causes of food allergies

Dr. Stephen Wangen of the IBS Treatment Center.
Dr. Stephen Wangen of the IBS Treatment Center.

Laura is a 35-year-old mother of two who had been experiencing fatigue, headaches, bouts of constipation and diarrhea, and obnoxious bloating. At times she looked and felt six months pregnant due to the bloating.

When Laura first came to see us, she was certain she must have a food allergy or intolerance. She knew she reacted to food, so she assumed food caused the problem, although she couldn’t put her finger on which food or foods were the trigger.

In fact, she told us it didn’t matter what she ate—everything she ate caused problems and she never really felt good. She further noted that fatty foods, sugary foods and raw foods seemed especially problematic, and with those she would feel even worse.

Laura was very frustrated. She wasn’t able to do the things that she wanted.

Her job was being affected because she couldn’t attend meetings as needed. And her social life was just as compromised, because everywhere she went she had to know where the bathroom was located.

Laura said that we were her last hope. She had seen lots doctors, had many tests done, and even had two different colonoscopies, but nothing had helped.

She was told that she would just have to live with her symptoms. Laura found this unacceptable. She knew that there had to be a cause for her symptoms and she was determined to find out what it was.

When we met with Laura, we agreed that there had to be a cause. First we had to narrow down the possibilities.

After testing, we discovered that she did not actually have any food reactions, even though she suffered symptoms from consuming most foods. So there had to be a different cause behind the reactions to the foods she ate.

This may sound confusing, but when a patient says they react to a food, that doesn’t necessarily mean that the food is the original cause of the problem. There are many reasons you can react to foods. Some of them are due to an actual immune reaction, and some are because of other problems that result in feeling reactive to foods. (A glaring example is food poisoning. If you have food poisoning, it’s not the food that is the problem.)

The next step for Laura was to determine why she still felt reactive to foods. After mapping out the ecosystem of her digestive tract, we discovered she had a yeast overgrowth.

There are few issues in medicine as controversial and as misunderstood as yeast. Yeast, commonly referred to as Candida, is usually associated with vaginal yeast infections; occasionally a patient may also contract oral thrush, or Candida of the tongue and mouth.

However, yeast can also over-colonize the digestive tract, such as in Laura’s case, with disastrous results.

Yeast is a common part of the digestive ecosystem, but only in very small amounts. The more territory yeast acquires, the more problematic it becomes. Yeast doesn’t ferment foods in the same way that healthy bacteria does, and this can result in a variety of digestive problems and bloating. Yeast overgrowth can also cause fatigue, headaches and many other ailments.

Once we began to treat Laura for her yeast she immediately noticed a difference. However, yeast is not easy to treat, and it took Laura four months to recover. Each month was better than the last, and now that she has gotten control of her yeast problem she is ecstatic.

Laura no longer has bloating, constipation, or diarrhea. Her headaches went away after the first month, and her energy is unbelievable. With her treatment Laura was able to get her life back, and we couldn’t be happier for her!


The immune system functions like a sentinel standing guard against foreign invaders.

In the case of an allergy, the invaders are called allergens. The primary weapon that it uses against invaders is the production of antibodies. The antibodies cause reactions that result in the offending allergens being removed from the body. In many people, foods act as allergens rather than nutrition. This can result in the symptoms of IBS.

The immune system produces numerous kinds of antibodies, called immunoglobulins. IgE and IgG are acronyms for the two different kinds of antibodies produced by the immune system in allergic reactions to food. You might be asking why you need to know this. Conventional allergy testing looks for IgE reactions only. These types of reactions typically occur immediately after contact with or ingestion of the allergen, and in some cases can cause serious, even fatal, health problems. Potential IgE reactions include swelling of the lips and tongue, hives, bloating, abdominal pain, or sudden diarrhea. These are the reactions that people usually think of when they hear the word allergy.


(image thanks to

This study shows that food allergies are correlated with schizophrenia.

Everyone with schizophrenia should be tested for IgG food allergies. We have seen the same thing in our practice. It may be the difference between suffering needlessly with this mental illness or having a normal life. Don’t wait around for your psychiatrist to figure this out. You have to stand up for your own health and get tested.

Gastrointestinal inflammation and associated immune activation in schizophrenia.
Severance EG, Alaedini A, Yang S, Halling M, Gressitt KL, Stallings CR, Origoni AE, Vaughan C, Khushalani S, Leweke FM, Dickerson FB, Yolken RH.

Schizophr Res. 2012 Jun;138(1):48-53. doi: 10.1016/j.schres.2012.02.025. Epub 2012 Mar 24.
Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Blalock 1105, Baltimore, MD 21287-4933, USA.


Immune factors are implicated in normal brain development and in brain disorder pathogenesis.

Pathogen infection and food antigen penetration across gastrointestinal barriers are means by which environmental factors might affect immune-related neurodevelopment. Here, we test if gastrointestinal inflammation is associated with schizophrenia and therefore, might contribute to bloodstream entry of potentially neurotropic milk and gluten exorphins and/or immune activation by food antigens. IgG antibodies to Saccharomyces cerevisiae (ASCA, a marker of intestinal inflammation), bovine milk casein, wheat-derived gluten, and 6 infectious agents were assayed.


(image thanks to

In the previous post, we explored the types of food allergies and the difference between allergies and an intolerance. But to help clarify the picture a little, let’s consider dairy and reflux.

Most people assume that a reaction to dairy is a lactose intolerance. Lactose is a sugar found in dairy products. A lactose intolerance is the result of an enzyme deficiency that causes an inability to digest lactose. This is not an allergy because it does not involve the immune system.

However, a lactose intolerance can cause symptoms like gas, bloating, and loose stools. A lactose intolerance is not usually associated with reflux, while dairy allergy often is. Therefore, avoiding lactose but still ingesting dairy may not be enough to resolve reflux caused by a dairy allergy.

As a result, many people discover that in order to resolve reflux, all dairy must be avoided, not just lactose. Many studies have shown this as well. This is due to an all too common immune reaction to dairy. This reaction will usually show up on blood tests as an IgG antibody reaction to cow’s milk.

Dairy is usually the first non-breast-milk food introduced into the human diet, and is unfortunately the most likely to cause health problems, including reflux. What is even more interesting is that when you run IgG food allergy tests you frequently find reactions to dairy in reflux patients. And even more importantly, when you take them off dairy they get better.

However, it’s not just a dairy allergy that can cause reflux. Gluten intolerance is also known to trigger reflux. (Note that reflux can be the only presenting symptom of celiac disease, the most researched form of gluten intolerance. But also note that you do not have to have celiac disease to be gluten intolerant.) In fact, any food can potentially trigger reflux. And the right kind of testing will point to the relevant food(s). But there are certain foods that come up more often than others as allergens. 

The top four food allergies that result in reflux are: 

1. Dairy

2. Egg

3. Soy

4. Gluten

But remember, it’s not the food that is the real problem. The real issue is how your body is reacting to that food rather than anything inherently bad in the food itself.


Image thanks to


(image thanks to

Yes, you can be allergic to meat. Most people would never consider that they could be, though.
This article/study focuses on delayed anaphylaxis (a life-threatening type of allergic reaction), but meat, as with any allergen, can cause hundreds of different common health problems.

From National Institutes of Health:


The association between the carbohydrate galactose-[alpha]-1,3-galactose (α-Gal) and anaphylaxis was first documented after severe hypersensitivity reactions to cetuximab, a chimeric mouse-human IgG1 monoclonal antibody approved for targeted therapy of carcinomas of colon, as well as of the head and neck region. α-Gal is a ubiquitous glycan moiety expressed on cells and tissue of non-primate mammals.

Since this epitope is not expressed in humans, it is very immunogenic for them. α-Gal is located on the Fab portion of cetuximab and thus on the murine part of the chimera. The anaphylactic reactions to the antibody were mediated by IgE specific for α-Gal. Anti-α-Gal-IgE were first detected in sera of patients from the southeastern U.S. and reacted with a wide range of mammalian allergens.

The geographic distribution prompted investigations of sensitization routes apart from the ingestion of red meat, such as tick bites und parasitic infections. Anti-α-Gal-IgE seems to be of clinical relevance for allergy to red meat and for the pork-cat syndrome. It is also associated with a novel form of delayed anaphylaxis, which appears more than 3 hours following the ingestion of red meat (beef, pork and lamb), a phenomenon which is still to be elucidated. For most of these patients conventional skin prick tests with commercial reagents proved insufficient for diagnosis.


Jappe U.

Klinik für Dermatologie, Allergologie und Venerologie, Universität Lübeck, Lübeck, Deutschland.

Image thanks to wikipedia


There have been many studies demonstrating that IgG antibodies to foods indicate an allergy that can produce a wide variety of symptoms, including IBS. (img thanks to

Definitions to understand for this study:

Antibody – also known as an immunoglobulin (Ig), is a large Y-shaped protein produced by B-cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses.

Immunoglobulin G (IgG) and Immunoglobulin E (IgE) are both antibody isotypes.

The opinion (unsupported by research) of many doctors, particularly allergists, has been that allergies can only be caused by immunoglobulin type E antibodies (IgE).  It has even been stated as commentary in research papers (again, not based on hard evidence) that the presence of IgG antibodies indicates that the patient is tolerant of the food. 

This does not make sense when you consider that  tolerance is when your body makes NO antibodies to the food.  Your body does not waste precious energy and resources making antibodies to things it tolerates. 

There have been many studies demonstrating that IgG antibodies to foods indicate an allergy that can produce a wide variety of symptoms, including IBS.  Now we have a study that shows that IgG antibodies are associated with conventional peanut allergy as well. Again, it’s associated with the peanut allergy – not as a tolerance. 

There are links both on the IBS Treatment Center References page and on the Food Allergy and Intolerance Foundation website.

The study from National Institutes of Health:

Peanut sensitization during the first 5 yr of life is associated with elevated levels of peanut-specific IgG.

Allergen-specific IgE antibodies are implicated in allergic diseases while allergen-specific IgG antibodies have been proposed to prevent allergic reactions. The objective for this study was to study whether the immune response (IgG and IgG4) to peanut differs in IgE-sensitized and non-sensitized young children.



Today’s article is composed of excerpts from a testimonial contributed by high school senior Andrew Accornero of Jackson High School in Bothell, Washington. Andrew used his diagnosis of multiple food allergies to inform his class project. The IBS Treatment Center applauds Andrew’s positive attitude, and supports his actions to improve his health and well being. Learning of major food allergies can be challenging, but this young man shows that the right attitude and a little effort can make addressing a new diet fun and rewarding. Congratulations Andrew!

It all began on April 21, 2011. My long awaited results from Dr. Wangen at the IBS Treatment Center had arrived! I quickly opened the email… thoughts raced through my head. If I am allergic to nothing am I always going to feel this crappy? What if I am allergic to everything and I won’t be able to eat? … I looked down at the paper which held the results of my blood test — I am allergic to gluten, dairy, soy, peanuts, lamb, eggs and beef. My heart dropped to the floor. …I would no longer be able to eat peanut butter sandwiches. Thus began my search for a new diet.

The next couple of days stretched on forever. I ate chicken, chicken, and more chicken. I had chicken for practically three days straight while my mother and I searched for other meal options. On the morning of the fourth day I woke up and literally did not know who I was. I felt like I had been reborn. I could see my mind was clear, the migraines were gone, my anxiety and negative, spiraling thoughts were not there; I was a complete stranger to myself. For the next couple of days I felt like I was in a dream, I kept on waiting for my next migraine or my next stomach cramp. They never came. The days went on and I finally believed that perhaps my troubles were behind me.

[After a terrible reaction to drinking a Mountain Dew I started taking an antifungal medication called Nystatin that helps destroy the yeast buildup in my stomach but with the Nystatin] I started feeling worse than before because of the yeast’s die-off effect. I knew that if I continued taking it I would eventually start feeling better but I decided that I would rather stop eating candy and heavy carbohydrates than continue feeling like I did for one more day. I could no longer eat candy, sodas, pastas, or other sugary foods. Now I had lost another part of my life.



Image thanks to joyofkosher

Most people with IBS are suffering at least in part because of an allergic reaction to one or more foods. This often surprises people, who don’t believe that they have allergies. This is because they have friends whose allergy symptoms are different, or they think that food allergies result in hives, a rash, or some kind of medical emergency.

But even for those who have already had food allergy testing, chances are it wasn’t very helpful. This is because the majority of food allergy testing is only designed to measure allergies that produce skin rashes. The skin prick testing that is standard practice does demonstrate whether or not the patient will have a rash in reaction to exposure to the allergens used. However it doesn’t and can’t measure other types of immune system responses or immune system activities that involve certain types of antibodies.

People often have a tough time believing that they may have a food allergy because they’ve eaten the “offending” foods before, some every day, and have not suffered from consistently severe symptoms. Maybe they’ve had just a little diarrhea or constipation once in a while, until suddenly it gets worse or new symptoms develop. Symptoms of food allergies, including IBS symptoms, can show up at any age, from birth to old age. The challenge in discovering the food allergy is in getting the proper testing done and in getting the proper education about where the offending foods are hidden in your diet. Most clinics offer neither, even those that supposedly focus on allergies.

The immune system functions like a sentinel standing guard against foreign invaders. In the case of an allergy, the invaders are called allergens. The primary weapon that it uses against invaders is the production of antibodies. The antibodies cause reactions that result in the offending allergens being removed from the body. In many people, foods act as allergens rather than nutrition. This can result in the symptoms of IBS.