This is a question I have heard often in my practice. 

I understand this desire to have the clarity to know once and for all what one should and should not eat, but unfortunately, it is not generally this easy. 

Food sensitivity testing can be an expensive undertaking. 

I have seen patients who have undergone hundreds and sometimes thousands of dollars of testing (not initiated by me) seeking to determine what foods they are reacting to.  But in the end, there still is no clear answer. 

At the risk of confusing the matter, I have also worked with people who were adamant that they wanted to get testing done.  Usually, they desired to confirm a suspicion they already had about a food to which they seemed highly reactive. In some instances, but not all, food sensitivity testing yielded results consistent with their suspicions.

So what sense can we make from this? 

First, let’s back up slightly and give a little background about the difference between food sensitivities and food allergies.

Allergies and sensitivities can develop to a wide range of substances and exposures.  We often think of allergic reactions occurring in reaction to medications, insect bites, and the topic that we are talking about here today, certain foods.  Allergic reactions are rapid in onset and can be severe and even life-threatening due to severe respiratory distress and rapid airway swelling leading to the inability to breathe.  This is a condition called anaphylaxis. IgE is the class of antibodies (immune system proteins) that governs these rapid immune responses. Food allergy determination is generally more straightforward due to both the rapid onset of symptoms making it easier to identify the likely trigger. Food allergy testing is often more. Blood-based IgE food allergy testing, while not perfect, does a very good job of ruling out potential allergens, and a somewhat less good job of identifying the potential allergy trigger.

Food sensitivity reactions are more complicated. For years many people have recognized that while they did not have a rapid allergic response to certain foods, they were nonetheless experiencing an immune response. The symptoms of these reactions could be quite varied and could include digestive symptoms like IBS,  constipation, or diarrhea. Sometimes the symptoms were extraintestinal (outside of the digestive tract) and might include joint aches, headaches, rashes, mood symptoms, and others.  Instead of developing over seconds to minutes, these symptoms often develop over hours or even a few days, making it more difficult to track the underlying cause. The IgG class of antibodies often governs these reactions. 

In the past, people were told that these delayed immune response reactions were not real allergies. But thinking has changed, and there is now widespread recognition that these are true immune system reactions that, left unchecked, can contribute to a host of chronic medical conditions. What remains less clear is the best way to assess these reactions.  Many testing options exist to assess for IgG reactions to particular foods.  These tests are not without their problems and limitations. 

The methodology used in running and interpreting these tests varies quite a bit from company to company, and the results are not generally very reproducible - meaning that one test result with one company does not always correlate with a similar test result with another company.  

This matches what I have found in my clinical practice. 

There is an adage that you will often find what you go looking for.  We generally only do food IgG testing in people that are having symptoms.  When it comes back with positive results, It is tempting to attribute what we find as the cause of the person’s symptoms.  

But what if we tested people without symptoms?  What would we find?  It turns out that this has been done, and it was found that at least 50% of people with no particular symptoms of concern also have elevated levels of food-associated IgG antibodies.

It is also worth noting that other reasons aside from IgE allergic responses and IgG-mediated food sensitivities can cause people to react to certain foods they eat.  Some of these reasons include other intolerances to specific components of the food. For example, lactose intolerance or histamine intolerance.  One can have an autoimmune response to a component of the food, such as gluten (in celiac disease), or a reaction to something that the food has been treated with, such as a pesticide or preservative.

Why should you care about any of this?

Determining the potential source of food sensitivity reactions is important because, left unchecked, chronic food sensitivities can be a source of physiologic stress, leading to an imbalanced immune response. Stress and immune system activation can often drive imbalances in the microbiome (and vice versa), all of which are associated with many chronic conditions, including autoimmune diseases, metabolic disorders like diabetes and heart disease, reproductive health concerns, and chronic pain. 

While food sensitivity testing may not always provide reliable results, there are still potentially effective (and low-cost) options to determine the source of food sensitivities.  These methods can often yield valuable results.

Elimination Diets as an alternative to testing...

One of the most commonly employed strategies for uncovering food sensitivity reactions is doing some form of elimination diet. Elimination diets can be done in a variety of ways.  But they generally involve eliminating a food or a grouping of foods for a fixed period of time and then observing to see if and when the target symptoms are reduced or eliminated. 

The foods that people are most commonly sensitive to are wheat (gluten), dairy, soy, eggs, nuts, and shellfish/seafood. Some diets will eliminate additional foods such as chocolate and legumes.  Most elimination diets also eliminate sugar because it is both disruptive to the microbiome and a trigger for an inflammatory immune response. 

I do not want to paint the picture that elimination diets always give a clear answer.  Our reactions to foods are complex. They are not black and white. The same food may generate a vastly different response depending on how it was prepared. For instance, raw foods can be more challenging to digest completely. Incompletely broken down food molecules and proteins, may not be easily recognized by our immune system and may trigger an inflammatory immune response. If we are operating under a high amount of stress, we also may not be able to digest food as completely.  How well do you digest a meal eaten at a stressful business meeting versus a leisurely meal with friends and loved ones? Foods that have been cooked and left sitting out or have been reheated are higher in histamine, which can trigger an immune response in some people.  These are just a few examples. The point is that our response to what we eat entails not just the food, but its preparation, and the whole social, environmental and emotional context in which it is eaten.
In spite of this complexity, there is evidence that elimination diets can be very effective as a clinical tool. One condition where elimination diets have been used is eosinophilic esophagitis (EOE).  In this condition, which can affect both children and adults, an inflammation of the esophageal lining triggered by certain foods can lead to trouble swallowing, heartburn, and other digestive symptoms like abdominal pain and vomiting.  Elimination diets involving one to six foods have yielded improvement in 69-93% of patients. This is pretty impressive. 

While food elimination can be a helpful strategy, It bears mentioning that:

• Food elimination diets are an assessment strategy and a way to calm and manage symptoms while addressing the root cause

• Whenever possible, attempts should be made to reintroduce eliminated foods at a future date

• Food elimination diets are not a good idea for people with a history of eating disorders or who are already on a very restricted diet for medical reasons.

Food elimination is a potentially useful tool that becomes even more powerful when combined with practices to support embodiment, balancing, and supporting our parasympathetic (rest and digest) nervous system response using various practices.  

In my experience, combining food-elimination diet trials with mindful and embodied self-observational skills and tracking can often yield superior results to food sensitivity testing. These approaches do not necessarily require a lot of time.  Instead, intention and consistency of practice are the most significant factors.  Equipping and supporting people with these skills has wide-ranging effects. Through learning to observe the subtle but discernible impacts of a food choice on one’s physical and emotional being, one can expand one’s insights and informational gathering capacity. This is transferrable learning to other interactions and situations. These practices also enable one to discern useful and actionable information to guide one’s choices not just around nourishment, but in a whole host of ways. These foundational skills allow us to develop a sense of authority and clarity that does not rely solely on an external person or testing paradigm to tell us what to eat.  

Would you like to get started on this path by learning some simple practices to support you in becoming or maintaining this body-mind connection, even during a busy day? Sign up for my Practices to Support and Create Energy During Your Day.  These quick practices are building blocks upon which to build a foundation of embodied awareness that will support you in all aspects of your life. 

Yours in Healing and Solidarity,

Dr. Nicole

Founder, Sankofa Healing Arts & Functional Medicine PLLC

Practical, Actionable, and Sustainable Care for Socially Conscious People.