Ignite Creation Date:
2024-05-05 @ 9:53 AM
Last Modification Date:
2024-10-26 @ 9:02 AM
Study NCT ID:
NCT00001870
Status:
COMPLETED
Last Update Posted:
2008-03-04
First Post:
1999-11-03
Brief Title:
Study of the Effects of Vitamin C on Patients With Type 2 Diabetes
Sponsor:
National Center for Complementary and Integrative Health NCCIH
Organization:
National Institutes of Health Clinical Center CC
Study Overview
Official Title:
An Exploratory Study of the Effects of Oral Vitamin C Administration on Insulin Sensitivity and Vascular Reactivity in Subjects With Type 2 Diabetes
Status:
COMPLETED
Status Verified Date:
2004-12
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
Diabetes is a disease characterized by decreased sensitivity to the action on insulin to promote sugar glucose use and blood vessel relaxation vasodilation in muscle Insulins ability to cause blood vessel relaxation is controlled in part by nitric oxide NO
Nitric oxide is a substance produced by the cells lining blood vessel walls endothelium Increased blood flow to the muscle accounts for increased sugar glucose to areas of the body Therefore if the cells of blood vessel walls endothelium are not functioning properly it may contribute to insulin resistance
Injections of Vitamin C directly into the arteries have been shown to improve blood vessel reaction to nitric oxide in diabetic patients Researchers believe this may be due to Vitamin Cs ability to increase the levels of nitric oxide in blood vessels
The goal of this study is to determine the effects of vitamin C on both insulin sensitivity and endothelium function of patients with type 2 diabetes An additional goal of the study is to determine the effects of vitamin C on patients with vitamin C deficiency
Patients participating in this study will undergo a series of testes to determine insulin sensitivity and blood vessel reactivity Patients will be divided into two groups One group will receive doses of oral vitamin C The other group will receive doses of a placebo inactive pill not containing vitamin C Patients will receive the medications for four weeks and then be tested again for insulin sensitivity and blood vessel reactivity
Researchers believe that doses of vitamin C in diabetics or patients with vitamin C deficiency will improve insulin sensitivity and function of endothelium Results gathered form this study may provide information about vitamin C levels in diabetics and may lead to the development of new therapies to treat insulin resistance and endothelium dysfunction
Nitric oxide is a substance produced by the cells lining blood vessel walls endothelium Increased blood flow to the muscle accounts for increased sugar glucose to areas of the body Therefore if the cells of blood vessel walls endothelium are not functioning properly it may contribute to insulin resistance
Injections of Vitamin C directly into the arteries have been shown to improve blood vessel reaction to nitric oxide in diabetic patients Researchers believe this may be due to Vitamin Cs ability to increase the levels of nitric oxide in blood vessels
The goal of this study is to determine the effects of vitamin C on both insulin sensitivity and endothelium function of patients with type 2 diabetes An additional goal of the study is to determine the effects of vitamin C on patients with vitamin C deficiency
Patients participating in this study will undergo a series of testes to determine insulin sensitivity and blood vessel reactivity Patients will be divided into two groups One group will receive doses of oral vitamin C The other group will receive doses of a placebo inactive pill not containing vitamin C Patients will receive the medications for four weeks and then be tested again for insulin sensitivity and blood vessel reactivity
Researchers believe that doses of vitamin C in diabetics or patients with vitamin C deficiency will improve insulin sensitivity and function of endothelium Results gathered form this study may provide information about vitamin C levels in diabetics and may lead to the development of new therapies to treat insulin resistance and endothelium dysfunction
Detailed Description:
Diabetes is characterized by decreased sensitivity to the actions of insulin to promote both glucose utilization and vasodilation in skeletal muscle beds Insulins vasodilator action is mediated in part by endothelial-derived nitric oxide NO Increased blood flow accounts for approximately 25 of the increase in skeletal muscle glucose disposal mediated by insulin Therefore endothelial dysfunction may contribute to insulin resistance Intraarterial administration of vitamin C improves NO-dependent vascular reactivity in diabetic subjects but not normal subjects This may be due to antioxidant properties of vitamin C that result in relative increases in the level of NO in the diabetic vasculature In this exploratory protocol our primary objective is to assess the effects of oral administration of vitamin C on both insulin sensitivity and endothelial function in subjects with type 2 diabetes A secondary peripheral objective is to study these effects in vitamin C-deficient clinical research volunteers Hyperinsulinemic euglycemic glucose clamp procedures and forearm blood flow measurements will be used to assess both insulin sensitivity and vascular reactivity in diabetic subjects and clinical research volunteers who have plasma vitamin C levels less than 30 microM The subjects will then be given either placebo or oral vitamin C supplementation 800 mgday for four weeks and assessment of insulin sensitivity and vascular reactivity will be repeated Plasma levels of vitamin C will be measured to confirm that subjects in the experimental group have an appropriate increase in vitamin C levels We hypothesize that chronic oral administration of vitamin C to diabetic or clinical research volunteers who are deficient in vitamin C will improve insulin sensitivity and endothelial function Our study will provide information about vitamin C levels in diabetic subjects and may suggest a potential therapy to significantly improve endothelial dysfunction and insulin resistance
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None
Secondary IDs
| Secondary ID | Type | Domain | Link |
|---|---|---|---|
| 99-AT-0033 | None | None | None |