McGill University
Montreal, Quebec, H2W 1S4, Canada
NCT Number: NCT07142486
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.
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Notify Me50 year–60 year
All sexes
Interventional
Not applicable
Montreal, Quebec, H2W 1S4, Canada
Healthy volunteers accepted: Yes
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
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.
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.
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.
Time frame: 5 hours
Free leucine, isoleucine, valine (combined) (µmol·L^(-1)·300 minutes)
Time frame: 5 hours
Free leucine (µmol·L^(-1)·300 minutes)
Time frame: 5 hours
Total amino acids, essential amino acids, branched chain amino acids, leucine (µmol/L)
Time frame: 5 hours
Total amino acids, essential amino acids, branched chain amino acids, leucine (minutes)
Time frame: 5 hours
Plasma glucose (mmol·L^(-1)·300 minutes)
Time frame: 5 hours
Plasma insulin (mmol·L^(-1)·300 minutes)
Time frame: 5 hours
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".
Time frame: Immediately after the second study visit (exit survey)
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.
Time frame: 120 days
Number of participants with adverse events
Time frame: 0-300 minutes post-meal (blood draws at baseline, 30, 60, 90, 120, 180, 240, and 300 minutes)
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.
McGill University
Other
Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal: A Pilot Study
OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.
View the official ClinicalTrials.gov record (opens in a new tab)This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.
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