Inclusion Criteria:  Age 18-65 years old Body mass index 20-35 kg/m2 IBS diagnosis  Exclusion Criteria:  Presence of other gastrointestinal disorders, such as gastritis, peptic ulcer, functional dyspepsia, celiac disease and inflammatory bowel disease Presence of other serious comorbidities, such as diabetes mellitus, active cancer, cardiovascular disease, pulmonary, kidney, liver, chronic inflammatory, autoimmune or psychiatric diseases Recent (within 6 months) surgery or hospitalization Habitual excessive alcohol consumption (> 210 or > 140 gr of alcohol per week for men and women, respectively) Currently on a weight-loss diet or recent change (within 6 months) in lifestyle habits Reception of any kind of dietary supplements Pregnancy or breast feeding (for women)