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The Body's Affect on Vitamin C

NCT00001309 · Status: COMPLETED · Phase: PHASE1 · Type: INTERVENTIONAL · Enrollment: 23

Last updated 2026-05-01

No results posted yet for this study

Summary

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.

Conditions

  • Healthy Volunteers

Interventions

OTHER

Vitamin C

Outpatient subjects will be encouraged to consume vitamin C in foods. As inpatients, vitamin C deficiency will be induced by placing subjects on a tightly restricted scorbutic diet. Plasma vitamin C will be monitored several times per week. When subjects have achieved a plasma ascorbate concentration of 5-10 micromolar, blood sampling and urine collection over 24 hours will be performed. After platelets and leukocytes are collected, ascorbate repletion will begin. Escalating doses of ascorbate will be administered orally and intravenously for the remainder of their inpatient admission. Total daily doses of 30mg, 60mg, 100mg, 200mg, 400mg, 1000mg and 2500mg will be given in two divided doses. Bioavailability of ascorbate will be determined at each dosage increment. When plasma ascorbate concentration reaches steady state for each dose, subjects will undergo 36 hr plasma sampling and a timed 48 hr urine collection.

Sponsors & Collaborators

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

    lead NIH

Principal Investigators

  • Mark A Levine, M.D. · National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Study Design

Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Max Age
35 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
1997-01-23
Primary Completion
1999-08-25
Completion
2019-03-04

Countries

  • United States

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00001309 on ClinicalTrials.gov