None listed
Conditions
Brief summary
Many people report digestive problems with dairy products. This dairy intolerance may sometimes be caused by lactose intolerance, but not all people reporting intolerance have confirmed lactose intolerance. Rather, some forms of dairy intolerance may be caused or exacerbated by the protein in milk which manifests as inflammation of the small intestine. Conventional milk contains the A1 version of bovine beta-casein protein. A1 beta-casein may cause intolerance type symptoms in some consumers, resulting in small intestinal inflammation that may also contribute to lactose intolerance. It is proposed that these effects are absent or reduced when dairy products free of this variant are consumed. The A2 version of beta-casein is broken down differently, and may not cause intolerance symptoms in consumers who are sensitive to the A1 beta-casein protein. However, the impacts of variation in beta-casein and intestinal inflammation on lactose malabsorption have not yet been investigated in humans. Due to the possible exacerbation of lactose malabsorption by intestinal inflammation, this study aims to understand whether tolerance to lactose is impacted by repeated exposure to variants of beta-casein.
Interventions
Subjects randomized to the intervention will be assigned, in a cross-over manner, to 2 weeks daily consumption of either conventional milk products or a2 milk products (500 ml of full fat milk + 80 g hard cheese), each preceded by 2 weeks of dairy avoidance. Participants need to avoid any other dairy products than provided and fill in the food questionnaires (checklist) throughout the intervention period.
Sponsors
University of Auckland
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
20 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
20-40 years BMI 18-28 kg/m2 Self-described lactose intolerant Lactose intolerant (confirmed by lactose tolerance test: breath hydrogen and symptoms) No history of gastrointestinal disease or metabolic disease.
Exclusion criteria
Are not lactose intolerant. Have an allergy to milk. Are diagnosed with gastrointestinal disease (i.e. celiac, Crohn’s, colitis, etc.) or pre-existing metabolic disease. Are currently taking medications expected to interfere with normal digestive or metabolic processes including proton pump inhibitors, laxatives, antibiotics etc. Have a medical history precluding a healthy state: history of myocardial infarction, angina, stroke, cancer or pre-existing diabetes, self-reported alcohol intake exceeding a moderate intake (>28 units per week).
Outcome results
None listed