Inclusion Criteria:  18-75 years; The ability of the subject to understand the character and individual consequences of the clinical trial Written informed consent  Exclusion Criteria:  A recent history of antibiotics (< 4 weeks before the enrolment) Current systemic or topic medication with steroids Active smoking or alcohol habits Vegan diet or dietary disorders (anorexia, bulimia) Immune system disorders Diabetes Obesity (defined as having a BMI > 30) Other current malignancies History of gastrointestinal tract resections, chronic gastrointestinal diseases (es. Inflammatory bowel diseases, or gastroesophageal reflux disease) Pregnant or breastfeeding patients Impaired mental state or language problems