Rooibos isn’t just a comforting cup of tea – it’s the heart’s best friend in a cup! And with years of research backing it up, rooibos is here to support your heart and pack in a bunch of other health perks too.
Dr Gerald Maarman, a senior lecturer at Stellenbosch University’s faculty of medicine and health sciences, has been leading the charge in uncovering the cardiovascular (heart and blood vessels) perks of rooibos. For him, this research is personal.
Coming from a family with deep roots in traditional plant medicine, he grew up hearing about the healing powers of buchu, Common rue (Ruta graveolens), wildeals, and cancer bush (Sutherlandia frutescens).
In 2016, when a call for novel research on the plant’s cardiovascular benefits was made, Maarman saw it as the perfect opportunity to put family wisdom to the test. His study focused on how rooibos could help heart cells affected by high blood pressure, a condition that causes the heart to enlarge over time.
Now, with groundbreaking findings in hand, he is eager to share why rooibos could be the secret weapon your heart has been waiting for. From reducing toxic build-up in the heart to promoting energy efficiency and muscle protection, rooibos offers more than just antioxidants.

Duncan Masiwa: What inspired you to dive into rooibos research and uncover its incredible health benefits?
Gerald Maarman: I come from a long line of family members who believed strongly in the benefits of medicinal plants and herbs like buchu (Agathosma crenulate), Common rue (Wynruit in Afrikaans or Ruta graveolens), wildeals (Artemisia afra), cancer bush (Sutherlandia frutescens). These plants have been used for many generations to treat common ailments and disorders such as asthma, colic, eczema, allergies, kidney problems etc.
Of course, among them is rooibos (Aspalathus linearis), a well-known tisane native* to South Africa. This shrub-like plant is primarily found within the Cederberg mountains but has since been produced in other regions.
There are two main forms, red and green rooibos. The red, also referred to as fermented rooibos, undergoes the process of fermentation after harvesting, where oxidation gives the distinct brick red colour.
Like many South Africans, I was introduced to rooibos as a child and drank it as a cheaper alternative to English tea, but also because of its many health benefits.
What is the inside scoop – any standout discoveries?
In 2016, I saw a funding call for novel research to investigate the cardiovascular benefits of rooibos, and seeing that I always wanted to test whether the claims of the family elders were true, I conceptualised a research study to investigate the potential benefits of rooibos in heart cells that have been caused to enlarged by a mechanism that causes high blood pressure in humans.
After eight years of strenuous experiments that have been verified and moderated extensively, we can now for certain say that rooibos does protect the heart against disease. My research group has demonstrated that rooibos does this by performing a cleaning function in the heart, as it neutralises toxic chemicals in the heart and by helping the heart to use its energy sparingly so that it can function better.
It also protects the heart muscles from damage by promoting the expression of protective proteins and genes. This research is currently published in the South African Journal of Botany, and under review in the journals, Cardiovascular Drugs & Therapy, and the Cardiovascular Journal of Africa.
We have now expanded our research, where my MSc student Amy Pretorius is testing rooibos against the proliferation of endothelial cells to see if rooibos may be a novel therapeutic alternative for patients with pulmonary hypertension.
Joshua Matthee (PhD student) and Lindiwe Malefane (MSc student), are in the process of synthesising rooibos nanoparticles to test them against different types of breast cancer. The data will be available in 2025.
Any surprising rooibos tea consumption trends brewing in Mzansi?
A recent survey conducted by the South African Rooibos Council among 700 South African men, showed that rooibos consumption is relatively high, compared to other beverages.
The majority of the men demonstrated existing knowledge of the health benefits of rooibos and chose to drink it for this reason too. Of course, other teas and herbs are also consumed, like camomile, hibiscus, and Camellia sinensis.
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Is rooibos just another trendy tea, or does it actually outshine the rest?
Like most medicinal plants and herbs, rooibos is high in antioxidants, which simply means it can neutralise toxic chemicals in the body.
After more than 40 years of research, it is now scientifically substantiated that rooibos has the following benefits: anti-tumour, anti-antioxidant, anti-inflammatory, anti-diabetic, cardioprotective, helps with weight management, anti-stress/relaxant, limits digestive issues, liver protective, helps to promote a good probiotic balance and anti-cholesterol.

How does sipping rooibos play into long-term health?
Research needs to be done to better understand the long-term benefits of rooibos in humans. However, if one considers that so many South Africans have been drinking rooibos for most of their lives without side effects, and it shows short-term benefits, it can only be good to human health in the long run.
Any downsides to drinking too much rooibos, or is it all good?
There are no properly designed research studies that show any side effects of rooibos. It is safe to consume, and clinical research has shown that six cups of rooibos per day has beneficial effects on the cardiovascular system.
Seeing that people hardly drink more than two cups a day, and because six cups per day showed no side effects, one could consider this a good upper limit.
[Editor’s note: “Tisane native” refers to a herbal tea made from plants that are indigenous or native to a specific region.]
*This article was first published by our sister publication, Food For Mzansi.
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