November 17, 2021

The 8 Most Common Signs Of A Food Sensitivity

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Medically Reviewed by

Updated On

September 17, 2024

Food sensitivities are extremely common and are on the rise. Recent studies show that our Standard American Diet and lifestyle can negatively affect the gut microbiome, causing inflammation and lower immunity.

Food sensitivities can be hard to diagnose due to their wide range of symptoms and can be delayed by up to 48 hours, making the offending food especially difficult to pinpoint. Because of this, food sensitivity testing has gained a lot of attention over the past few years.

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Food Sensitivities vs. Food Allergies

It’s very important to understand that food sensitivities and food allergies are two very different diagnoses.

Food Allergies (IgE) cause an immediate histamine reaction within minutes to hours of ingested food, and these allergies can be life-threatening. Most people know that they have a food allergy, which is typically diagnosed at a younger age. Common food allergens are tree nuts, seafood, dairy, and eggs.

Food Sensitivities (IgG) are more common than food allergies and can cause delayed symptoms hours to days after a person has ingested the food. Food sensitivities are not life-threatening but do cause discomfort and, if left untreated, can lead to inflammation in the gut causing many other symptoms. Food sensitivities can be diagnosed at any age and can be remedied with proper nutritional guidance and gut healing protocols.

Common Types of Food Sensitivity Testing

Immunoglobulin G (IgG):

IgG-specific antibody-mediated reactions are the body’s natural and normal defensive reactions to infiltrating food antigens. IgG food sensitivity has more published research compared to other food sensitivity tests and is the most common type of testing used.

Immunoglobulin G4 (IgG4):

A subclass of IgG testing. IgG4 indicates the presence of antibodies to foods that will not usually cause inflammation, even though high amounts of these antibodies indicate the presence of immune reactions against food antigens. Testing for IgG4 comes in handy for patients not currently showing any inflammatory reactions to foods.

Immunoglobulin A (IgA):

Found in mucous membranes, including the digestive tract. If IgA antibodies are elevated to a particular protein (antigen), this can indicate an immune response to mucosal irritation.

Food Sensitivity Signs & Symptoms

Food sensitivity symptoms can easily overlap with other common medical diagnoses. Therefore, it’s vital to rule these sensitivities out while looking for a root cause. The most common symptoms associated with food sensitivities are:

Unexplained loose stools or constipation
Gas, cramps, and bloating
Skin conditions (eczema, acne, psoriasis, and dermatitis
Headaches (not caused by tight muscles)
Brain Fog
Joint pain
Anxiety or Depression (due to the gut-brain connection)
Vitamin and mineral deficiencies (due to an inflamed small and large intestine)

Food Sensitivity Possible Causes

Stress and the Standard American Diet are two of the most common reasons for food sensitivities. They both play a role in disrupting the gut microbiome (good bacteria) and contribute to leaky gut syndrome.

What is Leaky Gut

A leaky gut is an unhealthy gut lining with microscopic cracks or holes, allowing partially digested food, toxins, and bacteria to penetrate the tissues beneath it. Once these larger food proteins are in the bloodstream, our immune system creates an inflammatory response to protect against these foreign invaders. Constant consumption of these trigger foods leads to food sensitivities causing an inflammatory response every time you consume that food.

Stress

Chronic stress is a significant risk factor for developing food sensitivities and is often overlooked. The gut-brain connection plays an essential role in overall gut health.

Cortisol is released when we are stressed, and when released in high amounts it can decrease Secretory Immunoglobulin A (sIgA).

sIgA is an immune antibody found throughout our mucosal barriers. It is the first line of defense against bacteria, food residues, yeast, parasites, and viruses.

When sIgA is decreased, our mucosal first line of defense is reduced. This can begin to disrupt the integrity of our intestinal lining, causing leaky gut syndrome.

High Cortisol -> Lower sIgA -> Reduced mucosal defense -> Leaky Gut

The Standard American Diet (SAD)

The SAD diet is loaded with processed, high inflammatory “foods.” I quoted the word “foods” because most people aren’t even eating actual food anymore. Fillers, additives, processed oils, and food colors make up a majority of the meals that American’s eat. These “foods” are not recognized by the body and create an inflammatory response when they are consumed. The body starts to make antibodies to attack these foreign substances to protect you, but long-term consumption leads to GI inflammation, dysbiosis (unbalanced gut bacteria), and eventually leaky gut.

Functional Medicine Labs for Food Sensitivities

Food sensitivity symptoms can show up days after consumption. This is why it is vital to test, not guess which foods are causing your reactions. Most food sensitivity tests look at at least 96+ different foods, and I can tell you from first-hand experience that it’s usually not the food you expect it to be. I have seen patients react to spices, additives, animal proteins, and varying fruits and vegetables.

The reason behind this is once those holes are in your intestinal lining, multiple different food proteins can slip through, causing a reaction.

The Top 2 Most Common Food Sensitivity Test Ordered on Rupa Health

‍Alletess Medical Laboratory
‍Ayumetrix

I prefer to offer my patients a blood spot option for food sensitivity testing to increase patient compliance. They can complete the test from the comfort of their own home. Most labs also offer serum and whole blood testing as well.

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Functional Medicine Treatment for Food Sensitivities: 4 Rs of Gut Healing

A therapeutic approach known as the 4 Rs is commonly prescribed to heal the gut. It’s important to note that healing your GI tract takes time and serious lifestyle adjustments. It’s best to start your gut healing journey when you are ready to commit to the healing process.

Remove

One of the first steps in addressing food sensitivity is eliminating the food or foods that are causing symptoms for a period of 3-6 months while addressing the other underlying factors. Research shows that it can take up to 6 months for the body to stop making antibodies against the food and longer depending on several other factors. It will most likely take you longer to stop producing IgG antibodies if you have a higher existing concentration and are not as strict with avoidance of foods.

Replace

The second step is to replace these foods with nutrients in the diet that help to reduce inflammation and optimize digestive health. It’s also essential to ensure that the patient has sufficient hydrochloric (stomach) acid and digestive enzymes to assist with breaking down the proteins, fats, and carbohydrates in the diet

Reinoculate

The third step is to reinoculate the intestinal microbiota with beneficial bacteria. Probiotics and fermented foods are added to rebuild good gut bacteria.

Repair

A Functional Medicine Practitioner will most likely add in therapeutic grade supplements to help heal the gut lining. L-Glutamine, Zinc Carnosine, Curcumin, Vitamin D, Collagen, and Fiber have all been shown to help decrease intestinal permeability and help reduce inflammation.

Functional Medicine Approach to Food Sensitivity Reintroduction

Here’s the silver lining in all of this. You don’t have to avoid food sensitivities forever. Patients should avoid highly reactive foods for at least three months. It’s essential to re-test and then re-introduce patients to their food sensitivities one by one once they show a significant clinical difference.

A typical reintroduction is one new food every three days to see if there is a delayed response. Typical food sensitivity responses will be unexplained digestive upset, headache, or skin condition reemerging.

Things to Keep in Mind

Food sensitivity tests don’t usually test for lactose intolerance or Celiac disease.

Most food sensitivity tests only test for sensitivities to the proteins in foods, and lactose is a sugar.

If you have an IgG response to dairy, this means you are sensitive to the proteins in milk (casein or whey protein), not the lactose (sugar).

If you want to test for lactose intolerance, a lactose hydrogen breath test or elimination of lactose are normally prescribed.

A Celiac diagnosis is complex and usually requires a combination of blood tests and other procedures. The antibodies traditionally tested for Celiac Disease are not the same antibodies measured in food sensitivity tests. We do have multiple different celiac disease tests on our Rupa Health platform.

Food sensitivities are commonly reintroduced after an elimination diet and most patients are able to handle them in small amounts after their immune system and gut has had time to heal.

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Summary

Food Sensitivities are on the rise. But with proper testing and treatment, along with nutritional guidance and education, patients can regain their gut health and enjoy their favorite foods again.

Food sensitivities are quite common and seem to be increasing. Recent studies suggest that our Standard American Diet and lifestyle may impact the gut microbiome, potentially leading to inflammation and affecting immune function.

Food sensitivities can be challenging to identify due to their wide range of symptoms and the possibility of delayed reactions, which can occur up to 48 hours after consumption. This makes it difficult to identify the specific food causing the issue. As a result, food sensitivity testing has gained attention in recent years.

[signup]

Food Sensitivities vs. Food Allergies

It’s important to understand that food sensitivities and food allergies are two different conditions.

Food Allergies (IgE) can cause an immediate reaction, such as a histamine response, within minutes to hours of consuming the food, and these allergies can be serious. Many people are aware of their food allergies, which are often identified at a young age. Common food allergens include tree nuts, seafood, dairy, and eggs.

Food Sensitivities (IgG) are more common than food allergies and can cause delayed symptoms hours to days after consuming the food. While not life-threatening, food sensitivities can cause discomfort and may contribute to inflammation in the gut if not addressed. Food sensitivities can be identified at any age and may be managed with nutritional guidance and gut health strategies.

Common Types of Food Sensitivity Testing

Immunoglobulin G (IgG):

IgG-specific antibody-mediated reactions are the body’s natural responses to food antigens. IgG food sensitivity testing is widely used and has more published research compared to other types of food sensitivity tests.

Immunoglobulin G4 (IgG4):

This is a subclass of IgG testing. IgG4 indicates the presence of antibodies to foods that typically do not cause inflammation, even though high levels of these antibodies suggest immune reactions to food antigens. Testing for IgG4 can be useful for individuals not currently experiencing inflammatory reactions to foods.

Immunoglobulin A (IgA):

Found in mucous membranes, including the digestive tract. Elevated IgA antibodies to a particular protein (antigen) may indicate an immune response to mucosal irritation.

Food Sensitivity Signs & Symptoms

Food sensitivity symptoms can overlap with other common medical conditions. Therefore, it’s important to consider these sensitivities when exploring potential causes. Common symptoms associated with food sensitivities include:

Unexplained loose stools or constipation
Gas, cramps, and bloating
Skin conditions (eczema, acne, psoriasis, and dermatitis)
Headaches (not caused by tight muscles)
Brain Fog
Joint pain
Feelings of anxiety or low mood (due to the gut-brain connection)
Vitamin and mineral deficiencies (due to an inflamed small and large intestine)

Food Sensitivity Possible Causes

Stress and the Standard American Diet are two common factors that may contribute to food sensitivities. They can both affect the gut microbiome (beneficial bacteria) and may be linked to leaky gut syndrome.

What is Leaky Gut

A leaky gut refers to an unhealthy gut lining with tiny cracks or holes, which may allow partially digested food, toxins, and bacteria to pass into the tissues beneath it. When these larger food proteins enter the bloodstream, the immune system may create an inflammatory response to protect against these substances. Regular consumption of these trigger foods may lead to food sensitivities, causing an inflammatory response each time the food is consumed.

Stress

Chronic stress is a potential risk factor for developing food sensitivities and is often overlooked. The gut-brain connection plays an important role in overall gut health.

Cortisol is released during stress, and high levels of cortisol may decrease Secretory Immunoglobulin A (sIgA).

sIgA is an immune antibody found throughout our mucosal barriers. It serves as a first line of defense against bacteria, food residues, yeast, parasites, and viruses.

When sIgA levels are reduced, the mucosal defense may be compromised, potentially affecting the integrity of the intestinal lining and contributing to leaky gut syndrome.

High Cortisol -> Lower sIgA -> Reduced mucosal defense -> Leaky Gut

The Standard American Diet (SAD)

The SAD diet often includes processed foods that may contribute to inflammation. These foods often contain fillers, additives, processed oils, and food colors, which may not be easily recognized by the body and could trigger an inflammatory response. Over time, this may lead to gastrointestinal inflammation, an imbalance in gut bacteria, and potentially leaky gut.

Functional Medicine Labs for Food Sensitivities

Food sensitivity symptoms can appear days after consumption, which is why testing can be helpful in identifying the foods that may be causing reactions. Many food sensitivity tests evaluate a wide range of foods, and it is often surprising which foods may be involved. Reactions can occur to spices, additives, animal proteins, and various fruits and vegetables.

This is because once the intestinal lining is compromised, different food proteins may pass through, potentially causing a reaction.

The Top 2 Most Common Food Sensitivity Tests Ordered on Rupa Health

‍Alletess Medical Laboratory
‍Ayumetrix

Some practitioners prefer to offer patients a blood spot option for food sensitivity testing to increase convenience, allowing them to complete the test at home. Most labs also offer serum and whole blood testing options.

[signup]

Functional Medicine Approach for Supporting Gut Health: 4 Rs of Gut Healing

A therapeutic approach known as the 4 Rs is often used to support gut health. It’s important to note that supporting gut health takes time and lifestyle adjustments. It’s best to begin this journey when you are ready to commit to the process.

Remove

One of the first steps in addressing food sensitivity is to avoid the food or foods that may be causing symptoms for a period of 3-6 months while addressing other factors. Research suggests that it can take up to 6 months for the body to stop producing antibodies against the food, and longer depending on several factors. It may take longer to stop producing IgG antibodies if there is a higher existing concentration and if avoidance of foods is not strict.

Replace

The second step is to replace these foods with nutrients that may help reduce inflammation and support digestive health. It’s also important to ensure sufficient hydrochloric (stomach) acid and digestive enzymes to assist with breaking down proteins, fats, and carbohydrates.

Reinoculate

The third step is to reinoculate the intestinal microbiota with beneficial bacteria. Probiotics and fermented foods may be added to support good gut bacteria.

Repair

A Functional Medicine Practitioner may suggest therapeutic grade supplements to help support the gut lining. L-Glutamine, Zinc Carnosine, Curcumin, Vitamin D, Collagen, and Fiber have been shown in studies to help support intestinal health and reduce inflammation.

Functional Medicine Approach to Food Sensitivity Reintroduction

Here’s the positive aspect of this process. You may not need to avoid food sensitivities forever. It is often suggested to avoid highly reactive foods for at least three months. It’s important to re-test and then gradually reintroduce foods one by one once there is a noticeable improvement.

A typical reintroduction involves adding one new food every three days to observe any delayed responses. Typical food sensitivity responses may include digestive upset, headache, or skin conditions reappearing.

Things to Keep in Mind

Food sensitivity tests do not usually test for lactose intolerance or Celiac disease.

Most food sensitivity tests only assess sensitivities to the proteins in foods, and lactose is a sugar.

If you have an IgG response to dairy, this means you may be sensitive to the proteins in milk (casein or whey protein), not the lactose (sugar).

To test for lactose intolerance, a lactose hydrogen breath test or elimination of lactose is often suggested.

A Celiac diagnosis is complex and usually requires a combination of blood tests and other procedures. The antibodies traditionally tested for Celiac Disease are not the same antibodies measured in food sensitivity tests. We offer multiple different celiac disease tests on our Rupa Health platform.

Food sensitivities are often reintroduced after an elimination diet, and many individuals can tolerate them in small amounts after their immune system and gut have had time to recover.

[signup]

Summary

Food sensitivities appear to be increasing. However, with appropriate testing and management, along with nutritional guidance and education, individuals may support their gut health and enjoy a variety of foods again.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.

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Lab Tests in This Article

184 IgG Food Sensitivity Panel by Alletess Medical Laboratory

Blood Spot

The 184 IgG Food Sensitivity Panel measures IgG response to 184 commonly consumed foods. This is the blood spot version of the test. It is also available as a serum test.