Protein Absorption and Amino Acid AvailabilityNCT07272668
MA of Tryptophan in Cornmeal in Healthy Adults>60y
A study testing Tryptophan in people with Protein Absorption and Amino Acid Availability, run by The Hospital for Sick Children at 1 site in Canada.
Trial summary
The world's population will reach 12 billion by this century's end. As the human population increases, the world faces the continuous challenge of optimizing a limited food supply. Protein is the key determinant of growth and bodily function. Read more about this study
- Who is it for?
- Ages 60 to 90 yearsHealthy volunteers can take part
- Conditions the study is for
- Protein Absorption and Amino Acid Availability
- What is being tested?
- Tryptophan
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 6 participants
- Where
- 1 siteCanada
- Study dates
- 29 Nov 2025to 15 Jul 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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
- 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.
About this study
Official title: Metabolic Availability of Tryptophan in Cornmeal in Healthy Adults >60 Yrs
The world's population will reach 12 billion by this century's end. As the human population increases, the world faces the continuous challenge of optimizing a limited food supply. Protein is the key determinant of growth and bodily function. Recently, our group showed that current protein recommendations for adults and children are underestimated by 30-50%. Animal protein production is "more resource intensive than any other form of food production" and their high saturated fat content is linked to chronic diseases in developed nations. Plant protein sources are important alternatives shown to "enhance ecosystem resilience and improve human health". Maize, commonly known as corn, is a staple food in the diets of more than 300 million Africans and ranks as the third most produced food globally. Maize supplies up to 80% of daily energy in sub-Saharan and Southern Africa alone. It is one of the main protein sources in these countries for vegetarians. Already, over 900,000 Canadians adults are vegetarians and globally plant protein consumption is encouraged. However, maize protein is limiting in the essential amino acid (EAA) tryptophan and anti-nutritional factors can affect tryptophan bioavailability (BA). Dietary protein quality (DPQ) depends on its amino acid (AA) composition and BA. Therefore, knowledge of tryptophan BA is fundamental to understand the extent to which cereal grains meet the body's requirement for protein synthesis (PS). Efforts aimed at increasing crop production and DPQ, should coincide with DPQ evaluation directly in humans so that the gap in knowledge between protein requirement and how best to provide it can be quickly and efficiently reconciled.
Read the detailed description
Protein quality evaluation assesses the capacity of food proteins to meet the EAA needs of the body. The DPQ of plant proteins have been little studied in humans despite their importance in the diet and their well-recognized positive effects on chronic diseases. Dietary guidelines are encouraging increased plant protein consumption due to the benefits of plant protein. With the increasing interest in vegetarian diets in North America, it is imperative that the DPQ of cereal grains be evaluated so that plant protein recommendations are accompanied by an empirical understanding of plant protein quality. The information gathered from this project will provide additional experimental data in humans on plant protein quality (have completed lentils and chickpeas), on which nutrition recommendations can be built. Globally, this will also help support the FAO's commitment to compile tables on AABA of foods for global distribution. The aim of the study is to apply the IAAO method to determine the MA of tryptophan in maize prepared by moist cooking method. Six healthy older adults will be recruited to conduct a total of 40 IAAO studies in a repeated measure design. Subjects will be tested on both reference (crystalline amino acids) and maize diets. Reference and maize slope will be constructed based on the response of C13 phenylalanine oxidation. The ratio of maize slope to reference slope determines the MA/bioavailability of maize.
- Being tested
- Tryptophan
- Keywords
- elderly, healthy, tryptophan, amino acid availability, metabolic availability, indicator amino acid oxidation, iaao, stable isotopes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TryptophanOther
Also called maize
4 different tryptophan test levels 0.5, 1, 1.5 and 2 mg.kg-1.day.1
| Study group | Role | What they receive |
|---|---|---|
| MA of tryptophan in maize | Experimental | Apply the IAAO method to determine the metabolic availability of tryptophan in maize prepared by moist cooking method Receives: Other: Tryptophan |
What is being measured
The primary outcome is the main question the study is designed to answer.
MA of tryptophan in maize
To measure the tryptophan metabolic availability 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 posted9 Dec 2025
- Study start29 Nov 2025
- Primary completion15 Jul 2026
- Study completion15 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Protein Absorption and Amino Acid AvailabilityStudies 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
- 6 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Hospital for Sick Children
- Sponsor type
- University, hospital or other
- 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
- NCT07272668
- Sponsor's protocol ID
- 3568
- Status last verified
- Sep 2026
- First submitted
- 26 Nov 2025
- Last updated
- 2 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Metabolic Availability of Tryptophan in Cornmeal in Healthy Adults >60 Yrs
- ClinicalTrials.gov ID
- NCT07272668
- Acronym / sponsor ID
- 3568
- Keywords
- elderly, healthy, tryptophan, amino acid availability, metabolic availability, indicator amino acid oxidation, iaao, stable isotopes
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 6 participants (actual)
- Lead sponsor
- The Hospital for Sick ChildrenUniversity, hospital or other
- Study start
- 29 Nov 2025 (actual)
- Primary completion
- 15 Jul 2026 (actual)
- Study completion
- 15 Jul 2026 (actual)
- First posted
- 9 Dec 2025 (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 world's population will reach 12 billion by this century's end. As the human population increases, the world faces the continuous challenge of optimizing a limited food supply. Protein is the key determinant of growth and bodily function. Recently, our group showed that current protein recommendations for adults and children are underestimated by 30-50%. Animal protein production is "more resource intensive than any other form of food production" and their high saturated fat content is linked to chronic diseases in developed nations. Plant protein sources are important alternatives shown to "enhance ecosystem resilience and improve human health". Maize, commonly known as corn, is a staple food in the diets of more than 300 million Africans and ranks as the third most produced food globally. Maize supplies up to 80% of daily energy in sub-Saharan and Southern Africa alone. It is one of the main protein sources in these countries for vegetarians. Already, over 900,000 Canadians adults are vegetarians and globally plant protein consumption is encouraged. However, maize protein is limiting in the essential amino acid (EAA) tryptophan and anti-nutritional factors can affect tryptophan bioavailability (BA). Dietary protein quality (DPQ) depends on its amino acid (AA) composition and BA. Therefore, knowledge of tryptophan BA is fundamental to understand the extent to which cereal grains meet the body's requirement for protein synthesis (PS). Efforts aimed at increasing crop production and DPQ, should coincide with DPQ evaluation directly in humans so that the gap in knowledge between protein requirement and how best to provide it can be quickly and efficiently reconciled.
Detailed description
Protein quality evaluation assesses the capacity of food proteins to meet the EAA needs of the body. The DPQ of plant proteins have been little studied in humans despite their importance in the diet and their well-recognized positive effects on chronic diseases. Dietary guidelines are encouraging increased plant protein consumption due to the benefits of plant protein. With the increasing interest in vegetarian diets in North America, it is imperative that the DPQ of cereal grains be evaluated so that plant protein recommendations are accompanied by an empirical understanding of plant protein quality. The information gathered from this project will provide additional experimental data in humans on plant protein quality (have completed lentils and chickpeas), on which nutrition recommendations can be built. Globally, this will also help support the FAO's commitment to compile tables on AABA of foods for global distribution. The aim of the study is to apply the IAAO method to determine the MA of tryptophan in maize prepared by moist cooking method. Six healthy older adults will be recruited to conduct a total of 40 IAAO studies in a repeated measure design. Subjects will be tested on both reference (crystalline amino acids) and maize diets. Reference and maize slope will be constructed based on the response of C13 phenylalanine oxidation. The ratio of maize slope to reference slope determines the MA/bioavailability of maize.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| MA of tryptophan in maize | Experimental | Other: TryptophanApply the IAAO method to determine the metabolic availability of tryptophan in maize prepared by moist cooking method |
Who may qualify
- Ages
- 60 to 90 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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.
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).
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 |
|---|---|---|
| TryptophanAlso: maize4 different tryptophan test levels 0.5, 1, 1.5 and 2 mg.kg-1.day.1 | Other | MA of tryptophan in maize |
Primary outcome
MA of tryptophan in maize
Time frame: Up to 24 months
To measure the tryptophan metabolic availability 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
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Oct 2026.
- Individual participant dataSharing planned: No
Related trials for Protein Absorption and Amino Acid Availability
Not yet recruiting
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Protein Absorption and Amino Acid Availability, Metabolomics
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. This study is not recruiting at the moment.
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 Protein Absorption and Amino Acid Availability, 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 5 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: finished, as of the sponsor's last update on 2 Oct 2026. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
MA of tryptophan in maize (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?
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 2 Oct 2026; AzTrials last refreshed its copy on 8 Nov 2026.