New Research Summaries Released

Rooibos has captured the imagination of researchers and food scientists around the world and has already featured in more than hundred articles in leading international scientific journals. The Rooibos Council has initiated a communications programme to make these scientific results more accessible and user-friendly for consumers, buyers and industry members. Summaries of key findings with the complete scientific references have been compiled and will be updated as new research results and reviews become available.

Download Rooibos Science Research Summaries

Rooibos Biodiversity Best Practices Launched in Oct 2008

The Rooibos Council has launched a world-first biodiversity project, which involves a pilot group of Rooibos producers implementing Biodiversity Best Practice Guidelines. The industry has joined hands with conservation authorities and government stakeholders to develop these guidelines to protect the Greater Cederberg Biodiversity Corridor’s important biodiversity and ensure sustainable production of Rooibos. The Rooibos Biodiversity Initiative forms part of the Rooibos Council’s portfolio for natural resources management.

The Rooibos Biodiversity Initiative features on the website of C.A.P.E. (Cape Partnership for People and the Environment), which hosts an extensive biodiversity information library.
Visit the CAPE website

Download release document.


Attending the launch of the Rooibos Biodiversity Guidelines on 28 October 2008 were Willie Nel, SA Rooibos Council director and participant of the biodiversity pilot project, Jenifer Gouza, project co-ordinator for CapeNature’s Greater Cederberg Biodiversity Corridor, Dawie de Villiers, SARC director: natural resources management portfolio, and Gerhard Pretorius, SARC biodiversity project manager.


Rooibos and potato farmers attended the biodiversity open day at Donkieskraal farm in the Sandveld to learn about the benefits of preserving on-farm biodiversity and methods to implement best practice production.


Results from a clinical trial showing that Rooibos significantly reduces the risk of heart disease were announced at a Rooibos Science Café at the MTN ScienCentre in Cape Town on 26 November 2008. About 150 members of the media, health sector and the Rooibos industry attended the event and were delighted about this new and conclusive evidence of the health promoting properties of Rooibos in humans.

Researchers traced the protective effect of Rooibos by looking at two important markers in the blood, as well as the oxidative status of the 40 adults who participated in the study. They found a significant decrease in conjugated dienes and malondialdehydes of 35% and 50% respectively – two blood markers that indicate oxidative damage – in the group that drank six cups of Rooibos per day for 6 weeks. “This means that Rooibos may help to slow down atherosclerosis, or the hardening of arteries,” explained Dr Jeanine Marnewick, who led the clinical trial at the Oxidative Stress Research Centre at the Cape Peninsula University of Technology. On top of this, Rooibos also increased the levels of the body’s own ‘super anti-oxidant’ called glutathione and helped to reduce the levels of “bad” LDL-cholesterol significantly.

“This is incredible news for Rooibos and the public,” said Mientjie Mouton, a director of the South African Rooibos Council. “We need scientific evidence to substantiate what we have always known – that Rooibos is good for you!”

Dr Marnewick also explained that they asked study participants for feedback on how they felt during the clinical trial. “Many of them reported feeling irritated during the washout period when they could not drink Rooibos, and much calmer once they were enjoying their six cups of Rooibos per day. That is why she will continue the clinical trial to look at the effect of Rooibos and stress.”

At the same science café Dr Carl Albrecht, head of Research at the Cancer Association of South Africa (CANSA) gave an overview of nearly a decade of research at South Africa’s Medical Research Council into the ability of Rooibos to prevent or slow down cancer. He also emphasised the importance of the ability of Rooibos to reduce oxidative stress in the body, as shown by the results of a study on rats, published in 2003. “I am elated that Dr Marnewick and her team were now able to prove that Rooibos also has this effect in the human body,” he added. Oxidative stress plays a role in the development of a whole range of diseases, including cancer, stroke, heart and liver disease, diabetes and Alzheimer’s. Another important milestone was the discovery, published in 2004, that Rooibos can prevent and slow down skin cancer in mice. “The next challenge is to prove that Rooibos can also prevent cancer in people, and I believe that there is a good chance that we’ll be able to prove this,” Dr Albrecht said.

This Rooibos Science Café was organised by the South African Rooibos Council who invests in Rooibos research, along with funding partners such as South Africa’s National Research Foundation as well as the Medical Research Council and CANSA.

New study proves Rooibos’ antioxidant potency in humans

A collaborative study by scientists at four international research facilities has found the first clinical evidence that drinking rooibos tea significantly increases the antioxidant capacity in human blood, thereby boosting the body’s natural defences.

The researchers in Rome and Glasgow found that the antioxidant capacity in the blood of 15 healthy volunteers peaked one hour after drinking 500ml ready-to-drink rooibos tea. Both traditional (fermented) and green (unfermented) rooibos tea had a significant effect.

“On the basis of the results of our study, we conclude that Rooibos tea is able to deliver antioxidant ingredients to the body, thereby stimulating the body’s internal redox network,” says Professor Mauro Serafini, leader of this research project and Head of the Antioxidant Research Laboratory at INRAN, a nutrition research insitute in Rome, Italy. “It is highly possible that, once absorbed in the circulatory stream, the unique ingredients of Rooibos may display other biological activities in the human body. That is why we are planning further intervention studies in humans to investigate the effect of Rooibos tea on the body’s strategy of defence to counteract the development of heart disease.”

“After an hour, the plasma antioxidant levels start to drop and that is why we recommend drinking up to six cups of rooibos spaced throughout the day for a sustained health benefit,” explains Professor Jeanine Marnewick from the Cape Peninsula University of Technology. She led a recent study that showed the beneficial effect of drinking six cups of rooibos a day to promote heart health.

Numerous studies over the past few decades have helped scientists to understand the complex and unique blend of antioxidants found in rooibos. They have also proved that the active compounds in rooibos are bioavailable and are metabolised (converted) in the body. The significance of the latest study is that it provides the first direct evidence that rooibos boosts antioxidant levels in the blood of healthy humans.

“This new research proves that the compounds in rooibos are potent enough to have a measurable effect on the antioxidant capacity of the blood,” says Professor Lizette Joubert, one of South Africa’s leading rooibos researchers, working on the quality and chemical composition of rooibos at South Africa’s Agricultural Research Council.

The most active antioxidant in rooibos – 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.

“This study underlines the value of rooibos as a widely available and affordable source of dietary antioxidants,” comments Mientjie Mouton, chair of the Product Research Committee of the South African Rooibos Council. “It is very encouraging that leading research institutions around the world are working on rooibos and producing such promising results. There is also a great deal of work being done by local rooibos researchers and we will continue to invest in this research.”

The South African Rooibos Council invests some R1 million a year to fund research into rooibos’ health properties. This year the Council is supporting research projects at several local universities and science councils focusing on how rooibos can counter cancer and stress, as well as the link between rooibos and exercise. A project on rooibos and obesity has been approved for funding in 2011.

Summaries of the most recent rooibos studies published in top peer-reviewed scientific journals can be found on the website of the SA Rooibos Council at

Notes to editors

The collaborative research was carried out at: Antioxidant Research Laboratory, Human Nutrition Unit, INRAN, Rome; Food and Nutrition Unit, IRCCS, Rome; Plant Products and Human Nutrition Group, University of Glasgow; Diabetes Unit, San Camillo Forlanini Hospital, Rome.
The study has been published in Food Chemistry: Villaño, D., et al. 2010. Unfermented and fermented rooibos teas (Aspalathus linearis) increase plasma total antioxidant capacity in healthy humans. Food Chemistry 123 (2016) 679-683.


The SA Rooibos Council supports several researchers at local universities and science councils to explore the quality and health properties of Rooibos. The scientific evidence that they produce is crucial to substantiate health claims of Rooibos, and provides a basis for the development of new value-added Rooibos products.

The following product research projects are currently supported:

Developing objective quality and sensory parameters for Rooibos
Research leader: Professor Lizette Joubert, Agricultural Research Council

This project aims to characterise a typical cup of Rooibos according to its total polyphenol content, the major individual flavonoids and antioxidant capacity. The research team is analysing hundreds of Rooibos tea samples from different regions and seasons, from 2009 into 2011.

A key finding so far is that pasteurisation decreases chemical parameters and colour values for Rooibos tea. The researchers were also able to demonstrate that high quality Rooibos (as measured by its sensory attributes such as taste and mouthfeel) has higher levels of soluble solids and total polyphenols.

This research is complemented by a project aimed at a comprehensive description of the taste, flavour and aroma of Rooibos, and the development of a “flavour and mouth-feel wheel” to support the local and international Rooibos trade. THRIP (Technology and Human Resources for Industry Programme) is a co-funder. Professor Joubert presented the latest version of the flavour wheel at the Research Day on 17 May 2011.

The influence of Rooibos on stress
Research leader: Professor Amanda Swart, Stellenbosch University

Rooibos is widely used as a herbal tea for enhancing well-being, supporting the immune system and combating stress. During stress, which is characterised by anxiety, sleeplessness and depression, there is an increased production of stress hormones. Professor Swart’s project looks at the influence of Rooibos on the biosynthesis of cortisol, since the inhibition of cortisol biosynthesis may alleviate stress symptoms, thus validating the anti-stress potential of Rooibos.

So far her team has been able to show that Rooibos decreases the levels of corticosterone in rats (the equivalent hormone in humans is cortisol, the so-called “stress hormone”). Rooibos is further able to enhance the inactivation of corticosterone to an inactive metabolite. This finding may have clinical applications in the treatment of hypertension and metabolic syndrome. Interestingly enough, they also found that Rooibos increases testosterone levels in male rats.

Rooibos and exercise
Research leader: Professor Jeanine Marnewick, Cape Peninsula University of Technology

Antioxidants play a vital role in protecting tissues from excessive oxidative damage during exercise. With this project, Professor Marnewick and her team want to determine whether the antioxidants in Rooibos, already found to protect the body against other conditions linked to oxidative stress, can also help to protect against exercise-induced oxidative stress, including biochemical damage and inflammatory responses in cells. They will look at the effect of Rooibos on sport performance in a group of volunteers who will take part in several acute exercise regimes. Between 30 and 40 volunteers will take part in the clinical trial during this project. The project kicked off in 2010, but requires an extensive amount of preparatory and analytical work, and therefore there are no findings to report yet.

What exactly is in a cup of Rooibos tea?
Research leader: Professor Andrew Marston, University of the Free State

Despite extensive studies on the polyphenols in Rooibos, relatively little is known about the polar fraction of the tea that is composed largely of polysaccharides and tannins. This study focuses on that part of the chemical makeup of Rooibos, and may in future help us understand how these components influence the sensory characteristics of the tea, as well as how they contribute to its health properties, including an influence on resistance to disease, cancer prevention and ageing.

The researchers prepared a polysaccharide-rich fraction of Rooibos tea and demonstrated – for the first time – that this fraction of Rooibos could stimulate the immune system (or has an immunomodulatory effect). They are now busy with further isolation of the different polysaccharides, characterizing them and testing the activity of the individual polysaccharides.

As far as the tannin-rich fraction of Rooibos is concerned, the team is using high-performance countercurrent chromatography to isolate these tannin compounds. They will then determine the structures of these tannins and study their biological activities.

Investigating the cancer-prevention properties of South African herbal teas
Research leader: Professor Wentzel Gelderblom, Medical Research Council

The complex mix of antioxidants in Rooibos is able to delay or prevent several kinds of cancer, and helps to protect us against carcinogens in our environment. Prof Gelderblom and his team are trying to unravel the complex interactions that take place in living cells to help us to understand how Rooibos achieves this cancer preventing effect. New data on the cancer preventing properties of green rooibos provide new opportunities in developing a product to protect against the effect of UV light-induced cell damage in the skin. This is a long-term project that has been ongoing at the MRC (with co-funding from many partners) for more than ten years.

The microbiological quality and safety of Rooibos
Research leader: Professor Pieter Gouws, University of the Western Cape

Prof Gouws and his team investigate the influence of processing on the microbiological quality of Rooibos. They look at how different microorganisms may be able to survive and even multiply during steps such as fermentation and steam pasteurisation and storage. They are focusing specifically on organisms that may be of public health concern. The aim is to advise the industry on critical control points (CCP) in a Hazard Analysis Critical Control Point (HACCP) system.

Could Rooibos help to battle the bulge?
Research leader: Professor Johan Louw, Medical Research Council

Worldwide there is a growing interest in the role of polyphenols (chemical substances found in plants) in the fight against obesity. Rooibos is rich in polyphenols and could potentially help to battle the bulge. This new project kicks off in 2011 and will investigate the impact of Rooibos extract on satiety, as well as the processes whereby the body stores and breaks down fat.

Rooibos shows promise in curbing diabetes

On 14 November 2011 – World Diabetes Day – the world will focus on this silent killer disease that is fast escalating into a global health epidemic. Obesity is directly associated with development of type 2 diabetes.

Responding to the diabetes challenge, a group of leading South African researchers are focusing their attention on a unique South African herbal tea – Rooibos – and specifically its anti-diabetic and anti-obesity properties. Dr Johan Louw at the Diabetes Discovery Platform at the Medical Research Council (MRC) and Prof Lizette Joubert at the Agricultural Research Council (ARC) are jointly supervising the research project. They are collaborating with an international biotechnology group – the MC2 Biotek Group.

“In healthy people, their cells take up and use glucose

effectively and the process is controlled by the insulin hormone, but in diabetics these processes are impaired,” Louw explains. “We have obtained encouraging results for Rooibos extracts in our pre-clinical studies with diabetic animals, as well as in cell models, showing that compounds in Rooibos can play a role in these processes.”

“We plan to continue with follow-up work to look at Rooibos and obesity in animals and humans.”

A positive outcome of this research in humans could lead to nutraceutical applications of Rooibos extract which could have far-reaching health implications.

This research project is supported by the South African Rooibos Council (SARC), as part of a portfolio of independent research projects to clarify and understand the health properties of Rooibos tea. SARC will invest about R1 million over three years in this specific study.


Notes for editors

More than 300 million people have diabetes. If no effective intervention is found, this number is likely to more than double by 2030. Almost 80% of diabetes deaths occur in low- and middle-income countries. (Source: World Health Organisation).
World Diabetes Day is celebrated on 14 November to mark the birthday of Frederick Banting who, along with Charles Best, was instrumental in the discovery of insulin in 1922, a life-saving treatment for diabetes patients.
South Africa’s focus on the potential of rooibos to manage diabetes builds on research in other countries: Slovak scientists have recommended Rooibos to help prevent and treat diabetic vascular complications, especially in eye membranes. Japanese scientists found that Rooibos, helps improve the glucose uptake of muscle cells, thereby maintaining normal blood sugar levels in diabetic mice, and also that it stimulates pancreatic beta-cells to secret insulin.
Summaries of the most recent rooibos studies published in peer-reviewed scientific journals can be found on

More than R2 Million for local rooibos research in 2012

Exercise, stress, ageing, cancer and obesity are some of the lifestyle challenges that feature prominently in the South African Rooibos Council’s R2 million research budget this year.

In addition to these health-focused projects, several more researchers will receive funding to explore the chemistry, composition and flavour profile of this unique African herbal tea, or to advance organic and environmentally friendly Rooibos farming.

The research is led by prominent, independent researchers at South African universities and science councils.

“The new knowledge generated by these research projects is of huge value to the industry,” says Mientjie Mouton, chair of the SARC’s product research committee. “In an increasingly competitive and regulated global market, it is becoming more and more important to substantiate centuries of anecdotal evidence about the health benefits of Rooibos with hard scientific facts.”

The South African Rooibos Council awards grants to local researchers, but encourages them to collaborate with experts around the world.

“Due to the growing interest in the health properties of natural products and specifically herbal teas, there are many more top biochemists around the world investigating Rooibos,” Mouton explains.

“During the past few years we have seen exciting and promising results about Rooibos and topics such as heart health and diabetes emerging from Sweden, Italy, Spain and Germany. Locally, SA Rooibos Council funding has contributed to major advances in our understanding of the health-promoting properties of Rooibos – specifically its ability to slow down and prevent various forms of cancer, as well as its potential to protect heart health in individuals at risk of cardiovascular disease.”

25.01.12, Cape Town

Rooibos tea could be a good way to prevent kids overheating

As children go back to school for the last term, warmer weather means mothers packing lunchboxes should give some thought to hydration.

Ensuring children get enough of the right kinds of liquids, particularly during the hot summer months, can be as important as making sure they’re properly fed. Mild or moderate dehydration can lead to sleepiness or tiredness and even headaches and dizziness, making it difficult to pay attention in class. In more severe cases delirium or even unconsciousness can occur.

But packing a water bottle isn’t always a guarantee that children are going to drink enough to compensate for fluids they lose while trying to cram as much fun as possible into break times.

The problem is that water can be bland and tasteless, particularly after a couple of hours in a plastic water bottle, so children simply don’t drink it or pour it out. The alternative is to add some sort of cordial and while this may make it more appealing not all of these are particularly healthy options. Nor are fizzy drinks and buying a fruit juice each day can be costly.

Fortunately there is a South African solution that’s affordable, tasty and amazingly beneficial – rooibos tea.

Although many people tend to think of rooibos as only a hot drink, it is an exceptional flavour enhancer and naturally sweet, which makes it a favourite ingredient for iced teas, fruit shakes, smoothies, iced lollies and many other tasty treats.

Add to this that it contains no caffeine, fats or carbohydrates and its proven health benefits include boosting the immune system, relieving allergies and preventing heart disease and cancer. Researchers are also investigating the link between rooibos and stress relief.

According to Professor Jeanine Marnewick of the Cape Peninsula University of Technology, rooibos is a natural thirst quencher and drinking the equivalent of six cups a day – hot or cold – will provide a sustained health benefit.

Making a simple rooibos iced tea is easy. Simply make a litre of rooibos tea using four to six teabags. Sweeten the tea with honey to taste and leave it in the fridge to cool overnight. You can then experiment with this basic iced tea, adding mint, lemon, orange, granadilla, mango or apple or a combination of flavours until you find one that your children really love. You can even get them involved in mixing their own flavours.

Juiced or squeezed fresh fruit usually deliver the best results, but you can also use preservative-free fruit juice. Mixing it with cold rooibos will make it go further and keeping a jug of the children’s favourite iced tea in the fridge should mean you don’t have to keep buying juice.

The good news is that once you’ve made up a jug of iced tea you don’t have to repeat the performance every evening as cold rooibos can be kept in the fridge for up to two weeks.

By pouring some iced tea into popsicle containers or ice-cube trays and freezing it, you can also make fun, refreshing, healthy after school or sports treats.

R50m state funding to boost exports of processed agricultural products including rooibos

Agriculture, Forestry and Fisheries Minister, Tina Joemat-Pettersson says that government has allocated R50 million…

Agriculture, Forestry and Fisheries Minister, Tina Joemat-Pettersson says that government has allocated R50 million… to promote local agro-processing businesses. The investment will target specific sectors including rooibos, soya, beverages, fruit and vegetables and forestry. The aim is to increase the export of processed agricultural products and increase access to markets for smallholder farmers.

Some two years ago the Dutch Government funded a SA Rooibos Council project to explore ways to improve rooibos’ export competitiveness. Based on the recommendations the International Trade Centre, a joint agency of the United Nations and the World Trade Organisation, funded marketing campaigns in Dubai and Taiwan to introduce rooibos to some new, established tea-drinking markets.

Called NTFII (Netherlands Trust Fund) also supported the development of a new strategic plan for the rooibos industry.

Top endurance athlete recommends rooibos over energy drinks

Writing for Do It Now magazine, endurance athlete Hannele Steyn, warns that many over-hyped energy products are ‘just glorified sweets that have added hype ingredients to push the price sky high’.

Steyn, who has represented South Africa in numerous endurance World Championships (1 x duathlon, 2 x biathlon, 3 x triathlon, 4 x mountain biking, 3 x road cycling) 11 Triathlon World Cups and nine Mountain Bike World Cups and whose CV includes a ladies Cape Epic win and two more pages of achievements, should know what she’s talking about after 25 years of competitive racing. She believes that for endurance athletes healthy, natural foods are a better option than sugary, artificial energy bars and sweet drinks.

She recommends rooibos espresso, with almond milk, a teaspoon of honey and a pinch of salt. The result is an energy drink with lots of rooibos antioxidants. The honey delivers fast energy, while the almond milk delivers slow energy in the form of protein and essential fats. Himalayan salt provides minerals. The SA Rooibos Council is funding a research project into rooibos and exercise, which is being conducted by Professor Jeanine Marnewick at the Cape Peninsula University of Technology.