Leucine Requirements During the Menstrual Cycle

Leucine Requirements During Different Phases of the Menstrual Cycle in Eumenorrheic Women

The existing guidelines for dietary amino acid intake for women are set the same as those established for men. These recommendations might not be appropriate for women, as they do not take into consideration important differences between male and female physiology, like the menstrual cycle. This study aims to determine the leucine requirements during the phases of the menstrual cycle. Leucine is an essential amino acid (cannot be made naturally in the body) and is necessary for protein synthesis, and other important cellular functions. Consuming an adequate amount daily is crucial for maintaining overall health. An innovative, non-invasive technique utilizing pre-determined diets, safe stable isotopes, and a simple breath collection method will be used. Previous work done by Elango Lab investigators has applied this method to investigate other amino acids in pregnant, non-pregnant, and lactating women.

Study Overview

• Status: Completed
• Conditions: Menstrual Cycle
• Intervention / Treatment: Other: Dietary Leucine Intakes

Detailed Description

The objective of the study is to determine leucine requirements using the indicator amino acid oxidation method during the follicular phase and the luteal phase of the menstrual cycle in healthy women (between the ages of 20-35 y).In comprehending protein needs and achieving protein targets, it is imperative to establish individual amino acid requirements. This clinical study aims to determine the dietary requirements of leucine for women, helping build a strong foundation for setting dietary guidelines for women. The existing values, derived from guidelines designed for men, overlook the crucial impact of the menstrual cycle on energy and dietary intake. Relying on amino acid requirements derived from studies in men for women significantly heightens the risk of potential harm. It is crucial to identify the distinct amino acid requirements for women and grasp how these needs are affected by various phases of the menstrual cycle. A minimum of 15 healthy women (20-35 y) will be recruited and studied at two menstrual phases over a range of test leucine intakes (10, 20, 30, 40, 55, 70, and 85 mg/kg/day). Women will be invited to participate in up to 7 study days/phase, and randomized to a different intake at each study day. Participants' eligibility will be assessed during a pre-study day. The goal is to study a minimum of 7 women at each intake, for a total of 49 study days in each stage.

• Study Type: Interventional
• Enrollment (Actual): 13
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V5Z 4H4
      • BC Children's Hospital Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• People with menstrual cycles
• Between the ages of 20 to 35y
• Regular menstrual cycle (21-35 day cycle) for the past 12 months
• Body mass index (BMI) of between 18 and 28 kg/m2
• Free from pre-existing health conditions

Exclusion Criteria:

• People who are currently using hormonal birth control or any contraceptive that would affect sex hormones
• People on hormone therapy
• People with an abnormal menstrual cycle history
• People with non-traditional dietary practices
• Recent weight loss/weight gain
• People with a history of endocrine disorders
• People who are pregnant
• People who are breastfeeding
• People who have given birth in the last 18 months
• People who depend on medication that affects normal metabolism. Any medication that alters normal body metabolism would skew the results and compromise the validity of the data set.
• People with a metabolic, neurological, genetic, or immune disorder likely to affect nutritional requirements or overall body metabolism.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Test Leucine Intake; Randomly assigned one of 7 test leucine intakes that range from deficient to excess (10mg/kg/d to 85mg/kg/d). Participants may complete up to 7 study days in each menstrual phase, at different randomly assigned intakes.

Other: Dietary Leucine Intakes; Participants consume 8 hourly meals that contain the assigned test leucine intake. Each meal will provide one-twelfth of the participants' daily energy requirements as estimated by 1.5 x Resting Energy Expenditure (REE) and adequate protein at 1.0 g.kg.d, to maintain a metabolic steady state. The meals are in the form of a crystalline amino acid protein shake, and protein-free cookies.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carbon 13 Oxidation	Urine and breath samples will be collected to measure the rate of L-[1-13C]phenylalanine oxidation.	8 hours

Collaborators and Investigators

• Sponsor: University of British Columbia

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Actual): June 1, 2025
• Study Completion (Actual): June 1, 2025

Study Registration Dates

• First Submitted: July 29, 2024
• First Submitted That Met QC Criteria: July 29, 2024
• First Posted (Actual): August 1, 2024

Study Record Updates

• Last Update Posted (Actual): February 12, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: H23-03387

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No