Observational studies have shown that consumption of grapes and grape products such as red wine is associated with reduced cardiovascular risk. The mechanisms accounting for this benefit remain incompletely understood. Resveratrol is a component of grapes and red wine that has favorable effects on endothelial function in diabetic and obese animals. Resveratrol is available to people over-the-counter in health food stores and the internet as a dietary supplement.

The endothelium plays a central role in the control of blood vessel function. When healthy, the endothelium prevents vasospasm, blood clot formation, and the development of atherosclerosis. Endothelial function is abnormal in patients with diabetes mellitus and this abnormality contributes to the development of cardiovascular disease.

The present pilot study is designed to test the hypothesis that resveratrol (90 mg/day and 270 mg/day for one week each) will have favorable effects on endothelial function in patients with diabetes mellitus.

Inclusion Criteria:

1. Male and Female subjects.
2. Age over 21 years old.
3. Body mass index greater than or equal to 25 and less than 35 kg/m2
4. Clinically stable Type 2 diabetes mellitus.
5. Willing to give written informed consent and able to understand, to participate in and to comply with the study requirements.
6. Willing to refrain from consumption of red wine, grape juice, and grape products beginning two weeks before and continuing throughout the entire study period.

Exclusion Criteria:

1. Women who lactating or pregnant. All women with childbearing potential will undergo a urine pregnancy test at each visit to exclude pregnancy.
2. Treatment with an investigational product within the last 30 days.
3. Clinically evident major illness of other organ systems, including end-stage cancer, renal failure, or other conditions that in the opinion of the principal investigator make a clinical study inappropriate.
4. Liver transaminase levels greater than 3X the upper limit of normal.
5. History of a psychological illness or condition such as to interfere with the subject's ability to understand the requirements of the study.
6. Vitamin supplements exceeding two times the recommending daily allowance (RDA) within the last 30 days prior to screening.
7. Resveratrol, green tea and isoflavone supplements within the last 30 days prior to screening.
8. Subjects who practice a vegetarian or vegan diet
9. Subjects taking budesonide, buspirone, eplerenone, eletriptan, felodipine, midazolam, saquinavir, sildenafil, triazolam, vardenafil, alfentanil, astemizole, cisapride, cyclosporine, diergotamine, ergotamine, fentanyl, irinotecan, pimozide, quinidine, sirolimus, tacrolimus, terfenadine, or warfarin.