Garcinia cambogia
is the
plant commonly referenced as
garcinia, citirn, cambooge or
Tamarind, and is a member of the Clusiaceae family.
It is
native to Southeastern Asia where it
has been used for centuries as a
food preservative, flavoring agent
and carminative. The fruit of the
plant is yellow, about the size of
an orange, and has a thin skin with
deep furrows. [1] The rind of the fruit is
the part of the plant emplyed for
various medicinal applications.
Garcinia does not have
a long history of use in Western
Herbalism, but has gained interest
due to its effects on fat metabolism
and appetite suppression.
The principle
constituent in garcinia is
hydroxycitric acid (HCA), or hydroxycitrate. This important
component makes up 10 - 30% of the
dried fruit rind. Garcinia is
discussed essentially in terms of
hydroxycitrate, with the majority of
research focusing on this chemical
compound. Garcinia also contains a
significant amount of beneficial flavonoids.
The exact mechanisms
of action for hydroxycitrate's
effect on physiologic and metabolic
processes are not fully known. Early
studies showed that it inhibits the
formation of fat in animals. [2,
3] HCA was
shown to be a potent inhibitor of
ATP citrate lyase, an enzyme that
catalyzes the extramitochondrial
cleavage of citrate to oxaloacetate
and acetyl-CoA:
-
citrate + ATP + CoA
--> acetyl-CoA + ADP + P(i) +
oxaloacetate - [4]
The significance of this metabolic
reaction is that inhibition limits
the availability of acetyl-CoA units
required for fatty acid synthesis
and lipogenesis; especially when a diet high in
carbohydrates is consumed. Furthermore, extensive animal
studies indicated that (-)-HCA
suppresses food intake and may
actually induce weight loss. [4,
5]
Hydroxycitrate also
appears to exert effects on
processes other than fuel
metabolism. One study in rats showed
that hydroxycitrate can inhibit
[3H]-5-HT (hydroxy-tryptophan)
uptake, while also increasing 5-HT
availability in isolated brain
cortical slices; similar to the way SSRIs (selective serotonin reuptake
inhibitors) work. The authors
conclude that these effects may be
applicable in controlling appetite,
as well as treatment of depression,
insomnia, migraine headaches, and
other serotonin-deficient
conditions. [6]
A novel derivative of
hydroxycitrate, called Super
Citrimax or HCA-SX, has been
commonly used in research studies. It appears to be safe when taken
orally and has demonstrated bioavailablity in human plasma when
studied by gas chromatography-mass
spectrometry. [7]
As mentioned, most of
the research on garcinia has
been linked to its effect on curbing
appetite and inhibiting body fat
biosynthesis. The majority of
studies have been conducted either
in vitro or in vivo
using animal models. There are, yet,
few positive articles published in
human subjects that are large enough
and designed well enough.
Data from animal
studies suggest Garcinia may
be of benefit in disorders of
glucose metabolism and also obesity. Garcinia and the isolated
hydroxycitrate have demonstrated
favorable effects on glucose,
insulin, and lipid metabolism in
animal studies. A study in mice
given a 3.3% Garcinia cambogia
extract demonstrated reduced levels
of serum insulin and leptin, as well
as the leptin/WAT ratio, versus
control. [8] Furthermore, glucose metabolism was
improved and leptin-like activity
was exhibited. Another animal study
showed that hydroxycitrate
suppresses de novo lipogenesis and
may improve glucose tolerance. [9]
The derivative
compound, Citrimax or HCA-SX, proved
to be effective in restricting body
weight gain in adult rats. The
results of another animal study showed that at doses relevant for
human consumption, dietary HCA-SX
significantly contained body weight
growth. Again, in this study leptin
levels were affected. However, in
this particular case study, lowered abdominal fat leptin expression was observed while
plasma leptin levels remained
unaffected. This study also
identified a small set
(approximately 1% of all genes
screened) of specific genes found in
fat tissue that are sensitive to
dietary HCA-SX. Vital genes for
transcribing mitochondrial/nuclear
proteins were not affected. The
results also showed that HCA-SX-sensitive
genes upregulated genes encoding
serotonin receptors, which is unique
to this compound. [7]
The one
well-designed, double-blind,
placebo-controlled study of the
use of garcinia in humans that
has been published was not
supportive. [10] This study found that garcinia was
no more effective than placebo for
overall body weight and/or fat weight
loss. Problems with the experimental
design include lack of measurement
of appetite suppressant effect or
the bioavailability of hydroxycitric
acid to the bloodstream, as well as
the use of a high fiber diet that
may have influenced bioavailability
of HCA. [11]
A review of natural products for
obesity concluded that the best
available human data indicates that
this garcinia is no more effective
than placebo. [12]
A novel application
for garcinia is in the
treatment of peptic ulcers. A study
in rats that were pretreated with a
G. cambogia fruit extract (1
g/kg body weight/day at interval of
7 and 15 days) demonstrated a
protective effect on gastric mucosa
against HCl-ethanol induced damage. The extract decreased the volume and
acidity of gastric juice. The
authors conclude that due to garcinia's ability to decrease
acidity and increase mucosal defense, it is a potential anti-ulcer agent. [13] Another study showed similar results
with indomethacin induced gastric
damage. [14]
Garcinia, in
combination with some other
botanicals, has also demonstrated
lipid lowering activity in rats. In
one study, flavonoids from Cocos
nucifera, Myristica fragrance,
Saraka asoka and Garcinia
cambogia exerted maximum
hypolipidaemic activity at a
flavonoid level of 10 mg/kg BW/day
from Garcinia cambogia. Interestingly, higher doses were
less effective in reducing lipid
levels in serum and tissues, which
were shown not to exert toxicity. [15]
In addition, garcinia
may aid endurance during
post-absorptive aerobic exercise by
promoting gluconeogenesis; may be
beneficial in hypertension,
dyslipidemias, diabetes mellitus, and
metabolic syndrome. As
previously stated, its most popular
application remains in controlling appetite, as
well as in treatments of depression,
insomnia, migraine headaches, and
other serotonin-deficient
conditions. [16,
17,
6]
Dosages are always
dependent on the preparation. Most
of the research has been conducted
in animals, so doses that are
effective in humans have not yet
been fully determined. However, a
typical dose of hydroxycitrate is
500 milligrams, three times daily .[1] As well, a low fat diet should be
maintained when taking this
supplement for weight loss.
|
Garcinia Toxicities and
Contraindications |
Long-term toxicity
studies in humans are lacking. Most
of the data on toxicity of
Garcinia extracts comes from
animal research. A review published
in 2004 stated that acute oral
toxicity studies in animals
demonstrate that CitriMax (50% HCA
as calcium salt) has a low acute
oral toxicity. Doses up to 2500
mg/kg/day in rats for a period of 90
days caused a significant decrease
in body weight and reduction in feed
consumption without any adverse
effects. [18]
Additionally, the authors of this
recent research review concluded
that based on its structure,
mechanism of action, and long history
of use, HCA is unlikely to cause
reproductive or developmental
effects. The animal study
demonstrated that the 90 day
treatment with HCA-SX (CitriMax)
does not cause any changes in major
organs or in hematology, clinical
chemistry, and histopathology. [19]
One case report of
rhabdomyolysis following the
ingestion of a weight-loss herbal
medicine, containing Garcinia
cambogia, in an otherwise
healthy 54-year-old woman has been
published. [20] Serum creatine kinase (CK) was
elevated. The condition resolved
when the supplement was
discontinued. As this was a
combination product, it is unknown
which component was causative.
The following table lists various
products that contain a safe and
reliable source of Garcinia:
|
Manufacturer |
Ingredient |
Amount |
US RDA |
Learn More |
|
Optalife Nutrition |
Garcinia Cambogia |
-- |
-- |
Click Here
|
|
Rainbow Light
|
Garcinia cambogia |
2400mg |
-- |
Click Here
 |
