Rooibos and cardiovascular protection

Rooibos helps to prevent hypertension, cardiovascular disease and type 2 diabetes
Rooibos and its polyphenols aspalathin and nothofagin caused a four-fold reduction in the total steroids produced by an adrenal gland cell line. The tea especially reduced the amount of precursors of aldosterone, a blood pressure-related hormone, and cortisol, a stress hormone. Imbalances and elevated levels of adrenal hormones are associated with hypertension, cardiovascular disease and type 2 diabetes, so Rooibos may be considered as a potential therapy for these ailments.

Schloms et al., 2012. The influence of Aspalathus linearis (Rooibos) and dihydrochalcones on adrenal steroidogenesis: Quantification of steroid intermediates and end products in H295R cells. The Journal of Steroid Biochemistry and Molecular Biology, 128, pp. 128-138.
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Rooibos helps to reduce cholesterol
Forty human volunteers consumed six cups of fermented Rooibos daily for six weeks, after which researchers assessed heart, liver and kidney function using various biochemical indicators. They found that the tea significantly reduced LDL-cholesterol, the "bad" cholesterol, and increased HDL-cholesterol, the "good" cholesterol. This is the first study to provide clinical evidence that regular Rooibos consumption improves blood lipid status. The study also found that the antioxidant activity of the tea could be relevant in reducing the risk of developing cardiovascular disease. More research is needed, but the results of this study are a promising start to confirm the health-promoting properties of Rooibos in people.

Marnewick et al., 2011. Effects of Rooibos (Aspalathus linearis) on oxidative stress and biochemical parameters in adults at risk for cardiovascular disease. Journal of Ethnopharmacology, 133(1), pp. 46-52.
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Rooibos aids blood supply to the heart
Researchers found that the hearts of rats who had consumed Rooibos extracts for seven weeks were protected against the effects of ischemia, or a restriction of blood supply, more so that if they had consumed regular Camellia sinensis tea. The researchers had artificially restricted and then restored blood supply to the rat hearts, thereby causing oxidative stress in the tissue. Rooibos seemed to protect against this injury and they suggested that this may be due to an inhibition of cell death by the flavonols present in the tea.

Pantsi et al., 2011. Rooibos (Aspalathus linearis) offers cardiac protection against ischaemia/reperfusion in the isolated perfused rat heart. Phytomedicine, 18(14), pp. 1220-8.
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Rooibos fights cardiovascular disease
A South African study in humans showed that taking six cups of Rooibos every day for a period of six weeks significantly reduced several of the pertinent biomarkers associated with cardiovascular disease and protects the body against oxidative damage of blood lipids. The liver and kidney functions of the 40 participants were monitored and no adverse effects from taking six cups of Rooibos per day were found.

Marnewick et al., 2010. Rooibos and Honeybush: Recent advances in chemistry, biological activity and pharmacognosy. In: African natural plant products: New discoveries and challenges in chemistry and quality; Juliani, H.R., Simon, J.E., Ho, C.T. (Eds.). ACS Symposium Series Volume 1021, American Chemical Society, Washington DC, USA, pp. 277-294.

Rooibos and the prevention and treatment of vascular disease
Chrysoeriol, an antioxidant present at low levels in Rooibos, can prevent and treat vascular disease in humans. Chrysoeriol is able to inhibit the migration of smooth muscle cells inside the aorta, a key cause of atherosclerosis (narrowing or hardening of the arteries). The research was done on human aorta cells. Scientists therefore recommend the use of chrysoeriol to prevent and treat the repeated narrowing of blood vessels following coronary angioplasty. During angioplasty, a small balloon is used to open up a blocked or narrowed heart artery. (Note: Often only trace quantities of chrysoeriol are found in Rooibos.)

Cha et al., 2009. An inhibitory effect of chrysoeriol on platelet-derived growth factor (PDGF) -induced proliferation and PDGF receptor signalling in human aortic smooth muscle cells. Journal of Pharmacological Science, 110, pp. 105-110.