Effect of 4 Weeks of Citrulline and Glutathione Supplementation on Arterial Function

Not Applicable

Completed

• Conditions: Menopause; Cardiovascular Risk Factor
• Interventions: Dietary Supplement: L-Citrulline; Dietary Supplement: Placebo; Dietary Supplement: Glutathione

• Registration Number: NCT04672447
• Lead Sponsor: Texas Tech University

Brief Summary

Examining the effects of 4 weeks of Citrulline alone or in combination with glutathione on the arterial function of postmenopausal women.

Detailed Description

L-Citrulline is a non-protein amino acid and an efficient precursor of L-arginine, the substrate for endothelial nitric oxide synthesis. Glutathione is a tripeptide with antioxidant effects. Postmenopausal women will ingest 6g/d of L-Citrulline or 2g of L-Citrulline plus 200mg/d of glutathione or placebo (maltodextrin) for 4 weeks with vascular function testing prior to and after the intervention.

Study Timeline

• Study Start: 2020-07-01
• Study First Submitted: 2020-12-10
• Study First Submitted QC: 2020-12-16
• Study First Posted: 2020-12-17
• Primary Completion: 2022-04-27
• Study Completion: 2022-04-27
• Status Verified: 2022-10
• Last Update Submitted: 2022-10-19
• Last Update Posted: 2022-10-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 39

Inclusion Criteria

1. Generally healthy, postmenopausal women (defined as the absence of menstruation for at least 1 year).
2. Between the ages of 50-79 years.
3. Body mass index of 18.5 - 34.9 kg/m2.
4. Brachial systolic blood pressure < 150 mmHg, and diastolic blood pressure < 90 mmHg.
5. Sedentary (defined as < 120 min/week of exercise).
6. Be willing and able to comfortably abstain from any of food supplements for the period of time beginning 1 month prior to the study to the time of the termination of the study.
7. Not participating as a subject in another study for at least 2 months prior to the study and for the duration of this study.

Exclusion Criteria

1. Current or prior use of tobacco products, e-cigarettes or other inhaled substance.

2. Use of medications and/or any supplements that may affect outcome variables (such as arginine-containing supplements, nitroglycerin, statin drugs, but not limited to those.)

3. Taking hormone replacement therapy during the 3 months before the study.

4. More than a moderate intake of alcohol (>7 drink per week).

5. Cardiovascular diseases, diabetes and other metabolic or chronic diseases.

6. Musculoskeletal disorders that will prevent exercise performance.

7. Currently taking more than one vasoactive drug for blood pressure control.

   • Subject having no more than one drug for prevention, which does not affect variables, may be included, but will be diagnosed as not having a disease.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
L-Citrulline + Glutathione	Glutathione	Citrulline: 2 grams/day, Glutathione: 200mg/day for 4 weeks
L-Citrulline	L-Citrulline	Citrulline: 6 grams/day
L-Citrulline + Glutathione	L-Citrulline	Citrulline: 2 grams/day, Glutathione: 200mg/day for 4 weeks
Placebo	Placebo	Maltodextrin: 6 grams/day

Primary Outcome Measures

Name	Time	Method
Blood pressure control during the cold pressor test	4 weeks	Blood pressure will be measured during the cold pressor test before and after the 4 weeks.
Change in endothelial function	4 weeks	Endothelial function will be measured before and after the intervention using brachial artery flow mediated dilation at rest, blood flow measured in the brachial artery during handgrip exercise, and blood flow in the common femoral artery during passive leg movement. All measurements performed using doppler ultrasound.
Change in arterial stiffness	4 weeks	Arterial stiffness will be assessed through measurement of pulse-wave velocity of the carotid-femoral, carotid radial, carotid-ankle and femoral ankle arterial segments before and after the 4 week interventions.
L-Arginine bioavailability	4 weeks	Plasma levels of arginine will be measured before and after the 4 week intervention.

Secondary Outcome Measures

Name	Time	Method
L-Citrulline levels	4 weeks	Plasma levels of L-Citrulline will be measured before and after the 4 weeks.
Glutathione peroxidase levels	4 weeks	Blood levels of glutathione peroxidase will be measured before and after the 4 weeks
Muscle Strength	4 weeks	Leg Extension strength will be measured before and after the 4 weeks.
Malondialdehyde	4 weeks	blood levels of malondialdehyde will be measured before and after the 4 weeks
L-Ornithine levels	4 weeks	plasma levels of L-ornithine will be measured before and after the 4 weeks
cardiovascular hemodynamics using pulse wave analysis during the cold pressor test	4 weeks	arterial tonometry will be measured during the cold pressor test before and after the 4 week intervention.
body composition	4 weeks	We will determine whether L-citrulline + glutathione changes body composition more than L-citrulline or placebo.

Trial Locations

Locations (1)

TTU Kinesiology and Sport Management Building; 🇺🇸 Lubbock, Texas, United States