Healthy AgingNCT06283706
The Tryptophan Requirement in Healthy Adults
A study testing Tryptophan in people with Healthy Aging, run by The Hospital for Sick Children at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages 60 to 90 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Aging
- What is being tested?
- Tryptophan
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteCanada
- Study dates
- 1 Jun 2024to 1 Dec 2025
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 60 to 90 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
Hospital for Sick Children
Toronto, Ontario, M5G 1X8
Glenda Courtney-Martin, PhD, 416-814-5744, glenda.courtney-martin@sickkids.ca
About this study
Official title: The Tryptophan Requirement in Healthy Adults Over 60 Years
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.
Read the detailed description
Tryptophan is an essential amino acid and must be obtained from the diet. It is required for protein synthesis and acts as a precursor for serotonin and nicotinic acid. It is of particular importance in the diet of people who receive a large percentage of their calories from cereal grains such as maize, as it is limiting in tryptophan. Therefore, accurate knowledge of tryptophan requirement is important for dietary planning particularly for older adults. In 1998, our lab determined the tryptophan requirement in young women to be 4.01 mg/kg/day, with a safe intake at 5 mg/kg/day, using the Indicator Amino Acid Oxidation method. Since then, the investigators have determined the tryptophan requirement and safe level in healthy school-age children to be 4.7 and 6 mg/kg/day. The investigators have recently found the requirements of essential amino acids such as leucine and total sulfur amino acids in older adults and have found to be higher than young adults and a difference between the sexes. Thus, there is a need to determine the threonine requirement in older adults.
- Conditions
- Healthy Aging
- Being tested
- Tryptophan
- Keywords
- elderly, healthy, tryptophan requirement, indicator amino acid oxidation, stable isotopes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TryptophanOther
There are 7 different tryptophan test levels ranging from 0.5, 2, 4, 6, 8, 10, 12 mg.kg-1.day.1
| Study group | Role | What they receive |
|---|---|---|
| Tryptophan in Adults >60y | Experimental | Tryptophan levels, up to 7 levels, will be tested in a random order in all subjects Receives: Other: Tryptophan |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: up to 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Feb 2024
- Study start1 Jun 2024
- Primary completion1 Jul 2025 (estimated)
- Study completion1 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Healthy AgingStudies of the same condition, open and under way.
- More trials run by The Hospital for Sick ChildrenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Hospital for Sick Children
- Sponsor type
- University, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Responsible party
- Principal investigator, Glenda Courtney-Martin, The Hospital for Sick Children
- Investigators
- Glenda Courtney-Martin, PhD, RD, Principal investigator, The Hospital for Sick Children
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06283706
- Sponsor's protocol ID
- 1000081113
- Status last verified
- Mar 2025
- First submitted
- 21 Feb 2024
- Last updated
- 30 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Wang Z, Tomlinson C, Pencharz P, Li B, Kong D, Elango R, Courtney-Martin G. Dietary Tryptophan Requirements in Adults Aged Over 60 Years is not Affected by Sex or Decades of Age. J Nutr. 2026 Sep 11:101827. doi: 10.1016/j.tjnut.2026.101827. Online ahead of print.
PubMed 42727854
Study at a glance
From the registry record, last updated by the sponsor on 30 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Tryptophan Requirement in Healthy Adults Over 60 Years
- ClinicalTrials.gov ID
- NCT06283706
- Acronym / sponsor ID
- 1000081113
- Conditions
- Healthy Aging
- Keywords
- elderly, healthy, tryptophan requirement, indicator amino acid oxidation, stable isotopes
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- The Hospital for Sick ChildrenUniversity, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Study start
- 1 Jun 2024 (actual)
- Primary completion
- 1 Jul 2025 (estimated)
- Study completion
- 1 Dec 2025 (estimated)
- First posted
- 28 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Tryptophan is an essential amino acid and must be obtained from the diet. It is required for protein synthesis and acts as a precursor for serotonin and nicotinic acid. It is of particular importance in the diet of people who receive a large percentage of their calories from cereal grains such as maize, as it is limiting in tryptophan. Therefore, accurate knowledge of tryptophan requirement is important for dietary planning particularly for older adults. In 1998, our lab determined the tryptophan requirement in young women to be 4.01 mg/kg/day, with a safe intake at 5 mg/kg/day, using the Indicator Amino Acid Oxidation method. Since then, the investigators have determined the tryptophan requirement and safe level in healthy school-age children to be 4.7 and 6 mg/kg/day. The investigators have recently found the requirements of essential amino acids such as leucine and total sulfur amino acids in older adults and have found to be higher than young adults and a difference between the sexes. Thus, there is a need to determine the threonine requirement in older adults.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Tryptophan in Adults >60y | Experimental | Other: TryptophanTryptophan levels, up to 7 levels, will be tested in a random order in all subjects |
Who may qualify
- Ages
- 60 to 90 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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.
Key exclusion criteria (6 listed)
- 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).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TryptophanThere are 7 different tryptophan test levels ranging from 0.5, 2, 4, 6, 8, 10, 12 mg.kg-1.day.1 | Other | Tryptophan in Adults >60y |
Primary outcome
Determination of tryptophan requirement in adults >60 years of age.
Time frame: up to 24 months
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.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 May 2025.
- Derived from this study: PubMed 42727854Wang Z, Tomlinson C, Pencharz P, Li B, Kong D, Elango R, Courtney-Martin G. Dietary Tryptophan Requirements in Adults Aged Over 60 Years is not Affected by Sex or Decades of Age. J Nutr. 2026 Sep 11:101827. doi: 10.1016/j.tjnut.2026.101827. Online ahead of print.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Glenda Courtney-Martin, PhD, RD principal investigator
The Hospital for Sick Children
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Tryptophan in people with Healthy Aging, run by The Hospital for Sick Children at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Zhiyao Wang, MSc (437 419 6224, zhiyao.wang@sickkids.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Determination of tryptophan requirement in adults >60 years of age. (time frame: up to 24 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06283706, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 May 2025.