The Pomegranate originated from Iran and the Himalayas in Northern India. It
has edible seed surrounded by a juicy pulp. It has been found to be a good source
of potassium, vitamin C and antioxidants. One pomegranate can give around 40%
of an adult’s daily requirement of vitamin C.
Pomegranates contain high numbers of polyphenols. Polyphenols have been at
great interest as research indicates that these have antioxidant characteristics,
which may provide health benefits. The research has been concentrated on cardiovascular
disease and cancer. The majority of polyphenols found in pomegranate are hydrolysable
(capable of undergoing hydrolysis) tannins. In particular punicalagins, this
is under research as being an antioxidant responsible for free radical ability.
Unfortunately pomegranates are not readily available year round. Pomegranate
juice and extracts in capsule or bottled form are available. The antioxidants
in pomegranate juice may help to reduce the plaque build up on artery walls.
It has also shown results in experiments to reduce the oxidative stress of endothelial
cells (cells which line the blood vessels). The endothelial cells produce nitric
oxide which is a chemical which causes vasodilatation (blood vessels to relax).
Research show that when heart cells are treated using pomegranate juice, there
is a 50% increase in production of nitric oxide. It also showed that when mice
were treated with pomegranate juice there was a 30% decrease in the rate of
plaque build up. The walls of the artery have also shown to benefit from pomegranate
juice in research. It demonstrates this by protecting the walls from fatty acid
depositions due to the increase in production of nitric oxide. Oxidative stress
of the arteries may be reduced by the polyphenols. These are also found in oranges,
blueberries, oranges and grapes.
The antioxidant levels in pomegranate juice has found to be higher than that
in other natural juices, such as blueberry, cranberry, and orange juices, as
well as red wine. The equivalent amount of pomegranate juice recommended in
humans is about 16 ounces daily.
Pomegranate extracts are sometimes favored over the juice as they have no calories,
sugar or additives. Pomegranate extracts are essentially ellagic acid. This
is a main byproduct of the juice extraction process. Ellagic acid has shown
in studies that it is only absorbed by the body when consumed as ellagitannins
such as punicalagins.
There have been several human clinical trials which has shown pomegranate to
be effective in reducing:
- LDL oxidation
- Macrophage oxidative status
- Foam cell formation
All of which are steps in atherosclerosis and heart disease.
Oxidized LDL is highly atherogenic, this is due to it stimulating foam cell
formation, it is cytotoxic to cells of the artery wall. It also stimulates inflammatory
and thrombotic processes. LDL oxidation can lead to a formation of aggregate
which will further inclrease the cholestrol accumilation. All cells found in
the artery wall can oxidize LDL (including enothelial cells). Macrphage mediated
oxidation of LDL is a mark in indicating early atherosclerosis. This is dependant
on the oxidative state of LDL and of the macrophages. LDL oxidative state is
elevated by increased ratio of poly and mono unsaturated acids and its reduction
by raised levels of LDL-associated antioxodants (found in pomegranates).
Tannins (found in pomegranates) have been identified as the main constiuent
responsible for the reduction of oxidative states which lead to these risk factors.
Another benefit of pomegranate which is under research is its ability to reduce
systolic blood pressure by inhibiting the serum angiotensin converting enzyme
(ACE). Other research ahs also suggested that pomegranate may usefull against
prostate cancer and osteoarthritis.