The Body's Affect on Vitamin C

Completed · Phase 1

Conditions studied: Healthy Volunteers

In brief

Pharmacokinetics is the term used for how the body affects a drug once it is taken. Vitamin C, also known as ascorbic acid, is an essential water soluble vitamin. Meaning, the body does not make Vitamin C it must be taken in through the diet. In this study researchers will attempt to determine how the amount of water consumed affects the level of vitamin C in the blood (specifically the plasma component of the blood). In this study researchers will take 13 subjects and place them on a Vitamin C restricted diet. Vitamin C levels will be measured twice a week on an outpatient basis until all subjects reach a desired low level of Vitamin C (12-15 micromolar plasma ascorbic acid concentration). Subjects will then be admitted and undergo 24 hour blood and urine collection. Following the collection of samples, subjects will then begin to receive Vitamin C orally (by mouth) and intravenously (injected into the vein). The dosage of Vitamin C will gradually increase from 30 mg-2500 mg divided into two daily doses. Blood and urine samples will be collected each time the dose is increased. The study will take approximately 18 weeks after which the subjects will be discharged in healthy condition.

Key facts

Study ID

NCT00001309

Run by

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

People needed

23

Starts

1997-01-23

Expected to finish

2019-03-04

Last updated by the study team

2026-07-28

Who can join

Age: 18 and older, up to 35. Sex: any. Healthy volunteers: not accepted.

You may not qualify if…

• Subject non-compliance with restricted diet.
• Pregnancy as determined by history, physical exam and urine b-HCG.
• History of diabetes mellitus, bleeding disorders, kidney stones, glucose-6- phosphate dehydrogenase deficiency, family history of hemochromatosis/iron overload.
• Platelet count <150,000/ul blood; prothrombin time/partial thromboplastin time (PT/PTT) > 1 second above normal upper limit.
• Positive test for exposure to human immunodeficiency virus.
• Positive tests for hepatitis B surface antigen, core antibody or surface antibody.

Where it is running

• National Institutes of Health Clinical Center — Bethesda, Maryland, United States

Full record on ClinicalTrials.gov

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