According to the internet, one of South Africa’s favourite beverages, rooibos tea, can cure many ills. But are these claims accurate?
Social media is littered with misleading and incorrect health advice. Recently Africa Check has noticed a popular drink being promoted as a remedy for a long list of ailments.
Need to treat prediabetes? Drink six cups of rooibos tea per day. Suffering from allergies? Rooibos is supposedly a “natural antihistamine”.
The tea, also known as “redbush” or “African red tea”, is indigenous to the Cederberg region in South Africa’s Western Cape province. But “rooibos is not a medicine”, Suzanne Herbst, spokesperson at the South African Rooibos Council, told Africa Check. The organisation works to “promote, grow and protect the rooibos industry of South Africa”.
Despite this, unsubstantiated claims about the tea continue to spread online. Medical experts helped Africa Check investigate four claims about the tea.
Claim 1: Six cups of rooibos each day can prevent prediabetes
A video on a health and beauty Facebook page advises that “drinking six cups of rooibos each day can help prevent prediabetes”.
According to the Mayo Clinic, a US non-profit medical centre, a person with prediabetes has higher than normal blood sugar levels.
“It's not high enough to be considered type 2 diabetes yet, but without lifestyle changes, adults and children with prediabetes are more likely to develop type 2 diabetes,” the clinic says.
Type 2 diabetes is a medical condition that affects the way the body processes blood sugar, also called glucose. It can lead to disorders of the circulatory, nervous and immune systems.
Prof Christo Muller is a chief specialist scientist at the South African Medical Research Council. His research focuses on preventing and treating insulin resistance, obesity and type 2 diabetes. He told Africa Check that type 2 diabetes can be managed by increasing exercise, improving diet and taking prescription medicine.
“Rooibos can further play a role in terms of adding beneficial polyphenols to your diet that help the body better regulate blood sugar levels and improve blood lipid levels,” Muller said.
Polyphenols are compounds found in certain plants, such as fruits and vegetables, that may fight against free radicals damaging the cells in your body which can cause diseases.
But Muller said that rooibos tea cannot replace antidiabetic medicine. This is because there is “an enormous variation in its polyphenolic content making a precise dosage impossible”.
“If you intend to start to use rooibos and you are on chronic medication you should first consult with your doctor as rooibos can interfere with the metabolism of certain diabetic medications,” he said.
Buyelwa Majikela-Dlangamandla, a diabetes nurse specialist from the Chronic Disease Initiative for Africa at the University of Cape Town, told Africa Check the safest source of information about diabetes treatment was a medical doctor.
“Ask questions when consulting your doctor or diabetes nurse. Use reliable internet resources,” she said. “Your health care provider can assist you.”
Claim 2: Rooibos tea can prevent kidney stones
The headline of an article posted on Facebook suggests “red rooibos tea” if you’re looking to prevent kidney stones. The red version of the tea is fermented before drying. Green rooibos tea, which is unfermented, has a milder taste and lighter colour.
Kidney stones are hard deposits that form inside the kidneys. They form when “urine contains more crystal-forming substances – such as calcium, oxalate and uric acid – than the fluid in your urine can dilute”.
The article shared on Facebook says “people who have kidney stones can drink red rooibos tea as much as they want because it has no oxalic acid”. Oxalic acid, which is found in plants, can attach itself to other minerals and form kidney stones.
“There are studies that suggest that rooibos is one of the best drinks for people with kidney-stone problems but there is no conclusive study that proves drinking rooibos prevents kidney stones,” Prof Antony Meyer, a nephrologist and chairperson of the National Kidney Foundation of South Africa, told Africa Check.
A nephrologist is a doctor who specialises in diseases and conditions that affect the kidneys.
Meyer directed Africa Check to two studies. Preliminary results from a 2016 study of the effects of rooibos and Japanese green tea on kidney stone formation suggested that neither teas reduced the risk factors for kidney stone formation. However, the authors said further studies were needed with larger sample sizes.
A 2021 review of 13 studies concluded that “available literature supports in general a protective role for tea against the stone formation, mainly for green tea”. But it stated that the variability of the data and a lack of standardisation meant that "final and clear conclusions” could not be given to patients.
Meyer suggested people with kidney stones drink enough water every day and avoid drinking black tea due to the high oxalate content, as well as sparkling water which often contains minerals.
“After being diagnosed with recurrent kidney stones, diet plays a very important role, but it needs to be adjusted according to the type of kidney stones,” said Meyer.
Claim 3: Rooibos tea can treat allergies
A Facebook post claims that rooibos tea can treat allergies as it is a “natural antihistamine”. Antihistamines are a type of medicine used to treat the symptoms of allergies, including congestion, runny nose, sneezing, itching and skin rashes.
Jonny Peter, head of the allergology and clinical immunology division at Groote Schuur Hospital, the teaching hospital of the University of Cape Town, told Africa Check he was not aware of “convincing evidence” from human trials that showed that rooibos could be used to treat allergies.
“All of the other data that you see with various benefits in the literature relates to in vitro studies,” Peter said. This refers to studies that are done outside a living organism. He said there were also animal studies which showed some benefits.
“We think that there is potential that rooibos may have good allergenic effects. Because of this we have two trials that are in process of being implemented,” Peter said. He said any treatment would need to have specific concentrations and be standardised.
“Those two trials at the moment are under review under the regulatory body. We hoped to do them last year but Covid-19 got in the way. Hopefully this year we will get them going again.”
Claim 4: Rooibos prevents and slows down the progression of cancer
Rooibos tea is also promoted on Facebook as a way to “prevent and slow down the progression of cancer”.
“Rooibos tea contains two powerful antioxidants which prevent free radicals from forming and aid in the prevention of cancer cells developing,” Prof Janet Poole told Africa Check. She is the principal paediatrician and head of paediatric haematology and oncology at the Charlotte Maxeke Johannesburg Academic Hospital.
According to the Mayo Clinic, free radicals are “molecules produced when your body breaks down food or when you're exposed to tobacco smoke or radiation”. They can damage cells, causing illness and aging.
“Certain antioxidants in rooibos tea have been shown to kill cancer cells and prevent tumor growth in test tubes,” Poole said. “However, no human studies have confirmed these effects. Rooibos may have a role in the prevention of cancer, but there is no evidence that the tea slows down cancer progression.”
Genetics can also play a role in the development of cancer, Poole said. “There are also certain cancers such as leukaemia, lymphoma and other blood disorders that are not related to lifestyle or diet. Therefore cancer can never be totally prevented."