Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal

NCT07142486 | Recruiting

• 1 other identifier: 25-03-040
• Study Type: interventional
• Target: 4
• Locations: 1 country
• Sites: 1

Brief 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 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.

Conditions

Digestive Health; Gastrointestinal Health

Keywords

Aminoacidemia; Omeprazole; Mixed Meal; Healthy Adults; Postprandial; Protein; Proton Pump Inhibitor; PPI

Outcome Measures

Primary Outcomes (1)

• 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.

  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

  5 hours

• Total (0-5 hours) postprandial plasma leucine concentration incremental area-under-the-curve

  5 hours

• Postprandial plasma amino acid maximum concentration

  5 hours

• Postprandial plasma amino acid time to peak concentration

  5 hours

• Postprandial plasma glucose concentration incremental area-under-the-curve

  5 hours

Study Arms (2)

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.

Drug: Omeprazole 20 mg

Placebo

PLACEBO COMPARATOR

Maltodextrin

Other: Placebo

Interventions

Omeprazole 20 mg DRUG

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.

Omeprazole 20mg capsule

Placebo OTHER

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.

Placebo

Eligibility Criteria

• Age: 50 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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)
• 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)

Sponsors & Collaborators

• McGill University: lead
• BIO-CAT, Inc.: collaborator

Study Sites (1)

McGill University

Montreal, Quebec, H2W 1S4, Canada

RECRUITING

MeSH Terms

Interventions

Omeprazole

Intervention Hierarchy (Ancestors)

2-Pyridinylmethylsulfinylbenzimidazoles; Sulfoxides; Sulfur Compounds; Organic Chemicals; Pyridines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Benzimidazoles; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Central Study Contacts

Tyler Churchward-Venne, PhD

CONTACT

514-399-9684; tyler.churchward-venne@mcgill.ca

Damian Papadopoulos, B.Sc

CONTACT

514-561-7860; damian.papadopoulos@mail.mcgill.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: August 19, 2025
• First Posted: August 26, 2025
• Study Start: September 1, 2025
• Primary Completion: March 1, 2026
• Study Completion: March 1, 2026
• Last Updated: February 6, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)