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The Irritable Bowel Syndrome Quandary:
Non-Celiac Gluten Sensitivity
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David Quig, PhD | December 15, 2021
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Non-organic, functional gastrointestinal disorders account for over 40% of referrals to gastroenterologists, and diagnosis of irritable bowel syndrome (IBS) is by far the most common. Rome criteria for diagnosis and classification of IBS subtypes have recently been further refined (Rome IV, 2016), but there aren’t specific etiology-based IBS diagnoses for non-celiac gluten sensitivity (NCGS). A lack of knowledge of mechanism(s) of action, and misunderstandings regarding proper testing protocol for NCGS leaves clinicians with an onerous task of diagnosis via exclusionary process. NCGS may certainly be associated with a variable array of extra-intestinal issues, but discussion will be limited to the immediate and sustained intestinal conditions with focus on currently available laboratory testing.
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Rule out Celiac disease (CD)
CD is most commonly diagnosed early in life, but adults are increasingly diagnosed with late onset CD in their fourth decade. Celiac serology testing includes IgA and IgG antibodies to tissue transglutaminase (tTG) and diaminated gliadin peptide (DGP). Very importantly the results are only valid when patients are in fact on a gluten inclusive diet. Positive CD serology is suggestive of CD and typically followed by HLA-DQ2 and -DQ8 genotyping. Negative genotyping results are exclusionary for CD.
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NCGS
NCGS is a syndrome characterized by intestinal and extra-intestinal symptoms occurring within hours or days after the ingestion of wheat/gluten in patients presenting with negative serology for CD and wheat allergy. IgA and IgG antibodies to gliadin are the most sensitive for all manifestations of NCGS, but results are only clinically valid when patients are consuming a gluten inclusive diet. If not, a gluten challenge of ≥ 3 gm gluten (i.e. 2 slices wheat bread) per day for up to two weeks progressively increases gliadin antibody levels in in gluten sensitive subjects. Importantly, consistent with the kinetics of humoral immune responses to antigens, serology testing should be performed 14 days after cessation of a gluten challenge. Positive gliadin antibodies are highly suggestive of NCGS. Failure to delay assessment of antibody response to gluten challenge in older studies contributes to the misconception of inadequate sensitivity and specificity of gliadin antibody testing for NCGS. Further, it is possible that symptoms consistent with NCGS may also be causally associated with different wheat proteins, such as the amylase trypsin inhibitors.
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Wheat Allergy
Wheat allergy (WA) may mimic the clinical presentation of NCGS, and WA is a common food allergy in children. WA may be investigated directly via IgE antibody titers to wheat. Positive results for any of the aforementioned lab tests indicate that a patient may benefit from gluten-free diet. However, negative results often leave patients stranded with a diagnosis of IBS, and prescriptions for anxiolytics, antidepressants or even rifaxamin.
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FODMAPS
Wheat is a source of FODMAPs, and some patients experience IBS symptom relief with dietary restriction of FODMAPs. With negative results for the aforementioned tests, a trial of severely restricted FODMAPs diet may provide important clinical information and IBS symptomatic relief. However, since the raffinose family oligosaccharides and other microbiota accessible carbohydrates are essential for a healthy microbiome and mucosal integrity, one might consider efforts towards selective, minimal, or intermittent restriction of FODMAPs. Recent research indicates that severe restriction of FODMAPs can be associated with gastrointestinal dysbiosis. A clinical conundrum for sure.
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Bottom Line
Many patients with a blanket diagnosis of IBS are sensitive to gluten, which can be determined by lab testing or clinical trial. Such IBS labelling may stymie or postpone effective and targeted clinical intervention for gluten sensitive patients.
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Hormone Testing Options Compared:
Saliva, serum, urine
Lylen Ferris, ND
January 5, 2021 at 9:30 AM and 12 PM Pacific
Approximately 60 minutes with Q&A
Learning Objectives:
- Examine the advantages and disadvantages of testing hormones in various mediums: serum, urine and saliva.
- Review basic steroid hormone physiology and how that informs appropriate testing mediums.
- Discuss free versus bound hormones and the challenges of testing to measure bio-available molecules.
- When hormone supplementation is employed, discuss the best mediums for follow up testing of various routes of administration.
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Practical and Applicable Neuroendocrine Training
for your Clinical Practice
February 4-6, 2022 | Las Vegas, NV or Online
Earn up to 18.5 AMA PRA Category 1 Credit(s)TM
Registration Now Open!
The Laboratory, Endocrine and Neurotransmitter Symposium (LENS) combines curriculum driven by research and real-world clinical scenarios, taught by engaging and seasoned practitioners and educators. Attendees return year after year to LENS to dive deep into neuroendocrine topics, leaving the weekend with a full toolkit of clinical tips, protocols, and practical applications that can be implemented right away in their practice.
Early bird registration is $379 through January 14th, 2022 (regular price $429). Buy a two-pack of early bird tickets for just $599 (one for you, one for a colleague) and save even more!
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Disclaimer: All information given about health conditions, treatment, products, and dosages are for educational purposes only and do not constitute medical advice.
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800.323.2784 (US and Canada)
+1.630.377.8139 (Global)
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