The Tryptophan Requirement in Healthy Adults

NCT06283706 | Recruiting

• 1 other identifier: 1000081113
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

The aging population is growing rapidly. For the first time ever, Canadian seniors outnumbered young adults in 2016. Aging is associated with many physical and metabolic deteriorations including the loss of muscle mass and strength, insulin resistance, increased inflammation and oxidative stress. The muscles of our bodies are composed of proteins and proteins are made of small building blocks called amino acids. Our bodies have the ability to make some amino acids which are called the non-essential amino acids. However, there are certain amino acids that our body's need to make protein but can only be supplied from the foods that we consume. These are called essential amino acids. Tryptophan is one of the essential amino acids that the body needs. Tryptophan is required for protein synthesis and acts as a precursor for serotonin and nicotinic acid. Therefore, there may be a need for more threonine in the diet of older adults. However, the current requirement for threonine is based on studies conducted exclusively in young adults. Thus, the purpose of this study is to find out how much tryptophan older adults need.

Conditions

Healthy Aging

Keywords

elderly; healthy; tryptophan requirement; indicator amino acid oxidation; stable isotopes

Outcome Measures

Primary Outcomes (1)

• Determination of tryptophan requirement in adults >60 years of age.

  To measure the tryptophan requirement investigators will collect breath samples from participants. From these samples, investigators will measure the amount of amino acids oxidized and how much is retained in the body when graded intakes of tryptophan are consumed by the participants consuming a controlled diet.

  up to 24 months

Study Arms (1)

Tryptophan in Adults >60y

EXPERIMENTAL

Tryptophan levels, up to 7 levels, will be tested in a random order in all subjects

Other: Tryptophan

Interventions

Tryptophan OTHER

There are 7 different tryptophan test levels ranging from 0.5, 2, 4, 6, 8, 10, 12 mg.kg-1.day.1

Tryptophan in Adults >60y

Eligibility Criteria

• Age: 60 Years - 90 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Consent provided.
• Aged 60 to 90 years old.
• In good general health as evidenced by medical history, physical health and blood draw.
• Fasting blood glucose, hemoglobin A1c (HbA1c), urea, creatinine.
• Willingness to participate in the study.
• BMI \<30 kg/m2.

You may not qualify if:

• Presence of chronic disease and/or acute illness known to affect protein/amino acid metabolism (e.g. HIV, diabetes, taking medications known to affect protein/AA metabolism (e.g. steroids).
• Inability to tolerate the diet (i.e. allergy).
• Significant weight loss during the past month or consumption of weight reducing diets.
• Significant caffeine consumption (\>2 cups per day).
• Significant consumption of alcohol (\>1 drink per day i.e. 1 beer or ½ glass of wine).
• Unwilling to have blood drawn from a venous access or using a ventilated hood indirect calorimeter for the purposes of the study.

Sponsors & Collaborators

• The Hospital for Sick Children: lead
• Canadian Institutes of Health Research (CIHR): collaborator

Study Sites (1)

Hospital for Sick Children

Toronto, Ontario, M5G 1X8, Canada

RECRUITING

MeSH Terms

Interventions

Tryptophan

Intervention Hierarchy (Ancestors)

Amino Acids, Aromatic; Amino Acids, Cyclic; Amino Acids; Amino Acids, Peptides, and Proteins; Amino Acids, Essential

Study Officials

• Glenda Courtney-Martin, PhD, RD

  The Hospital for Sick Children

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Zhiyao Wang, MSc

CONTACT

437 419 6224; zhiyao.wang@sickkids.ca

Mahroukh Rafii, BSc

CONTACT

647 215 1201; mahroukh.rafii@sickkids.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: Senior Associate Scientist

Study Record Dates

• First Submitted: February 21, 2024
• First Posted: February 28, 2024
• Study Start: June 1, 2024
• Primary Completion: July 1, 2025
• Study Completion: December 1, 2025
• Last Updated: May 30, 2025

Record last verified: 2025-03

Locations

CA (1)