Food Sensitivity Symptoms & Common Dietary Triggers

All About Food Sensitivities

Food Sensitivity Symptoms & Common Dietary Triggers

We digest and absorb nearly 97% of the food we consume.  However, our absorptive ability is severely restricted when the lining of our intestines becomes irritated or flattened.  This can occur with food allergies, food intolerances and/or inflammatory bowel diseases.  If these issues aren’t resolved, nutrient absorption will not occur.

What is a food allergy?

The immune system is a group of cells that help to protect our body from infectious agents. An allergic reaction to food involves an immune system response that starts with a protein molecule made by the body, called an antibody, which helps battle viruses and bacteria.

  An antibody can connect with and attach to a specific target, known as its antigen, which is usually located on the virus, bacterium, or allergen. Once bound to the invader, it’s a red alert, calling out the invading allergen, and provoking the body’s immune system to attack it.

A mast cell goes into action

The main antibody in most allergic conditions is called immunoglobulin E (IgE).  With a food allergy, IgE antibodies are produced in response to an innocent food molecule.  IgE antibodies are found on the surface of mast cells, and when activated, trigger the mast cells to release various chemical messengers.

Millions of mast cells line our skin, nose, intestines, and bronchial tubes.  In a normal immune response, the IgE/mast cell combo means bad news for microbes.

  In an exaggerated response, such as with an innocent food molecule, we have the symptoms that come with a severe food allergy.

In both cases, these symptoms typically occur in the areas that have a lot of mast cells: skin, nasal passages and airway, and gastrointestinal tract.

Think of the mast cell one of those loud, obnoxious car alarms.  It doesn’t always go off due to a true car thief (car thief = virus, bacteria, and/or parasite).  It may be triggered by a strong wind or a passing jogger (the innocent food molecule).

A cascade of events occur when chemical messengers are released from mast cells, including dilated blood vessels, a drop in blood pressure, and swelling of the lips, mouth, tongue and throat.

  This combination of symptoms, when powerful enough, is referred to as anaphylaxis.  A common example of this is a peanut or shellfish allergy. If someone eats one of these foods and has a true allergy, they could die without medical assistance.

  It’s a severe condition with severe consequences.

Food allergens can come into the body by one route, but cause symptoms somewhere else entirely because they travel in the bloodstream.

  Since this connection between food and symptoms isn’t always obvious, proving immune system involvement with a particular food usually requires a positive skin-prick test.

  A laboratory test measure of IgE response can confirm a food allergy as well.  However, not all food allergies involve IgE.

It’s estimated that 3-7% of children and about 2% of adults suffer from food allergy.

The 8 most common food allergens

  • Milk
  • Eggs
  • Peanuts
  • Tree nuts (e.g., almonds, cashews, walnuts)
  • Fish
  • Shellfish
  • Soy
  • Wheat

What is a food intolerance?

Many people say they are “allergic” to foods when they are actually intolerant. Food intolerances usually occur when the gut reacts poorly to a specific food or ingredient used in food preparation.  Intolerances can result from the absence of an enzyme needed to fully digest a food, such as with lactose intolerance.

Food intolerance is not regarded as a sound diagnosis by much of the medical community. In part, this may be because symptoms of food intolerance are milder and usually have a slower onset than food allergy (but not always).

  These symptoms can include gas/bloating, diarrhea, stomach cramping, stuffy nose, mucus production, nausea, vomiting, headaches, etc.

While some of these symptoms are benign, serious gastrointestinal complaints are often characteristic of severe intolerance; if left uninvestigated, more serious problems can result.

Common culprits in food intolerance tend to be foods eaten very regularly, wheat, milk, corn, and more recently, soy.  Lactose intolerance is a common example.  In people without enough lactase enzyme activity, undigested lactose from dairy products passes through the stomach into the intestines, where it must be fermented.

  Through this process, lots of gas is formed, causing stomach cramps, bloating, flatulence, and diarrhea.  Compounding the problem, other symptoms can be a result of milk protein sensitivity.  While casein protein has been implicated in more cases of milk protein problems than whey, both milk proteins can cause similar issues.

  This is because both casein and whey can cause an excessive inflammatory response in some individuals, leading to mucus production.  High mucus means blocked airways, stuffy noses, and thick throats.

  Un an allergy, in which sensitive people can react to minute quantities (or even odours), a food intolerance usually requires a larger quantity of food to be consumed before symptoms arise.

Intolerances are much more prevalent than food allergies; however, because the symptoms are milder and often not immediate, people can be unsure which foods are causing the problem. Thus, food intolerance testing is becoming more frequent.  Eliminating and re-introducing the suspected food in the diet is a dependable way to assess food intolerance.

The most common food intolerances are:

Type Found in
Lactose or milk proteinDairy (esp. cow’s milk)
Yeast (Candida albicans)Breads and baked goods; can be exacerbated by sugar
Gluten (including both celiac and wheat sensitivity)Grains such as wheat, barley, and rye
FructoseFruit; foods sweetened with fructose (as well as sorbitol)

Others may include:

TypeFound in
Food additivesProcessed foods
AminesFermented foods, e.g. sauerkraut, pickles, cheeses
SalicylatesFruits (such as apples, avocados, blueberries, dates, kiwi fruit, peaches, raspberries, figs, grapes, plums, strawberries, cherries, grapefruit and prunes); Vegetables (such as alfalfa, cauliflower, cucumbers, mushrooms, radishes, broad beans, eggplant, spinach, zucchini, broccoli and hot peppers); Some cheeses; Herbs, spices, and condiments (such as dry spices and powders, tomato pastes and sauces, vinegar, and soy sauce, jams and jellies); Beverages (such as coffee, wine, beer, orange juice, apple cider, regular and herbal tea, rum and sherry); Some nuts; Mint; Artificial flavourings
NitratesProcessed foods, e.g. preserved meats
Monosodium glutamateProcessed foods
PropionatesA preservative in commercial breads
Some antioxidantsProcessed foods (used to prevent spoilage)

It’s been estimated that 3 in 4 people have some form of food intolerance, whether mild or severe.  And these intolerances are uniquely individual.

  Everything from the nutrients and chemicals above, to specific minerals, to specific food additives can lead to a host of symptoms. Note that eating the PN way, i.e.

a diet that is low in processed foods, can help eliminate many of these common food offenders.

Another common type of food intolerance is Leaky Gut Syndrome (LGS). LGS is poorly recognized, and rarely tested for, but fairly common.  With LGS, the intestinal lining becomes extremely permeable, meaning that it may allow large molecules and toxins to enter the body undigested.

  This is possible when the intestinal lining becomes inflamed or damaged, disrupting its normal functions.  As a result, “spaces” develop between the cell walls and macromolecules (including histamine from food), antigens, and toxins sneak in.

  As these molecules, which should not be allowed to sneak in, invade the GI wall more frequently, additional damage occurs, exacerbating the problem.

Beyond damaging the intestinal mucosa, these molecules (which are much larger than the body prefers to absorb) can be treated as foreign invaders that trigger the body’s immune defenses.  This sets off a cascade of antibody production. The body sets up a defense against otherwise healthy food, and potentially against its own cells, although this is speculative.

  To make matters worse, as the damage to the intestinal mucosa gets worse, the carrier proteins also become damaged, causing nutrient deficiency.  There are many symptoms of LGS including GI distress (bloating, flatulence, and abdominal discomfort), immune reactions (including hives and mucus build up), nutrient deficiency, and more.

  The symptoms of LGS are similar to those of food intolerances.

Other interesting information about food sensitivities

Food allergies are usually present for years, or even a lifetime.  Food intolerances can dissipate after several months, only recurring if the food is eaten regularly again.

Human beings do a fairly poor job at identifying foods that cause non-acute, long-term illness.  It took a famine in Holland at the end of World War II to eradicate wheat from the diet, and an attentive doctor to identify that his celiac patients had been cured.

Some foods contain large amounts of histamine, the same inflammatory mediator released by mast cells.

  This can cause unpleasant symptoms, such as those listed above along with neuropathic symptoms (tingling, pins and needles), flushing of the skin, racing heart and other symptoms of anxiety and agitation (perhaps what scientists might refer to technically as “ants in your pants”).

  Well ripened cheeses and sausages are the main offenders, along with some types of fish, sauerkraut and alcoholic drinks.  The liver can metabolize histamine, however, the drug isoniazid (for treating tuberculosis) can limit the ability of the liver to break down histamine.  Thus, anyone on isoniazid should avoid foods with histamine.

Infants delivered via Cesarean section may have an increased risk of developing food allergies.  The low compressive forces against the infant during a Cesarean delivery might delay the growth of normal intestinal flora.

Among all allergic reactions, food allergy is the leading cause for emergency room visits in the United States, Great Britain, Canada, France and Australia.

Summary & recommendations

If you suspect you may have a food sensitivity, it’s important to first rule out the possibility of a true food allergy.  This can be done with your physician.  If you suspect you may have a food intolerance, keeping a diligent food diary/response log can help find the offending foods quickly and remove them.

Because of the delay between food ingestion and response, it’s easy to ignore food intolerance symptoms or simply accept them as part of life.  If any of the symptoms listed in this article are part of your normal day, you might look at your food intake to see what might be causing the problem(s).

Measures that may prevent food sensitivities

  • Varying the diet
  • Avoiding high quantities of high risk foods
  • Getting breast fed for the first year of life
  • Limiting excessive amounts of caffeine
  • Avoiding compounds that increase gut permeability, such as alcohol, spicy foods, raw pineapple, raw papaya, aspirin and other NSAIDs
  • Limiting exposure to pesticides, herbicides and fungicides used on food crops

Further resources

Food Allergy & Anaphylaxis Network

Gluten intolerance and celiac disease

Lactose intolerance and milk/casein allergy

Fructose intolerance/malabsorption

Yeast infection/candida


Click here to view the information sources referenced in this article.

Advanced Nutrition and Human Metabolism, 3rd Edition.  Groff JL, Gropper SS.  1999.  Delmar Publishers, Inc.

Anatomy & Physiology, 4th Edition.  Thibodeau GA, Patton KT.  1999.  Mosby, Inc.

Food, Nutrition & Diet Therapy, 11th Edition.  Mahan LK, Escott-Stump S.  2004.  Saunders.

Nutrition and Diagnosis-Related Care, 5th Edition.  Escott-Stump S.  2002.  Lippincott Williams & Wilkins.

The Merck Manual, 17th Edition.  Beers MH, Berkow R.  1999.  Merck Research Laboratories.

Food Allergies and Food Intolerances.  Brostoff J, Gamlin L.  2000.  Healing Arts Press.

On The Nature Of Food Allergy.  Hannaway PJ.  2007.  Lighthouse Press.

Food Allergy Field Guide.  Willingham T.  2000.  Savory Palate.

Eggesbo M, et al.  Is delivery by cesarean section a risk factor for food allergy?  J Allergy Clin Immunol 2003;112:420-426.

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Food intolerance

Food Sensitivity Symptoms & Common Dietary Triggers
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A food intolerance is difficulty digesting certain foods and having an unpleasant physical reaction to them. 

It causes symptoms, such as bloating and tummy pain, which usually happen a few hours after eating the food.

The number of people who believe they have a food intolerance has risen dramatically over recent years, but it's hard to know how many people are truly affected. Many people assume they have a food intolerance when the true cause of their symptoms is something else.

In general, people who have a food intolerance tend to experience:

  • tummy pain, bloating, wind and/or diarrhoea
  • skin rashes and itching

These symptoms usually happen a few hours after eating the food.

It can be difficult to know whether you have a food intolerance as these are general symptoms that are typical of many other conditions.

A number of companies produce food intolerance tests, but these tests are not scientific evidence and are not recommended by the British Dietary Association (BDA).

The best way of diagnosing a food intolerance is to monitor your symptoms and the foods you eat. See what happens when you cut out the suspected food for a while, and then reintroduce it into your diet.

Food diary

Try keeping a food diary, noting:

  • what foods you eat
  • any symptoms you have after eating these foods
  • when these symptoms happen

Trial elimination diet

Once you have an idea of which foods may be causing your symptoms, you can try excluding them from your diet 1 at a time and observing the effect this has.

Try cutting out the suspected food from your diet for 2 to 6 weeks and see if your symptoms improve.

Reintroduce the food to see if symptoms return. You may find you can tolerate a certain level and you only get symptoms if you have more than this amount.

Consider seeing a dietitian to make sure you're receiving all your recommended daily nutrients while you do this trial. Find a registered dietitian.

Never restrict your child's diet unless this has been advised by a dietitian or your doctor.

If you regularly have diarrhoea, bloating, tummy pain or skin rashes but you're not certain of the cause, see a GP.

A GP may be able to diagnose the cause from your symptoms and medical history. If necessary, they'll order tests, such as blood tests.

You can also do some research yourself. It may help to find out about other conditions that cause similar symptoms. For example, find out about:

The bowel is a sensitive organ and it's common to have bowel symptoms when you have been ill or feel run down or stressed.

A food intolerance is not the same as a food allergy. Here's how to tell the difference.

A food allergy:

  • is a reaction by your immune system (your body's defence against infection). Your immune system mistakenly treats proteins found in food as a threat
  • can trigger allergy symptoms, such as a rash, wheezing and itching, after eating just a small amount of the food (these symptoms usually happen quickly)
  • is often to particular foods. Common food allergies in adults include fish and shellfish and nut allergies. Common food allergies in children include milk, eggs, fish, peanuts and other nuts 
  • can be life-threatening

A food intolerance:

  • does not involve your immune system – there is no allergic reaction, and it is never life-threatening
  • causes symptoms that happen gradually, often a few hours after eating the problem food
  • only results in symptoms if you eat a substantial amount of the food (un an allergy, where just traces can trigger a reaction)
  • can be caused by many different foods

Find out more about diagnosis of food allergies.

It is often unclear why a person is sensitive to certain foods. 

If your symptoms happen after eating dairy products, it's possible you may have lactose intolerance. This means your body cannot digest lactose, a natural sugar found in milk, yoghurt and soft cheeses. A GP can usually diagnose lactose intolerance by looking at your symptoms and medical history.

Some people have trouble digesting wheat and experience bloating, wind, diarrhoea, being sick and stomach pain after eating bread. Read more about wheat intolerance (also known as wheat sensitivity).

Otherwise, the culprit may be a food additive, chemical or contaminant, such as:

  • monosodium glutamate (MSG)
  • caffeine
  • alcohol
  • artificial sweeteners
  • histamine (found in Quorn, mushrooms, pickled and cured foods, and alcoholic drinks)
  • toxins, viruses, bacteria or parasites that have contaminated food
  • artificial food colours, preservatives or flavour enhancers

Gluten intolerance

Many people cut gluten from their diet thinking that they are intolerant to it, because they experience symptoms after eating wheat.

But it's hard to know whether these symptoms are because of an intolerance to gluten, an intolerance to something else in wheat, or nothing to do with wheat at all. It may help to read more about cutting out bread from your diet. 

Very few people need to cut out gluten from their diet, although it's important to do so if you have coeliac disease (which is not an intolerance, nor an allergy, but an autoimmune condition).

If you're confident you are intolerant to a particular food, the only way to manage this is to stop eating the food for a while and then reintroduce small quantities while monitoring how much you can eat without causing symptoms.

Check food labels to see which sorts of foods to avoid.

If you think your child may have a food intolerance, check with a GP or dietitian before eliminating foods from their diet, as a restricted diet could affect their growth and development. Cows' milk, for example, is an important source of calcium, vitamin D and protein.

A GP may refer you to a specialist if they're not sure what's causing your symptoms and further tests are needed.

You may also be referred if your child has digestive symptoms (such as tummy pain and diarrhoea) and:

  • is not growing well
  • has not responded to any elimination diets that your healthcare professional recommended
  • has reacted suddenly or severely to a food 
  • has a suspected food allergy


Find the Source of Your Food Intolerance (and Finally Find Relief)

Food Sensitivity Symptoms & Common Dietary Triggers

You the foods you eat. Sometimes, though, your foods don’t you. It’s really your gastrointestinal (GI) tract that is responding with symptoms of food intolerance that can make you regret some of your food choices. Food intolerances are common. In fact, nearly everyone has eaten something that disagrees with them.

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If you’re sensitive to a food, you don’t necessarily have to remove it completely from your diet. The key is to identify the offending food and figure out how much, if any, of it you can eat without suffering the consequences.

“The most important thing is when you think you have a food sensitivity, really talk with your physician about it,” says Kristin Kirkpatrick, MS, RD, LD. “I see way too many people who cut foods their diet when maybe the food has nothing to do with it. You might be sensitive to one thing and not another. You have to do your due diligence.”

Why you’re intolerant

A food intolerance occurs when something in a food irritates your GI tract or you can’t digest that food due to a lack of necessary enzymes, sensitivity to certain components, or other factors.

Some signs of food intolerance are similar to those of a food allergy — namely, stomach pain, diarrhea, nausea and vomiting — but the two conditions differ in important ways. A food intolerance occurs in the GI tract, develops more gradually, and generally isn’t life threatening.

Other symptoms of food intolerance include headaches and heartburn, and some evidence has linked food intolerances with joint pain and mood changes, including irritability and nervousness.

Oftentimes, food-intolerance symptoms occur only if you eat a lot of a troublesome food or consume it frequently.

A true food allergy, however, is a larger immune system response that occurs suddenly when you are exposed to a food component that your body interprets as harmful.

Food allergies can cause more severe, potentially life-threatening problems, such as chest pain, a sudden drop in blood pressure, and difficulties swallowing or breathing (call 911 immediately).

And the symptoms of a food allergy can be triggered by exposure to even trace amounts of a problem food or food component.

Intolerance to lactose (the sugar found in milk and other dairy products) is the most common food intolerance, affecting about 1 in 10 Americans. Another common one is gluten, a protein in wheat, rye and barley that causes celiac disease as well as the less severe nonceliac gluten sensitivity.

It’s important to identify whether you have a food intolerance and not just diagnose yourself. If you have things that can’t be explained, especially GI issues, that’s when it’s time to think about getting evaluated.

Finding food intolerance

Your physician can order a blood test to find what’s causing your symptoms. More often, your doctor will recommend an elimination diet, in which you stop eating one or more potential problem foods for several weeks and gradually reintroduce them one at a time. As part of this process you should keep a food journal to document what you eat and how it affects you.

“You have to be very specific,” Kirkpatrick emphasizes. “If you do have a food sensitivity, it’s about looking at which foods you have to limit, but it doesn’t necessarily mean you have to give them up completely.”

Your doctor or dietitian may recommend certain digestive aids or alternatives that help you avoid GI symptoms — such as lactose-free dairy products, milk alternatives ( soy milk) or lactase supplements that can help you tolerate dairy.

“It can take a while to figure things out. You might be surprised about what foods you’re sensitive to,” Kirkpatrick says. “You have to take into consideration that it’s a process and it’s going to take some time. For a lot of people with food sensitivities, that’s the way to go.”

Common culprits for food intolerance

Here’s a look at common foods and food components that cause food intolerance and food allergies:

● Lactose (most common).

● Gluten (found in wheat, rye, and barley).

● Casein (a protein in milk products).

● Eggs (especially egg yolks).

● Soy products.

Fish and shellfish.

● Peanuts or tree nuts ( pecans, almonds, walnuts).

● Sulfites (compounds in red wine and beer that are also added to certain foods).

● Some food additives, such as monosodium glutamate (MSG).

What you can do

  • Tell your doctor about GI symptoms you believe could result from a food intolerance, and ask about testing for a food sensitivity or allergy.
  • Follow your doctor’s advice about an elimination diet, and learn which foods you can eat and how much you can consume.
  • Keep a food journal and carefully document which foods you eat and how you react to them.
  • Carefully read food labels. Check the ingredients for problem foods or ingredients.
  • Ask your physician about your risks from food allergies and whether you should carry an emergency epinephrine injection.

This article originally appeared in Cleveland Clinic Men’s Health Advisor.


What is a Food Sensitivity and How to Know if You Have One – Amy Myers MD –

Food Sensitivity Symptoms & Common Dietary Triggers

July 2nd, 2019 • Reading time: 6 minutes

Print • Free eBook: 35 Gut Recovery Recipes

Do you have symptoms that seem to mysteriously come and go, such as brain fog, fatigue, headaches, joint pain, or digestive issues? Or are you generally just not feeling “right”, and suspect it might be related to your diet?

If so, there’s a good chance you could be dealing with an undiagnosed food sensitivity. What’s more, the food you are sensitive to may just be one you would never suspect. In fact, it’s quite possible that a seemingly “harmless” food that you’ve been eating (maybe even daily throughout your whole life!) is to blame for your symptoms!

And yes, food sensitivities can be behind your symptoms even if you are eating a clean, Paleo, or AIP diet!

In this article, I will answer the question “what is a food sensitivity” (hint: it is NOT the same as a food allergy!), how to know if you have one, and what to do about it.

The Difference Between A Food Sensitivity and Food Allergy

The first thing I want to note is that food allergies and food sensitivities are two very different things. A food allergy triggers an extreme and potentially life-threatening reaction, known as an IgE-mediated immune response.

This happens whenever you are exposed to a certain type of food, such as peanuts or strawberries. Most allergic reactions happen within minutes and can range from mild—think hives or stomach cramping—to severe, such as anaphylaxis, which can impair your breathing, cause a dramatic drop in blood pressure, and affect your heart rate.

 Due to the severity of food allergies, you ly already know whether or not you have one.

A food sensitivity, on the other hand, is more difficult to diagnose because it triggers an IgG reaction in your system, which is a delayed immune response.

It could take up to 72 hours for symptoms of a food sensitivity to present. The problem with this delayed response is that you probably eat a wide range of foods in the time it takes for symptoms to appear.

This makes it difficult for you to spot a pattern between the specific foods you eat and your symptoms.

For example, let’s say you’ve been having migraine headaches and digestive issues. You eat scrambled eggs, fresh sliced tomatoes, and a banana every morning for breakfast. You think maybe it’s something in your breakfast that’s bothering you.

So on Monday you decide not to have the scrambled eggs to see if you get the migraines and digestive issues. Later on in the day, the headache and digestive issues are still there, so on Tuesday, you decide to try eliminating the tomatoes and your symptoms once again return.

Well, it could be that the eggs from two days prior are actually causing your migraines and digestive issues, and it’s just taken this long for the sensitivity symptoms to appear.

Additionally, food sensitivities can produce a wide array of symptoms depending on which area of your body the antibodies attack. So you may not even realize that your skin rashes or joint pain are diet-related.

Common signs of a food sensitivity:

  • Fatigue
  • Brain fog and difficulty concentrating
  • Joint pain
  • Headaches or migraines
  • Eczema
  • Rashes and skin irritations
  • Stomach aches
  • Acid reflux
  • Bloating
  • Constipation or diarrhea
  • Unexplained weight gain or loss
  • Behavioral issues (in children)

Fortunately, with a scientific approach, you can take out the guesswork and identify which foods are causing your symptoms.

Identifying Food Sensitivities with an Elimination Diet

The best way to discover your food sensitivities is to complete an elimination diet. This means you take out the most common inflammatory foods from your diet and then add them back in one at a time to see if you have a reaction. It’s getting to do your own science experiment on your diet!

I walk you through exactly how to do this (including providing recipes and shopping lists) in The Myers Way® Comprehensive Elimination Diet. Here’s an overview of how it works.

First, you’ll go through the elimination phase. One component of this phase is to remove the most toxic foods from your diet for good! These foods are damaging to your health, so even after completing the elimination diet, you won’t be adding these back in.

Toxic foods:

  • Sugar
  • Alcohol
  • Caffeine
  • GMOs
  • Artificial sweeteners
  • Additives, preservatives, and dyes
  • High-fructose corn syrup
  • Processed food, junk food, and fast food
  • Trans or hydrogenated fats

The other component of the elimination phase is to remove all inflammatory foods from your diet for two weeks.

Most common inflammatory foods:

  • Gluten*
  • Dairy*
  • Corn
  • Soy
  • Eggs
  • Nightshades (tomatoes, peppers, potatoes, and eggplant)
  • Citrus
  • Yeast
  • Gluten-free Grains
  • Legumes

*Gluten and dairy are the top 2 most inflammatory foods and I do not recommend ever adding them back in, particularly if you have an autoimmune or thyroid condition.

Once you’ve removed all of these foods from your diet, you will begin to slowly reintroduce the inflammatory foods one at a time in order to test your body’s response to individual foods.


Specifically, you will eat a particular food three times a day for three days. The idea here is to temporarily bombard your system with each food to produce a noticeable and definitive response.

If that food is causing inflammation for you, I want to give your body the best chance to determine that, rather than letting silent inflammation creep in! You also want to make sure your results are clean and reliable, which is why you’ll test only one food at a time.

Here is the exact reintroduction process:

  • Introduce one food at a time
  • Eat the reintroduction food three times a day for three days
  • Record whether or not you experience any symptoms
  • Go back to the program for three days in between each reintroduction food
  • If you have a reaction, take the food back out and return to the program guidelines until you are symptom-free
  • If you don’t have a reaction, take the food back out until you have finished the reintroduction phase
  • Add all safe foods back in after you’ve completed the reintroduction phase

You can follow this same process with any food you’d to test, even if it’s not on the list. For example, if you suspect you are sensitive to avocados you can remove them from your diet for 2 weeks and follow the reintroduction protocol to gauge your body’s response.

By paying close attention during this phase, you will be able to pinpoint exactly which foods trigger a reaction and what types of symptoms they produce. It can be a very enlightening and empowering process to finally identify what’s been causing your symptoms and, best of all, put an end to them!

IgG Food Sensitivity Blood Test

I always recommend an elimination diet first because your body knows better than any test. However, even a comprehensive elimination diet only tests the most common inflammatory foods. If you are looking to go a step further, food sensitivity testing is a great way to get a more comprehensive analysis of different foods so you can be as informed as possible.

I’ve personally found the best results with a company called Cyrex, which uses a blood test to measure your immune response to 180 foods in both their raw and cooked form. Each food is then given a green, yellow, or red light ranking, so you know which foods are safe, which to watch out for or minimize, and which to avoid completely.

The advantage of doing the blood test in conjunction with following an elimination diet is that it lets you collect as much information as possible about what is going on inside your body. The downside of this type of testing is that it is not always 100% accurate.

If your gut is leaky, you may show a reaction to food particles that are escaping into your bloodstream that would not normally trigger an immune response if your gut was healthy.

Also, if you’ve already removed a food from your diet for health reasons, you could get a false negative since your body is not currently producing antibodies for that food for the test to detect.

At the end of the day, how you feel is the best indicator. Knowing and really listening to your body is going to be what gets you the best results.

A Step-by-Step Guide to Identify Your Personal Food Sensitivities

To help you discover your own personal food sensitivities and reclaim your health and vitality, I’ve created a Comprehensive Elimination Diet eCourse. It is specifically designed to help you determine the diet that is best for your individual needs.

In it, you will find guided videos where I take a deeper dive into digestion, your immune system, and the power of food. You’ll also receive recipes, shopping guides, and checklists to take all of the guesswork the process.

The Comprehensive Elimination Diet will empower you to:

  • Formulate a tailored eating plan for life to optimize your nutrition and your health
  • Identify foods that are inflammatory triggers for you
  • Support weight loss, healthy sleep, mental clarity, beautiful skin, optimal energy, and vitality
  • Optimize energy levels, immune balance, digestive function, and skin health.

Take control of your health—sign up for my Comprehensive Elimination Diet eCourse today!


Food Intolerance

Food Sensitivity Symptoms & Common Dietary Triggers

ASCIA PCC Food intolerance 2019222.96 KB

Food intolerance is a broad term that is used to describe a wide range of adverse reactions to foods, that cause symptoms after eating some foods.

These include stomach pain, bloating, gas/flatulence, diarrhoea, irritable bowel syndrome (IBS), rashes, hives (urticaria), recurrent mouth ulcers or headaches.

If food intolerances are not properly managed, these symptoms can adversely affect general health and wellbeing.

Food intolerances are sometimes confused with, or mislabeled as food allergies.  Food intolerances involve the digestive system, whilst food allergies involve the immune system. Un Immunoglobulin E (IgE) antibody mediated food allergy, food intolerances (except for sulphite and benzoate reactions) do not cause anaphylaxis (severe allergic reactions), that can be life threatening.

Non-IgE mediated food allergies are sometimes called food intolerances, however these conditions involve the immune system, so they are different to food intolerances, that do not involve the immune system.  

Types of adverse reactions to foods 

Adverse food reactions can be grouped as follows:

Whilst some symptoms may be similar, food allergies are different to food intolerances (shaded in the above table), which include:

  • Metabolic conditions such as lactose intolerance (enzyme deficiency) and carbohydrate malabsorption (including fructose, polyols, sucrose).
  • Pharmacologic (chemical sensitivity) reactions to food components such as caffeine, monosodium glutamate (MSG) and other naturally occurring food chemicals (salicylates and amines).
  • Toxic reactions such as food poisoning and scombroid fish toxin.
  • Adverse reactions to artificial preservatives such as sulphites (often used in dried fruits) and benzoates (often used in soft drinks) have been shown to cause symptoms. These preservatives have also been reported as triggers for asthma and anaphylaxis.

Natural substances in foods can cause food intolerances

Foods are composed of proteins, carbohydrates, fats, various nutrients and several natural chemicals. These following naturally occurring substances often add flavour and smell to food but they can trigger symptoms in some people.

  • Lactose intolerance is an example of an enzyme deficiency, which occurs when people are born with, or develop, insufficient lactase enzymes to digest lactose in cow’s milk and other dairy products. This can result in bloating, gas/flatulence, stomach upset and diarrhoea after having dairy products.  This condition is uncomfortable but not dangerous and does not cause rashes or anaphylaxis. Diagnosis is by temporary elimination of lactose and reintroduction.
  • Monosodium glutamate (MSG, additive numbers 621 and 625) was originally isolated from seaweed in 1908 by a Japanese chemist. Glutamates also occur naturally in such foods as camembert cheese, Parmesan cheese, tomatoes, soy sauce and mushrooms. MSG stimulates nerve endings, which may be why it is used as a flavour enhancer when it is added to food.
  • Vasoactive amines such as tyramine, serotonin and histamine are well known triggers of migraines in some people. They are present naturally in pineapples, bananas, baked meat, vegetables, red wine, wood-matured white wine, avocados, chocolate, citrus fruits and mature cheese. Amines can act directly on small blood vessels to expand their capacity. This may be why they can trigger flushing, migraines and nasal congestion in some people.
  • Salicylates are natural aspirin compounds that are present in a wide variety of herbs, spices as well as fruit and vegetables. Reactions to salicylates may be even more common than reactions to artificial colours and preservatives. Aspirin can trigger hives by acting directly on skin mast cells, and therefore salicylates can also worsen hives in some people.
  • Toxins can cause severe symptoms. Contamination of food with micro-organisms (such as bacteria) or their products (due to spoilage) can cause food poisoning due to toxins. For example, if some types of fish are stored poorly, their gut bacteria can convert histidine to histamine, resulting in allergy symptoms.
  • Irritants. Caffeine and curry are gut irritants that can trigger indigestion in some people. It is important to realise that reactions to these substances are not due to allergy. 

Diagnosis of food intolerances

Food intolerances can often be difficult to diagnose. Some substances within foods, and the quantity (dose) of foods eaten, can increase the frequency and severity of symptoms. These include stomach pain, bloating, gas/flatulence, diarrhoea, IBS, rashes, hives or headaches,

Diagnosis of adverse reactions to foods should be clinical history, response to treatment and testing. Skin prick tests or blood tests for allergen specific IgE are negative for food intolerances.  However, they are useful if the history suggests that food allergy (as opposed to intolerance), is the problem.

The best approach is to first see your doctor to:

  • Make a diagnosis, such as migraine headaches, hives, IBS, recurrent mouth ulcers.
  • Check for other conditions that may be causing symptoms.
  • Determine if diet or other factors play a role in causing symptoms.
  • Identify individual triggers to be avoided.

Management of food intolerances may involve elimination diets

Once a diagnosis is made, a clinical history may help identify the role of diet or other factors that make symptoms worse. 

The only reliable way to determine if diet is playing a role is by people being placed on a temporary elimination diet, under the supervision of a dietitian and medical practitioner.

If removing the food from the diet helps, this is followed by challenges under controlled conditions to identify food triggers which may need to be avoided in the future.

It is important that elimination diets are temporary, so they should only be undertaken for a short term trial period, under strict medical supervision, as a diagnostic tool. Prolonged restricted diets can lead to problems with adequate nutrition, particularly in children.

It is important to note that low salicylate and low amine diets should not be used for investigation of food intolerance until other potential causes for reactions are explored.  

Unorthodox tests can be misleading

Some people use unorthodox methods for diagnosing health problems. Several misleading tests have been promoted for diagnosing food allergies and intolerances, without any credible evidence, amd at significant expense as these tests are not rebated.

These tests include cytotoxic food testing, Vega testing, kinesiology, allergy elimination techniques, iridology, pulse testing, Alcat testing, Rinkel's intradermal skin testing, reflexology, hair analysis and IgG food antibody testing. Not only do these tests lack any scientific rationale, but have been shown to be inaccurate and unreliable in published studies.

Treatment inaccurate results is not only misleading, but can result in ineffective and sometimes harmful treatments, and delay the proper management of food allergies and intolerances. 

Other adverse reactions to food

There are many other adverse reactions to foods, apart from allergy and intolerance, including:

  • Feeling unwell after eating from other causes such as heartburn after a fatty or spicy meal or a hangover after too much red wine.
  • Coeliac disease is not an allergy, but does involve an immune system response to foods containing gluten. When gluten-containing cereals ( wheat) are eaten, inflammation of the gut occurs, resulting in poor absorption of nutrients. Major symptoms are gut upset, fatigue, anaemia or weight loss.
  • Non-coeliac gluten intolerance is a recently recognised condition which can cause symptoms such as abdominal disturbance (usually bloating but sometimes other symptoms as well) and occasionally malaise and tiredness. It appears to be genuine as proven by blinded challenge studies but the mechanism is not known.
  • Food aversion is a condition where a person not only diss a food, but also experiences unpleasant physical symptoms when they see or smell the food. Symptoms are triggered by emotions associated with food rather than the food itself. This does not usually occur if the food is disguised.
  • Underlying anxiety can result in unconscious over-breathing or hyperventilation. The symptoms that result (dizziness, tight chest, blurred vision or numbness) can be very distressing, and can sometimes resemble food allergy.

© ASCIA 2019

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Updated May 2019


Could You Have a Food Intolerance?

Food Sensitivity Symptoms & Common Dietary Triggers

  • Common Symptoms of Food Intolerance
  • Common Problems
  • Tests and Treatment

If you have a bad reaction to a certain food, it may be an allergy or it could be a food intolerance. An intolerance means your body has a hard time digesting a food or an ingredient in it, such as a dye or a chemical.

That's different from an allergy. An allergy is when your body's immune system thinks the food is harmful and tries to fight it off.

Some symptoms of food intolerance — sometimes called sensitivity — and allergies are similar. You should see a doctor to learn for sure what's causing your problem, but there are some clues.

Intolerances usually show up as stomach trouble gas, pain, bloating, or diarrhea — not the rashes, hives, and watery eyes that are common with allergies.

You often have to eat a lot of the food, and it may take an hour or more for you to have symptoms. It can be uncomfortable, but food intolerances usually aren't dangerous.

Intolerances are often linked to things in the food, such as:

  • Lactose, a natural sugar found in milk, cheese, and other dairy products
  • Sulfites, for instance in wines, pickled foods, and sodas
  • Gluten, a protein in wheat, barley, rye, and some other grains
  • Fructose, a natural sugar found in most fruits and also in high-fructose corn syrup, a sweetener used in some soft drinks and some processed foods, pastries and cereal
  • FODMAPs (fermentable oligosaccharides disaccharides monosaccharides and polyols), carbohydrates that draw water into your intestine during digestion

FODMAPs cause gas, bloating, and abdominal pain in some people (usually those with other digestive issues). Many plant foods contain FODMAPs, including apples, honey, garlic, and wheat.

Your doctor will ask about your medical history, the foods you eat, and your symptoms and may suggest some screening tests. You also may need to keep a detailed food and symptoms diary.

Your doctor may suggest an exclusion diet: You'll stop eating foods that are the most common intolerance triggers. As these foods are slowly brought back into your eating plan, you and your care provider will keep track of your symptoms so you can see which foods or additives you are sensitive to.

Lactose intolerance is very common in adults. To see if you have it, your doctor may ask you to take dairy your diet for a couple of weeks to see if you feel better.

Your doctor also may recommend a test called a hydrogen breath test, which you can take at her office. Depending on what she thinks your intolerance might be, she'll give you a drink with large amounts of lactose, fructose, sucrose, or glucose.

She'll then test your breath every 15 minutes to check the amount of hydrogen or methane. If you have too much of one of these, it indicates your body isn't able to break it down. That ly means you have an intolerance.

For this test to work the way it should, you may need to eat a low-carb diet for a few weeks before testing.

Prevention for food intolerances is much the same as for allergies: Read labels and be careful when eating out to avoid the food or ingredient as much as possible.

WebMD Medical Reference Reviewed by Carol DerSarkissian on June 18, 2018


The British Allergy Foundation: “Identifying your Food Intolerances,””Sulphites and Airway Symptoms.”

American Academy of Allergy Asthma and Immunology: “Food Allergy Overview,””Food Allergy.”

Asthma and Allergy Foundation of America: “Food Intolerance.”

Canadian Digestive Health Foundation: “Understanding FODMAPs.”

Fedewa, A. and Rao, S.S.C, “Dietary fructose intolerance, fructan intolerance and FODMAPs.”

Food and Drug Administration: “High Fructose Corn Syrup: Questions and Answers.”

National Health Service (UK): “Diagnosing lactose intolerance.”

National Institute of Allergy and Infectious Diseases: “Food Allergy: An Overview.”

UpToDate: “Patient information: Food allergy symptoms and diagnosis (Beyond the Basics).”

University of Michigan Health System: “Hydrogen Breath Test.”

Food Allergy Research & Education: “Facts and Statistics.”

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