Guest Post by Dr. Kellie Ferguson: Food Sensitivity Testing – Let’s Talk About Your Options!

September 6, 2012 in Categories: , by

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Allow me to introduce Dr. Kellie Ferguson, N.D., a Naturopathic Physician in British Columbia, Canada.  Kellie is actually a very old friend of mine–we went to high school together!  But don’t worry; neither one of us remembers high school so no embarrassing stories can be told.  I asked Kellie to give an overview of food sensitivity testing since this is so relevant for anyone battling autoimmune conditions, non-autoimmune skin conditions, gastrointestinal disease, and allergies.   It is a particularly important option to consider for anyone following the autoimmune protocol and not seeing improvement.  You can read more about Kellie’s practice at her website and her blog

As promised in my last guest post, today I’ll give you a little more information about testing for Food Sensitivities.  Just to backtrack a little, food sensitivities happen when the body reacts to proteins in specific foods and the immune system is activated by those proteins in much the same way as it is activated by proteins on bacteria.  A reaction is mounted by the immune system and can cause inflammation both at the gut level and systemically throughout the whole body.  Because of the complexity of the immune reaction, food sensitivities are often one of the key underlying triggers for many different complaints.  I almost always think about them when dealing with three key complaints including: skin conditions like eczema or psoriasis, GI upset including anything from heartburn to diarrhea, and behavior difficulties in kids (ADHD, temper or Autism Spectrum Disorder).  Also, many people with autoimmune disorders, arthritis or migraine benefit from knowing if there are any food triggers aggravating their symptoms.

So we know it’s important to check for food sensitivities but how do you do it?  There are three different testing choices available to identify food sensitivities. Please note, that food sensitivities are very different from food allergies and the following testing methods are not adequate to diagnose food allergies. The gold standard is a physician controlled Elimination and Challenge test.  In this case, we limit the diet to a very restricted set of hypo-allergenic foods (usually foods that are outside the normal diet) for a good period of time (usually 3-6 weeks) and then challenge with each food, generally in a medically controlled environment.  The goal is to allow the body a chance to heal up as we take away any provoking foods and then we slowly add each single food type one at a time and gauge for reactions.  For example, we might do our elimination for 3 weeks and eat only lamb, pear and brown rice, then introduce dairy products for a few days while we watch for skin or tummy symptoms.  This type of diet needs a lot of planning and commitment and, because the elimination diet is so limited, it should not be done without the supervision of a qualified practitioner.  It should be mentioned that challenging with foods can cause quite pronounced reactions with asthma or serious autoimmune conditions and should be done exceptionally carefully (and only with medical supervision).

The next type of testing is called EAV testing, which is also known as Biomeridian or VEGA testing.  This testing uses an electronic tool to evaluate the energy in specific acupuncture meridians and how that energy reacts when challenged with foods.   It sounds a little odd but is really very effective for many complaints.  The advantage to this is that it can be done quickly and in-office and is non invasive.  It does require that the patient be able to sit relatively still for a period of time, so it can be difficult with younger kids or kids with restlessness/hyperactivity.  It is also fairly specialized and difficult to do well, so I always suggest asking lots of questions of the practitioner first.  A variation of this type of testing is called muscle energy testing, which measures muscle strength when foods or supplements are held close to the body.  Both types of testing measure the body’s energetic reaction to the foods.  Muscle energy testing is quick and easy but can be easily manipulated by the tester or the patient (as can EAV testing, though to a lesser degree).  It is really important that the tester be really careful not to allow his or her bias to influence the results. This is partly why this type of energetic testing isn’t well accepted by conventional medical practitioners.

The last type of testing, and the only one that can allow us some information about food allergies, is called ELISA testing.  ELISA testing measures how much (if any) of an antibody (immune) reaction there are to specific food proteins.  Before we get into the specifics of this test it’s worth talking a little about the different types of antibodies and their immune reactions. Antibodies are little proteins, made by the immune system, that tag and attach to foreign proteins (food proteins, bacterial, viral or parasite proteins) and signal for inflammatory or other immune processes.  There are several classes of antibodies but there are only three that are relevant for food testing.  IgG is the most commonly tested antibody for food sensitivities since is the most abundant and long lasting antibody.  Total IgG is used to give a broad view of the overall immune sensitivity reaction, however any positive results need to be interpreted given the individual and the diet and target symptoms as there are often many mild positive reactions that do not provoke symptoms.  IgE is specific to allergy reactions but not sensitivities.  IgE proteins have a very short life and are much more difficult to test, so the number of foods tested is generally limited to most common allergens and must be done through a blood draw.  IgE testing is sometimes done with a slightly different test called a RAST test.  This test is almost identical to ELISA but has a slightly different procedure in the testing laboratory.  The final antibody that can be relevant is IgA.  IgA is the only antibody that gets secreted into the digestive fluids and so is very specific to digestive sensitivity symptoms.  It is possible to have IgG be negative for some food reactions but positive IgA or vica versa.  Your Naturopathic Physician should be able to discuss all the testing options and help you to choose the best type or combination of testing for your symptoms and budget.

There are many lab companies in North America that offer antibody testing and they have widely variable pricing and reliability of their tests.  Most have different food lists available that can be chosen specific for the patient’s needs (ie. vegetarian panels or specific IgE, IgG or IgA tests).  This testing does require a blood sample, and depending on the type of tests, it is either with an arm drawn sample or a dried blood spot taken using a finger stick.  Most kids find the finger prick quick and easy enough that they don’t complain… at least not much.

For patients coming into my office, I always suggest we discuss their complaints and talk about the testing options to figure out which, if any, is the best choice.  The best option might depend on your financial situation, time goals and the condition itself.  Most Naturopathic Physicians have done a good investigation into the testing options available in your area and can give you good guidance.  It also takes experience and finesse to decide how to incorporate the results into a reasonable diet plan, which licensed Naturopathic Physicians will have.  Most testing methods will show that there are many reactions, most of which are fairly mild.  It’s not reasonable or necessary to completely eliminate all those items.  The practitioner’s experience will help to show which foods are not generally significant triggers and which can be common suspects and how to tell the difference. Reactions that are really strong should be avoided completely.  Other food reactions are mild but cumulative and their symptoms will depend on the amount and frequency of their exposures.  Eating small amounts of those foods only a couple of times a week won’t be an issue but a big serving or using it as a staple in your diet will start to trigger symptoms. I generally start with IgG finger stick testing, as the company I use has excellent pricing and turn-around time and has a choice for an expanded panel with many extra spices and foods.  I find that this provides the most information at a reasonable cost and can be interpreted well given the patient history and symptoms.

To find a Naturopathic Physician in Canada go to to find one in the US try  . If you have any questions or comments please feel free to email or post via my blog, where you can also find more tips about current news topics, allergies, Autism and other Naturopathic topics.


Food sensitivities change over time. People think the tests are inaccurate because they will test positive for one food one time and not the next. While allergies tend not to go away, when you have a food sensitivity, your body will eventually stop producing antibodies against that food if you stop eating it (typically takes about 6 months). If I was going to have a test done (and I am strongly considering it), I would have a blood test (IgG and IgA ELISA) done. While it doesn’t test as many different foods as Vega testing, and if you form unusual antibodies, a sensitivity can still be missed, I think it is the most reliable method (or rather least likely to be influenced by my own preconceived ideas about what foods I may be sensitive to).

So food sensitivities change over time, but what about food allergies? I had ELISA testing done (6+ years ago) and showed an IgE reaction to milk (although not to other forms of milk–yogurt, cheese, etc.) and beef. I have never noticed a reaction when I eat either of these foods and eliminated them for a short time, with no improvement in my UC symptoms, so started eating them again.

HI Sarah, that was fun! Is Kellie really busy or do you think she might like to do a quick little skype interview like we did together? I’m in Calgary and Vancouver a fair bit, so I”m thinking a spot on Youtube and Paleo Diet News might be fun for her, and rustle up a new patient or ten in the next little while.

Will food allergies show up as sensitivities on the EAV testing? In other words, will the EAV testing still show a food we have an allergic response to, even though we can’t differentiate the results between sensitivities and true allergies?

Great question, Tina! I never suggest EAV, IgG or IgA testing for food allergies (hives, mouth swelling, anaphylaxis etc). While an allergy may show up, these tests are not specific enough to the allergic pathway to be used to reliably for this purpose. Given an allergy can be life threatening, I would only suggest IgE or RAST testing to identify food allergy triggers. In this situation, its definitely better to go for the most accurate and most specific testing!

I just had ELISA testing done, and I’m so glad I did. I have celiac disease and was really frustrated by the autoimmune protocol–I could tell that some foods were definitely causing reactions, but other reactions seemed to be happening out of nowhere. I was not at all surprised to learn that I react to eggs, dairy, and almonds, but VERY surprised to learn that I reacted to pineapple and mushrooms–two foods that I’ve never seen on an autoimmune protocol list and didn’t know to try eliminating. For me, another benefit of having these results is that it’s very motivating for me to completely eliminate these foods for the next six weeks. I know there’s some degree of uncertainty in the results, but I feel more certain that there is a need for me to avoid these foods than I did when I was following the autoimmune protocol, trying to eliminate SO many things.

I’m a big fan of the ELISA testing too, especially when the autoimmune protocol isn’t working for someone. I’m actually reading up more on mushrooms now and trying to decide if they should be omitted in the AIP. There’s good evidence that they should be avoided in thyroid disorders. Anne Angelone omits mushrooms in her version of the AIP in her kindle book

I’ll be curious to know what you learn about mushrooms. I never liked them at all, but had been trying to be a good sport about them, so I’m not sad to see them go. Growing up, we always thought of them as the things in the woods that could kill a person–not food.

The AIP is not working for me either…I find that I get itchy after eating and still have occasional reactions. I kept a food diary and still couldn’t pin point the problem but I noticed that pineapple makes my throat hurt. I am thinking about getting ELISA testing to give me insight. I want to start reintroduction of foods but I am scared to because I feel like I am missing some to eliminate already.

Sarah has an excellent guide to troubleshooting the AIP in her book The Paleo Approach, but some of the things you might consider are histamine intolerance, yeast intolerance, and SIBO or FODMAP intolerance. – Christina, Sarah’s assistant

Help! I already know, by sheer dumb luck, that I have very low IgA. What does that mean for all of this? That I’m definitely sensitive to something and have to figure out what by process of elimination?

Just for some background, I definitely do have Hashimoto’s Hypothyroiditis, and I have had a colonoscopy to look for Celiac disease and the results were negative. I don’t *think* I have severe reactions to lactose, but I do sometimes get loose bowel (so sorry) for reasons I’ve never bothered to figure out. It’s not very common; it happens about biweekly.

Hi Amanda,

Low IgA is associated with autoimmune disease (which Hashi’s is) and can also be a sign of general inflammation in the gut. It sounds like you aren’t paleo? You can be sensitive to dairy and gluten in dozens of ways that doesn’t show up on any current tests so the only way to be sure is to cut both out completely. I would suggest one (or even two) steps further and try a very strict (no dairy) paleo diet for a month. Even better would be if you can wrap your head around the idea of doing the paleo diet Autoimmune Protocol but that might feel a bit overwhelming if you are coming from a standard American diet (in which case, you can try standard paleo and then once you’re comfortable with that try the autoimmune protocol). The reason why the autoimmune protocol is so powerful is because it eliminates all of the most common food sensitivities but also foods that can aggravate inflammation and stimulate the immune system in other ways.

I hope this helps!

Hi There,
I’m a little late in finding this post, but wanted to know what Kellie feels about The Carroll Test? I had this test done by my naturopath for my food intolerances and was told that what I’m intolerant to now I’ve always been intolerant to and will always be. Any insight or thoughts on this?

Great article! I have a question regarding serum IgA levels. A few years ago, I had been tested for celiac which turned out negative. However, my IgA level was elehvated at 451.( Reference range on test went as high as 394.)
I have no symptoms now but was curious and got my IgA checked again hoping it was lower. Not much! It was still high at 428. Any clues as to why? I”m 45, the mother of 2 small children. I feel great but always wonder why this is high

Also, I just started Paleo 2 weeks ago and feel incredible since cutting out grains and dairy! My daughter has bad eczema which doctors keep prescribing steroid creams for. I hate using them on a young child! I definitely notice flare-ups as soon as she eats dairy. I’m also wondering if gluten is the culprit! It will be hatd to do the elimination challenge on her, as she is one stubborn little girl, but I will try. I will ger back to you with results. My Father had severe psoriasis for most of his life. He always loved his grains and beer, but swears that gluten and dairy are the culprit of his psoriasis. It always went away or lessened dramatically when he cut these out of his diet. Now, at age73, the psoriasis is completely gone and has been for 8 years. He just rarely eats gluten or dairy. Now he is allergic to peanut butter though…go figure!

IgA are typically elevated in autoimmune conditions, so it might be because of an undiagnosed autoimmune disease (perhaps one in the earlier stages), but it could also be due to allergies, or some kind of persistent infections.

Well, I don’t have any autoimmune diseases or allergies or infections. In fact, I’m extremely healthy! My doctors said it’s nothing to worry about and that they worry when iga is low. All my labs are perfect otherwise so I won’t look for a problem 😉 I guess I was thinking you might suggest some gluten sensitivity. It will be interesting to see if my Paleo lifestyle could bring it to normal. Interestingly, a few doctors said that my slightly elevated iga is actually a good thing, saying it’s the reason I rarely get sick. Who knows?

do you have any recommendations about which testing lab to use , to get a igG/Ige blood allergy elisa test ….It seems you cannot get them done in NY …thanks pauld

Hi Paleo Mom
I recently received results from EnteroLab re gluten/antigenic food sensitivities and my fecal IgA is elevated for anti gliadin and anti ovalbumin (chicken egg). Does this mean I most likely have an autoimmune condition?

I am trying to stay on the AIP diet…seems it’s taking a few attempts. The days I follow it, I feel great gi wise but i know skin issues can take longer. My question is specific to oral allergy syndrome. I do not test allergic to these foods,and have yet to do sensitivity testing. All my life, I have experienced throat closing sensation/puffy lips after eating some raw fruits/veggies (carrots apples pears to be specific). There could be more fruits, I’ve never had a wide variety. Gi wise, I tolerate these foods fine cooked.
I feel like to best let my body heal, regardless of the season (as reactions are stronger in pollen season), I should avoid these. My question is, to what extent? Is it best to avoid these all year long, whether they are baked or not? I keep thinking that if my body reacts to it in even one form, it isn’t the best for me. However, with multiple food allergies, sensitivity, my list of aip okay foods is smaller than what’s already on the list.
This impacts my three year old as well. He has heightened gi symptoms due to cross reactivity/oral allergy syndrome, more severe than mine. It was advised we avoid cross reactors during this season, but I wonder for him too if it’s just not worth it all year long…I’d love him to be paleo, but I get as close to primal as I can at this age.
Appreciate any thoughts! Absolutely love your work!

They probably tell you to avoid those foods during pollen season because your baseline inflammation will be higher from environmental allergens, but if you have autoimmune disease, you tend to have high baseline inflammation anyway. Which foods you eliminate and how long you eliminate them for really depends on how you react to them and how long it takes to heal your gut and reduce inflammation. Eliminating certain fruits and veggies is fine as long as you are still eating a wide variety of the allowed foods that remain. – Christina, Sarah’s assistant

I am currently under the care of a Naturapath who practices NRT and I am having great results. He is able to pin point toxins, food sensitivities and other issues without any standard testing. I have thyroid, adrenal, GERD from hiatal hernia, parasites and I am improving slowly. His diet recommendations are very similar to yours.
I am curious as to your thoughts on this protocol and wonder why it isn’t used more often.
It has been a life saver for me.

Can you eat certain foods that are prohibited on the Paleo autoimmune protocol if your IGg tests come back negative for those foods?

Do you know of a lab in the U.S. that tests for IgA reactions to food? I haven’t been able to find one here (there’s a Canadian one — Rocky Mountain Analytical but they can’t deal with U.S. patients). I’m actually a doctor and am certain what I have is not merely IgA reactions but IgA allergies (they cause mast cells to release histamine) to certain foods and the preservative benzalkonium chloride. I’d like to figure out if this the case or not. Thanks for your help.

Dear Sara,
I have been suffering from alopecia areata since last Sep. and have lost almost half of my hair in the span of a few months.

For me it came out of nowhere, as growing up I have never felt that I was allergic to any foods and ate basically anything (I have to admit as it had no apparent consequence at the time, I wasn’t a healthy eater)
After been to many Dermatologist, they could not offer any treatment that could cure this condition. Thankfully I found your blog and info on AIP and autoimmune disease. Everything I have started the AIP diet since 3 weeks ago. I am happy that AA has triggered the motivation for healthy eating!

However, as I never felt any discomfort when eating any common sensitive foods before, and I’m tested negative for gluten sensitivities in a blood test in Denmark, I have no idea what is going to happen when I reintroduce foods. Or as so far there is no significant change yet, I am kinda worried if I would be secretly sensitive to things allowed on AIP like coconut..
Hence, I am hoping to do a food sensitivity test to aid my AIP diet so I have some idea what could be the problem that never occurred to me.

I am moving to Princeton from Copenhagen Denmark next week.
I did a search on
But it shows no Naturopathic Physicians in the area of autoimmune disease in the Princeton area.

Is there any IgG test you would recommend or could I conduct one through you?
Best Lolo

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