LactationNCT06366204
Lysine Requirements During Lactation
A study testing Dietary Lysine Intakes in people with Lactation and Breastfeeding, Exclusive, run by University of British Columbia at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages 20 to 40 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Lactation, Breastfeeding, Exclusive, Breastfeeding
- What is being tested?
- Dietary Lysine Intakes
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 1 siteCanada
- Study dates
- 1 Jan 2024to 17 Jul 2025
- 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 20 to 40 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy
- Female
- 20-40 years
- Had a singleton pregnancy and is breastfeeding a single child.
- Exclusively breastfeeding an infant 3 - 4 months of age OR complimentary. feeding an infant 9-10 months of age.
Who cannot join
- Participants not in good health or have a history of metabolic, cardiovascular, neurological, genetic, endocrine, immune, or physical mobility disorders.
- Participants that had major pregnancy or delivery complications (e.g., preeclampsia/ eclampsia, placenta previa, postpartum haemorrhage, neonatal intensive care, gestational diabetes).
- Participants with substance dependence issues (e.g., nicotine, alcohol, marijuana, illicit drugs).
- Participants that have had breast surgery that may impact lactation, lactogenesis or breastfeeding.
- Participants that use medications that affect lactation (e.g. estrogenic birth control, anti-dopaminergic drugs, Methyldopa) or other continuous prescription medication.
- Participants with a pre-pregnancy BMI below 18 kg/m² or above 28 kg/m².
Show all 11Show fewer
- Participants who are below 20 years of age or greater than 40 years of age.
- Infants' weight and length are under 3rd or above the 97th percentile, using the World Health Organization (WHO) percentile growth chart.
- Infants born before 38 weeks or after 42 weeks of gestation.
- Infants who use infant formula milk.
- Infants with known metabolic, cardiovascular, neurological, genetic, endocrine, immune, or physical mobility disorders.
Trial locations and contacts
1 site in 1 country.
Canada1 site
BC Children's Hospital Research Institute
Vancouver, British Columbia, V5Z 4H4
About this study
Official title: Determining Dietary Lysine Requirements in Healthy Lactating Women Using the Indicator Amino Acid Oxidation Technique
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.
Read the 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).
- Conditions
- Lactation, Breastfeeding, Exclusive, Breastfeeding
- Being tested
- Dietary Lysine Intakes
- Keywords
- Dietary Reference Intake, Lysine, Lactation, Indicator Amino Acid Oxidation, Lysine Requirements, Stable Isotopes
- Medical subject headings
- Breast Feeding
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary Lysine IntakesOther
Participants consume 8 hourly meals that contain the assigned test lysine intake. Each meal will provide one-twelfth of the participants' daily energy requirements as estimated by 1.7 x Resting Energy Expenditure (REE) and adequate protein at 1.5 g.kg.d, to maintain a metabolic steady state. The meals are in the form of a crystalline amino acid protein shake, and nitrogenous free cookies.
| Study group | Role | What they receive |
|---|---|---|
| Test Lysine Intake | Experimental | Randomly assigned one of 7 test lysine intakes that range from deficient to excess (12mg/kg/d to 84mg/kg/d). Participants may complete up to 4 study days, at different randomly assigned intakes. Receives: Other: Dietary Lysine Intakes |
What is being measured
The primary outcome is the main question the study is designed to answer.
Carbon 13 Oxidation
Urine and breath samples will be collected to measure the rate of L-[1-13C]phenylalanine oxidation.
Measured: 8 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Apr 2024
- Study start1 Jan 2024
- Primary completion17 Jul 2025
- Study completion17 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for LactationStudies of the same condition, open and under way.
- More trials run by University of British ColumbiaThe sponsor's other registered studies.
- 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
- Not applicable
- Intervention model
- Single group
- Model description
- Single day interventions; Repeated measures design.
- Masking
- None (open label)
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of British Columbia
- Sponsor type
- University, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Responsible party
- Principal investigator, Rajavel Elango, PhD, University of British Columbia
- Investigators
- Rajavel Elango, Principal investigator, University of British Columbia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06366204
- Sponsor's protocol ID
- H23-03119
- Status last verified
- Jul 2025
- First submitted
- 10 Apr 2024
- Last updated
- 30 Jul 2025
- 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 30 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Determining Dietary Lysine Requirements in Healthy Lactating Women Using the Indicator Amino Acid Oxidation Technique
- ClinicalTrials.gov ID
- NCT06366204
- Acronym / sponsor ID
- H23-03119
- Conditions
- Lactation, Breastfeeding, Exclusive, Breastfeeding
- Keywords
- Dietary Reference Intake, Lysine, Lactation, Indicator Amino Acid Oxidation, Lysine Requirements, Stable Isotopes
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- University of British ColumbiaUniversity, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 17 Jul 2025 (actual)
- Study completion
- 17 Jul 2025 (actual)
- First posted
- 15 Apr 2024 (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.
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).
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Single day interventions; Repeated measures design.
| Arm | Type | Receives |
|---|---|---|
| Test Lysine Intake | Experimental | Other: Dietary Lysine IntakesRandomly assigned one of 7 test lysine intakes that range from deficient to excess (12mg/kg/d to 84mg/kg/d). Participants may complete up to 4 study days, at different randomly assigned intakes. |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Healthy
- Female
- 20-40 years
- Had a singleton pregnancy and is breastfeeding a single child.
- Exclusively breastfeeding an infant 3 - 4 months of age OR complimentary. feeding an infant 9-10 months of age.
Key exclusion criteria (11 listed)
- Participants not in good health or have a history of metabolic, cardiovascular, neurological, genetic, endocrine, immune, or physical mobility disorders.
- Participants that had major pregnancy or delivery complications (e.g., preeclampsia/ eclampsia, placenta previa, postpartum haemorrhage, neonatal intensive care, gestational diabetes).
- Participants with substance dependence issues (e.g., nicotine, alcohol, marijuana, illicit drugs).
- Participants that have had breast surgery that may impact lactation, lactogenesis or breastfeeding.
- Participants that use medications that affect lactation (e.g. estrogenic birth control, anti-dopaminergic drugs, Methyldopa) or other continuous prescription medication.
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 |
|---|---|---|
| Dietary Lysine IntakesParticipants consume 8 hourly meals that contain the assigned test lysine intake. Each meal will provide one-twelfth of the participants' daily energy requirements as estimated by 1.7 x Resting Energy Expenditure (REE) and adequate protein at 1.5 g.kg.d, to maintain a metabolic steady state. The meals are in the form of a crystalline amino acid protein shake, and nitrogenous free cookies. | Other | Test Lysine Intake |
Primary outcome
Carbon 13 Oxidation
Time frame: 8 hours
Urine and breath samples will be collected to measure the rate of L-[1-13C]phenylalanine oxidation.
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 30 Jul 2025.
- Individual participant dataSharing planned: No
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Experiences of Mothers Considering Breastfeeding Cessation: Decision-Making, Method Exploration, and Support Needs
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Methyl Donor-Rich Diet in the Postpartum Period
Postpartum Depression (PPD), Breastfeeding
Not yet recruiting
Postpartum Care in the NICU Multi-Site Breastfeeding
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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.
Rajavel Elango principal investigator
University of British Columbia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dietary Lysine Intakes in people with Lactation and Breastfeeding, Exclusive, run by University of British Columbia 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 5 inclusion and 11 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 30 Jul 2025. 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. 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?
Carbon 13 Oxidation (time frame: 8 hours). 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 30 Jul 2025.