A pilot study of 15 subjects will be conducted to confirm an acute effect of grape seed
extract on endothelial function. We then will perform a a randomized, double blind, placebo
controlled crossover study designed to investigate the benefit of grape seed extract/vitamin
C treatment on endothelial function. Participants (n=40) will take a food supplement
containing 450 mg of grape seed extract and 1500 mg of vitamin C or matching placebo for
four weeks and then cross over to the alternative treatment (active supplement or placebo)
for four weeks. We will examine endothelial function before and after each of the two
treatment periods. The study will provide information about the vascular effects of these
- Coronary artery disease
- Clinical history of other major illness including end-stage cancer, renal failure,
hepatic failure, gastrointestinal disorders that may impair absorption, or other
conditions that in the opinion of the principal investigator make a clinical study
- Treatment with an investigational new drug within the last 30 days.
- History of a psychological illness or condition such as to interfere with the
subject's ability to understand the requirements of the study.
- Vitamin E, Vitamin C, and beta carotene, lipoic acid, and other food or herbal
supplements within 1 month of enrollment.