Malnutrition In Non-Celiac Wheat Sensitivity Patients

Inclusion Criteria: To diagnose NCWS the recently proposed criteria will be adopted. All the patients will meet the following criteria: * negative serum anti-transglutaminase (anti-tTG) and anti-endomysium (EmA) immunoglobulin (Ig)A and IgG antibodies; * absence of intestinal villous atrophy; * negative IgE-mediated immune-allergy tests to wheat (skin prick tests and/or serum specific IgE detection); * resolution of the IBS symptoms on standard elimination diet, excluding wheat, cow's milk, egg, tomato, chocolate, and other self-reported food(s) causing symptoms; * symptom reappearance on double-blind placebo-controlled (DBPC) wheat challenge. As the investigators previously described in other studies, DBPC cow's milk protein challenge and other "open" food challenges will be performed too. Additional inclusion criteria will be: * age \>18 years; follow-up duration longer than six months after the initial diagnosis; * at least two outpatient visits during the follow-up period. Exclusion Criteria: * positive EmA in the culture medium of the duodenal biopsies, also in the case of normal villi/crypts ratio in the duodenal mucosa; * self-exclusion of wheat from the diet and refusal to reintroduce it, before entering the study; * other "organic" gastrointestinal disorders; * nervous system disease and/or major psychiatric disorder; * physical impairment limiting physical activity; * menopause; * steroid and sex steroid therapy, hormone replacement therapy or ovariectomy.