Japanese and German studies validate rooibos’ health properties

Important scientific evidence that supports some of the health benefits associated with rooibos tea has emerged from studies in Japan and Germany.

A study carried out at the Tokyo University of Agriculture and Technology confirmed that aspalathin – the unique flavonoid in rooibos tea – is able to help lower raised blood sugar levels and improve the metabolism of glucose. The Japanese research team investigated the anti-diabetic action of aspalathin in living muscle cells and a diabetic mouse model which was able to shed light on the specific mechanisms involved at molecular and cellular level. Its results have been published in the December 2012 issue of the European Journal of Nutrition. (The abstract is available online at http://www.ncbi.nlm.nih.gov/pubmed/23238530.)

The team in Japan currently collaborates with South African rooibos researchers at the Medical Research Council and the Agricultural Research Council (ARC) as part of a scientific co-operation agreement between Japan and South Africa.

These latest results add further weight to a previous study by them, published in 2009, and a 2012 study by the South Africa researchers. The latter study found that an aspalathin-enriched extract of green Rooibos is able to lower raised glucose levels in the blood of diabetic rats. Further work to elucidate the mechanism(s) whereby the chemical constituents present in Rooibos can affect the metabolism is on-going.

In another study, this time at Heidelberg University in Germany, scientists demonstrated that rooibos tea has the potential to promote longevity in living organisms. Using roundworms (Caenorhabditis elegans) as a model, they produced evidence that rooibos decreased oxidative damage in their cells. They were also able to show that aspalathin played a major role in their survival rate by targeting stress and ageing related genes. Local researchers from the ARC and the University of Johannesburg are co-authors on the research paper published in the December 2012 issue of the scientific journal Phytomedicine. (The abstract is available online at http://www.ncbi.nlm.nih.gov/pubmed/23218401.)

“It is encouraging that international researchers are taking such an interest in South Africa’s herbal teas and that their findings help to improve our understanding of the health properties of rooibos tea,” says Professor Lizette Joubert, herbal tea expert at the Agricultural Research Council. “This should provide further impetus to our efforts to understand the chemistry and biological properties of rooibos and other herbal teas so that we will be able to advise people how to get the maximum health benefit from these unique South African teas.”

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