Identification of Physiological Biomarkers of Gastro-intestinal Discomforts Induced by Milk Consumption

Inclusion Criteria: * Drinking milk (maximum 150 ml/week for non-habitual milk consumers and minimum of 700 ml/week for habitual milk consumers) * BMI between 18.5 - 30 kg/m2 * Available for three visits (with one week in between). * Willing to drink 250 ml of milk in fasting condition within 10 min * Written informed consent * Negative lactose breath test result (increase in H2 concentrations \< 20 ppm vs basal value) and without symptoms or with any symptoms except "vomiting" and "Loose, mushy or watery stools" * Lactose malabsorbers (increase in H2 concentrations \> 20 ppm vs basal value but without symptoms) Exclusion Criteria: * Presence of any relevant organic, systemic or metabolic disease or abnormal laboratory values. * Ascertained intestinal organic diseases, including celiac disease or inflammatory bowel diseases. * Previous major abdominal surgeries. * Active malignancy of any type, or history of a malignancy (patients with a history of other malignancies that have been surgically removed and who have no evidence of recurrence for at least five years before study enrolment are also acceptable). * Untreated food intolerance. * Lactose intolerant * Assumption of probiotics or topic and/or systemic antibiotic therapy during the last month. * Systematical/frequent assumption of contact laxatives. * Pregnant and lactating women. * Inability to conform with protocol. * Treatment with any investigational drug within the previous 30 days. * Recent history or suspicion …