Comparing the Gastric Transit of Commercial Milk and A2 Milk

Inclusion Criteria: Ability/desire to provide informed consent Aged 18 to 65 years of age inclusive at screening Milk intolerant and identified as a lactose maldigester while participating in the Milk Protein Study (applicable only for subjects from the previous milk protein study and not applicable for new subjects) Current or recent history of intolerance to or avoidance of dairy of at least one month duration (by self-report and self-reported symptoms). Willing to return for all study visits and complete all study related procedures Able to understand and provide written informed consent in English Exclusion Criteria: • Currently pregnant Diagnosed with any of the following disorders known to be associated with abnormal gastrointestinal motility such as; Gastroparesis, amyloidosis, neuromuscular diseases (including Parkinson's disease), collagen vascular diseases, alcoholism, uremia, malnutrition, or untreated hypothyroidism History of surgery that alters the normal function of the gastrointestinal tract including, but not limited to: gastrointestinal bypass surgery, bariatric surgery, gastric banding, vagotomy, fundoplication, pyloroplasty [Note: history of uncomplicated abdominal surgeries such as removal of an appendix more than 12 months prior to screening will not be excluded] Past or present : Organ transplant, chronic pancreatitis, pancreatic insufficiency, symptomatic biliary disease, Celiac disease, chronic constipation, diverticulosis, inflammatory bowel disease (IBD), ulcerative colitis (UC), Crohn's disease (CD), small intestine bacterial overgrowth syndrome (SIBO), gastroparesis, gastro-esophageal reflux disease (GERD), Irritable Bowel Syndrome (IBS) or any other medical condition with symptoms that could confound collection of adverse events. Active ulcers, or history of severe ulcers Diabetes mellitus (type 1 and type 2) Congestive Heart Failure (CHF) Human Immunodeficiency Virus (HIV), Hepatitis B or Hepatitis C Recent use of systemic antibiotics defined as use within 30 days prior to screening Any of the following: Worked with metal (grinding, fabrication, etc.) or had an injury to the eye involving a metallic object (e.g., metallic slivers, foreign body, been injured by a metallic object that may NOT have been completely removed (e.g., bullets, shrapnel, BBs), had a reaction to a contrast medium used for MRI or CT, have claustrophobia (fear of closed places), been diagnosed with epilepsy/seizure, any reason you would be unable to remain still for long periods of time, Cardiac pacemaker, Any type of prosthesis (eye, penile), Implanted cardiac defibrillator, Heart valve prosthesis/stents, Aneurysm clip, Shunt (spinal/intraventricular), Neuro or Bone Stimulator, Wire sutures or surgical staples, Insulin or Infusion Pump, Bone/joint pin, screw, nail, plate, Implanted drug infusion device, Body tattoos, Cochlear, otologic or ear implant, Tattooed makeup (eyeliner, lip, etc.), Prostate radiation seeds, Breast tissue expander, IUD (intrauterine device), Hearing aids, Transdermal medicine patch (Nitro),Body piercing(s), Any metallic implants or objects, any other reason the participant thinks they would not be a good candidate for MRI. Any other conditions/issues noted by the study staff and/or Principal Investigator that would impact participation and/or protocol compliance