Food Allergies vs. Food Sensitivities – What’s the Difference?

food sensitivities

The terms ‘food allergy’, ‘food sensitivity’, and ‘food intolerance’ are often used interchangeably, but while they each describe an adverse reaction to food, they are actually three very different conditions.

Many people are becoming more familiar with these terms as these conditions have seen a dramatic increase in recent years, but this can actually lead to even more confusion. A common misconception seems to be that because a food allergy is a serious medical condition, a food sensitivity must be, well… not.  Misunderstandings like these can leave those of us with food sensitivities and intolerances feeling the need to justify our limited diets to skeptical friends and family, as though our condition is somehow not a legitimate concern, or even worse… imaginary.

Anytime the question, “Is this gluten-free?” is asked at a church potluck, family Thanksgiving, or even in line at Panera, there’s sure to be someone rolling their eyes.

Or maybe you’re fortunate enough to have fully supportive friends and family, but have been from doctor to doctor unable to find someone who will take your symptoms seriously.  When doctors are unable or unwilling to diagnose your condition (whatever it may be) you may begin to feel that maybe it really is ‘all in your head’.

But it’s not.

Actually, it’s all in your gut.


Let’s clear up the confusion shall we?

Food Allergies

First let’s take a look at food allergies.  These are probably the most familiar of the three, but are actually the least common, though numbers are certainly on the rise.  Approximately 15 million Americans, 1 in 30 children, suffer from true food allergies.

In an allergic reaction the immune system immediately responds to a normally harmless food (most often peanuts, tree nuts, shell-fish, eggs, dairy, or soy) as if it were a threat.

The job of the body’s immune system is to identify and destroy germs (such as bacteria and viruses) that make you sick.  A food allergy results when the immune system mistakenly targets a harmless food protein – an allergen – as a threat and attacks it.

Food allergies are “IgE mediated”.  This means that your immune system produces abnormally large amounts of an antibody called Immunoglobulin E – IgE for short.  IgE antibodies fight the “enemy” food allergens by releasing histamine and other chemicals, which trigger the symptoms of an allergic reaction.  (Source)

These symptoms may range from mild to life-threatening and can include:  hives, itchy mouth, swelling of the throat, wheezing, and in extreme cases, anaphylactic shock.

If you go to the doctor suspecting a food allergy, you will likely be referred to an allergist for testing.  Both skin-prick tests and blood tests are available to help identify and diagnose food allergies.

But what if your IgE test comes back negative?  Does this mean that your symptoms are not a result of an inflammatory immune response to food?

Not necessarily.

It may be that your symptoms are not the result of a food allergy, but a food sensitivity.

Food Sensitivities

While food allergies produce an immediate IgE response (usually within a few minutes to a few hours), food sensitivities produce a delayed IgG response (taking anywhere from 45 minutes to several days to manifest).  This can make food sensitivities very difficult to identify, meaning that the vast majority of these cases go either undiagnosed or misdiagnosed.  It is likely that most people who suffer from food sensitivities don’t even realize that this is the cause of their trouble.

While not immediately life-threatening, food sensitivities can greatly reduce a person’s quality of life.  Reactions may include fatigue, brain-fog, mood swings, IBS and other digestive conditions, eczema, psoriasis, and more.  If the food sensitivity is not identified and eliminated, chronic inflammation caused by the immune response can eventually lead to much more serious conditions and autoimmune diseases. 

Unfortunately, because IgG testing can be somewhat unreliable, you may have trouble finding a doctor who is willing to test for them at all.  Most likely you will be advised to try an elimination diet first.  (Read here to find out why elimination diets didn’t work for us – though they definitely do work well for some people.)

Your doctor may also prescribe a topical steroid cream if your symptoms are skin related.  I would STRONGLY advise you to do your homework before using a steroid product.  This can mask symptoms temporarily, but does not address the underlying issue and can actually aggravate the condition it was meant to treat.  (Read here about our experience with steroid cream and please remember, I am not a doctor.  I am a mom… who’s walked a hard road.)

Though possibly not 100% accurate, IgG testing was absolutely the best thing that we could possibly have done, allowing us to clear up a severe, chronic eczema problem in under 4 weeks. 


You can order an IgG blood test independently (without a doctor’s referral) through Direct Labs online. 

The friendly staff there will walk you through how to have your blood drawn and shipped properly by a local phlebotomist.  This sounds scary, but really it isn’t complicated.  I only wish I’d known I could have ordered testing myself instead of going from doctor to doctor.


In order to find relief from symptoms the offending foods will need to be avoided completely.  This can be overwhelming, especially if there are multiple sensitivities (ask me how I know), but there is hope!  Food sensitivities are actually the result of a weakened (leaky) gut barrier through which undigested food particles make their way into the blood stream.  The immune system then responds to this foreign invader as it would toward anything else that shouldn’t be floating around in your body.  Thankfully, this damaged gut barrier can heal!  (Read more about how we healed leaky gut here.)


Food Intolerances

Unlike the first two conditions, a food intolerance is not an immune response at all, though it can also result in very real, very uncomfortable symptoms.  An intolerance usually refers to an inability to digest a certain food, possibly a food that has been modified in some way causing trouble in the digestive system (like pasteurized dairy or hybridized wheat).  In some cases, an intolerance may not be to a “food” at all, but instead to a chemical preservative, dye, or other additive.

The most commonly known food intolerance is lactose intolerance.  This is when the body is not able to produce enough of the enzyme ‘lactase’ in order to break down the sugar ‘lactose’ in dairy.  This undigested sugar begins to ferment inside the gut causing mild to severe discomfort.  You may have seen milk labelled “Lactaid”.  This brand of milk has added lactase to help those who are lactose intolerant.  However, many people who are not able to drink regular store-bought milk find that raw milk does not cause any uncomfortable symptoms.  This is because God has already provided all the lactase we need for digesting lactose – right inside the milk!  The pasteurization process destroys the natural enzymes already present in milk, making it difficult for many people to digest.



So, to recap let’s take dairy as our (very common) example.

A person may have a food allergy, sensitivity, or intolerance to dairy.

If a person is allergic to dairy their body will immediately produce an IgE immune response causing symptoms anywhere from hives to anaphylaxis.  This can be deadly.

If a person has a dairy sensitivity their body will (anytime within a few hours to a few days) produce an IgG response causing chronic conditions such as migraines, IBS, eczema, psoriasis, etc.. and potentially autoimmune disease if left unaddressed.

If a person has a dairy intolerance their body will not produce an immune response at all.  Instead, the dairy is not digested properly and begins to ferment in the gut causing GI symptoms.


Are you wondering why all of these conditions are on the rise???  


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Food Allergies vs. Food Sensitivities


And as always friends, please remember that I’ve got kids sledding down the stairs on Costco boxes as I write to you…

So, if you think I’ve forgotten something important, have any questions or comments, or simply a bit of encouragement to share, please use the comments below, send me an email, or find us on Facebook.

I’d love to hear from you.



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