Assessing Neurocognitive Effects of Gluten Exposure

Inclusion Criteria: 1. Male or female 2. 18-50 years of age 3. Celiac Disease Group: Positive small intestinal biopsies meeting Marsh II or III histologic criteria for celiac disease at least six months since the time of study entrance as well as positive IgA anti-tissue transglutaminase antibody or positive IgA/IgG anti-Deamidated Gliadin Peptide (DGP) with normal serum IgA 4. Non-Celiac Gluten Sensitive Group: Negative small intestinal biopsies and negative IgA anti-tissue transglutaminase (tTG) or negative IgA/IgG anti-Deamidated Gliadin Peptide (DGP) with normal serum IgA, but with symptomatic response to gluten withdrawal 5. Subject should have well controlled celiac disease and have been on a gluten-free diet for at least six months prior to study enrollment 6. Subject must provide informed consent, as approved by the Institutional Review Board, and agree to complete required study visits, blood work neuropsychological testing and a urine pregnancy test (if applicable). 7. Subject agrees to use appropriate birth control for the duration of the study. Exclusion Criteria: 1. Subject has other food intolerances or food allergies (other than gluten) that would interfere with the conduct of the study (e.g. corn starch, soy). 2. Subject has a history of severe, acute symptomatic reactions to sporadic gluten ingestion 3. Subject has any chronic active gastrointestinal disease other than celiac disease (e.g. Crohn's disease, irritable bowel syndrome, autoimmune enteropathy, eosinophilic enteritis). 4. Subject should not have daily symptoms concerning for brain fog such as mental confusion or difficulty concentrating, at baseline. 5. Subject has symptomatic neurological or psychiatric disease(s) that would interfere with the conduct of the study. 6. Subject should not have been on corticosteroids or other immunosuppressive agents in the past 3 months. 7. Significant other co-morbidity as determined by the Principal Investigator 8. Subject is deemed inappropriate by the Principal Investigator. 9. Subject is pregnant or breast-feeding at time of participation. 10. Subject weighs less than 110 pounds.