Lactose IntolerantsOral NaloxoneNCT07884123
Milk Beta Caseins on Digestive Discomfort, Gastric Emptying
A study testing A1/A2 milk with oral naloxone and A1PF milk with oral naloxone in people with Lactose Intolerants and Lactose Malabsorption, run by Purdue University at 1 site in United States.
Trial summary
A1 and A2 β-casein are genetic variants of β-casein in cow's milk that differ by a single amino acid at position 67. Digestion of A1 β-casein may result in greater release of beta-casomorphin-7 (BCM-7), an opioid peptide that may influence gastrointestinal function. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Lactose Intolerants, Lactose Malabsorption, Caseins
- What is being tested?
- A1/A2 milk with oral naloxone and A1PF milk with oral naloxone
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Jan 2025to 30 Jan 2026
- 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
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Ability to provide informed consent.
- Aged between 18 and 65 years (inclusive) at the time of screening.
- Self-identified as milk intolerant or milk avoider.
- Agree to refrain from all treatments and products for milk intolerance (e.g., laxatives, stool softeners, Pepto Bismol®, Lactaid® Dietary Supplements) during the study.
- Willing to return for all study visits and complete all study-related procedures.
- Understand and provide written informed consent in English.
Who cannot join
- Any known allergy to Naloxone.
- Allergic to milk.
- Currently pregnant, lactating or considering pregnancy.
- Cigarette smoking or other use of tobacco or nicotine containing products within 3 months of screening.
- Diagnosed with any of the following disorders associated with abnormal gastrointestinal motility, such as: gastroparesis, amyloidosis, neuromuscular diseases (e.g., Parkinson's disease), collagen vascular diseases, alcoholism, uremia, malnutrition, untreated hypothyroidism.
- History of surgery that alters the normal function of the gastrointestinal tract, including:
Show all 27Show fewer
- gastrointestinal bypass surgery, bariatric surgery, gastric banding, vagotomy, fundoplication, pyloroplasty. (Note: A history of uncomplicated abdominal surgeries, such as appendix removal more than 12 months before screening, will not be excluded).
- Past or present diagnosis of any of the following: organ transplant, chronic pancreatitis or pancreatic insufficiency, symptomatic biliary disease, celiac disease, chronic constipation, diverticulosis, inflammatory bowel disease (e.g., ulcerative colitis, Crohn's disease), small intestine bacterial overgrowth syndrome, gastro-esophageal reflux disease (GERD), irritable bowel syndrome (IBS), any other medical condition with symptoms that could confound data collection (e.g., gas, diarrhea, bloating, cramps, stomach pain, fecal urgency).
- Diagnosed with active ulcers, or history of severe ulcers.
- Diagnosed with diabetes mellitus (type 1 and type 2)
- Diagnosed with Congestive Heart Failure (CHF)
- Diagnosed with Human Immunodeficiency Virus (HIV), Hepatitis B or Hepatitis C
- Weigh less than 16.5 kg or have a BMI greater than 35 kg/m².
- Had recent bowel preparation for endoscopic or radiologic investigation within 4 weeks of screening (e.g., colonoscopy prep).
- Have used treatments for milk intolerance (e.g., laxatives, stool softeners, Pepto Bismol®, Lactaid®) within 7 days of screening.
- Chronic antacid or proton pump inhibitor (PPI) use.
- Used systemic antibiotics within 30 days prior to screening (you may participate one month after discontinuing antibiotics).
- Used a high colonic enema within 30 days prior to screening. 8MAY2025 IRB-2024-731 Page 3 of 11
- Had symptoms or diseases that interfere with the assessment of milk intolerance symptoms (e.g., gas, diarrhea, bloating, cramps, stomach pain, fecal urgency).
- History of alcohol abuse.
- History of opioid drug abuse (e.g., oxycodone, hydrocodone, heroin, fentanyl, morphine).
- Currently undergoing chemotherapy.
- Have used any investigational drug or participated in an investigational study within 30 days prior to screening.
- Have any 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, internal electrodes or wires**
- Have claustrophobia (fear of closed spaces)
- Cannot lie still for up to 75 minutes for any reason (e.g., movement disorder, severe cold with coughing).
- Worked with metal (grinding, fabrication, etc.) or had an injury to the eye involving a metallic object (e.g., metallic slivers, foreign body), injured by a metallic object that may NOT have been completely removed (e.g., bullets, shrapnel, BBs), had surgery or any similar invasive procedure, had a reaction to a contrast medium used for MRI or CT, diagnosed with epilepsy/seizure **Exceptions to the Exclusion Criteria are allowed in the following circumstances: Certain implants, tattoos, metallic objects, or jewelry may be allowed and can be considered safe to image after having been reviewed and approved of by the Purdue MRI Staff. If it is safe, you will be able to participate in the study.
Trial locations and contacts
1 site in 1 country.
United States1 site
Clinical Research Center
West Lafayette, Indiana, 47907
About this study
Official title: Comparing the Gastro-Intestinal Transit Time of Commercial Milk Containing A1 β-casein in Presence of the Opioid Antagonist Naloxone
A1 and A2 β-casein are genetic variants of β-casein in cow's milk that differ by a single amino acid at position 67. Digestion of A1 β-casein may result in greater release of beta-casomorphin-7 (BCM-7), an opioid peptide that may influence gastrointestinal function. Previous work from our group in lactose maldigesters found differences in gastric emptying following consumption of A1/A2 milk compared with A1 protein-free (A1PF) milk.
This randomized, masked, crossover study evaluated whether opioid receptor blockade with oral naloxone influenced gastric emptying following consumption of A1/A2 milk compared with A1PF milk in lactose maldigesters. Participants consumed each milk treatment with 2 mg oral naloxone during separate study visits. Gastric volume was measured using magnetic resonance imaging (MRI) over 120 minutes, and gastrointestinal symptoms were assessed. The study was designed to investigate whether opioid receptor signaling contributes to differences in gastric emptying between A1/A2 milk and A1PF milk.
Read the detailed description
A1 and A2 β-casein are genetic variants of β-casein in cow's milk that differ by a single amino acid at position 67: histidine in A1 β-casein and proline in A2 β-casein. This structural difference can influence proteolytic cleavage during gastrointestinal digestion. Digestion of A1 β-casein may result in greater release of beta-casomorphin-7 (BCM-7), an opioid peptide that can interact with opioid receptors in the gastrointestinal tract and may influence gastrointestinal function.
Gastric emptying may contribute to gastrointestinal symptoms in lactose maldigesters by affecting the rate at which lactose is delivered to the small intestine. Previous work from our group using magnetic resonance imaging (MRI) demonstrated faster gastric emptying following consumption of A1/A2 milk compared with A1 protein-free (A1PF) milk in lactose maldigesters. More rapid gastric emptying may increase the rate of lactose delivery to the small intestine and potentially increase the amount of unabsorbed lactose reaching the colon, where microbial fermentation can contribute to gas production and gastrointestinal symptoms.
One potential mechanism underlying differences in gastrointestinal responses to β-casein variants involves opioid receptor signaling. Because BCM-7 has opioid activity, opioid receptor blockade provides an approach for investigating whether this pathway contributes to differences in gastric emptying following consumption of A1/A2 milk and A1PF milk.
This randomized, masked, crossover study evaluated gastric emptying following consumption of A1/A2 milk and A1PF milk during administration of 2 mg oral naloxone, an opioid receptor antagonist. Lactose maldigesters consumed each milk treatment during separate intervention visits. Gastric volume was assessed using MRI at baseline and at 10, 30, 60, and 120 minutes following milk consumption. Gastrointestinal symptoms were also assessed during the intervention visits.
The study was designed to determine whether differences in gastric emptying between A1/A2 milk and A1PF milk persisted during opioid receptor blockade, thereby evaluating the potential contribution of opioid receptor signaling to the gastric emptying response.
- Conditions
- Lactose Intolerants, Lactose Malabsorption, Caseins
- Being tested
- A1/A2 milk with oral naloxone, A1PF milk with oral naloxone
- Keywords
- Lactose intolerance, Dairy avoiders
- Medical subject headings
- Lactose Intolerance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
A1/A2 milk with oral naloxoneOther
Participants consumed A1/A2 milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit.
A1PF milk with oral naloxoneOther
Participants consumed A1/A2 milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit.
| Study group | Role | What they receive |
|---|---|---|
| A1/A2 Milk Followed by A1PF Milk | Experimental | Participants assigned to this sequence received A1/A2 milk during the first intervention visit and A1 protein-free (A1PF) milk during the second intervention visit. At each visit, participants consumed up to 500 mL of milk, with the amount determined by body weight, along with 2 mg oral naloxone. Receives: Other: A1/A2 milk with oral naloxone; Other: A1PF milk with oral naloxone |
| A1 protein-free (A1PF) milk with oral naloxone | Experimental | Participants consumed A1 protein-free (A1PF) milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit. Receives: Other: A1/A2 milk with oral naloxone; Other: A1PF milk with oral naloxone |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gastric volume measured by MRI
Gastric volume was measured in milliliters (mL) using magnetic resonance imaging (MRI). Images of the stomach were acquired at baseline and at 10, 30, 60, and 120 minutes following consumption of A1/A2 milk or A1 protein-free (A1PF) milk with 2 mg oral naloxone. Gastric volume was determined from the MRI images to assess gastric emptying over the 120-minute postprandial period.
Measured: Baseline and 10, 30, 60, and 120 minutes after milk consumption during each of the two intervention visits
Secondary outcomes (1)
Gastrointestinal symptom severity
Gastrointestinal symptoms were assessed using participant-reported symptom ratings at baseline and at 30, 60, 90, and 120 minutes following consumption of A1/A2 milk or A1 protein-free (A1PF) milk with 2 mg oral naloxone during each intervention visit.
Measured: Baseline and 30, 60, 90, and 120 minutes after milk consumption during each of the two intervention visits
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Oct 2026
- Study start30 Jan 2025
- Primary completion30 Jan 2026
- Study completion30 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Lactose IntolerantsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This is a single center, randomized, double-blind, cross-over trial.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Purdue University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dennis A. Savaiano, Purdue University
- Investigators
- Dennis A Savaiano, Doctoral, Principal investigator, Purdue University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07884123
- Sponsor's protocol ID
- IRB-2024-731
- Other IDs
- F.90029218. 06.002
- Acronym
- Oral Naloxone
- Status last verified
- Oct 2026
- First submitted
- 13 Oct 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparing the Gastro-Intestinal Transit Time of Commercial Milk Containing A1 β-casein in Presence of the Opioid Antagonist Naloxone
- ClinicalTrials.gov ID
- NCT07884123
- Acronym / sponsor ID
- Oral Naloxone / IRB-2024-731
- Conditions
- Lactose Intolerants, Lactose Malabsorption, Caseins
- Keywords
- Lactose intolerance, Dairy avoiders
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Purdue UniversityUniversity, hospital or other
- Study start
- 30 Jan 2025 (actual)
- Primary completion
- 30 Jan 2026 (actual)
- Study completion
- 30 Jan 2026 (actual)
- First posted
- 20 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A1 and A2 β-casein are genetic variants of β-casein in cow's milk that differ by a single amino acid at position 67. Digestion of A1 β-casein may result in greater release of beta-casomorphin-7 (BCM-7), an opioid peptide that may influence gastrointestinal function. Previous work from our group in lactose maldigesters found differences in gastric emptying following consumption of A1/A2 milk compared with A1 protein-free (A1PF) milk.
This randomized, masked, crossover study evaluated whether opioid receptor blockade with oral naloxone influenced gastric emptying following consumption of A1/A2 milk compared with A1PF milk in lactose maldigesters. Participants consumed each milk treatment with 2 mg oral naloxone during separate study visits. Gastric volume was measured using magnetic resonance imaging (MRI) over 120 minutes, and gastrointestinal symptoms were assessed. The study was designed to investigate whether opioid receptor signaling contributes to differences in gastric emptying between A1/A2 milk and A1PF milk.
Detailed description
A1 and A2 β-casein are genetic variants of β-casein in cow's milk that differ by a single amino acid at position 67: histidine in A1 β-casein and proline in A2 β-casein. This structural difference can influence proteolytic cleavage during gastrointestinal digestion. Digestion of A1 β-casein may result in greater release of beta-casomorphin-7 (BCM-7), an opioid peptide that can interact with opioid receptors in the gastrointestinal tract and may influence gastrointestinal function.
Gastric emptying may contribute to gastrointestinal symptoms in lactose maldigesters by affecting the rate at which lactose is delivered to the small intestine. Previous work from our group using magnetic resonance imaging (MRI) demonstrated faster gastric emptying following consumption of A1/A2 milk compared with A1 protein-free (A1PF) milk in lactose maldigesters. More rapid gastric emptying may increase the rate of lactose delivery to the small intestine and potentially increase the amount of unabsorbed lactose reaching the colon, where microbial fermentation can contribute to gas production and gastrointestinal symptoms.
One potential mechanism underlying differences in gastrointestinal responses to β-casein variants involves opioid receptor signaling. Because BCM-7 has opioid activity, opioid receptor blockade provides an approach for investigating whether this pathway contributes to differences in gastric emptying following consumption of A1/A2 milk and A1PF milk.
This randomized, masked, crossover study evaluated gastric emptying following consumption of A1/A2 milk and A1PF milk during administration of 2 mg oral naloxone, an opioid receptor antagonist. Lactose maldigesters consumed each milk treatment during separate intervention visits. Gastric volume was assessed using MRI at baseline and at 10, 30, 60, and 120 minutes following milk consumption. Gastrointestinal symptoms were also assessed during the intervention visits.
The study was designed to determine whether differences in gastric emptying between A1/A2 milk and A1PF milk persisted during opioid receptor blockade, thereby evaluating the potential contribution of opioid receptor signaling to the gastric emptying response.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- This is a single center, randomized, double-blind, cross-over trial.
| Arm | Type | Receives |
|---|---|---|
| A1/A2 Milk Followed by A1PF Milk | Experimental | Other: A1/A2 milk with oral naloxone, Other: A1PF milk with oral naloxoneParticipants assigned to this sequence received A1/A2 milk during the first intervention visit and A1 protein-free (A1PF) milk during the second intervention visit. At each visit, participants consumed up to 500 mL of milk, with the amount determined by body weight, along with 2 mg oral naloxone. |
| A1 protein-free (A1PF) milk with oral naloxone | Experimental | Other: A1/A2 milk with oral naloxone, Other: A1PF milk with oral naloxoneParticipants consumed A1 protein-free (A1PF) milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Ability to provide informed consent.
- Aged between 18 and 65 years (inclusive) at the time of screening.
- Self-identified as milk intolerant or milk avoider.
- Agree to refrain from all treatments and products for milk intolerance (e.g., laxatives, stool softeners, Pepto Bismol®, Lactaid® Dietary Supplements) during the study.
- Willing to return for all study visits and complete all study-related procedures.
Key exclusion criteria (27 listed)
- Any known allergy to Naloxone.
- Allergic to milk.
- Currently pregnant, lactating or considering pregnancy.
- Cigarette smoking or other use of tobacco or nicotine containing products within 3 months of screening.
- Diagnosed with any of the following disorders associated with abnormal gastrointestinal motility, such as: gastroparesis, amyloidosis, neuromuscular diseases (e.g., Parkinson's disease), collagen vascular diseases, alcoholism, uremia, malnutrition, untreated hypothyroidism.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| A1/A2 milk with oral naloxoneParticipants consumed A1/A2 milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit. | Other | A1 protein-free (A1PF) milk with oral naloxone, A1/A2 Milk Followed by A1PF Milk |
| A1PF milk with oral naloxoneParticipants consumed A1/A2 milk at a volume calculated to provide 0.5 g lactose/kg body weight, using the formula: milk volume (mL) = [0.5 g lactose × body weight (kg) / 11 g lactose] × 245 mL milk. Participants also received 2 mg oral naloxone during the MRI intervention visit. | Other | A1 protein-free (A1PF) milk with oral naloxone, A1/A2 Milk Followed by A1PF Milk |
Primary outcome
Gastric volume measured by MRI
Time frame: Baseline and 10, 30, 60, and 120 minutes after milk consumption during each of the two intervention visits
Gastric volume was measured in milliliters (mL) using magnetic resonance imaging (MRI). Images of the stomach were acquired at baseline and at 10, 30, 60, and 120 minutes following consumption of A1/A2 milk or A1 protein-free (A1PF) milk with 2 mg oral naloxone. Gastric volume was determined from the MRI images to assess gastric emptying over the 120-minute postprandial period.
1 secondary outcome
Gastrointestinal symptom severity
Time frame: Baseline and 30, 60, 90, and 120 minutes after milk consumption during each of the two intervention visits
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Dennis A Savaiano, Doctoral principal investigator
Purdue University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing A1/A2 milk with oral naloxone and A1PF milk with oral naloxone in people with Lactose Intolerants and Lactose Malabsorption, 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 6 inclusion and 27 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?
Gastric volume measured by MRI (time frame: Baseline and 10, 30, 60, and 120 minutes after milk consumption during each of the two intervention visits). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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.