Rooibos, known for its many health benefits, from reducing the risk of heart disease and strokes to preventing cancer and boosting the immune system, may also be beneficial for managing diabetes.
A number of local and international studies have found encouraging evidence that rooibos could help to control diabetes and its complications.
A 2006 study in the Slovak Republic found that rooibos provides effective protection against oxidative stress in diabetic rats. The scientists recommended the use of rooibos for the prevention and therapy of diabetic vascular complications, especially in protecting eye membranes against peroxidation.
Last year a Japanese team found that aspalathin, the most active antioxidant in rooibos, helped improve the glucose uptake of muscle cells and consequently maintain normal blood sugar levels in mice with Type 2 diabetes. They also found aspalathin stimulated pancreatic beta-cells to secrete insulin and helped to improve impaired glucose tolerance in the animals.
Type 2 diabetes
Two South African researchers, Professor Elizabeth Joubert of the Agricultural Research Council and Dr Johan Louw of the Diabetes Recovery Platform at the Medical Research Council, are co-applicants for a worldwide patent to develop and produce an anti-diabetic extract of rooibos for the treatment of Type 2 diabetes.
These two local scientists are also leading a new study to determine whether rooibos can play a role in combating obesity. The SA Rooibos Council is funding the three-year R1 million study, which starts in 2011.
Doctors believe that Type 2 diabetes and obesity are connected as many people who develop the disease are overweight or clinically obese.
"Numerous studies over the past few decades have helped us understand the complex and unique blend of antioxidants found in rooibos. These studies indicate that there may be more health benefits than we may have thought, which is why we are funding the additional research," says Mientjie Mouton, the SA Rooibos Council’s director for product research.
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.
The SA Rooibos Council supports a number of local studies into rooibos' health benefits. In addition to the obesity study it is funding several research projects into how rooibos can counter cancer and stress as well as the link between rooibos and exercise.
Summaries of the most recent rooibos studies published in peer-reviewed scientific journals can be found here.
Ulièná, O., Vanèová, O. Božek, P., Èársky, J., Šebeková, K., Boor, P., Nakano, M., Greksák, M., 2006. Rooibos tea (Aspalathus linearis) partially prevents oxidative stress in streptozotocin-induced diabetic rats. Physiology Research 55, 157 – 164.
Kawano,M., Nakamura, H., Hata, S., Minakawa, M., Minura, Y., Yagasaki, K., 2009. Hypoglycemic effect of aspalathin, a rooibos tea component from Aspalathus linearis, in type 2 diabetic model db/db mice. Phytomedicine 16, 437 – 443.
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