Upper Limit of Leucine Intake in Adults

NCT ID: NCT00972582

Last Updated: 2013-07-29

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE1
• Total Enrollment: 5 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2009-05-31
• Study Completion Date: 2010-02-28

Brief Summary

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.

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

Conditions

Healthy

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Blinding Strategy: SINGLE

Study Groups

Leucine

Group Type: EXPERIMENTAL

Leucine Increase

Intervention Type: DIETARY_SUPPLEMENT

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

Interventions

Leucine Increase

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

Intervention Type: DIETARY_SUPPLEMENT

Eligibility 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

The Hospital for Sick Children

OTHER

Sponsor Role: lead

Responsible Party

Dr. Paul Pencharz

Emeritus Scientist

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Paul B Pencharz, MD

Role: PRINCIPAL_INVESTIGATOR

The Hospital for Sick Children, Toronto, Canada

Locations

The Hospital for Sick Children

Toronto, Ontario, Canada

Countries

Canada

References

Elango R, Chapman K, Rafii M, Ball RO, Pencharz PB. Determination of the tolerable upper intake level of leucine in acute dietary studies in young men. Am J Clin Nutr. 2012 Oct;96(4):759-67. doi: 10.3945/ajcn.111.024471. Epub 2012 Sep 5.

Reference Type: DERIVED

PMID: 22952178 (View on PubMed)

Other Identifiers

1000012066

Identifier Type: -

Identifier Source: org_study_id