A study has found that Rooibos is good for the hart. Picture: Paul Yeung/South China Morning Post via Getty Images
Drinkers of rooibos tea are cheekier about their tea than guzzlers of any other beverage. However, a new study will make lovers of the South African tea more steadfast in their beliefs about the tea.
A new study conducted by the Applied Microbial and Health Biotechnology Institute at the Cape Peninsula University of Technology (CPUT) has revealed that rooibos is good for the heart.
The study, led by Prof Jeanine Marnewick and the institute’s director and researcher Maria Hartnick, builds on previous research, which indicated Rooibos’ ability to modulate risk factors associated with cardiovascular disease (CVD).
However, this latest study takes a significant step further by using advanced diagnostic methods to assess heart function in real time.
“While our previous studies focused on biochemical markers, we wanted to take a deeper look into how Rooibos impacts the actual functioning of the heart. This is where the use of transthoracic echocardiography, a diagnostic ultrasound examination, came into play,” said Prof Marnewick.
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Echocardiography, commonly referred to as “sonar”, enabled the team to observe the heart in real time, providing a more detailed understanding of Rooibos’ potential health benefits.
This was the first time such technology had been used to explore the effects of Rooibos on heart health, with the aim of detecting early cardiovascular changes in individuals at risk.
The results of the study were promising, particularly in relation to several key cardiovascular parameters.
“We observed a significant reduction in left atrium dimensions, interventricular septum thickness and left ventricular mass in participants who consumed Rooibos, particularly green Rooibos,” said Hartnick.
“These reductions are indicative of improvements in cardiac structure and function, which can reflect better endothelial function (flow of blood by relaxing and tightening the blood vessels) and overall cardiovascular health.”
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The study involved both male and female participants with at least two modifiable risk factors for CVD, such as high blood pressure, elevated cholesterol and unhealthy lifestyle habits.
The participants consumed the equivalent of six cups of either fermented (red) or unfermented (green) Rooibos daily for 12 weeks. These results underscore the potential for Rooibos, particularly in its green form, to positively influence heart health.
One of the unique aspects of the study was its focus on the consumption of whole Rooibos, rather than isolating individual compounds.
“We used a water extract of Rooibos to simulate a ‘cup of tea’,” Prof Marnewick said.
“This was important because Rooibos is often consumed as a beverage and we wanted the results to be as applicable to daily life as possible.”
While previous studies have identified compounds like aspalathin and nothofagin as potent antioxidants in Rooibos, this study took a holistic approach to the tisane’s cardiovascular benefits.
The antioxidants in Rooibos are thought to help reduce inflammation and oxidative stress, which are key contributors to cardiovascular disease.
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This study was designed differently from earlier research. Instead of a six-week, crossover study, this was a randomised, placebo-controlled, parallel design that spanned 12 weeks. This design provided more robust data and allowed for the inclusion of echocardiographic measurements, which had never been done before in Rooibos research.
“Baseline and post-intervention echocardiograms were used to measure changes in heart function,” Hartnick explains.
“We adhered to strict guidelines from the American Society of Echocardiography to ensure accuracy and reliability. This methodology has given us a much clearer picture of how Rooibos can affect cardiovascular health.”
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The study’s most significant finding was the reduction in left atrium size, interventricular septum thickness and left ventricular mass.
These are critical markers for hypertensive heart disease, which is a major risk factor for heart failure and other cardiovascular complications.
“To see these parameters improve with Rooibos consumption is a major breakthrough,” said Prof Marnewick. “It’s the first time we’ve been able to show these effects in humans.”
Although the clinical significance of these findings needs further investigation, the results are an exciting step forward.
The researchers note that while Rooibos is not a curative solution for cardiovascular disease, it holds promise as a preventive strategy that can be easily incorporated into daily life, along with a healthy lifestyle.
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The global burden of non-communicable diseases (NCDs), particularly cardiovascular disease, highlights the need for effective and accessible preventive measures.
“Our research contributes to the growing body of evidence that Rooibos could be a valuable part of the solution,” says Hartnick. “By promoting the regular consumption of Rooibos, especially in at-risk populations, we could help reduce the incidence of CVD.”
Prof Marnewick envisions this research playing a role in shaping public health guidelines around Rooibos consumption.
“We believe this study has the potential to influence future dietary recommendations, particularly in countries like South Africa where Rooibos is readily available,” she said.
“As a natural, low-cost intervention, Rooibos could be part of broader public health strategies aimed at improving cardiovascular outcomes.”
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Looking ahead, researchers plan to continue investigating the long-term cardiovascular effects of Rooibos.
“We’ve laid the groundwork with this study, but there’s still much to explore,” Prof Marnewick averred.
“Future research will focus on understanding the clinical relevance of these findings and how Rooibos can be used as part of a comprehensive approach to heart health.”
In the meantime, Rooibos enthusiasts have yet another reason to enjoy their favourite brew – it may just be helping to keep their hearts healthy.
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