What Every Practitioner Needs to Know About Food Sensitivity Testing


Do you have patients with unexplained weight gain, fatigue, pain, digestive upset, or maybe even a challenging case of eczema that they can’t get rid of.


These conditions might be coming from food sensitivities! The goal of this blog is to help you understand the difference between food sensitivities and food allergies, as well as give insight into my go to food sensitivity testing.

What Every Practitioner Needs to Know About Food Sensitivity Testing.

Food Sensitivity has gained a lot of attention in the past few years. A new study from Food Allergy Research & Education (FARE) reveals that 85 million Americans avoid buying food with the top nine allergens and spend $19 billion per year on specialty food products. (1)

But why? Do they have a food sensitivity or allergy? Do they know the difference? This is why it’s vital for us, as practitioners, to have the facts ready at our disposal when our patients come in to see us.

How to Distinguish Between Food Allergies and Food Sensitivities:

First, it’s very important to understand that food allergies and food sensitivities are two very different diagnoses. The only thing they have in common is the word “food” in their name.

Food Allergies cause an IgE response:

An IgE-mediated response is a permanent allergy and causes an immediate histamine reaction within minutes to hours of ingested food. These allergies can be life-threatening.

Food Sensitivities cause an IgG response:

Food Sensitivities can cause delayed symptoms hours to days after ingested food that can mimic many other diagnoses. IgG-mediated responses are temporary sensitivities that do not activate a histamine response and can usually be remedied with proper nutritional guidance.

The “Leaky Gut” Connection to Food Sensitivities:

A healthy gut has a tight barrier that controls what gets absorbed into the bloodstream. The presence of circulating IgG antibodies creates inflammation in our intestines and causes tight junctions to loosen over time. Once the tight junctions become loose, larger substances can “leak” through into our bloodstream, causing inflammation throughout the body.


The most common symptoms I see in patients with underlying food sensitivities:

· Unexplained digestive disorders (loose stools or constipation hours to days after eating)

· Skin conditions (eczema, acne, psoriasis, and dermatitis)

· Headaches (not causes by tight muscles)

· Brain Fog

· Joint pain

The Importance of Food Sensitivity Testing.

Food sensitivity testing can help pinpoint the exact foods and spices that are affecting our patients’ health. Once the tight junctions have opened up, it is common for the body to react to multiple foods making it hard to narrow down the exact cause.


For food sensitivity testing I utilize Genova’s IgG food sensitivity profile, but I order it through Rupa Health. Rupa Health makes it easy to order functional medicine labs by giving you access to all the labs at once without having to sign up for an account with each company.

Genova Diagnostics offers three different types of IgG Food Sensitivity testing.

IgG Foods: 87 foods plus total IgE

IgG Vegetarian: 21 foods plus total IgE

IgG Spices: 23 spices plus total IgE

As a functional medicine practitioner specializing in GI disorders, I highly recommend Genova’s IgG Foods Antibody Profile with an add on of IgG Spices profile. Together this will test 87 foods and 23 commonly used spices.

What if my patient is Vegan/Vegetarian? Why test for animal products?

Even if your patient is vegan or vegetarian, I still highly suggest testing all 87 foods due to cross-contamination and hidden animal products. I’ve had; on multiple occasions, vegan patients test positive for animal products.

IgG Foods Test:

Type: Serum

Patient Price: $99 (some insurances will cover it, including Tricare and Medicare)

Average sample processing time: 21 business days Sample Report:


IgG Spices Test:

Type: Serum

Patient Price: $50 as an add on (some insurances will cover it including Tricare and Medicare) Average sample processing time: 21 business days. Sample Report:

I hope this helps narrow it all down and you feel a little more comfortable knowing when to order food sensitivity testing.

Let me know if you have any questions on testing; I'd love to hear from you!

Dr. Shawn Greenan, A.P., DACM

(1) FARE. (n.d.). Retrieved from Food Allergy Consumer: https://www.foodallergy.org/food-allergy-consumer-journey

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