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Completed

NCT Number: NCT00972582

Upper Limit of Leucine Intake in Adults

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.

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Key information

Conditions

Healthy

Age range

18 year–35 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 1

Primary location

The Hospital for Sick Children

Toronto, Ontario, Canada

About this study

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

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Leucine Increase

Dietary Supplement

Graded stepwise increases in leucine intakes (50, 250, 500, 750, 1000, 1250 and 1500mg/kg/day)

Primary outcomes

  1. Breath carbon dioxide production

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

Secondary outcomes

  1. Plasma

    Time frame: Study Visits 1-7 (Hourly)

  2. Urine

    Time frame: Study Visits 1-7 (8hr timepoint)

  3. VCO2

    Time frame: Study Visits 1-7 (after 5hr meal)

Sponsors and collaborators

Lead sponsor

The Hospital for Sick Children

Other

Registry information

Official study title

Determination of the Tolerable Upper Limit of Leucine Intake in Adult Humans

Important dates

Study start
2009
Primary completion
2010
Study completion
2010
First posted
Sep 7, 2009
Registry last updated
Jul 29, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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