Ignite Creation Date:
2025-12-24 @ 7:59 PM
Ignite Modification Date:
2025-12-25 @ 5:33 PM
Study NCT ID:
NCT06366204
Status:
COMPLETED
Last Update Posted:
2025-07-30
First Post:
2024-04-10
Is NOT Gene Therapy:
False
Has Adverse Events:
False
Brief Title:
Lysine Requirements During Lactation
Sponsor:
University of British Columbia
Organization:
Study Overview
Official Title:
Determining Dietary Lysine Requirements in Healthy Lactating Women Using the Indicator Amino Acid Oxidation Technique
Status:
COMPLETED
Status Verified Date:
2025-07
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
The study aims to establish lysine requirements using the indicator amino acid oxidation (IAAO) method in women exclusively breastfeeding a single infant aged 3-4 months, and how maternal lysine needs change once infant transition to complimentary feeding at a later age of 9-10 months. Each 8-hour study day will have an assigned test lysine intake ranging from deficient to excess. The diets will be provided in a complete protein shake format, meeting all nutrient requirements except for the test lysine intake. Breath samples evaluate the indicator's oxidation to determine protein synthesis in response to lysine intake. Urine and one blood sample will be collected to assess metabolite concentrations.
Detailed Description:
This study is a single-day intervention study where participants will be studied in a repeated measures design, with an individual having the option of participating in up 4 test lysine intakes for each lactation stage. A minimum of 10 women will be recruited, and the investigators hope to retain the same women for 8 study days to minimize data variability.
Potential participants will meet the researchers for a 1-hour preliminary assessment, where the investigators will evaluate their eligibility to participate in the study. During each study day, the participants will randomly receive a lysine test intake ranging from deficient to excess. The study day diets will consist of 8 hourly isocaloric and isonitrogenous meals in a protein shake, each presenting 1/12 of the daily energy requirement. The diets are composed of crystalline amino acid mixtures based on the composition of egg protein.
A Carbon-13 (13C) stable isotope tracer ( L-\[1-13C\]phenylalanine) will be added to the 5th-8th meal. The investigators will measure the rate of oxidation of this tracer expired in breath and the flux of this tracer by its enrichment in urine. The investigators will also collect a single blood sample to measure lysine metabolites. Lysine requirements will be determined by a two-phase linear regression crossover model on L-\[1-13C\]phenylalanine tracer oxidation using mixed-models regression to take repeated measures into account. The oxidation rate of the indicator amino acid exhibits a linear increase as the lysine intake rises until it reaches a plateau. The point at which this steady state is reached signifies that the test amino acid is predominantly utilized for protein synthesis. The primary endpoint is the lysine intake level at which the transition occurs from indicator oxidation (linear increase) to protein synthesis (plateau).
Potential participants will meet the researchers for a 1-hour preliminary assessment, where the investigators will evaluate their eligibility to participate in the study. During each study day, the participants will randomly receive a lysine test intake ranging from deficient to excess. The study day diets will consist of 8 hourly isocaloric and isonitrogenous meals in a protein shake, each presenting 1/12 of the daily energy requirement. The diets are composed of crystalline amino acid mixtures based on the composition of egg protein.
A Carbon-13 (13C) stable isotope tracer ( L-\[1-13C\]phenylalanine) will be added to the 5th-8th meal. The investigators will measure the rate of oxidation of this tracer expired in breath and the flux of this tracer by its enrichment in urine. The investigators will also collect a single blood sample to measure lysine metabolites. Lysine requirements will be determined by a two-phase linear regression crossover model on L-\[1-13C\]phenylalanine tracer oxidation using mixed-models regression to take repeated measures into account. The oxidation rate of the indicator amino acid exhibits a linear increase as the lysine intake rises until it reaches a plateau. The point at which this steady state is reached signifies that the test amino acid is predominantly utilized for protein synthesis. The primary endpoint is the lysine intake level at which the transition occurs from indicator oxidation (linear increase) to protein synthesis (plateau).
Study Oversight
Has Oversight DMC:
False
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
False
Is an FDA AA801 Violation?: