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COOL KIDS DRINK ROOIBOS

Rooibos tea has formed part of the diet of South African children for generations, and with good reason. Given its unique ability to cure and soothe, coupled with its lack of caffeine, this remarkable tea has been used by moms to help relieve a range of little ones’ ailments such as insomnia, food allergies, stomach cramps and eczema.

These days, parents are becoming increasingly concerned about the possible effects that colourants, preservatives and other additives found in a number of beverages could have on their kids, such as behavioural changes and allergic reactions. Rooibos tea, which can be served hot or as a refreshing iced tea, is an ideal beverage choice for children as it is 100% natural and nutritious and is free of colourants, caffeine, sugars and preservatives.

Japanese research and anecdotal evidence has shown that Rooibos tea can help to alleviate allergies and may even relieve asthma. In addition, because it is rich in antioxidants that fight destructive free radicals, Rooibos tea can help to strengthen the immune system which means fewer runny noses and colds. These antioxidants can also help to protect the liver, which allows the body to eliminate toxins.

Sleep is vital for children since it is during this time that growth hormones are released. Whilst your child is asleep, his or her body is busy repairing itself and replenishing the energy supplies that have been depleted during waking hours. To ensure that your child has a restful night’s sleep cup of Rooibos tea at night can help to round off the day on a good note as the calmative properties in Rooibos are known to soothe and ease nervous tension thereby promoting a good night’s sleep.

 

More evidence that Rooibos protects the heart

With World Heart Day being celebrated on 29 September 2015, new research findings of a natural, affordable and uniquely South African product that promotes heart health is good news.

A recent study in Spain found that Rooibos helps to reduce cholesterol and other fats and fatty acids in the blood of mice with abnormally high blood fat levels that were fed an unhealthy high-fat, high-cholesterol, western-style diet for 14 weeks.

The findings of a team of researchers, representing several Spanish biomedical research centres and universities, were published in the journal Phytomedicine (15 March 2011, Vol 18, No 5, pp 414 – 424).

The results show that Rooibos can prevent the development of serious health conditions by preventing the liver from storing excessive fat, without increasing the accumulation of fat under the skin and around major organs. Rooibos not only reduced the number and size of the fat cells, but also completely prevents the development of fatty liver disease – a condition where fat accumulates in the cells of the liver. Rooibos probably achieves these health benefits by increasing the body’s metabolic rate.

The researchers also looked at the make-up of the polyphenols in Rooibos and concluded that the complex mix of antioxidants in Rooibos are jointly responsible for its beneficial effects, and that it is therefore better to drink Rooibos tea, rather than isolated compounds from Rooibos.

This study confirms the findings of a 2009 South African study in humans, led by Professor Jeanine Marnewick, a specialist researcher at the Cape Peninsula University of Technology. She was able to show a very favourable effect in adults, at risk of heart disease, who drank six cups of Rooibos every day for six weeks. Rooibos not only protected against oxidative lipid damage, but also favourably improved the lipid profile of the participants by reducing the total blood cholesterol levels by 10%, with a significant reduction in the “bad” LDL cholesterol levels. Her study also collected safety data for Rooibos and confirmed that it is safe to drink, with no negative effects on liver or kidney functions, and no effect on iron levels in the blood.

According to the World Health Organisation, cardiovascular diseases are the world’s largest killers, claiming 17.1 million lives a year. Risk factors for heart disease and stroke include raised blood pressure, cholesterol and glucose levels, smoking, inadequate intake of fruit and vegetables, overweight, obesity and physical inactivity.

RESEARCH PUTS ROOIBOS TO THE TEST

The Rooibos Council is investing over R2million in independent research this year in an ongoing programme to find out more about the properties, applications and cultivation of Rooibos.

Six product research grants, totalling R974 705, have recently been awarded to two existing research projects, plus four new projects. These latest grants are in addition to R1,2 million already allocated to cultivation research (plant improvement, integrated pest management and organic cultivation practices). Furthermore, rooibos research has been independently undertaken and is ongoing at international universities and research organisations as far afield as Sweden, the USA, Japan, and other countries.

Of the six latest South African research grants, two existing projects that have received funding examine the cancer-preventing properties of South African herbal teas (Prof. Wentzel Gelderblom of the Medical Research Council); and objective quality parameters for rooibos (Prof. Lizette Joubert of the Agricultural Research Council).

Four new research projects examine the influence of rooibos on stress (Dr Amanda Swart of Stellenbosch University); rooibos and exercise (Prof. Jeanine Marnewick of the Cape Peninsula University of Technology); the hygienic processing of rooibos (Prof. Pieter Gouws of the University of the Western Cape); and determining what exactly is in a cup of rooibos tea (Prof. Andrew Marston, University of the Free State.)

The six grants were approved after a rigorous process beginning in June 2009, when a call for expression of interest in rooibos research was issued to South African universities and science councils, as well as to all members of the Indigenous Plant Use Forum.

Researchers were invited to submit expressions of interest in three broad research areas: The chemistry, biochemistry and bioactivity of rooibos; the health promoting properties of rooibos and its potential to prevent and/or treat lifestyle diseases; and genetic improvement of the rooibos plant to optimise its cultivation, disease and drought resistance and biochemical composition.

Nine applications were finally reviewed by the SA Rooibos Council’s Product Research Committee and board of directors, plus a panel of three independent scientists.

“There is a need to gather reliable information on the kind of scientific evidence that is required to substantiate health claims (on product packaging, as well as in advertising, advertorials and editorial copy) in different countries – for example South Africa, the EU, countries in the Far East, USA, Canada and Australia,” said Product Research director Mientjie Mouton.

“Extensive anecdotal evidence also suggests that rooibos has other beneficial effects not yet fully verified or understood by science. Future research challenges for rooibos include exploring its anti-allergic properties and immune-boosting effects, better understanding the active compounds in rooibos and exactly how they achieve their anti-cancer and anti-ageing effects, the optimal use of rooibos as part of a healthy lifestyle, additional comparative studies with other herbal teas, plus more human studies.”

Researchers have already found that rooibos can prevent or slow down cancer and promote heart health (South Africa), may help to control diabetes and its complications (Slovak Republic), could contribute to hormone replacement therapy (Japan), and be used in the treatment of stomach cramps and diarrhoea (Pakistan, Canada and Germany).

The Rooibos Council was established in April 2005 as a non-profit company to promote the interests of the South African Rooibos industry locally and internationally. It serves as a representative platform for its members consisting of producers, processors, manufacturers, as well as local marketers and exporters.

Note to editors:
The research reviews listed below provide a comprehensive overview of recent research into the potential health benefits, production and quality aspects of rooibos and related products. Research abstracts are also available on the website www.sarooibos.co.za.

1.Joubert, E. & Schulz, H., 2006. Production and quality aspects of rooibos tea and related products. A review. Journal of Applied Botany and Food Quality 80, 138-144.
2.McKay, D.L., & Blumberg, J.B., 2007. A review of the bioactivity of South African herbal teas: Rooibos (Aspalathus linearis) and Honeybush (Cyclopia intermedia). Phytotherapy Research 21, 1-16.
3.Joubert, E., Gelderblom, W.C.A., Louw, A., De Beer, D., 2008. South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides: A review. Journal of Ethnopharmacology, 119, 
376-412.
4. Joubert, E., Gelderblom, W.C.A., Louw, A., De Beer, D., 2008. Phenolic contribution of South African herbal teas to a healthy diet. Natural Product Communications 4, 1-18.

 

 

NEW FLAVOUR WHEEL DISCERNS INFUSED NUANCES OF ROOIBOS TEA

South African researchers have developed a flavour and mouthfeel wheel that provides 27 descriptive attributes for Rooibos tea as a tool to facilitate communication among producers, processors, grading experts, marketers, flavour houses, importers and consumers.


Many of us have taken a sip of tea and immediately been able to distinguish the taste as either good or bland, without being able to say why.  In order to go beyond simplistic distinctions and to properly discern the great many tastes and aromas that give rooibos tea its flavoured nuances, South African researchers have developed a flavour and mouthfeel wheel for the unique homegrown brew.

The novel wheel provides 27 descriptive attributes for rooibos – 20 flavour and seven taste and mouthfeel descriptors – and will be a practical tool to facilitate communication among rooibos producers, processors, grading experts, marketers, flavour houses, importers and consumers.

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The wheel is the work of a team including Ilona Koch, a Masters student at Stellenbosch University. Under the leadership of Professor Elizabeth Joubert of the Agricultural Research Council, (who designed the project proposal together with Stellenbosch University lecturer Ms Nina Muller), Koch and a team of researchers have spent over a year compiling data through numerous experiments with rooibos tea.

“This study was conducted to characterise and quantify the sensory attributes associated with rooibos flavour (taste and aroma) and mouth-feel to paint a more comprehensive picture of what is frequently referred to as ‘typical’ or ‘characteristic’ rooibos flavour,” said Koch.

The researchers studied 69 different rooibos samples originating from 64 different plantations in various production areas. These samples had been graded from A to D, representing the highest to the lowest tea quality respectively.

A strict protocol was followed when brewing the tea – 300g of boiling, deionised water was poured onto 5.8 g of dry tea leaves, which was infused for five minutes. The tea was strained and stored in a stainless steel thermos flask to keep the temperature constant, and 100 ml of tea was served to each taster in a white porcelain cup covered with a plastic lid to prevent evaporation and loss of volatiles. The tea cups were preheated in an oven set to 70°C, and kept in water baths with the temperature regulator set at 65°C throughout the sensory analysis session.

Nine judges took part in the study, selected on availability and interest. “Most of them had extensive experience with descriptive analysis of a wide range of products.  None of them, however, had previous experience with sensory analysis of rooibos,” said Koch.

During the first training stage the panellists were exposed to a number of rooibos samples to become familiar with the product and the evaluation protocol. During 22 one hour sessions, the 69 samples were analysed and compared to one another, and the panel generated aroma, taste and mouth-feel terminology.

Some 85 aroma and 38 taste and mouthfeel descriptors were generated at this stage, but this proved to be too large a field of data for the efficiency necessary to produce the wheel. The number of descriptors was subsequently reduced to eight aroma descriptors and nine taste and mouth-feel descriptors. A score card was developed which showed each of these 17 descriptors together with a 10cm unstructured line scale ranging from “none” to “prominent”.

After training was over, the panel used the score card to rate the intensity of the 17 attributes for each of the 69 samples during 40 sessions spread out over eight weeks.

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Through the research, it was uncovered that the positive sensory characteristics such as floral, woody, honey and sweet could be separated from the negative attributes such as green plant, hay-like, dusty and sour. In light of this, the descriptors were grouped according to the positive or negative impact on the quality of the sensory experience.

While the research delved into a number of experiments to deduce specific data including the effect of steam pasteurisation, the effect of particle size and the oxygen radical absorbance capacity of rooibos (ORAC), the flavour and mouthfeel wheel represents the attributes of unpasteurised rooibos infusions.

The wheel will be further updated and refined with samples from another season during the three-year project, which will run until March 2012.  It is being funded by the SA Rooibos Council and the Technology and Human Resources for Industry Programme (THRIP) that aims to boost South African industry by supporting research and technology development.

Now drinking tea will no longer be about whether it’s simply good or average, but a sensory experience akin to the tasting of wine where you will be able to indulge in the subtle tannins and fine distinctions in taste and aroma that rooibos infuses into each of its products.

Contacts:
Professor Elizabeth Joubert
Agricultural Research Council
Phone: +27 21 809 3444 – Fax: +27 21 809 3430
joubertl@arc.agric.za

 

 

Homegrown herb may provide hope for diabetics

4 August 2011

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 that aspalathin stimulated pancreatic beta-cells to secret insulin and helped to improve impaired glucose tolerance in the animals.

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 three-year R1million, SA Rooibos Council-funded study – kicking off in 2011 – to determine whether rooibos can play a role in combating obesity.

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, Chair of the Product Research Committee of the South African Rooibos Council..

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.

New evidence proving that people can absorb the active compounds in Rooibos tea

A new collaborative study between researchers at two German universities (Leibniz University and Braunschweig Technical University) confirmed that the active compounds in Rooibos tea can be absorbed and broken down by the human body. These new findings about the bioavailability of Rooibos help scientists to understand and explain the multitude of health benefits that Rooibos tea offers, including protection against heart disease and cancer.

The researchers took blood and urine samples of 12 healthy male volunteers before and after drinking Rooibos. They found several metabolites (breakdown products) of the key antioxidants in rooibos – aspalathin and nothofagin. They also found intact aspalathin, proving that humans can absorb aspalathin into the bloodstream, even if only at low levels. Aspalathin is the major flavonoid in rooibos. It is a novel compound (found only in Rooibos), but also the most active antioxidant in Rooibos in many cases.

Scientific reference: Breiter, T., Laue, C., Kressel, G., Groll, S., Engelhardt, U.H., Hahn, A., Bioavailability and antioxidant potential of rooibos flavonoids in humans following the consumption of different rooibos formulations, Food Chemistry (2011), in press.

Available online at ScienceDirect.com

Research confirms rooibos is good for you

February 2011

‘Rooibos is good for you’, is a contention that’s been around for at least the past 40 years, but increasingly scientific research indicates that there’s more than a little substance to the claim.

The first evidence of people making tea with rooibos only occurs about 300 years ago. Wild plants were harvested using axes and the leaves were bruised with hammers before being left to ferment in heaps and then dried in the sun. It’s essentially the same process used today, although now the equipment is a little more sophisticated.

Rooibos became popular with the early Dutch settlers, not for its health but economic advantages. It was a cheap alternative to the expensive black tea that was imported from Europe.

Carl Thunberg, a botanist from Europe, was the first to document the rooibos plant and the tea brewed from it in 1772. After this, the scientific community doesn’t appear to have lavished much attention on the ‘mountain’ tea until the early 20th century.

That’s when Dr Le Frans Notier, a doctor and nature lover, began researching rooibos’ medicinal value and agricultural potential.

Rooibos of course is not a true tea, but a herb and the brew made from the dried leaves is a herbal infusion known as a tisane. The vibrant amber hue comes from the natural colorants that develop during the post-harvest fermentation or oxidation process and is brought about by natural enzymes in the plant.

Green or unfermented rooibos is lighter, with a milder taste. Both traditional and green rooibos are natural products and contain no colorants, additives or preservatives – although they can be stored for long periods without the taste or quality deteriorating. They have no kilojoules and contain no caffeine.

Scientific interest in rooibos remained muted until after 1968, when Mrs Annetjie Theron used rooibos to help soothe her allergic baby’s colic. She published a book called ‘Allergies: An Amazing Discovery’ and went on to launch a range of health and skin-care products with rooibos as the main ingredient.

Although Mrs Theron’s evidence was anecdotal rather than scientific, there’s little doubt that her claims stirred considerable interest in rooibos’ health benefits. Since then there’s been considerable research done in South Africa and abroad into how rooibos might help prevent or treat a variety of illnesses.

Rooibos contains a complex and unique blend of antioxidants, the most active of which – aspalathin – is found only in the plant species Aspalathus linearis. Antioxidants bind with free radicals, preventing them from damaging cells and causing cancer or oxidising with cholesterol to clog blood vessels resulting in heart attacks and strokes. Research over the past decade has proven the therapeutic ability of rooibos to fight cancer, protect the liver against disease, boost the immune system, relieve allergies and treat digestive disorders.

By investing in research in South Africa and keeping a close eye on studies done overseas, the South African Rooibos Council is able to provide scientific evidence to confirm the plant’s health benefits as well as police inaccurate or unsubstantiated claims.

Its research budget is R1 million a year and it is currently supporting studies at several local universities and science councils on how rooibos can counter cancer and oxidative stress as well as the link between rooibos and exercise. A project on rooibos and obesity has been approved for funding in 2011.

Scientists here and around the world continue to research rooibos to gain a better understanding of this unique herbal tea. Some are investigating the health benefits of rooibos and its potential to combat a range of diseases, while others are trying to understand how the bioactive components in rooibos work.

Recent and ongoing research:

International researchers found the antioxidants in rooibos are potent enough to measurably elevate the antioxidant levels in blood, boosting the body’s natural defences. The effect peaks an hour after drinking two cups of rooibos.
“That’s why we recommend drinking up to six cups of rooibos spaced throughout the day for a sustained health benefit,” says Professor Jeanine Marnewick from the Cape Peninsula University of Technology, who led a local study that showed the beneficial effect of drinking rooibos to promote heart health.
The benefits are the same whether the rooibos is drunk hot, as tea, or cold as iced tea. Six cups also provide the recommended daily hydration.
South African scientists from the Medical Research Council’s PROMEC Unit and the Oxidative Stress Research Centre at the Cape Peninsula University of Technology have found that rooibos could help prevent skin cancer. The implications are particularly relevant in South Africa which, with 20 000 reported cases annually and 700 deaths, has the second highest incidence of the disease in the world after Australia.
The CPUT study concluded that the polyphenolic-rich extracts from rooibos and honeybush have anti-tumour and photoprotective properties. This indicates potential for use in cosmeceuticals for sun protection and as part of a strategy for preventing non-melanoma skin cancers in humans.
The MRC team found that rooibos exacerbated cell death in UV exposed cells, which could play a role in cancer prevention. It also concluded that rooibos may prevent skin cancer by delaying the progression of abnormal cells, interfering with their growth and viability.
Researchers in Pakistan, Canada and Germany joined forces to explore the use of rooibos to treat gastrointestinal upsets, using an animal model. Their results explained the biochemistry of how the flavonoids and other active ingredients in rooibos achieve a calming effect on the digestive system. They concluded that it is justified to use rooibos for the treatment of gastrointestinal disorders such as gut spasms.
Two South African researchers, Professor Elizabeth Joubert and Dr Johan Louw, are co-applicants of a worldwide patent (filed in 2007) to develop and produce an anti-diabetic extract of rooibos, particularly for the treatment of Type 2 diabetes.
A Japanese study showed that rooibos could reduce inflammation in rats with colitis (open sores in the colon) via increased antioxidant activity and a consequent reduction in damage to DNA caused by oxidation.
Researchers in Japan showed that the active ingredients in a water-soluble fraction of rooibos restored immune function in immune-suppressed rats. These results hold significant potential for future research into the immune-boosting properties of rooibos that might benefit people living with HIV/Aids.
Researchers from the Slovak Republic have demonstrated the anti-ageing effect of rooibos in Japanese quails. The birds were given rooibos to drink and had ground rooibos added to their food. The hens on the rooibos diet laid more eggs and kept laying eggs as they were getting older, compared to the control group.

Local study examines rooibos anti-ageing potential

The pharmaceutical and cosmetic industries have long sought to restore and reverse the effects of ageing, now local scientists are investigating whether rooibos may hold some answers.

The contention that this indigenous plant could beneficial in countering the effects of time is not that far-fetched. The most accepted theory of ageing is the free-radical hypothesis. Rooibos is rich in antioxidants, which bind with free-radicals and prevent them from damaging cells.

Numerous local and international studies have proved that the antioxidants in rooibos slow down and prevent various forms of cancer, reduce the risk of heart attack and stroke and provide a plethora of other health benefits. There is, however, little published research on its precise molecular and cellular involvement against ageing.

Professor Maryna van de Venter of the Department of Biochemistry and Microbiology and her colleague, Dr Trevor Koekemoer, at the Nelson Mandela Metropolitan University are seeking to rectify this.

Prof Van de Venter explains that one of the characteristics associated with ageing is the progressive redistribution of body fat. This results in a decrease in the subcutaneous fat (the layer just under the skin) and an expansion in abdominal fat.

Subcutaneous fat loss leads to cosmetic changes such as wrinkles, sunken eyes and skin folds. The accumulation of body fat is potentially more harmful. Visceral fat is associated with increased risk of many age-related diseases, including insulin resistance, diabetes and heart disease.

“In layman’s terms there’s less fat in the places where it should be and more in the places it shouldn’t, with substantial clinical consequences,” she explains.

Preadipocytes, the cells from which fat cells develop, may be the reason this happens. These represent between 15% and 50% of the cells in adipose (fat) tissue and consequently are likely to have a significant influence on its growth and function.

Recent studies have shown that over time preadipocytes lose their ability to multiply and develop into mature fat cells. Although scientists are not yet sure why this happens, they believe inflammation of the fatty tissue, oxidative stress and the introduction of factors which prevent the cells from dividing may contribute.

Prof Van de Venter’s research will investigate the potential influence that the antioxidants contained in rooibos may have on these molecular mechanisms thought to cause preadipocyte dysfunction. Preventing this may slow or even reverse age-related adipose redistribution and associated cosmetic changes and health risks.

The findings will contribute to our understanding of the health benefits of rooibos and provide much-needed scientific evidence to substantiate its anti-ageing properties, beyond what is already known about its antioxidant capacity.

 

Enjoy Rooibos – red or green – as both offer health benefits

Green Rooibos tea has higher levels of antioxidants than traditional Rooibos, but recent studies are proving that both kinds of Rooibos protect against a range of diseases, and that drinking green Rooibos is not necessarily better.


Prof Jeanine Marnewick has been involved in Rooibos research for more than 15 years

Prof Jeanine Marnewick has been involved in Rooibos research for more than 15 years.

“People should drink the kind of Rooibos they enjoy most, since we now know that Rooibos with a higher-antioxidant content does not always provide the best benefits,” recommends Professor Jeanine Marnewick, manager of the Oxidative Stress Research Centre in the Faculty of Health and Wellness Sciences at Cape Peninsula University of Technology.

Professor Marnewick, who has been actively involved in Rooibos research over the last 15 years, explains that it is not only the level of antioxidants, but also the specific combinations of bio-active compounds in Rooibos that are important. “The health benefits from drinking Rooibos tea will also be different for every person – depending on your overall health status,” she adds.

Scientists are still busy unravelling the complex pathways whereby the active compounds in Rooibos can play a role in disease prevention, but several studies done on skin, liver, heart and oesophagus models, researchers have shown that traditional rooibos offers similar (and sometimes even better) health properties compared to green Rooibos.

Researchers at the Cape Peninsula University of Technology found that both traditional and green Rooibos were able to protect and aid recovery of hearts tissue in rats following damage of the heart .

A recent study at South Africa’s Medical Research Council showed that green and traditional Rooibos could play a significant role in preventing or slowing done cancer of the oesophagus .

A collaborative study in Europe showed that both green and fermented Rooibos significantly increases the antioxidant capacity in human blood, thereby boosting the body’s natural defences.

In an earlier study on skin cancer in mice researchers at South Africa’s Medical Research Council Found that traditional rooibos was even more effective than green rooibos at inhibiting cancer.

Much like making wine, making a good quality Rooibos tea is both a science and an art. The characteristic colour and flavour of Rooibos tea develops when enzymes that occur naturally in the plant turns the shredded green tea leaves reddish brown. This happens on the tea court while the moist tea is slowly dried in the sun. When making green Rooibos, this step is skipped and the tea is dried as soon as possible in order to inactivate the enzymes in the plant and retain the green colour in the dried leaves.

Researchers optimistic about anti-diabetic potential of rooibos

Cape Town, South Africa – With World Diabetes Day in sight on 14 November, new evidence of the anti-diabetic potential of Rooibos has emerged …

Cape Town, South Africa – With World Diabetes Day in sight on 14 November, new evidence of the anti-diabetic potential of Rooibos has emerged from a study conducted jointly at the Diabetes Discovery Platform from South Africa’s Medical Research Council (MRC) and the Agricultural Research Council’s (ARC) Infruitec-Nietvoorbij Institute. Researchers found that an aspalathin-enriched extract of green Rooibos is able to lower raised glucose levels in the blood of diabetic rats. Aspalathin is a unique antioxidant found in nature only in the Rooibos plant (Aspalathus linearis). When combined with rutin, another key compound in Rooibos tea, the glucose-lowering action was further enhanced.

Working with diabetic rats, the researchers were able to show that the Rooibos extract could achieve a glucose lowering effect comparable to known diabetic drugs.

“Our work confirms the constituents present in Rooibos could prove beneficial in the fight against diabetes,” says Doctor Johan Louw of the MRC who led the study. “We believe that Rooibos can provide a basis to develop a standardised anti-diabetic product and in a country like South Africa, where a large section of the population relies on herbal medicines, such a product could be of huge value.”

“We have also confirmed that the polyphenols in complex mixtures, such as Rooibos tea, work synergistically to achieve favourable health effects,” Louw explains. “This points to the value of drinking the ‘whole’ tea containing the required amount of these beneficial constituents, rather than a tablet containing just one of the compounds.

“Our Rooibos research to date focused mostly on the antioxidant activity of Rooibos, but this evidence of its ability to lower blood glucose levels opens up new and exciting possibilities for this unique South African herb” says Prof Lizette Joubert of the ARC who collaborated on this project. “We now need to dig deeper to determine the optimal combination and ratio of the active compounds such as aspalathin and rutin in controlling blood glucose levels, and also to understand the exact mechanisms involved.” Follow-up studies indicated that other compounds are also important.

The study has been published online on 19 October 2012 in the Journal of Phytomedicine. (http://www.phytomedicinejournal.com/article/S0944-7113(12)00320-0/abstract)

This Rooibos and diabetes study was funded jointly by the National Research Foundation of South Africa, the Medical Research Council and the Agricultural Research Council, with contributions to post-doctoral fellowships from the Department of Science and Technology. Prof Stephen Fey from the University of Southern Denmark also collaborated on the study.

Notes for editors

The World Health Organization (WHO) estimates that 439 million people will have diabetes by 2030, with the major increase occurring in developing countries.