NCT07142486

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

Effects of Omeprazole Ingestion on Postprandial Amino Acid Concentrations in Response to a Mixed Meal: A Pilot Study

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 4 (estimated)
• Sponsor: McGill University · Academic / Other
• Sex: All
• Age: 50 Years – 60 Years
• Healthy volunteers: Accepted

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

Interventions

Type	Name	Description
DRUG	Omeprazole 20 mg	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.
OTHER	Placebo	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.

Timeline

• Start date: 2025-09-01
• Primary completion: 2026-03-01
• Completion: 2026-03-01
• First posted: 2025-08-26
• Last updated: 2026-02-06

Locations

1 site across 1 country: Canada