Blood vessels are lined with a thin layer of cells called the endothelium, which plays a key role in regulating blood flow and vascular health. Endothelial dysfunction is an early marker of atherosclerosis and cardiovascular disease.
A study published in the Circulation Journal (2010 Feb 4; epub ahead of print) examined the effects of green tea catechins (GTC)—antioxidant compounds found in green tea—on endothelial function in 30 smokers with no major health conditions. Participants were randomly assigned to one of three groups for two weeks: 80 mg of GTC per day, 580 mg of GTC per day, or a placebo.
Only the group receiving the higher dose of GTC (580 mg/day) showed significant improvements in vascular function. This group demonstrated increased blood flow in response to acetylcholine and sodium nitroprusside, indicating improved endothelial responsiveness. They also had higher levels of nitric oxide, a compound that promotes vasodilation, along with reduced levels of inflammatory markers, including C-reactive protein.
These improvements were not observed in the placebo group or in those receiving the lower dose of green tea catechins, suggesting a dose-dependent effect.
