Comparing the Gastric Transit of Commercial Milk and A2 Milk
Condition: Lactose Intolerance, Adult Type
MeSH terms: Lactose Intolerance
Study type: Interventional

Summary: 
      Cow's milk contains two types of β-casein: A1 and A2. The μ-opioid peptide BCM-7 is released
      from A1 but not from A2. BCM-7 is associated with slower gastrointestinal transit and hence
      increased gastrointestinal transit times. Lactose maldigesters reported an increase in
      abdominal pain due to consumption of milk containing A1 beta-casein as compared to milk
      containing only A2 beta-casein. The hypothesis of this study is that the differential
      abdominal pain is due to the differential gastric transit. This is a double-blinded,
      randomized, controlled trial conducted to determine if the transit of A1 β-casein milk is
      modified in the stomach as compared to milk with only A2 β-casein.
    

Detailed description: 
      Recruitment:

      Flyers, emails, and advertisements in local and university newspapers will be used for
      recruitment of study participants.

      Phone screening:

      Interested individuals will be contacted via phone by study staff to assess eligibility by
      asking questions listed in the inclusion and exclusion criteria.

      Informed consent:

      If the individual is eligible through phone screening, the study staff will read and explain
      the informed consent to the individual. Informed consent will contain all the information
      regarding study procedure, compensation, risks and benefits. If Informed Consent is granted,
      the participant will be contacted through their preferred method of contact (email or phone)
      to schedule a hydrogen breath test (HBT).

      Screening lactose maldigesters via HBT:

      Maldigestion will be classified by a rise of breath hydrogen concentration of greater than
      20ppm after a challenge dose of 2% commercial milk containing 0.5g lactose per kg body
      weight. Participants will consume a low-fiber meal and then fast 12 hours prior to HBT. A
      breath sample will be obtained from participants just before drinking the milk dose.
      Participants will then consume milk containing 0.5 grams lactose per kilogram body weight.
      Breath samples will be obtained according to the following schedule: 0 hour (pre dose), 30
      minutes, 1 hour, 90 minutes, 2 hours, 3 hours, 4 hours, 5 hours and 6 hours. Participants who
      exhibit a rise of breath hydrogen concentration of greater than 20ppm between any two
      timepoints of the 6-hour test will be classified as lactose maldigesters, and will be
      qualified to enter the intervention portion of the study.

      Intervention:

      There will be two in-person visits in intervention.

      Visit 1:

      Participants should fast for 12 hours and avoid consuming water for 3 hours prior to the MRI
      scanning appointment. On the day of the visit, participants will undergo a safety screening
      for MRI compatibility as required by the Purdue MRI Facility and Inner Vision West. Prior to
      MRI scanning, all participants will remove any metal objects and change into medical scrubs
      provided by the facility. Participants will then consume their first randomized milk
      containing 0.5 grams lactose per kilogram body weight (Upper limit - 0.5g/kg up to 50g of
      lactose). Images of the stomach will be obtained at 0 (pre dose/baseline), 10, 30, 60 and 120
      minutes using a Magnetom 3T Prisma MRI scanner. Participants will rate their abdominal pain
      at 0, 30, 60, 90 and 120 minutes.

      Visit 2:

      There will be at least a 6-day interval between Visit 1 and Visit 2. The same procedure from
      visit 1 will be followed in visit 2. Participants will consume the second randomized milk
      containing 0.5 grams lactose per kilogram body weight during this visit.
    

Intervention name(s): Milk containing A1 and A2 beta-casein; Milk containing only A2 beta-casein
Intervention type(s): Other; Other
Intervention description(s): Single dose of commercial milk; Single dose of A2 milk
Other intervention name(s): Commercial milk; A2 milk
Intervention MeSH terms: Caseins
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other