The Straits Times (12 February 2015) - Some types of roselle
are used to promote
cardiovascular health.
Roselle flowers are used
in traditional
Chinese
medicine
to treat
hypertension
and high
cholesterol.
WHAT IS IT
Roselle is a species of
hibiscus native to West Africa.
In Iran, it is typically known as
sour tea; in English-speaking
countries, it is called red sorrel.
It is commonly used to make jelly,
jam, juice, wine, syrup, gelatin,
pudding, cake, ice cream and
flavouring.
Originally from Angola, it is now
cultivated throughout tropical and
sub-tropical countries, such as
Sudan, Egypt, Thailand, Mexico and
China.
There are three types of roselle,
identified by their colours – the dark
red type has the highest content of
anthocyanins, followed by the light
red type, while the green type has
only traces of the antioxidant pigment
or none at all, reported the Journal Of
American Science in 2010.
Anthocyanins are said to promote
cardiovascular health.
Roselle flowers, whether fresh or
dried, have similar levels of efficacy,
said Madam Catherine Cheung, a senior acupuncturist at the
Complementary Integrative Medicine
Clinic at Tan Tock Seng Hospital.
The flowers should be whole and
free of contamination during
purchase, she advised.
A 100g packet of dried roselle
flowers costs $4 at some medical
halls here.
HOW TCM USES IT
The sour roselle
flower is cold in nature.
This makes it suitable for clearing
“heaty” symptoms associated with
hot and humid weather, such as a
sore throat, a dry mouth, thirst, dry
stool and yellowish urine, she said.
It is thought that the diuretic effect
of roselle flowers helps remove heat
from the body.
In traditional Chinese medicine
(TCM), excessive consumption of
high-calorie food affects the digestive
functions of the spleen and stomach,
said Madam Cheung.
In addition, when there is
deficiency of yin (the element
responsible for cooling organs) in the
kidneys and liver, heat builds up in
the body and hinders blood flow.
Poor functioning of these organs
causes phlegm and other unwanted
substances to accumulate in the
body, disrupting the proper
circulation of blood and qi.
A person with poor qi or blood flow
will experience symptoms, such as
a red face, heart palpitations,
numbness in the limbs, and would
get agitated and tired easily.
That is why he may also have high
cholesterol levels or blood pressure,
said Madam Cheung.
WHO IT IS FOR
People with neutral
or “heaty” bodies can benefit from
taking a “cold” herb, such as roselle
flowers, to balance their body
constitutions, said Madam Cheung.
It is also suitable for those with
hypertension and high cholesterol.
The latest National Health Survey
in 2010 found that 23.5 per cent of
Singapore residents had
hypertension and 17.4 per cent had
high cholesterol.
One should consume no more
than 3g of roselle flowers a day, said
Madam Cheung.
WHO SHOULD AVOID IT
People with
a weak stomach and spleen, which is
marked by a bloated abdomen,
diarrhoea and a poor appetite,
should avoid taking cold herbs.
The same is true for pregnant
women and those having their
periods, said Madam Cheung.
Taking sour herbs, such as roselle
flowers, will also aggravate the
symptoms of people with stomach
ulcers, she added.
WHAT RESEARCH HAS SHOWN
Daily consumption of a tea or extract
produced from roselle flowers has
benefits for adults, according to a
review of human and animal studies
published in the journal for the study
of medicinal plants, Fitoterapia, in
March 2013.
Specifically, it helped to
significantly lower one’s systolic and
diastolic blood pressure in people
with pre- to moderate primary
hypertension and type 2 diabetes,
based on results from randomised
controlled trials.
In addition, the tea was as
effective at lowering blood pressure
as the drug Captropril, but less
effective than another drug,
Lisinopril. Both drugs are used to
treat high blood pressure.
More than half of the trials
showed that daily consumption of
roselle tea or extracts improved
one’s lipid levels.
Namely, it lowered participants’
levels of total cholesterol, low-density
lipoprotein or “bad” cholesterol, and
triglycerides. At the same time, it
boosted their levels of high-density
lipoprotein or “good” cholesterol.
The observations were likely a
result of the antioxidant effects of
the anthocyanins. These compounds
inhibit the oxidation of “bad”
cholesterol, hence impeding the
development of atherosclerosis
(hardening of the arteries), which can
lead to cardiovascular disease.
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Source: The Straits Times © Singapore Press Holdings Limited. Reproduced with permission.
