Leucine Requirements During the Menstrual Cycle

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.

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Key information

Conditions

Menstrual Cycle

Age range

20 year–35 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

BC Children's Hospital Research Institute

Vancouver, British Columbia, V5Z 4H4, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Dietary Leucine Intakes

Other

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.

Primary outcomes

Carbon 13 Oxidation

Time frame: 8 hours

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

Sponsors and collaborators

Lead sponsor

University of British Columbia

Other

Registry information

Official study title

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

Important dates

Study start: 2024
Primary completion: 2025
Study completion: 2025
First posted: Aug 1, 2024
Registry last updated: Feb 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed