Leaky Gut and Food Allergies - What’s the Connection?

by Dr. Nick Zyrowski June 25, 2021

When you think of food allergies, you probably think of serious allergic reactions like an allergy to milk or peanuts. However, mild food allergies are more common than most people believe. In some cases, the symptoms are comparatively minor, including little more than an upset stomach or mild fatigue.

But in other cases, food allergies could lead to a condition called "leaky gut". Leaky gut is much more serious and, if left unchecked, could lead to widespread health effects and long-term discomfort.

Let’s break down what leaky gut is and explore the connection between this condition and food allergies.

What is Leaky Gut Syndrome?

Leaky gut syndrome is a condition that is still not as well understood as many physicians would like. In short, it’s a condition that occurs when the gut lining of the intestinal tract is slightly damaged or weakened. When this happens, certain substances that should not cross the intestinal lining manage to do so anyway.

Under normal and healthy circumstances, only nutritional compounds like vitamins, minerals, and amino or fatty acids can cross the intestinal barrier and be infused into our bloodstream, giving our tissues the nutrients they need to survive. With leaky gut, other compounds like bacteria or toxins can make it into the bloodstream and lead to a number of uncomfortable or negative side effects.

When this occurs, your body may kick its immune response into action, which may lead to ancillary side effects like fevers or nausea.

Symptoms of Leaky Gut

The symptoms of leaky gut syndrome are unique for everyone. But they are usually characterized by allergic symptoms or mild discomfort, including:

  • Vomiting
  • Diarrhea
  • Nausea
  • Stomach cramps
  • Indigestion
  • Fatigue
  • Headaches
  • Runny nose
  • Soreness
  • IBS or irritable bowel syndrome
  • Joint pain
  • Hives and other skin problems
  • Exacerbation of acne or eczema
  • Constipation
  • Irritability
  • Brain fog (difficulty concentrating)
  • And more

In addition, leaky gut syndrome causes an inflammatory response. Microbes from the intestines get into the blood or tissues they shouldn't, plus undigested food particles. The bad bacteria and viruses then cause the above digestive problems and all around discomfort.

How Do Food Sensitivities Cause Leaky Gut?

The exact causes of leaky gut are not fully understood. It’s likely that leaky gut is caused by a number of potential origins. For instance, some physicians believe that SIBO or small intestinal bacterial overgrowth can contribute to gut inflammation and lead to intestinal leakiness over time. With SIBO, intestinal permeability is compromised when the small intestine is overrun by unhealthy bacteria that shouldn't be there.

But in many other cases, food sensitivities may be the root cause of most people’s leaky guts.

What’s a Food Sensitivity?

In a nutshell, food sensitivities are simply allergic or quasi-allergic reactions to one or more food items or compounds. Rather than a true allergic reaction, such as someone with a peanut allergy eating a peanut and experiencing anaphylactic shock, a food sensitivity is characterized by moderate but still uncomfortable symptoms like:

  • Indigestion
  • Nausea
  • Fatigue
  • Cramps
  • Bloating
  • Etc.

When you experience a food sensitivity, your body reacts to some part of the food item and either fails to absorb nutrients correctly or reacts negatively to the ingredients of the food.

Food sensitivities are more common than many people believe. It’s likely that everyone has at least a few mild food sensitivities that they simply ignore or don’t notice because their symptoms are so minor.

However, food sensitivities are typically dose-dependent, meaning that minor sensitivities only become noticeable if an affected person eats a lot of whatever food they are sensitive to. Furthermore, symptoms can be delayed by several hours, so it can be difficult to pinpoint which foods a person is sensitive to if they ate a meal with a variety of foods.

Regardless, food sensitivities can cause inflammation or irritation in the intestinal lining. Given enough time, this may cause the lining to weaken or degrade, leading to leaky gut syndrome. You can find out exactly which foods you are sensitive to here

Additionally, some foods can cause unhealthy bacteria to line the intestine, potentially leading to SIBO or the general destruction of the gut microbiome.

Normally, the gut microbiome is an ecosystem of healthy and helpful bacteria that direct your appetite to crave healthy foods. When you eat too many unhealthy foods, like processed carbs or saturated fats, unhealthy bacteria can take the place of a healthy gut microbiome and cause you to crave unhealthy foods in turn.

Does Every Food Intolerance Hurt Gut Health?

No. Additionally, food intolerances are unique to every person; what may trigger one person’s immune system or cause indigestion could be perfectly fine for another.

As a result, leaky gut can’t be said to be caused by one or more foods for everybody. However, there are certain foods that may be more likely to cause leaky gut due to their inflammatory properties or general unhealthiness, such as:

  • Overly spicy foods if one’s digestion is not prepared for them, such as peppers
  • Dairy products, especially if one is mildly allergic to dairy products like milk or cheese
  • Overly processed carbohydrates like certain pasta products or breads
  • Sugary foods like cake or cookies, especially those that contain synthetic additives like food dyes
  • And more

In general, people have to study their diets and habits closely in order to discern whether they have one or more food intolerances. If you suspect that a food sensitivity may be causing indigestion or even leaky gut, you’ll need to practice a special sort of diet to identify and then eliminate the allergen (more on this below).

Can Seasonal Allergies Also Lead to Leaky Gut?

Sometimes. Your gut health actually affects the rest of your body. In some cases, gut health can cause allergy symptoms to flare up every spring.

Seasonal allergies are essentially responses from your immune system, which flares up when it detects plant pollen or other allergens in the air you breathe or in the food you eat.

Since springtime causes an excess of pollen to flow through the air, many people experience mild seasonal allergic effects as their immune systems incorrectly think that pollen is an intruding virus. Their immune systems then create antibodies and develop other symptoms like a mild fever, runny nose, headaches, and so on.

In some cases, seasonal allergic reactions can lead to a leaky gut or vice versa. For example, if you have a leaky gut from eating gluten and you have celiac disease, your immune system might think that the gluten seeping into the bloodstream is an intruder and cause allergy-like symptoms. Autoimmune diseases may also lead to leaky gut symptoms depending on their conditions.

This goes to show that leaky gut is a complex condition and it’s not usually fixed by a single measure!

Treating Leaky Gut Caused by Food Allergies

That being said, it is often possible to isolate which inflammatory foods are causing your leaky gut and gradually eliminate them from your diet through a Low-FODMAP elimination diet.

The Low-FODMAP diet focuses on FODMAPs, which include fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These compounds are comprised of a wide variety of foods, some healthy and some less healthy, such as:

  • Oligosaccharides including wheat, rye, fruits and vegetables, legumes, and garlic and onions
  • Disaccharides like milk, yogurt, and cheese
  • Monosaccharides like fruits including mangoes and figs and a variety of sweeteners like honey and agave nectar
  • Polyols like fruits and vegetables including blackberries or low-calorie sweeteners found in sugar-free products like soda or gum

With this diet, you’ll pick a food group to eliminate over an “elimination period”. You’ll then monitor your health and digestive responses. If you start to feel better, you can reintroduce the food group gradually and try to narrow down what food products are causing the allergic flareups in your gut and the rest of your body.

Over time, you may discover the one or two food items that could be causing the majority of your discomfort, eliminate them from your diet, and continue on healthier and happier than before. Eventually, your immune reaction will decrease and your wellness will improve.

You'll also want to focus on boosting the gut microbiome by eating probiotics (which contain good bacteria) or taking certain supplements to improve the digestive system. Specifically, I look at repairing the intestinal lining with clinically-relevant dosing of nutrients like aloe vera, l-glutamine, arabinogalactan, and licorice root extract. 

Healing the GI system and ensuring a healthy intestinal lining can be done naturally with the right tools.


Overall, leaky gut is inextricably tied to food allergies and sensitivities.  To fully recover from leaky gut, you have to give your intestine time to rebuild a healthy gut microbiome and rebuild its intestinal walls with specific nutritional protocols. You may need to work with a natural doctor to assist with this process. 

Dr. Nick Zyrowski
Dr. Nick Zyrowski