Upper Limit of Leucine Intake in Adults
July 26, 2013 updated by: Dr. Paul Pencharz, The Hospital for Sick Children
Determination of the Tolerable Upper Limit of Leucine Intake in Adult Humans
When dietary amino acid supplements are consumed by humans they are normally in addition to their normal daily requirements.
The investigators' laboratory played a leading role in defining the estimated average requirement (EAR) and the recommended dietary intake for the "essential" amino acids (Dietary Reference Intakes 2005).
The other important but less well studied component of Dietary Reference Intakes (DRI) is - What is a safe upper limit of intake?
The investigators now propose to determine the safe upper limits of the dietary essential amino acids.
The recently published DRI (2005) defines the Tolerable Upper Intake Level (UL) as 'the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population.'
As intake increases above the UL, the potential risk of adverse effects may increase'.
In this proposal, the investigators define a novel method to define the safe upper limit where the 'maximum oxidative potential' of an amino acid identifies the 'metabolic limit' to dispose the amino acid.
Intakes of amino acid above this level will increase the potential for adverse effects to appear.
Study Overview
Detailed Description
The objective of the study will be to determine the 'metabolic limit' of leucine oxidation in healthy young men by:
A) Measuring leucine oxidation in response to short term (8 hr) graded excess leucine intake B) Correlating changes in leucine oxidation with changes in plasma concentrations of keto-isocaproic acid (KIC, the first breakdown product of leucine metabolism), other essential amino acids, ammonia, urea, creatinine, glucose, insulin, and electrolytes (sodium, potassium, chloride) to identify potential biomarkers C) Correlating changes in leucine oxidation with changes in urinary excretion of leucine and ketoisocaproic acid (KIC), urea and creatinine to identify potential biomarkers
Study Type
Interventional
Enrollment (Actual)
5
Phase
- Phase 1
Contacts and Locations
This section provides the contact details for those conducting the study, and information on where this study is being conducted.
Study Locations
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Ontario
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Toronto, Ontario, Canada
- The Hospital for Sick Children
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Participation Criteria
Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
Eligibility Criteria
Ages Eligible for Study
18 years to 35 years (Adult)
Accepts Healthy Volunteers
No
Genders Eligible for Study
Male
Description
Inclusion Criteria:
- Male
- 18-35 years old
Exclusion Criteria:
- Report a recent history of sudden weight loss
- Have unusual dietary habits such as chronic consumption of caffeinated beverages or alcohol
- Have any endocrine disorders
- Are currently using any prescribed medications
Study Plan
This section provides details of the study plan, including how the study is designed and what the study is measuring.
How is the study designed?
Design Details
- Allocation: Non-Randomized
- Interventional Model: Single Group Assignment
- Masking: Single
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
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Experimental: Leucine
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Graded stepwise increases in leucine intakes (50, 250, 500, 750, 1000, 1250 and 1500mg/kg/day)
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Time Frame |
|---|---|
|
Breath carbon dioxide production
Time Frame: Study Visits 1-7 (-45min,-30min,-15min, +2.5hrs, +3hrs, +3.5Hrs +4hrs)
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Study Visits 1-7 (-45min,-30min,-15min, +2.5hrs, +3hrs, +3.5Hrs +4hrs)
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Secondary Outcome Measures
Outcome Measure |
Time Frame |
|---|---|
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Plasma
Time Frame: Study Visits 1-7 (Hourly)
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Study Visits 1-7 (Hourly)
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Urine
Time Frame: Study Visits 1-7 (8hr timepoint)
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Study Visits 1-7 (8hr timepoint)
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VCO2
Time Frame: Study Visits 1-7 (after 5hr meal)
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Study Visits 1-7 (after 5hr meal)
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Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Investigators
- Principal Investigator: Paul B Pencharz, MD, The Hospital for Sick Children, Toronto, Canada
Publications and helpful links
The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.
Study record dates
These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.
Study Major Dates
Study Start
May 1, 2009
Primary Completion (Actual)
February 1, 2010
Study Completion (Actual)
February 1, 2010
Study Registration Dates
First Submitted
September 4, 2009
First Submitted That Met QC Criteria
September 4, 2009
First Posted (Estimate)
September 7, 2009
Study Record Updates
Last Update Posted (Estimate)
July 29, 2013
Last Update Submitted That Met QC Criteria
July 26, 2013
Last Verified
July 1, 2013
More Information
Terms related to this study
Keywords
Other Study ID Numbers
- 1000012066
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.