Following GF diet but feeling unwell

Melinda Dennis MS, RDN, LDN

Q: What should I do if I have confirmed celiac disease and follow a strict gluten-free diet but am still unwell?


There are several reasons why a person with celiac disease might have symptoms despite following a gluten-free diet. The first one is the most common – either accidental or intentional gluten exposure.1 Gluten exposure accounts for about 7-30%2 of persistent symptoms in an individual with celiac disease on the gluten-free diet.

Additional causes of non-responsive celiac disease (NRCD) include, but are not limited to, small intestinal bacterial overgrowth (SIBO),1,3 irritable bowel syndrome,1,3 secondary lactose intolerance,1,3 microscopic colitis,1,4 and disaccharide deficiency*.5 To a lesser extent, other causes include eating disorders, peptic ulcer disease, gastroparesis, Crohn’s disease, food allergies, common variable immune deficiency, duodenal adenocarcinoma,1 pancreatic exocrine dysfunction,6 cow’s milk protein sensitivity,3 and refractory CD (a rare, serious cause of NRCD).1,7,8 Non-responsive celiac disease is a major reason for long-term follow-up among patients with celiac disease.9

If you are still having symptoms it is important to see your gastroenterologist. Your gastroenterologist will assess you for the conditions listed above. He/she will make recommendations which may include blood work, breath testing, food allergy testing, an endoscopy with small bowel biopsy, and/or a colonoscopy, etc. A referral to a registered dietitian nutritionist (RDN) skilled in celiac disease is also important. The RDN will first carefully assess your diet and lifestyle to uncover any overlooked sources of gluten. She/he will also assess and manage all causes of NRCD to select the appropriate dietary intervention.1 Both the gastroenterologist and the RDN will monitor your celiac antibody levels (IgA-tTG, IgA-DGP or IgG-DGP, and sometimes EMA)* and your nutrition levels.  


Disaccharide deficiency: the inability of the body to either digest or absorb certain sugars, such as  lactose
Tissue transglutaminase IgA antibody level (commonly known as "tTG")
Deamidated Gliadin Peptide IgA/IgG antibody level (commonly known as "DGP")
Endomysial Antibody test (EMA), an earlier version of the tTG test


  1. Leffler DA, Dennis M, Hyett B, et al. Etiologies and predictors of diagnosis in nonresponsive celiac disease. Clin Gastroenterol Hepatol 2007;5(4):445–50.
  2. Rubio-Tapia A, Hill ID, Kelly CP, et al. ACG clinical guidelines: diagnosis and management of celiac disease. Am J Gastroenterol 2013;108(5):656–76.
  3. Ludvigsson JF, Bai JC, Biagi F, et al. Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology. Gut 2014;63(8):1210–28.
  4. Kelly CP, Bai JC, Liu E, et al. Advances in diagnosis and management of celiac disease. Gastroenterology 2015;148(6):1175–86.
  5. Fine K, Meyer R, Lee E. The prevalence and causes of chronic diarrhea in patients with celiac sprue treated with a gluten-free diet. Gastroenterology 1997;112(6):1830–8.
  6. Scaramuzza AE, Mantegazza C, Bosetti A, et al. Type 1 diabetes and celiac disease: the effects of gluten free diet on metabolic control. World J Diabetes 2013;4(4):130–4.
  7. Abdulkarim AS, Burgart LJ, See J, et al. Etiology of nonresponsive celiac disease: results of a systematic approach. Am J Gastroenterol 2002;97(8):2016–21.
  8. Dennis M, Lee AR, McCarthy T. Nutritional considerations of the gluten-free diet. Gastroenterol Clin N Am 48 (2019) 53–72.
  9. Silvester JA, Graff LA, Rigaux L, et al. Symptoms of functional intestinal disorders are common in patients with celiac disease following transition to a gluten-free diet. Dig Dis Sci 2017;62(9):2449–54.

Note: This information is provided by NCA and Melinda Dennis, NCA's Senior Consulting Dietitian. This information is meant for educational purposes and is not intended to substitute for personalized medical advice or replace any medical advice provided directly to you by your health care provider. This information can be printed and used in consultation with your physician or dietitian. No liability is assumed by NCA, Ms. Dennis or her nutrition consulting service Delete the Wheat, LLC. by providing this information.

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About Melinda Dennis MS, RDN, LDN

Melinda Dennis, Senior Nutrition Consultant for NCA, is an expert celiac dietitian and and Nutrition Coordinator for the Celiac Center at Beth Israel Deaconess Medical Center in Boston, MA. Diagnosed with celiac disease in 1990, she specializes in the nutritional treatment of patients with celiac disease and gluten-related disorders.

Melinda lectures internationally and has written extensively on the nutritional management of celiac disease including the award-winning book Real Life with Celiac Disease. Melinda was the original founder of NCA in 1993 and so it is only fitting that she comes back to us in this capacity. We are truly honored to have her on our team.