Allergies and Gut Health: The Surprising Connection

Image of dandelions for the allergies and gut health post by The Healthy RD

Do you suffer from allergies? If so, have you considered the health of your gut? Allergies and gut health are tightly connected as it turns out.

This is because our digestive and immune systems are very closely connected.

A so-called leaky gut may contribute to food intolerances, sensitivities, and even seasonal allergies.

You might be thinking, doesn’t everyone suffer from allergies? Aren’t they normal? Well not exactly. Finding the root cause of this immune reaction is essential to curing your allergies or food sensitivities.

In this post, we will discuss the relationship between gut health and allergies. Additionally, we will review which nutritional supplements can heal the gut lining.

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What is a Leaky Gut?

The gut lining acts as a gut keeper by separating our digestive tract from our bloodstream. We absorb all of our nutrients through this gut lining too. 

When we have a leaky gut, also known as increased intestinal permeability, food particles, and other toxins can leak into our blood. As a result, our immune system then must decide if this particle or toxin is a friend or foe. 

Due to this, the immune system easily becomes overwhelmed.

For this reason, we see so many different symptoms of a leaky gut. For one person it might be brain fog and anxiety while another suffers from allergies, eczema, and bloating. 

With a leaky gut, the host (you) allows toxins, allergy compounds, and bacteria from the gut to enter the bloodstream. 

Gut Health and Allergies Overview

Graphic of a healthy gut and immune system for the Allergies and Gut Health post by The Healthy RD

The frontline of this gut defensive mechanism is maintained by one single layer of specialized epithelial cells linked together by tight junctions.

These tight junctions, located in the gut, allow digested food particles such as amino acids, fatty acids, simple sugars, vitamins, and minerals to cross into the bloodstream.

However, when the gut becomes leaky, unwanted substances leak into our blood. This can cause migraines, irritable bowel syndrome (IBS), skin conditions, malabsorption, allergies, and many more. 

Other compounds made in the gut, such as mucins, immunoglobulins, and cytokines aid or hinder in this process.

Signs and Symptoms of a Leaky Gut

Symptoms of a leaky gut vary widely from person to person and the degree of leakage.

Not only can leaky gut affect your digestive system but other parts of the body like your skin, mental clarity, and even joint pain. 

Some other signs of leaky gut include: 

So, why does a leaky gut happen in the first place?

Related post: 14 Of The Best Supplements For Allergies (

What Causes a Leaky Gut?

Gut leakage may be responsible for a wide variety of health issues. Let’s review these next.

Celiac Disease

When someone suffers from celiac disease gut cells are damaged, which increases the permeability of the intestine lining when eating gluten. The body creates a chemical called zonulin which directly causes the tight junctions to open up.

Not only celiac disease but other individuals with autoimmune diseases such as type 1 diabetes may have high zonulin levels.

Undoubtedly, gluten is also not processed like in past generations.

Today gluten-containing foods are processed, sprayed, and stored in ways our gut cannot process. 

Therefore, removing gluten could help the gut repair and heal for many people. 

Small intestinal overgrowth

Another potential cause of a leaky gut is small intestinal bacterial overgrowth (SIBO).

SIBO occurs when the bad bacteria outnumber the good. This imbalance can create inflammation and unwanted allergy symptoms. 

When we have an allergic reaction our body releases histamine. The mast cells and basophils store and secrete histamine in response to toxins or immune IgE-mediated machines.

In addition, certain bacteria in the gut can also produce histamine. These bacteria include Citrobacter freundii and Morganella.

Keeping our bacteria in check helps to balance the release of histamine and decreases our chance of allergic reactions.

Related post: Best probiotic for SIBO and Histamine Intolerance (

Other causes of leaky gut include: 

  1. Poor Diet: aka Standard American Diet. The SAD is low in fiber and high in processed foods and refined sugars
  2. Alcohol use also alters both the quality and quantity of the microbiome
  3. Medications: birth control, allergy medications, metformin, ibuprofen, and steroids
  4. Nutrient deficiency: caused by medication interactions or lack of nutrients in the diet
  5. Gut Dysbiosis: Growing evidence has shown the gut microbiome to protect the epithelial barrier
  6. Toxins in the environment 
  7. Chronic stress: this can weaken and inflame the immune system. Sleep hygiene, meditation, and relaxation are crucial to proper gut healing.
  8. Irritable bowel syndrome (IBS)

Tip: Most of the immune system is located in the gastrointestinal tract.

How are Allergies and Gut Health Connected?

When the gut becomes permeable the tight junctions allow foreign substances and toxins into the bloodstream, the immune system attacks them.

Every time the immune system is activated it causes inflammation. If the gut is constantly leaking the immune system works overtime. 

Although a healthy immune system is essential, chronic inflammation from the immune system due to a leaky gut leads to chronic diseases.

What Type of Allergies Can Leaky Gut Cause? 

About one-fifth of the world population experiences adverse dietary reactions. 

IgE=mediated food allergies are associated with gut imbalance, leaky gut, and impaired gut epithelial integrity. In addition, studies show a link between the gut microbiome and food allergies.

When the gut microbiome is not in balance the health of the intestinal epithelial barrier and adaptive immune responses suffer.

Food Sensitivity vs Food Intolerance 

Adverse food reactions are divided into two categories: food intolerance and food sensitivity. Let’s explore those more next.

Food Intolerance

Food intolerance is non-immune mediated and is caused by a variety of reasons. Examples include IBS, enzyme deficiency, or enzyme malfunction. 

Food Sensitivity

Food sensitivity, also known as a food allergy, are a response caused by the immune system in the gut.

This can be immune IgE-mediated or non-IgE-mediated.

Interestingly, most food allergies are related to immunoglobulin IgE including celiac disease.

An immune IgE reaction occurs in the mast cells of the gastrointestinal mucosa layer. The mast cells are triggered by the allergens in the gut lining and inflammatory compounds are then released.

Imagine if this inflammation occurs over and over again every time you eat?

Ignoring food sensitivities can be harmful to the body. 

The inflammation created by allergic reactions can make us feel crummy and long-term inflammation can be detrimental to our health. 

Studies show who suffer from food intolerances or food allergies commonly have a leaky gut.

Not only is IgE immunoglobulin involved in an allergic reaction, so is immune IgA.

In fact, IgA is produced in larger quantities than all other types of antibodies combined during an allergy attack!

But, our bodies can counteract these allergic responses with diet and nutrients. Let’s learn more about this.

What is Secretory IgA?

Secretory IgA (SigIgA) is an immune compound that lives in the mucous secretion providing protection against pathogenic microbes while resisting enzyme breakdown and harsh environments.

SigIgA is the first line of defense against bacteria, undigested food, and even parasites.

When the body comes across an allergen the immune B cells release SigIgA.

Every day the body produces about 50 mg/kg of SigIgA.

Sadly, a deficiency of SigIgA is common with stressful lifestyles and heavily processed food items.

Low SigIgA is associated with a leaky gut and decreased immune system activity in the gut, which increases the risk of food sensitivities, IBS symptoms, and leaky bowel.

Are you curious about your IgA levels? You can test your SigIgA levels with a stool test.

What Causes Low SigIgA Levels?

Chronic stress, medications, and antibiotics are some of the few causes of low IgA. So are low levels of nutrients in the body.

High cortisol levels due to stress are related to decreased sigIgA.

Other causes of low SigIgA levels are drugs such as Sulfasalazine, Thyroxine, and Levamisole.

Therefore, keeping stress levels low and having a well-balanced diet might help keep sigIgA at a normal level.

Allergies and Gut Health: How to Heal

If you have allergies or food sensitivities increasing secretory IgA and healing the gut lining can improve allergy symptoms.

Your gut cells regenerate every couple of days so if dietary irritants are removed the gut can heal itself.

Healing your leaky gut means getting the gut microbiome back into balance. 

Find the foods that trigger your symptoms and try avoiding them for a couple of weeks. Then slowly add them back one at a time and see how your body reacts. 

Finally, let’s discuss possible supplement options to aid in the healing of your gut!

Supplements for Allergies and Gut Health

Infographic titled How to Heal Leaky Gut with 5 methods to heal leaky for allergies by the Healthy RD   L-Glutamine Glutamine is known for reducing intestinal permeability and is the preferred substrate for enterocytes and colonocytes. Glutamine works with leucine and arginine to maintain the integrity and function of the gut. Bovine Colostrum Colostrum is the first stage of cow’s milk and has been shown to increase SIgA levels and reduce intestinal permeability in multiple studies.
Colostrum also contains immune proteins and immunoglobulins aiding in immune function.  Probiotics Supplementing with probiotics has been shown to restore intestinal lining and raise SIgA levels.  Eat lots of yogurt, kefir, sauerkraut, tempeh, or kumbutcha  Beta-Glucan Mushrooms are high in prebiotic polysaccharides known as beta-glucan which stimulate the immune system and feed the beneficial microbes in your gut.  Try Reshi, Chaga or Miatake to inhibit pathogen proliferation and enhance the growth of good bacteria.  Short Chain fatty Acids SCFA are produced from undigested carbohydrates in the colon.The most common include acetate, propionate and butyrate. Eating a diet rich in prebiotics such as garlic, onion, asparagus, and bananas can increase the production of butyrate and protect the intestinal lining.


L-glutamine is an amino acid important for repairing the digestive tract.

Glutamine is known for healing leaky gut and is the preferred fuel for intestinal cells.

This amino acid works with other amino acids like leucine and arginine to maintain the integrity and function of the gut.

To supplement glutamine, try taking 5 to 15 grams a day of 100% L-glutamine with 8 ounces of water in the morning or evening or sipping bone broth, also high in glutamine. Some people prefer to start at a lower dose and increase their way up to the optimal dose.

You should also make sure you take adequate B-vitamins, especially vitamin B6 as pyridoxal-5-phosphate if you take L-glutamine. This is because vitamin B6 helps to properly metabolize glutamine in the body.

Two of my favorite brands of glutamine are Thorne and Nutricost.

Bovine Colostrum

Colostrum is the first stage of cow’s milk and has been shown to increase SigIgA levels, which can help heal the gut, and reduce intestinal permeability in multiple studies.

For example, Bovine colostrum can increase Bifidobacterium longum, which is a probiotic that aids in the gut barrier function.  

Colostrum also contains immune proteins and immunoglobulins aiding in immune function. In addition, bovine colostrum decreases intestinal permeability (heals a leaky gut) and concentrations of zonulin in athletes.

Sovereign Laboratories Colostrum is an all-natural, concentrated source of immunoglobulins, lactoferrin, colostrum polypeptides, and growth factors that may help rebalance the body’s microbiome and promote a healthy immune system response.

To learn more about Colostrum and allergies read my blog post.



Multiple studies prove that supplementing with probiotics or eating food rich in probiotics can treat gastrointestinal issues.

Supplementing with a probiotic called Saccharomyces Boulardii helps to restore intestinal barrier function and raise sIgA levels in our bodies.

Another probiotic called Bifidobacterium longum subsp infantis has been shown to improve gut barrier integrity and reduces the expression of inflammatory genes in the intestinal cells.

Eating foods rich in probiotics such as yogurt, kefir, sauerkraut, tempeh, and kombucha will help feed the good bacteria provide gut balance, and may relieve allergy symptoms.

Seeking Health ProBiotia Bidido is a good probiotic for helping heal a leaky gut.

Medicinal Mushrooms 

Nowadays, mushrooms are popular foods due to their healing abilities and functional nutrition professionals use them for many health benefits.

Using medicinal mushrooms help the body because they are prebiotics that feed healthy bacteria while providing vitamins and minerals.

In addition, mushrooms contain high amounts of prebiotic fibers known as beta-glucan. Beta glucan stimulates the immune system and feed the beneficial microbes in your gut.

Some of the most popular species of mushroom include Reishi, Chaga, and Maitake. These mushrooms inhibit unwanted bacteria and enhance the growth of good bacteria.

Not only do mushrooms enhance the gut microbiome they also can lower cholesterol while providing antioxidants and blood sugar control.


In the colon, microbial fermentation of undigested carbohydrates forms short-chain fatty acids including acetate, propionate, and butyrate.

Butyrate plays a particular role in maintaining the intestinal barrier.

To get more butyrate in your diet, include ghee, grassfed cheeses, and grassfed beef.

Also, try eating a diet rich in prebiotics such as garlic, onion, asparagus, and bananas, which can increase the production of butyrate and protect the intestinal lining. 

Designs for Heatlh Tri Butyrin is a highly-rated butyrate supplement.

I personally like and use Bodybio Butyrate.

Digestive Enzymes

Indigestion can contribute to allergies. This is because any indigestion of carbohydrates, protein, or fat can increase the risk of food allergy or sensitivity.

Taking digestive enzymes may aid in the breakdown of food making nutrients easy to absorb and easier to assimilate.

Digestive enzymes also work to clean up the mucosal lining in the gut by breaking down toxins and harmful proteins.

Foods high in digestive enzymes include:

Seeking Health Digestive Enzymes is a good broad-spectrum enzyme supplement that may help both leaky gut and allergies.

Related post: The Best Digestive Enzymes for Bloating and IBS


Zinc is essential to cell turnover and repair systems in the body.

This trace mineral is known to support the immune and digestive systems. Inflammatory conditions are risk factors for zinc deficiency.

A 2015 study found zinc to increase gut strength and regulate tight junctions.

Zinc carnosine is most often used to help heal the gut lining as far as supplements go.

Final Thoughts

When curing your allergies it often comes down to healing the gut while supporting the immune system.

Having a healthy sleep routine, moving your body, and combating stress will have major benefits for any allergies and gut health. Always be patient and give the body time to rest and regrow.

Disclaimer: The information on this website has not been evaluated by the Food & Drug Administration or any other medical body and is shared for educational purposes only. While The Healthy RD’s posts are backed by research, you are unique, so you must seek care from your own dietitian or healthcare provider. This post is not meant to diagnose or treat any conditions. Consult your doctor or healthcare provider before making changes to your supplement regimen or lifestyle.

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