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Upper Limit of Leucine Intake in Adults

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00972582
First Posted: September 7, 2009
Last Update Posted: July 29, 2013
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Dr. Paul Pencharz, The Hospital for Sick Children
  Purpose
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.

Condition Intervention Phase
Healthy Dietary Supplement: Leucine Increase Phase 1

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Single (Participant)
Official Title: Determination of the Tolerable Upper Limit of Leucine Intake in Adult Humans

Resource links provided by NLM:


Further study details as provided by Dr. Paul Pencharz, The Hospital for Sick Children:

Primary Outcome Measures:
  • Breath carbon dioxide production [ Time Frame: Study Visits 1-7 (-45min,-30min,-15min, +2.5hrs, +3hrs, +3.5Hrs +4hrs) ]

Secondary Outcome Measures:
  • Plasma [ Time Frame: Study Visits 1-7 (Hourly) ]
  • Urine [ Time Frame: Study Visits 1-7 (8hr timepoint) ]
  • VCO2 [ Time Frame: Study Visits 1-7 (after 5hr meal) ]

Enrollment: 5
Study Start Date: May 2009
Study Completion Date: February 2010
Primary Completion Date: February 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Leucine Dietary Supplement: Leucine Increase
Graded stepwise increases in leucine intakes (50, 250, 500, 750, 1000, 1250 and 1500mg/kg/day)

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

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

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
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00972582


Locations
Canada, Ontario
The Hospital for Sick Children
Toronto, Ontario, Canada
Sponsors and Collaborators
The Hospital for Sick Children
Investigators
Principal Investigator: Paul B Pencharz, MD The Hospital for Sick Children, Toronto, Canada
  More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Dr. Paul Pencharz, Emeritus Scientist, The Hospital for Sick Children
ClinicalTrials.gov Identifier: NCT00972582     History of Changes
Other Study ID Numbers: 1000012066
First Submitted: September 4, 2009
First Posted: September 7, 2009
Last Update Posted: July 29, 2013
Last Verified: July 2013

Keywords provided by Dr. Paul Pencharz, The Hospital for Sick Children:
leucine intake
tolerable upper limit
adults
amino acid supplements
Excessive Leucine Intake