Investigating Vitamin C Loss in Diabetic Patients

Urinary Vitamin C Loss in Subjects With and Without Diabetes

Observational National Institutes of Health Clinical Center (CC) · NCT00071526

This study tests if people with diabetes have lower vitamin C levels in their blood and higher amounts in their urine compared to healthy individuals.

Quick facts

Study typeObservational
Enrollment5000 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorNational Institutes of Health Clinical Center (CC) NIH
Locations1 site (Bethesda, Maryland)
Trial IDNCT00071526 on ClinicalTrials.gov

What this trial studies

This study examines the relationship between vitamin C levels in plasma and urine among diabetic individuals compared to healthy controls. It aims to clarify whether diabetic patients experience both low plasma vitamin C concentrations and increased urinary loss. Participants will have their vitamin C levels measured in various biological samples, and those who consent will undergo further testing to assess vitamin C pharmacokinetics. The study also seeks to identify genetic factors that may influence vitamin C transport in the body.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18-65 with either Type 1 or Type 2 diabetes or healthy individuals without diabetes.

Not a fit: Patients with significant organ malfunction or serious chronic illnesses may not benefit from this study.

Why it matters

Potential benefit: If successful, this research could lead to better understanding and management of vitamin C levels in diabetic patients, potentially improving their overall health.

How similar studies have performed: While some studies have suggested similar findings, this research aims to provide more controlled and comprehensive insights into vitamin C metabolism in diabetic patients.

Eligibility criteria

Show full inclusion / exclusion criteria
* INCLUSION CRITERIA:

To be included in the study, study subjects should be:

* Aged 18-65 years.
* Either:

  * Have no diagnosis of diabetes: "nondiabetic controls", or
  * Have a diagnosis in their medical history of either Type 1 or Type 2 diabetes

EXCLUSION CRITERIA (for outpatient study, arm 1)

Exclusion criteria will include the following:

* Unable or unwilling to provide a signed and dated informed consent form
* Unable or unwilling to comply with study procedures and lifestyle considerations

EXCLUSION CRITERIA (for inpatient studies, arms 2 and 3)

Study participants interested in participating in Arms 2 and/or 3 will be excluded from this further participation if they meet any of the following:

* significant organ malfunction leading to clinical instability including liver disease, pulmonary disease, ischemic heart disease, heart failure, stroke, peripheral vascular disease, and anemia at investigator discretion
* other serious or chronic illness; history of serious or chronic illness; coronary artery disease, or peripheral vascular disease resulting in clinical instability
* pregnancy or lactation
* presence of other conditions which, in the judgment of the investigators, can influence vitamin C metabolism or vitamin C renal handling

Where this trial is running

Bethesda, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions DiabetesRenal ThresholdDiabetes MellitusProteinuriaPlasma ConcentrationsHealthy Volunteer
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.