Phenylalanine Requirements in the Menstrual Phases

NCT07481201 | Recruiting

• 1 other identifier: H26-00530
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

Phenylalanine is an essential amino acid that must be obtained through food. Current adult phenylalanine recommendation is based on male-conducted studies and set the same for females. These recommendations may not be appropriate for females, as they do not take into consideration the hormonal changes over the menstrual cycle. The menstrual cycle is a rhythmic hormonal process split into two phases, with hormones regulating metabolism differently. The aim of this study is to find phenylalanine requirement for healthy, menstruating females. 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 females as well as in children.

Conditions

Menstrual Cycle

Outcome Measures

Primary Outcomes (1)

• Carbon 13 Oxidation

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

  8 hours

Study Arms (1)

Test Phenylalanine Intake

EXPERIMENTAL

Randomly assigned one of 7 test phenylalanine intakes that range from deficient to excess (2.5mg/kg/d to 22.5mg/kg/d). Participants may complete up to 7 study days in each menstrual phase, at different randomly assigned intakes.

Other: Dietary Phenylalanine Intakes

Interventions

Dietary Phenylalanine Intakes OTHER

Participants consume 8 hourly meals that contain the assigned test phenylalanine 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.

Test Phenylalanine Intake

Eligibility Criteria

• Age: 20 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of British Columbia: lead

Study Sites (1)

BC Children's Hospital Research Institute

Vancouver, British Columbia, V5Z 4H4, Canada

RECRUITING

Central Study Contacts

Rajavel Elango

CONTACT

+4911 604-875-2000; relango@bcchr.ubc.ca

Paloma DeLisle

CONTACT

778-683-2256; paloma.delisle@bcchr.ca

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: Principal Investigator

Model Details: Single-day interventions; Repeated Measures Design

Study Record Dates

• First Submitted: March 13, 2026
• First Posted: March 18, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: May 7, 2026

Record last verified: 2026-05

Locations

CA (1)