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

Lactose Breath Test is performed during the recruitment step. Fasting subjects are asked to ingest 20 g of lactose in a 10% water solution. Breath samples are collected at baseline and every 30 min after lactose ingestion, for an overall test duration of 4 h. A cut-off value of 20 ppm over the baseline will be used to identify lactose malabsorbers.

A 3-sugar probes test is conducted by administering 5 g lactulose, 2 g mannitol and 2 g sucralose in water solution to fasting subjects. Urine are collected at baseline (before sugar ingestion) and for time periods 0-5 h and 5-24 h.

Milk test will be performed by administering to fasting subjects a portion of 250 ml of semi-skimmed milk treated with ultra-high temperature (UHT). Glycaemia measurements, blood withdrawals and questionnaires completion will be performed at baseline and repeated after 30 minutes, 1, 2, 4 and 6 hours after milk ingestion. Urine collection will be performed at baseline and for 6 time intervals after milk ingestion (0-2, 2-4, 4-6, 6-8, 8-12, 12-24 hours).