Clinical Trial Shows Cardiovascular Benefits of Rooibos, Popular Antioxidant Herbal...

Clinical Trial Shows Cardiovascular Benefits of Rooibos, Popular Antioxidant
Herbal Tea from South Africa

AUSTIN, Texas, Sept. 10 /PRNewswire-USNewswire/ -- The first-ever human
clinical trial on a popular traditional South African herbal tea was recently
conducted, testing whether the tea can possibly lower the risk of
cardiovascular disease.

The new trial also generated the first human safety data in a controlled
clinical trial environment, scientifically showing that short-term consumption
of rooibos tea is safe for the liver and kidneys while keeping various blood
parameters (e.g., blood pressure, cholesterol levels, etc.) in a normal
range.(1)

Provisional results from this study indicate that rooibos tea protects the
body against oxidative damage, as seen by the approximate 21% decrease in
conjugated dienes in the blood. Conjugated dienes are products formed in large
numbers during the early stages of oxidation (destruction) of important
cellular components such as fats (lipids). These lipid peroxidation products
may be implicated in the development of vascular disease.

The trial (entitled "Modulation of blood oxidative stress markers and DNA
damage by rooibos tea in volunteers at risk for coronary heart disease") was
conducted by Jeanine L. Marnewick, Ph.D., senior researcher at the Oxidative
Stress Research Centre at Cape Peninsula University of Technology in Cape
Town, South Africa.

The trial was conducted on 40 individuals (males and females), between the
ages of 30 and 60, from the Western Cape Province with any two or more of the
following cardiovascular disease risk factors: hyperlipidemia (high
cholesterol), hypertension (high blood pressure), smoking, and/or increased
body mass index (BMI: 25 or higher), but not requiring any oral medication for
these medical conditions. The actual risk of each participant was determined
using a calculation based on the famous multi-year Framingham heart disease
trial based on the patient's age, gender, smoking status, blood pressure,
triglycerides and HDL cholesterol (so-called "good cholesterol"). A person
with two major risk factors has a risk of heart disease or stroke six times as
great as a person with no risk factors. With three factors, the risk of
cardiovascular disease is 20 times as great.

Participants in this trial were required to consume six cups of rooibos tea
per day for six weeks with the six-cup intake spread across the day. In order
to maintain a high degree of consistency, the preparation of the rooibos tea
was standardized as 2% weight of dried rooibos tea to volume of water, with
each cup consisting of one rooibos tea bag with the addition of 200 mL of
boiling water (equal to about 7 ounces, slightly less than 1 cup), brewing for
5 minutes before consumption. Subjects consumed the rooibos with or without
milk and/or table sugar, as previous research on green and black teas (from
the tea plant, Camellia sinensis) have demonstrated that milk does not
eliminate the increase in plasma antioxidant activity in humans. (2) (The
class of beneficial antioxidant chemicals found in rooibos, black and green
tea, and chocolate are called flavonoids; the flavonoids in rooibos are
different from those in tea and chocolate.) The six-cup amount of rooibos
consumed by participants in this trial was based on a human trial published in
2003 where the consumption of six cups of green tea increased the antioxidant
capacity in the blood of human subjects.(3)

In a study of this type, it is important to modify the diet of participants in
order to remove the consumption of other flavonoid-rich foods which may
confuse the study results. To do this, the participants were requested to omit
flavonoid-rich beverages (red wine, black or green tea and/or herbal teas,
coffee, fruit juices, etc.) and to restrict flavonoid-rich foods (grape
products, citrus fruits and their juices, berries and their juices, apples,
onions, broccoli, etc.) from their diet for two weeks before initiation of the
intervention study. (Analysis of participants' fasted blood and urine samples
taken after this period served as a baseline standard to help determine the
extent of participant compliance with the study guidelines.)

As a quality control for the rooibos, a large quantity of rooibos of the same
batch was obtained from Rooibos Ltd., the major rooibos producer and supplier
in Clanwilliam, South Africa. To ensure consistent quality the researchers
took random samples of the rooibos from this one large batch and analyzed them
for key chemical compounds (e.g. flavonols) and antioxidant capacity.

The clinical trial design and some of its initial results were announced in a
presentation by Dr. Marnewick at the World Tea Expo in Las Vegas, Nevada in
May. The trial paper will be submitted to a medical journal for publication
after all the statistical data has been fully analyzed, probably by the end of
this year.

"Despite its long history of traditional use in South Africa and growing
popularity around the world as a tasty and healthful beverage, this is the
first time that rooibos has been subjected to a tightly controlled human
clinical trial to determine its potential benefit in reducing cardiovascular
disease factors," said Mark Blumenthal, founder and executive director of the
American Botanical Council, the leading nonprofit organization dealing with
herbs, medicinal teas, and related plant-based ingredients.

"With cardiovascular disease being the biggest killer of people in North
America and elsewhere in the world, this study's preliminary positive results
may help increase the relevance of rooibos as a beneficial beverage for
consumers and healthcare providers seeking safe, low-cost ways to reduce
cardiovascular disease risk," he added.

Members of the tea industry welcomed the preliminary research findings. "We
are extremely excited about the preliminary results of this clinical trial,"
says Hugh Lamond from Herbal Teas International of Anaheim, California, the
largest distributor of rooibos in North America. "The trial appears to confirm
the anecdotal promise for rooibos in fighting heart disease and reducing
oxidative stress in humans. As a result, we expect a huge boost in the
worldwide consumption of rooibos in the coming years."

The research was conducted at the following South African institutions: Cape
Peninsula University of Technology and the University of Cape Town. Funding
was provided by Cape Peninsula University of Technology, THRIP National
Research Foundation, and the South African Rooibos Council.

Note: The American Botanical Council advises that with all scientific and
clinical research that has yet to be published in a peer-reviewed journal, the
preliminary announcement of trial results and related statistics may
eventually be modified as a result of the peer review process. Thus, some of
the data reported in this news release are subject to revision upon
publication of this trial.

About Rooibos

Rooibos (Aspalanthus linearis) in the pea family (Fabaceae) is a popular
beverage from South Africa. The name comes from the local Afrikaans name for
"red bush," referring to the red-auburn color of the plant material, which
changes after it is harvested and allowed to ferment. The pleasant-tasting
red-colored beverage is high in antioxidant compounds, which have been shown
to be beneficial for cardiovascular health, among other benefits. Rooibos does
not contain any natural levels of caffeine. A comprehensive review of the
history and scientific publications of rooibos was published in the American
Botanical Council's quarterly journal, HerbalGram (issue #59)
(http://cms.herbalgram.org/herbalgram/issue59/article2550.html) in 2003.

About the American Botanical Council

Founded in 1988 the American Botanical Council is the leading nonprofit
organization in North America addressing research and educational issues
regarding herbs, medicinal teas, essential oils, and other plant-based
ingredients. ABC's members include academic researchers and educators,
universities and libraries, health professionals and medical institutions,
botanical gardens and arboreta, government agencies, members of the herb,
dietary supplement, cosmetic, and pharmaceutical industries, journalists,
consumers, and other interested parties from over 70 countries. ABC occupies a
historic 2.5-acre site in Austin, Texas where it publishes HerbalGram, a
peer-reviewed journal on herbal medicine; a monthly e-newsletter,
HerbalEGram(TM); plus HerbClip, a twice-monthly literature service summarizing
and reviewing recently-published clinical and scientific literature; and
reference books and other educational materials dealing with herbal
therapeutics and quality control. Information: Contact ABC at P.O. Box 144345,
Austin, TX 78714-4345, Phone: 512-926-4900. Website:
http://www.herbalgram.org/.

References
1. Marnewick JL. Rooibos Power. World Tea Expo, May 31, 2008.
2. Leenen R, Roodenburg AJ, Tijburg LB, Wiseman SA. A single dose of tea with
or without milk increases plasma antioxidant activity in humans. Eur J Clin
Nutr. 2000;54(1):87-92.
3. Rietveld A, Wiseman S. Antioxidant effects of tea: evidence from human
clinical trials. J Nutr. 2003;133(10):3285S-3292S.

Editor's Note: ABC Founder & Executive Director Mark Blumenthal is available
for interviews. Please contact Lucy Bruno.

SOURCE American Botanical Council

Lucy Bruno of American Botanical Council, +1-512-926-4900 x121, Fax:
+1-512-926-2345, marketing@herbalgram.org