Special
brew
Until
recently the best cancer prevention advice has been: don't smoke, don't get fat,
and cross your fingers. But a strange-tasting drink from South Africa could
provide new hope, as Rory Carroll reports
The Guardian
Tuesday
August 31, 2004
http://www.guardian.co.uk/
Scientists say there are three major ways to cut the risk of cancer. Don't
smoke, don't become fat, and follow a balanced diet. Now from South Africa comes
a potential fourth tip: drink rooibos tea. If you have never heard of it, you
are not alone. Rooibos has been one of the more esoteric products in the
herbal-remedy section of health shops, a strange-sounding name to match a
strange taste drawn from the needle-like leaves of a plant found only on the
slopes of the Cederberg mountains outside Cape Town.
For
centuries, indigenous bushmen have sworn by the health-giving properties of the
tea. European settlers who picked up the habit agreed there was something
special about rooibos - Afrikaans for red bush - and even bathed their children
with it. Now science suggests they may have been on to something. New research
provides tantalising evidence that the tea can help ward off cancer. Rats and
mice that drank it were found to have effective protection against a variety of
cancers.
There is no proof yet that humans benefit, but makers are anticipating increased
demand, with the likes of Tetley's, Twinings and Taylor's introducing ranges.
Boxes are popping up in Tesco, Waitrose, Sainsbury and Boots. Coca-Cola is
rumoured to be preparing to get in on the act with a rooibos-flavoured iced tea.
"I'm pretty confident it will protect humans from environmentally and
dietary-induced cancer, but to what extent isn't clear yet," said Dr
Jeanine Marnewick, a biochemist leading a rooibos study at South Africa's
Medical Research Council. She thinks extracts might one day be included in sun
creams, and that the version you drink could be classified a drug rather than a
refreshment. Clinical trials are years away, but Marnewick is not waiting that
long: "I now drink about a litre a day, five or six cups."
Aspalathus linearis, to give the plant its Latin name, is in fact a legume, not
a tea in the conventional sense. Laboratory tests show the rich level of
antioxidants help rodents prone to cancer by "scavenging" the
free-radical molecules which attack their cells. In other words, rooibos boosts
the body's ability to prevent the disease by increasing detoxifying liver
enzymes and arresting, or at least slowing down, DNA mutation ("antimutagenic
activity").
"If the presence of these reactive cellular components is not controlled,
damage to the genetic material of the cell may occur, resulting in an increased
risk of cancer. An optimal balance of antioxidants is needed to strengthen the
body's defence in controlling the level of these cancer-causing free
radicals," said Marnewick.
Researchers first tested rooibos in a test tube and found that it inhibited 90%
of bacterial DNA mutations. The next stage was to put the tea in rats' drinking
water for 10 weeks, after which a sample of their livers was added to a
bacterium exposed to a toxic chemical. Again, the mutations were inhibited. This
showed that rooibos was available to and absorbed by the body and responsible
for the protection, said Marnewick.
The next step was to test rooibos using a cancer model. Mice were divided into
two groups, with one group treated with rooibos and the other water. Cancer was
induced in all. Photographs taken weeks later tell a dramatic story: those
denied the tea developed angry-looking lesions on their skin, known as
papillomas.
These studies are due to be published in separate articles in international
journals later this year. Meanwhile, the scientists in Cape Town are preparing
new experiments with rats to see if the tea helps prevent liver, colon and
oesophagus cancer. After that they hope to start clinical trials with humans.
Dr Richard Sullivan, head of clinical programmes at Cancer Research UK, welcomed
the research as a potentially valuable contribution to fighting the disease.
"Green and black herbal teas also boast high levels of antioxidants but
rooibos has the advantage of being free of caffeine. That makes it close to zero
toxicity, and so the plant could turn out to be a safer, more effective form of
chemo-prevention than synthetic alternatives," he said.
But Sullivan cautioned that there were "legions" of substances that
cured cancer in rats but did nothing for humans, and that clinical trials would
require monitoring thousands of volunteers over more than a decade. In any case,
even if proven to be a cancer-fighter, rooibos would not compensate for smoking,
obesity and a poor diet. "Having a cup with a cigarette would not balance
out," he said.
Such caveats do not dampen enthusiasm in the highlands of Western Cape, a
wilderness of sandstone outcrops where bushmen have harvested rooibos for
centuries to treat a range of ailments. British and Dutch settlers created
plantations, but the harvesting methods - chopping the branches with axes,
bruising the leaves with hammers and leaving them in piles to ferment and dry in
the sun - remained more or less the same.
Western Cape is one of the world's most biodiverse areas and nowhere else do
climate and soil so lend themselves to rooibos. The first brewed beverage was
recorded by a botanist in 1772, but it was not until 1904 that a Russian
immigrant, Benjamin Ginsberg, decided to export it. South Africa's love affair
with rooibos deepened when a young mother, Annique Theron, published a book in
1974 celebrating its healing powers on her son and other children.
Today 13,000 hectares are under cultivation, yielding around 8,000 tonnes
annually of which just under half is drunk in South Africa and the rest exported
mostly to Germany, Japan and the Netherlands. Sales in the US have been stymied
by a court battle with an American firm which trademarked rooibos as its own
brand.
Britain is the fourth biggest export market, consuming 188 tonnes last year, a
leap from 72 tonnes in 2001. "It started with the health and organic
drinkers but is now entering the mainstream," said Bruce Ginsberg, a
London-based importer and grandson of the Russian immigrant. "But it's
never going to be a major player like PG Tips because it's very hard to grow. It
will always be a minority drink." A box of 40 rooibos bags usually sells
for under £2.
Though rooibos producers partly financed Marnewick's research - she insists it
is a small proportion and does not compromise her independence - they are
reticent about plugging the tea's potential as a cancer-beater. This is partly
because US and European regulations prohibit medicinal claims without firm
clinical evidence. Packaging can refer to richness in antioxidants and absence
of caffeine but cannot boast of healing powers.
"You don't want to be a snake-oil salesman. You have to be able to back up
what you say," said Dawie de Villiers, managing director of Cape Natural
Tea Products. He cited a Fijian tea that suffered a backlash after hyping its
health properties. Besides, Rooibos producers do not want their product viewed
as medicine. "That could increase the value of the product but narrow the
market. We want people to regard it as a pleasant drink," said De Villiers.
But the taste is an acquired one. A pair of British expatriates in Cape Town
grimaced at the mention of rooibos: "Wet socks in wellington boots. We
don't touch the stuff." Other critics are equally scathing, saying it would
have to be proven to beat cancer, enhance sex appeal and make you rich to pass
their lips.