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Lactose IntoleranceNCT05669274

Comparing the Adaptation of Commercial Milk and A2 Milk in Lactose Maldigesters

A study testing Milk containing A1 and A2 beta-casein and Milk containing only A2 beta-casein in people with Lactose Intolerance, run by Purdue University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Cow's milk contains two types of β-casein: A1 and A2. It is evident from human clinical trials that milk with A1 protein produces more hydrogen and symptoms of lactose intolerance. A pro-inflammatory μ-opioid peptide BCM-7 is released from A1 but not from A2. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Lactose Intolerance
What is being tested?
Milk containing A1 and A2 beta-casein and Milk containing only A2 beta-casein
Could I receive a placebo?
No, everyone receives an active treatment
How many people
24 participants
Where
1 siteUnited States
Study dates
2 Dec 2021to 6 Dec 2025
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 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

Who cannot join

  • 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

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Purdue University

    West Lafayette, Indiana, 47907

Other trials in United States

About this study

Official title: Comparing Inflammation, Lactose Intolerance and Lactose Maldigestion in Lactose Maldigesters on Consumption of Commercial Milk Containing A1 and A2 Beta-Casein and A2 Milk Containing Only A2 Beta-Casein for Two Weeks

Cow's milk contains two types of β-casein: A1 and A2. It is evident from human clinical trials that milk with A1 protein produces more hydrogen and symptoms of lactose intolerance. A pro-inflammatory μ-opioid peptide BCM-7 is released from A1 but not from A2. Milk containing A1 β-casein produced more inflammatory markers than A2 β-casein. This is a double-blinded, randomized, controlled trial conducted to determine if there are changes in inflammatory markers following two weeks of milk feeding, due to milk containing A1 and A2 beta-casein as compared to milk containing only A2 beta-casein.

Read the 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 phases in intervention. Each phase is 15 days long.

Phase 1:

Blood will be drawn from the participants before consumption of milk on day 1 of the phase. Participants will then consume the 500 ml of first randomized milk every day from day 1 to day 14 (14 days in total). Dietary intake, stool type and symptoms (abdominal pain, bloating, flatulence, fecal urgency, and diarrhea) severity will be recorded on each day from day 1 to day 14 after milk consumption.

Participants will consume a low-fiber dinner and fast for 12 hours prior to HBT on day 15. Participants will provide their first breath sample before consumption of milk. Participants will then consume a challenge dose of first randomized milk containing 0.5g lactose per kg body weight. Breath samples will be collected at 0 hour (pre dose), 30 minutes, 1 hour, 90 minutes, 2 hours, 3 hours, 4 hours, 5 hours and 6 hours. Participants will be asked to report and rate any symptoms including abdominal pain, bloating, flatulence, fecal urgency, and diarrhea they might experience during the 6 hour test. Blood will be drawn from participants at 0 hour (pre-dose), 1 hour, 2 hours and 3 hours time-point via catheter and serum will be isolated from whole blood for analyses of markers including hs-CRP, IgG, IgG1, Il-4, GSH and BCM-7.

Phase 2:

There will be at least a 6-day interval between Phase 1 and Phase 2. The same procedure from phase 1 will be followed in phase 2. Participants will consume the second randomized milk for 14 days and undergo HBT on day 15.

Being tested
Milk containing A1 and A2 beta-casein, Milk containing only A2 beta-casein
Medical subject headings
Lactose Intolerance

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Milk containing A1 and A2 beta-caseinOther

    Also called Commercial milk

    Milk dose for 2 weeks

  • Milk containing only A2 beta-caseinOther

    Milk dose for 2 weeks

Study groups in NCT05669274
Study groupRoleWhat they receive
Old World milkExperimentalOld World milk containing only a2 beta-casein vs. New World milk that includes both a1 and a2 beta-casein
Receives: Other: Milk containing only A2 beta-casein
New World milkExperimentalOld World milk containing only a2 beta-casein vs. New World milk that includes both a1 and a2 beta-casein
Receives: Other: Milk containing A1 and A2 beta-casein

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Difference in inflammation between commercial and A2 milk

    The concentration of inflammatory markers hs-CRP, IL-4, IgG, IgG1, BCM-7, GSH in serum will be measured using ELISA kits, Cobas 400 plus analyzer and a Cobas e411 analyzer in nanometers.

    Measured: Baseline blood draw on day 1 and within the 3 hours following milk dose on day 15

  2. Difference in hydrogen between commercial and A2 milk

    Hydrogen concentration (ppm) will be measured in breath sample using a hydrogen breath analyzer.

    Measured: Within the 6 hours following milk dose on day 15

  3. Difference in symptoms between commercial and A2 milk

    Participants will record and rate abdominal pain, bloating, flatulence, diarrhea and fecal urgency using a 6-point Likert Scale during the 6-hour test. The scale ranges from a score of 0 to 5 (0 = none, 1 =slight, 2 = mild, 3 = moderate, 4 = moderately severe, 5 = severe).

    Measured: From day 1 to day 14 after 500 ml milk consumption and within the 6 hours following milk dose on day 15

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted30 Dec 2022
  2. Study start2 Dec 2021
  3. Primary completion6 Dec 2024
  4. Study completion6 Dec 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Crossover
Model description
New World milk containing both a1 and a2 beta-casein vs. Old World milk containing only a2 beta-casein
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
24 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05669274
Sponsor's protocol ID
IRB-2021-1407
Status last verified
Oct 2026
First submitted
20 Dec 2022
Last updated
20 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No

Publications

  • Jianqin S, Leiming X, Lu X, Yelland GW, Ni J, Clarke AJ. Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows' milk. Nutr J. 2016 Apr 2;15:35. doi: 10.1186/s12937-016-0147-z.

    PubMed 27039383
  • Ramakrishnan M, Eaton TK, Sermet OM, Savaiano DA. Milk Containing A2 beta-Casein ONLY, as a Single Meal, Causes Fewer Symptoms of Lactose Intolerance than Milk Containing A1 and A2 beta-Caseins in Subjects with Lactose Maldigestion and Intolerance: A Randomized, Double-Blind, Crossover Trial. Nutrients. 2020 Dec 17;12(12):3855. doi: 10.3390/nu12123855.

    PubMed 33348621
  • Cieslinska A, Kostyra E, Kostyra H, Olenski K, Fiedorowicz E, Kaminski S. Milk from cows of different beta-casein genotypes as a source of beta-casomorphin-7. Int J Food Sci Nutr. 2012 Jun;63(4):426-30. doi: 10.3109/09637486.2011.634785. Epub 2011 Nov 14.

    PubMed 22080615

Questions about this trial

What is this clinical trial studying?

A study testing Milk containing A1 and A2 beta-casein and Milk containing only A2 beta-casein in people with Lactose Intolerance, run by Purdue University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Difference in inflammation between commercial and A2 milk (time frame: Baseline blood draw on day 1 and within the 3 hours following milk dose on day 15). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05669274, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Oct 2026.

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