Phenylalanine Requirement of Adults >65 Years.

NCT ID: NCT02971059

Last Updated: 2018-09-18

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2016-08-31
• Study Completion Date: 2018-06-30

Brief Summary

Currently there are insufficient published studies on amino acid requirements in the elderly. Phenylalanine is one of the indispensable amino acids. Low levels of phenylalanine has been observed in in the blood of older adults. It is due the increased uptake by the liver and intestine. This decreased levels of phenylalanine could lead to decreased skeletal muscle protein synthesis. Requirement for elderly individuals have been set based on studies conducted in younger adults hence may be inaccurate. The goal of this study is to directly measure the phenylalanine requirement of male and female elderly subjects over 65 years using the direct amino acid oxidation (DAAO) technique.

Detailed Description

1. To determine and compare the phenylalanine requirement of healthy elderly male and female adults over the age of 65 years using the DAAO technique (by measuring the oxidation of L-[1-13 C] phenylalanine to 13 CO 2 [F 13 CO 2] ) in response to graded intakes of phenylalanine.

2. To compare the requirement so derived to that of young healthy adult previously determined in our lab.

Conditions

Older Adults

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Adult Males >65 years

Participants will be seen initially for pre-study assessment (3 hour). They will then be studied weekly for up to 7 levels of phenylalanine intake (7 Study periods). Each study period will include a period of 3 days. The first 2 days they will consume a liquid milkshake based diet at home. On the 3rd day they will come to the hospital for a total of 8 hours.

Group Type: EXPERIMENTAL

Phenylalanine intake

Intervention Type: DIETARY_SUPPLEMENT

Phenylalanine will be provided as graded intakes ranging from 7-40 mg/kg/day

Adult Females >65 years

Participants will be seen initially for pre-study assessment (3 hour). They will then be studied weekly for up to 7 levels of phenylalanine intake (7 Study periods). Each study period will include a period of 3 days. The first 2 days they will consume a liquid milkshake based diet at home. On the 3rd day they will come to the hospital for a total of 8 hours.

Group Type: EXPERIMENTAL

Phenylalanine intake

Intervention Type: DIETARY_SUPPLEMENT

Phenylalanine will be provided as graded intakes ranging from 7-40 mg/kg/day

Interventions

Phenylalanine intake

Phenylalanine will be provided as graded intakes ranging from 7-40 mg/kg/day

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

1. Healthy elderly males and females > 65 years

2. Willingness to participate in the study and completed the screening procedures (height, weight, fasting blood sample and medical history questionnaire).

3. No recent history of weight loss

4. Absence of chronic disease or acute illness that could affect protein and AA metabolism (diabetes, cancer, liver or kidney disease, HIV, acute cold or flu, hypo or hyperthyroidism, rheumatoid arthritis treated with anti-inflammatory medications.

5. Non-smoking

6. Willingness to consume the diet provided

Exclusion Criteria

1. Presence of disease known to affect protein and AA metabolism (diabetes, cancer, liver or kidney disease, HIV, acute cold or flu, hypo or hyperthyroidism, rheumatoid arthritis treated with anti-inflammatory medications).

2. On medications known to affect protein and amino acid metabolism (steroids).

3. Recent significant weight loss.

4. Individual on weight reducing diets.

5. Inability to tolerate the diet

6. Unwilling to have blood drawn from a venous access, or using a ventilated hood indirect calorimeter for the purposes of the study.

7. Significant coffee consumption of more than 2 cups/day

8. Significant alcohol consumption of more than one drink/day

• Minimum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

The Hospital for Sick Children

OTHER

Sponsor Role: lead

Responsible Party

Glenda Courtney-Martin

Project Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Glenda Courtney-Martin

Role: PRINCIPAL_INVESTIGATOR

Hospital for Sick Children, Toronto, Ontario

Locations

The Hospital for Sick Children

Toronto, Ontario, Canada

Countries

Canada

References

Martin KE, Pencharz PB, Rafii M, Ball RO, Szwiega S, Elango R, Courtney-Martin G. The Phenylalanine Requirement of Elderly Men and Women Measured by Direct 13C Carbon Oxidation Method Is Similar to That of Young Adults. J Nutr. 2019 Oct 1;149(10):1776-1784. doi: 10.1093/jn/nxz137.

Reference Type: DERIVED

PMID: 31271193 (View on PubMed)

Other Identifiers

1000051682

Identifier Type: -

Identifier Source: org_study_id