Luminal Fructose Kinetics (MARTINI Study)

The investigators will perform a non blinded single centre intervention study in 2x 11 participants

Participants will be either healthy volunteers with a BMI < 25 and Age 18-65 or patients with MASLD with a BMI >25, Age 18-65

The objective of the investigators is to study the fructose host/microbial kinetics in humans and to establish the role of (small) intestinal pH on fructose fermentation and endogenous ethanol production in a MASLD/MASH population versus healthy subjects

Subjects will be given omeprazole orally given twice a day 40mg for four weeks

At baseline and after four weeks of omeprazole, a fructose challenge test with labelled fructose and fomepizole and a gastroscopy will be performed, during which a nasal-intestinal catheter will be placed to allow for luminal sampling during the fructose challenge test.

Inclusion criteria

In case of the healthy subject group:

• Adult individuals, age > 18 <65 years
• Male or postmenopauzal females
• BMI <25
• Ability to give informed consent In case of the MASLD/MASH group
• Adult individuals, age > 18 <65 years
• Male or postmenopauzal females
• BMI > 25
• Biopsy proven MASLD/MASH
• Ability to give informed consent

Exclusion criteria

• History of sustained excess alcohol ingestion: daily consumption >30g/day (3 drinks per day) for males and >20 g/day (2 drinks per day) for females
• Patients with diabetes
• Bariatric surgery
• Other forms of liver disease (e.g. Hepatitis B,C, Wilson disease, hemochromatosis)
• Proton-pump inhibitor usage one year prior to study participation
• GLP1, SGLT2i or insulin use
• Antibiotic use for the past 3 months
• Probiotic or symbiotic usage
• Pregnant women
• Chronic illness (including a known history of heart failure, renal failure (eGFR <30 ml/min), pulmonary disease, gastrointestinal disorders, or hematologic diseases), or other inflammatory diseases
• Active infection
• Use of ascal, clopidogrel or other platelet inhibition
• Smoking
• Blood thinners
• Heart failure