Digestive HealthNCT07142486
Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal
A study testing Omeprazole 20 mg in people with Digestive Health and Gastrointestinal Health, run by McGill University at 1 site in Canada.
Trial summary
Omeprazole is a proton pump inhibitor commonly used to reduce stomach acid in the treatment of heartburn, gastroesophageal reflux disease, and gastric ulcers. By blocking the H⁺/K⁺-ATPase pumps in the gastric lining, it raises gastric pH and can alter the normal activation of pepsin, the enzyme responsible for… Read more about this study
- Who is it for?
- Ages 50 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Digestive Health, Gastrointestinal Health
- What is being tested?
- Omeprazole 20 mg
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 4 participants
- Where
- 1 siteCanada
- Study dates
- 1 Sep 2025to 19 Jun 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 50 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adult female or male participants who are 50 to 60 years of age at screening (inclusive)
- Has a BMI between 18.5 to 29.9 kg·m-2 (inclusive) at screening visit
- In good general health (no uncontrolled diseases or conditions) as deemed by the investigator and able to consume the study product
- Has maintained stable use of medication and supplements stable dietary and lifestyle habits, and stable body weight, for the last 3 months prior to screening and agree to maintain them throughout the study
- Agree to avoid strenuous exercise 48 h prior to each study visit
- Willing to limit daily alcohol consumption to no more than 3 standard drinks per day throughout the study, and agree to entirely avoid alcohol consumption 48 h prior to each visit (a standard serving is defined here as 4 oz wine, 12 oz beer, 1 oz spirits)
- Willing to maintain current use of cannabinoids (if applicable) throughout the study
- Willing and able to agree to the requirements and restrictions of this study, be willing to give voluntary consent, be able to understand and read the questionnaires, and carry out all study-related procedures.
Who cannot join
- Individuals who are lactating, pregnant or planning to become pregnant during the study
- Individuals who adhere to a diet (e.g., vegan diet) that restricts consumption of dairy products
- Has a known sensitivity, intolerability, or allergy to any of the study products or their excipients (i.e., lactose intolerant)
- Weight loss or gain > 3 kg in the 3 months prior to study visit 1
- Currently or planning to be on a weight loss regimen during the study
- Received a vaccine for COVID-19 in the two weeks prior to screening or plans to receive a vaccine for COVID-19 during the study period, currently has COVID-19 or tests positive for COVID-19 within 28 days prior to baseline visit, or currently has any post COVID-19 condition(s) as defined by World Health Organization (WHO) (i.e., individuals with a history of probable or confirmed SARS-CoV-2 infection, usually three months from the onset of COVID-19 with symptoms that last for at least 2 months and cannot be explained by an alternative diagnosis)
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- Recent (within 2 weeks of screening visit) history of an episode of acute GI illness such as nausea/vomiting or diarrhea
- Have a history of irritable bowel syndrome (IBS), inflammatory bowel disease (IBD, including ulcerative colitis and Crohn's disease), functional constipation or diarrhea (defined by the Rome IV diagnostic criteria), celiac disease, malabsorption, gastroparesis, diverticulosis, gastric or duodenal ulcers, pancreatitis, or eating disorder; or have a history of intestinal surgery (excluding appendectomy or herniorrhaphy) or bariatric surgery
- Have an abnormality or obstruction of the gastrointestinal tract precluding swallowing (e.g., dysphagia) and/or digestion (e.g., history of bowel obstruction)
- Participated in upper gastrointestinal endoscopy and/or colonoscopy or preparation within 3 months prior to screening visit
- Diagnosed with hypercholesterolemia or hypertriglyceridemia (i.e., elevated fasting low-density lipoprotein (LDL) (≥ 135 mg·dL-1; ≥ 3.5 mmol·L-1) or elevated triglycerides (≥ 150 mg·dL-1; ≥1.7 mmol·L-1)
- Has a history of heart disease/cardiovascular disease, uncontrolled hypertension (≥ 140 systolic or ≥ 90 diastolic mmHg), kidney disease (dialysis or renal failure), hepatic impairment or disease
- Is Type I or Type II diabetic or pre-diabetic [i.e., elevated fasting blood glucose levels (≥ 100 mg·dL-1; ≥ 5.6 mmol·L-1) and/or elevated hemoglobin A1c (≥ 6.0%)]
- Has a history of liver or gallbladder disease or stomach ulcers
- Has a positive medical history of unstable thyroid disease, previously diagnosed major affective disorder, psychiatric disorder that required hospitalization in the prior year, immune disorders and/or immunocompromised (e.g., HIV/AIDS)
- Diagnosed with cancer (except localized skin cancer without metastases or in situ cervical cancer) within 5 years prior to the screening visit, or any clinically significant disease or disorder which, in the opinion of the investigator, may either put the potential participant at risk because of participation in the study, or influences the results or the potential participant's ability to participate in the study
- Major surgery in 3 months prior to screening or planned major surgery during the study
- History of alcohol or substance abuse (including cannabinoids) in the 12 months prior to screening (including having been hospitalized for such in an in-patient or out-patient intervention program)
- Receipt or use of test products in another research study within 30 days prior to study visit 1 or longer if the previous test product is deemed by the investigator to have lasting effects that might influence the eligibility criteria or outcomes of the current study
- Current or previous tobacco use within the last 6 months
- Self-report of blood donation totaling between 101 mL to 449 mL of blood within 30 days prior to screening or a blood donation of more than 450 mL within 56 days prior to baseline
- Self-report of donating plasma (e.g., plasmapheresis) within 14 days prior to screening.
- Any other active or unstable medical conditions or use of medications, supplements, or therapies that, in the opinion of the investigator, may adversely affect the participant's ability to complete the study or its measures or pose a significant risk to the participant.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal: A Pilot Study
Omeprazole is a proton pump inhibitor commonly used to reduce stomach acid in the treatment of heartburn, gastroesophageal reflux disease, and gastric ulcers. By blocking the H⁺/K⁺-ATPase pumps in the gastric lining, it raises gastric pH and can alter the normal activation of pepsin, the enzyme responsible for beginning protein breakdown in the stomach.
Under normal conditions, dietary proteins are denatured by gastric acid and cleaved by pepsin into smaller peptides. These peptides enter the small intestine, where pancreatic enzymes (trypsin, chymotrypsin) and brush-border peptidases (aminopeptidase, dipeptidase) further hydrolyze them into free amino acids that are absorbed into the bloodstream. Suppressing stomach acidity may allow larger peptides to pass into the intestine, potentially reducing the efficiency of amino acid liberation and absorption.
Read more
In this randomized, crossover study, adults aged 50-60 years will attend two study visits at least one week apart. In one visit they will take a standard dose of omeprazole before consuming a mixed meal with a fixed protein content; in the other visit they will consume the same meal without medication. Blood samples will be collected before the meal and at multiple time points afterward to measure plasma amino acid concentrations and compare postprandial responses.
Older adults experience anabolic resistance, meaning they require higher protein intakes to stimulate muscle protein synthesis effectively. If omeprazole reduces amino acid availability after a meal, individuals taking this medication may need adjusted dietary protein recommendations. Findings from this study will help refine nutrition guidelines for people on proton pump inhibitors and support optimal muscle health and recovery in middle-aged and older adults.
- Conditions
- Digestive Health, Gastrointestinal Health
- Being tested
- Omeprazole 20 mg, Placebo
- Keywords
- Aminoacidemia, Omeprazole, Mixed Meal, Healthy Adults, Postprandial, Protein, Proton Pump Inhibitor, PPI
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Omeprazole 20 mgDrug
Omeprazole 20mg capsule
1 dose = 1 capsule
Participants will consume one dose per day for 5 days prior to their study visit. They will also consume one dose the day of the study visit in the laboratory setting. They will also consume one dose with the standardized mixed meal containing chicken, peas, potatoes, and butter the day of the study treatment visit in the laboratory.
PlaceboOther
Placebo
1 dose of placebo = 1 capsule filled with maltodextrin
Participants will consume 1 dose per day for 5 days prior to their study visit. They will then consume 1 dose the day of their study visit in the laboratory setting. They will also consume one dose with the standardized mixed meal containing chicken, peas, potatoes, and butter the day of the study treatment visit in the laboratory.
| Study group | Role | What they receive |
|---|---|---|
| Omeprazole 20mg capsule | Active comparator | Pharmaceutical Intervention: Omeprazole 20 mg capsule
1 dose = 1 capsule of Omeprazole 20mg
1 dose will be consumed per day for 5 days before the study visit. The participant will then also consume 1 dose on the day of the study visit in the laboratory environment. Receives: Drug: Omeprazole 20 mg |
| Placebo | Placebo comparator | Maltodextrin Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incremental Area Under the Curve for Total Plasma Amino Acid Concentrations
Plasma total amino acid concentrations (µmol·L-¹) measured by LC-MS at each time point; iAUC calculated using the trapezoidal rule to quantify the postprandial rise in amino acids after a single mixed meal in the Omeprazole versus placebo condition.
Measured: 0-300 minutes post-meal (blood draws at baseline (0), 30, 60, 90, 120, 180, 240, and 300 minutes)
Secondary outcomes (10)
Total (0-5 hours) postprandial plasma branched chain amino acid concentration incremental area-under-the-curve
Free leucine, isoleucine, valine (combined) (µmol·L^(-1)·300 minutes)
Measured: 5 hours
Total (0-5 hours) postprandial plasma leucine concentration incremental area-under-the-curve
Free leucine (µmol·L^(-1)·300 minutes)
Measured: 5 hours
Postprandial plasma amino acid maximum concentration
Total amino acids, essential amino acids, branched chain amino acids, leucine (µmol/L)
Measured: 5 hours
Postprandial plasma amino acid time to peak concentration
Total amino acids, essential amino acids, branched chain amino acids, leucine (minutes)
Measured: 5 hours
Postprandial plasma glucose concentration incremental area-under-the-curve
Plasma glucose (mmol·L^(-1)·300 minutes)
Measured: 5 hours
Postprandial plasma insulin concentration incremental area-under-the-curve
Plasma insulin (mmol·L^(-1)·300 minutes)
Measured: 5 hours
8-Item Modified Gastrointestinal Tolerance Questionnaire scores
Participants will be asked to complete an 8-item modified Gastrointestinal Tolerance Questionnaire at the conclusion of each aminoacidemia trial (t = 4 hours). Gastrointestinal symptoms including abdominal bloating/distension, burping, gas/flatulence, borborygmus/stomach rumbling, abdominal cramping, reflux (heartburn), nausea, and vomiting, will be ranked on a 4-point scale ranging from "none" to "severe".
Measured: 5 hours
Accuracy of participant guesses for intervention order
At the end of the study, participants complete a brief survey indicating which intervention (Omeprazole or placebo) they believe they received in each arm. We will report the proportion of correct vs. incorrect guesses for visit 1 and visit 2 as a measure of blinding effectiveness.
Measured: Immediately after the second study visit (exit survey)
Incidence of adverse events
Number of participants with adverse events
Measured: 120 days
Incremental Area Under the Curve for Essential Plasma Amino Acid Concentrations
Plasma essential amino acid concentrations (µmol·L-¹) measured by LC-MS at each time point; iAUC calculated using the trapezoidal rule to quantify the postprandial rise in amino acids after a single mixed meal in the Omeprazole versus placebo condition.
Measured: 0-300 minutes post-meal (blood draws at baseline, 30, 60, 90, 120, 180, 240, and 300 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2025
- Study start1 Sep 2025
- Primary completion19 Jun 2026
- Study completion19 Jun 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Digestive HealthStudies 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
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 4 participants (actual)
Sponsor and investigators
- Lead sponsor
- McGill University
- Sponsor type
- University, hospital or other
- Collaborators
- BIO-CAT, Inc.
- Responsible party
- Principal investigator, Tyler Churchward-Venne, McGill University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07142486
- Sponsor's protocol ID
- 25-03-040
- Status last verified
- Jul 2026
- First submitted
- 19 Aug 2025
- Last updated
- 15 Jul 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 15 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal: A Pilot Study
- ClinicalTrials.gov ID
- NCT07142486
- Acronym / sponsor ID
- 25-03-040
- Conditions
- Digestive Health, Gastrointestinal Health
- Keywords
- Aminoacidemia, Omeprazole, Mixed Meal, Healthy Adults, Postprandial, Protein, Proton Pump Inhibitor, PPI
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 4 participants (actual)
- Lead sponsor
- McGill UniversityUniversity, hospital or other
- Collaborators
- BIO-CAT, Inc.
- Study start
- 1 Sep 2025 (actual)
- Primary completion
- 19 Jun 2026 (actual)
- Study completion
- 19 Jun 2026 (actual)
- First posted
- 26 Aug 2025 (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.
Omeprazole is a proton pump inhibitor commonly used to reduce stomach acid in the treatment of heartburn, gastroesophageal reflux disease, and gastric ulcers. By blocking the H⁺/K⁺-ATPase pumps in the gastric lining, it raises gastric pH and can alter the normal activation of pepsin, the enzyme responsible for beginning protein breakdown in the stomach.
Under normal conditions, dietary proteins are denatured by gastric acid and cleaved by pepsin into smaller peptides. These peptides enter the small intestine, where pancreatic enzymes (trypsin, chymotrypsin) and brush-border peptidases (aminopeptidase, dipeptidase) further hydrolyze them into free amino acids that are absorbed into the bloodstream. Suppressing stomach acidity may allow larger peptides to pass into the intestine, potentially reducing the efficiency of amino acid liberation and absorption.
In this randomized, crossover study, adults aged 50-60 years will attend two study visits at least one week apart. In one visit they will take a standard dose of omeprazole before consuming a mixed meal with a fixed protein content; in the other visit they will consume the same meal without medication. Blood samples will be collected before the meal and at multiple time points afterward to measure plasma amino acid concentrations and compare postprandial responses.
Older adults experience anabolic resistance, meaning they require higher protein intakes to stimulate muscle protein synthesis effectively. If omeprazole reduces amino acid availability after a meal, individuals taking this medication may need adjusted dietary protein recommendations. Findings from this study will help refine nutrition guidelines for people on proton pump inhibitors and support optimal muscle health and recovery in middle-aged and older adults.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Omeprazole 20mg capsule | Active comparator | Drug: Omeprazole 20 mgPharmaceutical Intervention: Omeprazole 20 mg capsule 1 dose = 1 capsule of Omeprazole 20mg 1 dose will be consumed per day for 5 days before the study visit. The participant will then also consume 1 dose on the day of the study visit in the laboratory environment. |
| Placebo | Placebo comparator | Other: PlaceboMaltodextrin |
Who may qualify
- Ages
- 50 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Healthy adult female or male participants who are 50 to 60 years of age at screening (inclusive)
- Has a BMI between 18.5 to 29.9 kg·m-2 (inclusive) at screening visit
- In good general health (no uncontrolled diseases or conditions) as deemed by the investigator and able to consume the study product
- Has maintained stable use of medication and supplements stable dietary and lifestyle habits, and stable body weight, for the last 3 months prior to screening and agree to maintain them throughout the study
- Agree to avoid strenuous exercise 48 h prior to each study visit
Key exclusion criteria (23 listed)
- Individuals who are lactating, pregnant or planning to become pregnant during the study
- Individuals who adhere to a diet (e.g., vegan diet) that restricts consumption of dairy products
- Has a known sensitivity, intolerability, or allergy to any of the study products or their excipients (i.e., lactose intolerant)
- Weight loss or gain > 3 kg in the 3 months prior to study visit 1
- Currently or planning to be on a weight loss regimen during the study
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 |
|---|---|---|
| Omeprazole 20 mgOmeprazole 20mg capsule 1 dose = 1 capsule Participants will consume one dose per day for 5 days prior to their study visit. They will also consume one dose the day of the study visit in the laboratory setting. They will also consume one dose with the standardized mixed meal containing chicken, peas, potatoes, and butter the day of the study treatment visit in the laboratory. | Drug | Omeprazole 20mg capsule |
| PlaceboPlacebo 1 dose of placebo = 1 capsule filled with maltodextrin Participants will consume 1 dose per day for 5 days prior to their study visit. They will then consume 1 dose the day of their study visit in the laboratory setting. They will also consume one dose with the standardized mixed meal containing chicken, peas, potatoes, and butter the day of the study treatment visit in the laboratory. | Other | Placebo |
Primary outcome
Incremental Area Under the Curve for Total Plasma Amino Acid Concentrations
Time frame: 0-300 minutes post-meal (blood draws at baseline (0), 30, 60, 90, 120, 180, 240, and 300 minutes)
Plasma total amino acid concentrations (µmol·L-¹) measured by LC-MS at each time point; iAUC calculated using the trapezoidal rule to quantify the postprandial rise in amino acids after a single mixed meal in the Omeprazole versus placebo condition.
10 secondary outcomes
Total (0-5 hours) postprandial plasma branched chain amino acid concentration incremental area-under-the-curve
Time frame: 5 hours
Total (0-5 hours) postprandial plasma leucine concentration incremental area-under-the-curve
Time frame: 5 hours
Postprandial plasma amino acid maximum concentration
Time frame: 5 hours
Postprandial plasma amino acid time to peak concentration
Time frame: 5 hours
Postprandial plasma glucose concentration incremental area-under-the-curve
Time frame: 5 hours
Postprandial plasma insulin concentration incremental area-under-the-curve
Time frame: 5 hours
8-Item Modified Gastrointestinal Tolerance Questionnaire scores
Time frame: 5 hours
Accuracy of participant guesses for intervention order
Time frame: Immediately after the second study visit (exit survey)
Incidence of adverse events
Time frame: 120 days
Incremental Area Under the Curve for Essential Plasma Amino Acid Concentrations
Time frame: 0-300 minutes post-meal (blood draws at baseline, 30, 60, 90, 120, 180, 240, and 300 minutes)
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 15 Jul 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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Omeprazole 20 mg in people with Digestive Health and Gastrointestinal Health, run by McGill University at 1 site in Canada.
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 8 inclusion and 23 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 15 Jul 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 Canada. 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. Some participants in this study may receive a placebo. 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?
Incremental Area Under the Curve for Total Plasma Amino Acid Concentrations (time frame: 0-300 minutes post-meal (blood draws at baseline (0), 30, 60, 90, 120, 180, 240, and 300 minutes)). 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 15 Jul 2026.