A collaborative study by scientists at four international research facilities has found the first clinical evidence that drinking rooibos tea significantly increases the antioxidant capacity in human blood, boosting the body’s natural defences.
Antioxidants bind with free radicals preventing them from damaging cells and causing cancer or oxidising with cholesterol to clog blood vessels resulting in heart attacks or strokes.
The researchers in Rome and Glasgow found that the antioxidant capacity in the blood of 15 healthy volunteers peaked one hour after drinking 500ml of rooibos tea. Both traditional and green rooibos had a significant effect.
“After an hour, the plasma antioxidant levels start to drop and that is why we recommend drinking up to six cups of rooibos spaced throughout the day for a sustained health benefit,” explains Professor Jeanine Marnewick from the Cape Peninsula University of Technology. She led a recent study that showed the beneficial effect of drinking six cups of rooibos a day to promote heart health.
Numerous studies over the past few decades have helped scientists to understand the complex and unique blend of antioxidants found in rooibos. They have also proved that the active compounds in rooibos are bioavailable and are metabolised (converted) in the body. The significance of the latest study is that it provides the first direct evidence that rooibos boosts antioxidant levels in the blood of healthy humans.
“This new research proves that the compounds in rooibos are potent enough to have a measurable effect on the antioxidant capacity of the blood,” says Professor Lizette Joubert, one of South Africa’s leading rooibos researchers, working on the quality and chemical composition of rooibos at South Africa’s Agricultural Research Council.
The most active antioxidant in rooibos – aspalathin – is unique to the plant species Aspalathus linearis. This fynbos plant thrives in the Western Cape’s Cedarberg region where it is commercially cultivated and wild-harvested for the production of rooibos tea.
“This study underlines the value of rooibos as a widely available and affordable source of dietary antioxidants,” says Mientjie Mouton, chair of the Product Research Committee of the South African Rooibos Council. “It is very encouraging that leading research institutions around the world are working on rooibos and producing such promising results. There is also a great deal of work being done by local rooibos researchers and we will continue to invest in this research.”
SA Rooibos Council press release
- (Health24, updated January 2012)
The health benefits of rooibos