Comparing the effects of A1 and A2 milk on lactose intolerance symptoms

Comparing the Acute Effects of A1 Containing Commercial Milk and A2 Milk on Inflammation, Lactose Intolerance and Lactose Maldigestion in Lactose Maldigesters

Not applicable Interventional Purdue University · NCT05660278

This study is testing whether drinking A1 or A2 milk affects symptoms of lactose intolerance differently in people who have this condition.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment35 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorPurdue University Academic / other
Drugs / interventionschemotherapy
Locations1 site (West Lafayette, Indiana)
Trial IDNCT05660278 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the differences in inflammatory responses and symptoms caused by A1 and A2 beta-casein found in cow's milk. Participants with lactose intolerance will undergo a hydrogen breath test after consuming both types of milk to measure hydrogen levels and inflammatory markers. The study is designed as a double-blinded, randomized, controlled trial to ensure unbiased results. Recruitment will involve local outreach and phone screenings to assess eligibility based on specific criteria.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 to 65 who have a current or recent history of lactose intolerance.

Not a fit: Patients who are allergic to milk or have gastrointestinal disorders affecting motility may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could help identify which type of milk is better tolerated by individuals with lactose intolerance, potentially improving their quality of life.

How similar studies have performed: Other studies have indicated that A2 milk may be better tolerated by individuals with lactose intolerance, suggesting a potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* • Ability/desire to provide informed consent

  * Aged 18 to 65 years of age inclusive at screening
  * Current or recent history of intolerance to or avoidance of dairy of at least one month duration (by self-report and self-reported symptoms).
  * Agrees to refrain from all other treatments and products used for dairy intolerance (e.g., Lactaid® Dietary Supplements) during study involvement
  * 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:

* • Allergic to milk

  * Currently pregnant
  * Currently lactating
  * Cigarette smoking or other use of tobacco or nicotine containing products within 3 months of screening
  * 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
  * Height: ___ Weight: ___ BMI: ___

    o Weighing \<16.5 kg and BMI \> 35 kg/m2
  * Recent bowel preparation for endoscopic or radiologic investigation within four weeks of screening (e.g., colonoscopy prep)
  * Use of concurrent therapy(ies) or other products (e.g., laxatives, stool softeners, Pepto Bismol®, Lactaid® Dietary Supplements) used for symptoms of dairy intolerance within 7 days of screening
  * Chronic antacid and/or PPI use
  * Recent use of systemic antibiotics defined as use within 30 days prior to screening
  * Recent high colonic enema, defined as use within 30 days prior to screening
  * Any concurrent disease or symptoms which may interfere with the assessment of the cardinal
  * symptoms of dairy intolerance (i.e., gas, diarrhea, bloating, cramps, stomach pain)
  * History of ethanol (alcohol) and/or drug abuse in the past 12 months
  * Currently undergoing chemotherapy
  * Use of any investigational drug or participation in any investigational study within 30 days prior to screening
  * Prior enrollment in this study
  * Any other conditions/issues noted by the study staff and/or Principal Investigator that would impact participation and/or protocol compliance

Where this trial is running

West Lafayette, Indiana

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Lactose Intolerance
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.