Berry Good Health
By Susan Thorpe-Vargas Ph.D.
Multiple studies have discovered that phytonutrients found in raspberries
can protect us from cancer and can even shrink some types of cancer tumors.
These substances can also act as an antibacterial and as an antiviral
agent. Does this sound too good to be true? One particular substance found
in this natural "medicine chest", is a series of compounds called
ellagitannins. The highest levels are found in raspberries, but the ellagitannins
are also in certain types of grapes, strawberries, blackberries, blueberries
and some nuts too. Recent work (2001), published by Dr. Gary Stoner at
Ohio State University, showed that components in the seeds and berry,
but particularly ellagitannins, inhibited the initiation and promotion/progression
stages of esophageal cancer. This is an extremely important finding, considering
the potential benefits.
We do not as yet know all of the functions of the ellagitannins in terms
of cancer. A study at Hollings Cancer Center, Medical University of South
Carolina has shown one of the ways they work is to "turn on"
a normal cellular process called apoptosis. Apoptosis is "science
speak" for something called programmed cell death. This natural cell
death is just one of several ways our body protects us from cancer. As
we age, cellular replication mistakes can occur. Cancer cells somehow
become immune to the signals that cause cells to self-destruct, so they
become virtually immortal and reproduce indefinitely. Another way ellagitannins
work is to inhibit the growth of tumors. Because of the
need for an independent blood supply inhibition of angiogenesis limits
the size of the tumor to less then 2 cm.
The disease with a thousand faces
Cancer is not just one disease but is the general name for more than
200 different types of malignancies. Cancers are classified by the tissue
type from which they arise, for example:
- osteosarcoma - bone cancer
- melanoma - skin cancer
- lymphoma - cancer of lymph nodes
- leukemia - blood cancer
Every cellular type has its own form of cancer. The one thing all cancers
share in common is uncontrolled growth. Cancer occurs when cells lose
control over critical checkpoints during the process of one cell splitting
and becoming two cells. This control over cellular replication is in the
hands of several specific types of genes.
Two classes of genes are suspected of being associated with the occurrence
of cancer. A mutation in a tumor suppressor gene is like having faulty
brakes in your car. Just as their name implies, tumor suppressor genes
function by making sure there are no mistakes in the genes that are replicated
prior to one cell becoming two. In this "quality control" process,
if errors are detected, the cell is instructed not to divide. Thus, tumor
suppressor genes put the brakes on cellular division. The genes of the
other class thought to be involved with preventing cancer are called proto-oncogenes.
Researchers have found that these genes "code" for proteins
involved in mechanisms that regulate the social behavior of cells. Signals
from those cells in the immediate environment induce their neighbors to
divide, differentiate and even undergo apoptosis. So, this type of gene
is involved in promoting the normal growth and division of cells and could
be likened to your car's accelerator. A change in the genetic message
- a mutation, can turn the proto-oncogene into an oncogene and cause your
accelerator to become stuck, thus initiating "runaway" cellular
replication. Nevertheless, there seem to be no pattern to these mutations.
What is so frustrating for both researchers and clinicians alike is that
different combinations of mutations are found in different types of cancer
and even in cancers of supposedly the same type in different patients.
What is most important to remember is that cancer begins as a single abnormal
cell that begins to multiply out of control.
So, what causes most mutations?
We live in a polluted environment. For instance, the outgassing from
asphalt on a hot summer day produces the deadly carcinogen benzo{a}pyrene,
the same chemical found on meat that has been charcoal broiled. This is
just but one example. Exposure to such chemicals in the environment can
cause the mutations in our genetic material that lead to cancer. Even
normal metabolic processes like breathing and exercise produce free radicals
that can wreak havoc on our cellular DNA. We can protect ourselves from
mutations caused by environmental toxins and free radicals by taking antioxidants.
Guess what? Ellagitannins are also very good antioxidants and chemoprotective
agents. Researchers at Wayne State University have a theory about how
ellagitannins might work. The liver produces enzymes that rid the body
of toxins. These enzymes break down or chemically change toxic substances
we ingest or inhale so that they can be excreted. During this detox process,
the breakdown products, called metabolites, are frequently more damaging
then the original substance. It appears that ellagitannins are able to
safeguard the liver from damage caused by these breakdown products. Another
theory held by some investigators is that ellagitannins are able to protect
our genetic material from certain types of chemical reactions that lead
to misreading of damaged DNA.
Why does chemotherapy and radiation eventually stop working?
It is becoming clear that normal therapeutic cancer treatment works
by turning on apoptosis. We used to think that chemotherapy and radiation
killed rapidly dividing cells, which is why these procedures were able
to shrink tumors. However, at some point these treatments begin to lose
their effectiveness. Why is that? Scott Lowe, a research scientist at
Cold Spring Harbor Laboratory may have found the answer. Instead of killing
these cells, chemotherapy and radiation damage their cellular DNA. This
alerts the cell watchdogs that control the cell cycle that something is
wrong and tells the cell to stop dividing or to commit suicide. Therefore,
chemotherapy and radiation act somewhat like a "vaccination"
that works by helping the body help itself. The evidence for Dr. Lowe's
theory is pretty convincing, because when these treatments start to fail,
researchers have found that the genes that control apoptosis are no longer
functioning.
Why don't ellagitannins induce normal cells to commit suicide?
As we know, cancer cells become immortal, this means that they are able
to replicate themselves after something called the Hayflick limit has
been reached. The Hayflick limit is the number of "allowed"
cellular replications. Each cell type has its own limit. Human cancer
studies show that mutations in the tumor suppressor gene called p53 account
for many of the tumors found. One of the functions of this gene is that
it normally prevents cells with damaged DNA from proceeding through the
cell cycle. The presence of the protein product encoded by p53 turns on
the waf-1 gene. The waf-1 gene produces a protein that normally inhibits
the activity of several similar cellular proteins called kinases. These
proteins are involved in stopping cell cycle progression. A mutation in
either the p53 or waf-1 gene can cause the loss of that "emergency
brake" function and allow uncontrolled growth. However, only "damaged"
cells are induced to commit suicide and so normal cells are not effected.
An Antibacterial and an Antiviral agent
Ellagitannins can act as antibacterial agents and as antiviral agents
too, and now we know how. Think of the genetic material of bacteria as
a rubber band that is all twisted up. In order to replicate, the DNA must
untwist itself through a process requiring the enzyme gyrase. Ellagitannins
inhibits gyrase activity so replication of the bacterial DNA is restricted.
Importantly, bacteria cannot easily become resistant to this type of antibacterial
action. Resistance to antibiotics has become a real concern to the international
medical community. A federal government task force noted that antibiotic
resistance was "a growing menace to all people" but children,
the elderly and those with weakened immune systems are especially at risk.
Besides its antibacterial action, ellagitannins have antiviral activity
also. Viruses do not have the ability to replicate themselves. Instead
they must "hijack" the host cell and insert their own DNA into
the host cell genome. This requires an enzyme called integrase and the
ellagitannins inhibit this enzyme also.
Citizen: Heal Thyself. (With apologies to Mr. Hippocrates)
People are turning to alternative forms of medical treatment and prevention.
Not only is the medical delivery system failing but, our costs for health
services are rising at an astronomical rate. What this means for the medical
consumer is that we need to be more responsible for our own health. We
need to look at prevention instead of always looking to health care providers
to "fix" what exposure to a toxic environment and/or years of
unhealthy lifestyle practices have wrought. The quality of medical care
is uneven at best. Too often, our insurance providers do not cover necessary
tests and procedures, especially those of a preventative nature. However,
we can become involved in our own health care. A diet rich in fresh fruits
and vegetables is a good start towards preventing disease. Unfortunately,
current tests show that our soil is severely lacking in many minerals
or electrolytes and other components that are essential for proper nutrition.
It is necessary to sometimes take supplements as it may not be physically
or economically possible to eat enough food to get the proper nutrition.
In addition, the cost of fresh fruits and vegetables can be prohibitive.
For instance, unless you grow your own raspberries, the cost of the American
Cancer Institute's recommended daily bowl of the whole berries could
run as high as $300 a month. Not only that, but research has shown that
the ellagitannin content is much higher in the seeds then in
the fruit. So nutraceutical supplements may be the answer. Raspberry
seeds contain many more times the ellagic acid than the fruit at one-tenth
the cost. It's your choice, whatever form you may decide to use- the
take home message is: "Eat your ellagitannins!"
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