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Diagnosing Non-Celiac Gluten Sensitivity: How To + Challenges

Figuring out whether or not you have a sensitivity to gluten unrelated to celiac disease (CD) or wheat allergy can be a confusing and frustrating process. The scientific evidence is there supporting the fact that non-celiac gluten sensitivity (NCGS) does in fact exist, yet arriving at a definitive diagnosis isn’t always easy, and for most it’s a down right challenge. Read on to find out how to navigate a NCGS diagnosis and how to overcome the challenges you might face during the process.

What Is NCGS?

NCGS refers to an intolerance to gluten that results in intestinal symptoms, most commonly bloating and gas, and sometimes extra-intestinal symptoms like anxiety, behavioral changes, brain fog, depression, fatigue, headaches, joint pain, rashes, and tingling in the extremities – all of which subside when gluten is eliminated from the diet. To date, it’s estimated that between 0.6 and 6% of the population have NCGS. The inability to nail down an exact number is due to a lack of awareness of the condition, the fact that no definitive test exists to diagnose it, and because the symptoms are so non-specific. 

Diagnosing NCGS

The gold standard for diagnosing NCGS is based on an article published in 2015 referred to as the Salerno Experts’ Criteria of NCGS. Diagnosing NCGS is a two-step process, including:

  • Step 1: an elimination diet (a gluten free diet (GFD) for 6-weeks) first
  • Step 2: followed by a reintroduction of gluten

This should be done alongside a continuous assessment of symptoms, including assessing symptoms before the diet, during the diet, and after the diet during gluten reintroduction. Clinical research supports a modified version of the Gastrointestinal Symptom Rating Scale (GSRS) to assess symptoms, although if you’re doing this on your own, simply writing down your symptoms (pick 1 to 3 primary symptoms) and rating them daily on a scale from 1 to 10 (ten being the worst) will suffice.

A diagnosis is confirmed if a positive response (subsiding of symptoms) to eliminating gluten from the diet is experienced, followed by the reappearance of symptoms when gluten is reintroduced. While this diagnostic model seems simple enough, there are challenges along the way to arriving at a definitive NCGS diagnosis. These challenges include:

1). Misdiagnosis The nature of NCGS symptoms can make diagnosis extremely challenging and elusive at times. NCGS symptoms (see image below) overlap heavily with other gluten-related diseases, including wheat allergy, irritable bowel syndrome (IBS), and Crohn’s disease, a form of inflammatory bowel disease (IBD).

Most often, NCGS patients are misdiagnosed with IBS. It’s important to rule out these other conditions, as well as investigate NCGS when trying to reach a diagnosis.

2. Lack of gluten consumption before GFD

Be sure you are consuming gluten regularly for a period of time before embarking on your gluten elimination diet. This will ensure that you can observe an improvement in symptoms (if one exists) in the absence of gluten.

As a side note, it’s also very important to chart your symptoms before and after your 6-week GFD, in order to observe the differences in symptoms as they pertain to gluten.

3. Diet adherence

A GFD can be challenging, as gluten is found in many food products, even those we don’t think about. Gluten contamination is also a huge issue both in GF products as well as GF menu items at restaurants. To help adhere to the diet, avoid eating out during your 6-week GFD and stay away from packaged gluten free foods. Focus on whole, plant-based foods, especially vegetables, fruits, GF whole grains (quinoa, GF oats, brown rice, millet, amaranth, etc.), nuts, and seeds.

You may also want to work with a dietician, nutritionist, or health coach for support. These healthcare professionals can act as the foundation in adhering to a GFD and can be a game changer in reaching a diagnosis.

If after you complete the two-step diagnostic process for NCGS you find that your symptoms did not subside during the 6-week GFD period, you most likely do not have NCGS. It’s important that you continue searching for an accurate diagnosis to pinpoint the root cause of your symptoms. Investigating other conditions that share similar symptoms is worthwhile, including things like IBS, small intestinal bacterial overgrowth, and inflammatory bowel disease. 

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Dr Robynne Chutkan
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