Lysine Requirements During Lactation

NCT06366204 | Completed

• 1 other identifier: H23-03119
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

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.

Conditions

Lactation; Breastfeeding, Exclusive; Breastfeeding

Keywords

Dietary Reference Intake; Lysine; Lactation; Indicator Amino Acid Oxidation; Lysine Requirements; Stable Isotopes

Outcome Measures

Primary Outcomes (1)

• Carbon 13 Oxidation

  Urine and breath samples will be collected to measure the rate of L-\[1-13C\]phenylalanine oxidation.

  8 hours

Study Arms (1)

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.

Other: Dietary Lysine Intakes

Interventions

Dietary Lysine Intakes OTHER

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.

Test Lysine Intake

Eligibility Criteria

• Age: 20 Years - 40 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy
• Female
• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• University of British Columbia: lead
• Canadian Institutes of Health Research (CIHR): collaborator

Study Sites (1)

BC Children's Hospital Research Institute

Vancouver, British Columbia, V5Z 4H4, Canada

Location

MeSH Terms

Conditions

Breast Feeding

Condition Hierarchy (Ancestors)

Feeding Behavior; Behavior

Study Officials

• Rajavel Elango

  University of British Columbia

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principle Investigator

Model Details: Single day interventions; Repeated measures design.

Study Record Dates

• First Submitted: April 10, 2024
• First Posted: April 15, 2024
• Study Start: January 1, 2024
• Primary Completion: July 17, 2025
• Study Completion: July 17, 2025
• Last Updated: July 30, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)