Study of the Effects of Vitamin C on Patients With Type 2 Diabetes
Status:
Completed
Trial end date:
2004-12-01
Target enrollment:
Participant gender:
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. Insulin's
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
C's 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.
Phase:
Phase 2
Details
Lead Sponsor:
National Center for Complementary and Integrative Health (NCCIH)