Glutathione (GSH) Synthesis in Healthy School-aged Children and Healthy Young and Old Adults

Sponsor

The Hospital for Sick Children (Other)

Overall Status

Recruiting

CT.gov ID

NCT02971046

Collaborator

(none)

Enrollment

Location

Arm

Anticipated Duration (Months)

1.5

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

To measure the fractional and absolute synthesis rates of GSH, an antioxidant that protects cells from damage, in the erythrocytes of healthy school-aged children, young adults and old adults in response to graded intakes of protein in order to determine if increasing the protein intake above the current recommended DRI produces increases in the GSH synthesis rates in erythrocytes of these individuals. Participants will consume specially formulated diets with varying protein levels.

Condition or Disease	Intervention/Treatment	Phase
Healthy	Other: varying protein intakes	N/A

Detailed Description

The current dietary reference intake (DRI) recommendations for protein in children (6-11 years old) and adults (>19 years old) are based on nitrogen balance data and set at a mean (EAR) of 0.76 and 0.66 g/kg/day respectively and population safe (RDA) recommendation of 0.95 and 0.80 g/kg/day respectively. Using the indicator amino oxidation (IAAO) method we estimated higher protein requirements in these populations. This suggests that current recommendations are underestimated. Studies in adults have shown that protein recommendation set on the basis of nitrogen balance data, while sufficient to maintain nitrogen balance, does not maintain GSH status.

Glutathione (GSH) is most important intracellular antioxidant and scavenger and its deficiency has been shown to compromise recovery in acute as well as chronic stressors. Deficiency of GSH results when protein and/or cysteine intake is inadequate. Inadequate protein intake in children not only compromises growth, but could increase susceptibility to, and compromise recovery from regular childhood illness. Similarly, in young and older adults' inadequate intakes may result in increased oxidative stress and compromised immune function. Measurement of GSH synthesis provides a functional method whereby the current protein recommendation can be tested against higher estimates derived using the IAAO method. The purpose of this study therefore is to measure GSH synthesis in healthy school aged children (6-11 years), and healthy young (19 - 40 years) and old (60 - 90 years) adults in response to current recommended protein intakes and in response to protein requirement estimates derived using the IAAO method.

In healthy school-aged children, each level of protein will be studied over three days. For two days (adaptation days), participants will eat some low protein foods plus a milkshake drink. On the study day, participants will consume 8 hourly protein drinks and special cookies at SickKids. In healthy young and old adults, each level of protein will be studied over three days. For two days (adaptation days), young adults will eat some low protein foods plus a milkshake drink. On the one study day, young adults will consume 10 hourly milkshake diets at SickKids. In old adults, each level of protein will be studied over four days. For three days (adaptation days), old adults will eat some low protein foods plus a milkshake drink. On the one study day, old adults will consume 10 hourly milkshake diets at SickKids.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

55 participants

Allocation:

N/A

Intervention Model:

Single Group Assignment

Masking:

None (Open Label)

Primary Purpose:

Other

Official Title:

Glutathione (GSH) Synthesis in Response to Graded Protein Intakes: a Functional Measure of Protein Requirement in Healthy School-aged Children and Healthy Young and Old Adults

Actual Study Start Date :

Oct 1, 2020

Anticipated Primary Completion Date :

Nov 1, 2023

Anticipated Study Completion Date :

Nov 1, 2023

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Protein intake Varying protein intakes.	Other: varying protein intakes In healthy school-aged children: Four randomly assigned levels of protein intake in a repeated measured design. The levels of protein intake are 0.95, 1.3,1.55, and 2.0 grams per kilogram of bodyweight per day. In healthy young and old adults: Up to six randomly assigned levels of protein intake in a repeated measured design. The levels of protein intake are : 0.66, 0.8, 1, 1.2, and 1.5 grams per kilogram of bodyweight per day.

Arm

Intervention/Treatment

Experimental: Protein intake

Varying protein intakes.

Other: varying protein intakes

In healthy school-aged children: Four randomly assigned levels of protein intake in a repeated measured design. The levels of protein intake are 0.95, 1.3,1.55, and 2.0 grams per kilogram of bodyweight per day. In healthy young and old adults: Up to six randomly assigned levels of protein intake in a repeated measured design. The levels of protein intake are : 0.66, 0.8, 1, 1.2, and 1.5 grams per kilogram of bodyweight per day.

Outcome Measures

Primary Outcome Measures

Erythrocyte GSH Fractional synthesis rates [up to 24 months]
To measure the fractional synthesis rates of GSH in the erythrocytes of healthy school-aged children and healthy young and old adults in response to graded intakes of protein.

Secondary Outcome Measures

Erythrocyte GSH absolute synthesis [up to 24 months]
To determine the absolute synthesis rate of GSH in erythrocyte of healthy school aged children and healthy young and old adults in response to varying protein intakes.

Eligibility Criteria

Criteria

Ages Eligible for Study:

6 Years to 90 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria in:

Healthy school-aged children

Body weight ≥ 22 kg
No history of anemia
Willingness to participate

Healthy Young Adults

Consent provided
Aged 19 - 40 years old
In good general health as evidenced by medical history, physical health and blood draw
Fasting blood glucose, hemoglobin A1c (HbA1c), urea, creatinine, vitamin-B6, vitamin-B12 and folate levels within normal ranges for age.
Willingness to participate in the study.
BMI <25 kg/m2.

Healthy Old Adults

Consent provided
Aged 60- 90 years old
In good general health as evidenced by medical history, physical health and blood draw
Fasting blood glucose, hemoglobin A1c (HbA1c), urea, creatinine, vitamin-B6, vitamin-B12 and folate levels within normal ranges for age.
Willingness to participate in the study.
BMI <30 kg/m2.

Exclusion Criteria in:

Healthy school-aged children

HIV
Diabetes
Anaemia
Significant weight loss within 30 days of study
On weight loss diets
Body weight less that 22kg
Inability to tolerate diet
Unwilling to have blood drawn

Healthy Young and Old Adults:

Presence of chronic disease and/or acute illness known to affect GSH and/or protein/amino acid metabolism (e.g. HIV, diabetes, cancer, liver or kidney disease, acute cold or flu).
Anemia (15 - 20% outside lower limit of normal lab reference ranges)
Taking medications known to affect GSH and/or protein/AA metabolism (e.g. acetaminophen, steroids).
Significant weight loss during the past month or consumption of weight reducing diets.
Significant caffeine consumption (>2 cups per day).
Significant consumption of alcohol (>1 drink per day i.e. 1 beer or ½ glass of wine).
Inability to tolerate the diet
Unwilling to have blood drawn from a venous access during the isotope infusion day.