Food Allergies In Kids– Are IgG Food Sensitivity Tests Useful?


Is there any real reason to take certain foods out of a child's diet if they don't have a full-blown allergy? Could food sensitivity be causing your child's troubling symptoms - like their aggression or their tantrums or their eczema? Is there value in testing for food sensitivity?

Yes, food is one source of stress I explore with the families I work with (there are four others). But food sensitivity testing isn't always a good idea.

This blog post outlines where I stand on food sensitivities and food sensitivity testing, and how I suggest you think about the issue. 

The Tricky Thing About Food Sensitivity

Unlike a full-blown allergy, which is fairly straightforward for your doctor to diagnose, food sensitivity can be tricky to tease out.

For one thing, symptoms of a food sensitivity can be just about anything. Fatigue, hyperactivity, skin rashes, tummy pain... pretty much anything.

The second tricky thing about food sensitivity is that reactions can be delayed... if you eat something today, you might feel the symptom in 2-3 days.

Tricky. And this is why people often turn to food sensitivity tests for answers. As you'll read, though, they're not always a great idea; you need to know why you're doing them and pick the right time.


What Is A Food Sensitivity?

Food sensitivity happens when either the immune or nervous system mounts a hyper-response to certain foods or environmental stimuli. Inflammatory chemicals are released and those have been implicated in myriad symptoms as well as complex conditions like asthma, ADHD, Autism, and many more.

So that's the first thing I want you to understand. Food sensitivity is a situation in which food triggers inflammation. It's the inflammation that's the problem.

For some kids, food sensitivity is a big contributor to their health issues, and figuring this out yields great results. I think of a young client, Jonah, who went from 5 meltdowns a week to one and completely stopped having panic attacks when we took out gluten, cashews, and cucumbers. That was a pretty extreme case.

But I want you to clearly understand what food sensitivities tell you and don't tell you. I also want you to clearly understand the controversy around food sensitivity testing so you don't waste your money.

(For more details on different types of food reactions read this post:


Food Sensitivity Is A Symptom, Not A Diagnosis

The first thing to understand when it comes to food sensitivities is that it's not a diagnosis. It's not an endpoint. It's a symptom of something deeper.

I'll explain by telling you about an interaction I had with a mom recently.

A mom of three approached me, interested in running a food sensitivity test for her son who was experiencing ADHD-like behavior, dry patchy eczema-like skin, and interrupted sleep. She wanted to know if food might be the trigger.

Typical food sensitivity tests run about $300. They look in the blood for an IgG immune reaction in response to dozens of foods. 

The validity of this test is hotly debated because IgG antibodies are "memory" antibodies; they can be triggered simply because they have seen a food for a second time.

But on the other hand, an IgG test can be a helpful screening tool to see if any foods are eliciting an extreme response. An extreme IgG response would be a red flag indicating that a particular food could be a source of inflammation and immune activation.

So the test can be a helpful way to point us towards a potential source of irritation and stress. We can use that information to construct a careful elimination-provocation diet to determine if these foods are, in fact, contributing to symptoms. 

For this mom, though, I asked her these questions:

  • How urgently do you need to resolve the behavior of concern? Do you have time to tinker?
  • What do you think he's reacting to?
  • How traumatic is it for your son to go through a blood draw?
  • How comfortable are you in the kitchen? Do you cook? Are you open to experimenting?

For this mom, I told her that I did not think the IgG test was the right place to spend her money right now. She had observed that when her son ate cheese and tomatoes he got lethargic and irritable. When she took them out he felt better. Those were trigger foods for him. She was ok with taking them out and willing to try some new recipe ideas.

I explained that the problem was not actually the cheese and tomatoes; the problem was how the body was receiving them. The cheese and tomato problem was a symptom of poor digestive capacity.  And in the presence of poor digestive capacity it was very likely there were other foods triggering food.

So that is where I suggested she focus her energy first, before testing... digestion.

I gave this mom a copy of my book, which outlines how to improve digestive capacity while also nourishing the body, and suggested she work on those strategies. I suggested that at the same time she keep out the cheese and tomatoes, and any other food that was clearly causing noticeable symptoms.

Then, if her son was still not tolerating cheese and tomatoes (or anything else) she could consider the test as a way to go deeper, and that she combine it with an assessment of the microbiome to better understand where digestive capacity needed support. 


So Are Food Sensitivity Tests Helpful?

They can be. But they are not always.

There is no doubt in my mind that irritation caused by food is worth exploring if your child is exhibiting troubling symptoms of any kind. Food is one of 5 sources of stress I consider (the others are: toxic load & detox, nutrient imbalances, infection, gut imbalance).

If left undetected food sensitivities can cause myriad symptoms that involve the skin, the bowel, the brain, behavior, hormones…. just about every body system can be affected because the problem is not the food itself, it's the inflammation being triggered by the food.  

IgG food sensitivity tests can highlight foods that are potentially triggering inflammation. But it's important to use them to construct an elimination diet to see if those foods are actually problematic. Eliminating a source of inflammation is helpful while you work on improving digestive capacity. But since restricting a child's diet can be difficult and can open the door to nutritional deficiencies, we have to be careful.

The IgG test is not a diagnosis of an allergy, nor does it tell us much about the function of the gut; it is just a screening tool to help identify potential irritation.

Why Are Food Sensitivities So Common & What Should We Do? 

It is estimated that 1 in 3 children suffers from a food sensitivity and the issue seems to be on the rise. 

They're becoming so common because our digestive and immune systems are under increased pressure. Here are a few possible reasons for an increase in food sensitivity:

  • Increased exposure to environmental toxins is putting extra burden on our immune systems and making it more likely to over-respond,
  • Nutritional deficiencies lead to slower digestion and poor digestive ecology,
  • Things like antibiotics, sugar, stress, and chemicals weaken the digestive and immune systems,
  • Genetically modified food is interfering with digestive and immune response,
  • Increased rate of cesarean births but kids at risk of developing a hyperimmune response 

All of this can contribute to food sensitivities so it’s not that surprising that we are seeing more kids becoming sensitive to more foods. 

But the real key to managing food sensitivities is to address those things that are eroding resilience. When we do, we often see sensitivities resolve on their own without ever having to restrict foods or test.

If you do use an IgG food sensitivity test, use it as a guide to construct a temporary elimination diet to relieve pressure while you work on restoring gut ecology.   


Related posts:




Are Attention Deficit Hyperactivity Disorder and Chronic Fatigue Syndrome Allergy Related? What is Fibromyalgia?

ADHD, a Food-Induced Hypersensitivity Syndrome: in Quest of a Cause.

Inflammatory symptoms, immune system and food intolerance: One cause – many symptoms.



About Jess Sherman, FDN-P, M.Ed, R.H.N

Jess is a Functional Diagnostic Nutrition® Practitioner, Registered Holistic Nutritionist and a trauma-sensitive Family Health Educator specializing in brain health & resilience for kids. She is also a teacher, with a Master's degree in education. Her Calm & Clear Kids introductory course, her Amino Acids (with kids!) Quickstart program, and her signature Roadmap to Resilient Kids,  along with her book Raising Resilience, have helped families in at least 44 countries improve the lives of their children with learning differences, anxiety, ADHD, and mood disorders and reduce their reliance on medication. She is the 2019 recipient of the CSNNAA award for Clinical Excellence for her work with families, and she continues to bring an understanding of the Nourishment Needs and Biological Stress to the mainstream conversation about children’s mental health, learning, and overall resilience through her blog, courses, workshops and as a contributor to print and online magazines. 

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The content on this website and in the guides and courses offered here is meant to provide information so that parents can make informed decisions and discuss these issue with their health care teams. It is not intended as, nor should it be considered a substitute for professional medical advice, diagnosis, treatment, or individualized care.