According to the National Cancer Institute, the polyphenols in tea have been shown to decrease tumor growth in both animal and laboratory studies. Researchers believe that it is the high level of polyphenols in tea that help kill cancerous cells and stop them from growing, although the exact mechanism by which tea inhibits and prevents cancerous cells is uncertain.
Rooibos tea is anti-inflammatory in nature, which means that it reduces blood pressure and scavenges free radicals like other antioxidants. Quercetin, another powerful antioxidant found in rooibos tea, has been linked to preventing a wide variety of heart conditions. It promotes an increase in HDL cholesterol (good cholesterol) and inhibits the LDL cholesterol (bad cholesterol) from binding to the walls of arteries and blood vessels.