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

Status

Completed

Conditions

Intervention / Treatment

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

  • Canada
    • Ontario
      • Toronto, Ontario, Canada
        • The Hospital for Sick Children

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
Experimental: Leucine
Dietary supplement: Leucine Increase
Graded stepwise increases in leucine intakes (50, 250, 500, 750, 1000, 1250 and 1500mg/kg/day)

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)
Study Visits 1-7 (-45min,-30min,-15min, +2.5hrs, +3hrs, +3.5Hrs +4hrs)

Secondary Outcome Measures

Outcome Measure
Time Frame
Plasma
Time Frame: Study Visits 1-7 (Hourly)
Study Visits 1-7 (Hourly)
Urine
Time Frame: Study Visits 1-7 (8hr timepoint)
Study Visits 1-7 (8hr timepoint)
VCO2
Time Frame: Study Visits 1-7 (after 5hr meal)
Study Visits 1-7 (after 5hr meal)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The Hospital for Sick Children

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.

General Publications

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.

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