. There are a ton of — seemingly impossible — claims on the internet about people curing their cancer or some other awful disease by eating clean. Modern medicine does have it’s place, but some conditions really can be helped by diet change (even protecting yourself from the coronavirus).

Your gut is actually your first line of defense in your immune system. It’s your only internal structure that is exposed to the outside world. You eat your food and it is exposed to everything you just consumed. 

There are a lot of different structures to your gut, but here are some of the main components that ‘cross-talk’ with your immune system. These are the reason your diet can boost your immune health.

  • Toll-like receptors (TLRs) are gatekeepers of a sort for your intestinal tract. They help to let your immune cells know if there’s a potential pathogen. TLRs are the first initiation of the inflammatory/immune response within your body. 
  • Short-chain fatty acids (SCFAs) are talked about a lot around here on the Atrantil website. They are the result of insoluble fibers that are fermented in your gut. They help your immune system by:
    • Anti-inflammatory properties
    • Helping with intestinal barrier repair via cellular proliferation and differentiation
    • Maintaining homeostasis in the gut
  • Microbiota in the gut affects your immune system in several ways:
    • Vitamin synthesis (allowing your body to actually use the byproducts that make vitamins support your immune system)
    • Regulate neutrophil migration and function
    • Turning T cells into the necessary form that your immune system is calling for

What you put into your body matters. Diets high in unhealthy fats and low in fiber are a recipe for disease. Studies have linked poor microbiome health to higher incidences of autoimmune disease and food allergies.

People who have food allergies and autoimmune disorders tend to have higher percentages of active immune cells. It’s no mere coincidence. 

What you eat matters. What you fuel your body with makes a huge impact on your health. Protect your body by eating highly nutritious foods, drinking water, exercising regularly, and sleeping well. 

All of these practices support good gut health. All of these practices support good immune health. 

Protect yourself from these dangerous diseases like COVID-19 and eat a diet rich in polyphenols. If you can’t find fresh produce in the store, buy canned (in fruit juice, not syrup) or frozen options. 

What are you doing to support your immune health right now? Have you found that when you eat unhealthy foods you end up sick? Let us know your thoughts in the comments below!

How the Gut Affects Your Immune System