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Antioxidants
– The Key to Long Life
You
are only as old as your cells.
Research shows that cells are only allowed so many cell divisions in
a human lifetime before they would have to give out. Based on their
findings, scientists say that by the time you are 20 years old, most
of the cells that make up your body have already used up half of
their available cell divisions in their cell lifespan. That means by
the time you are 40, your cells may only have 30 per cent of cell
divisions left. This is actually the reason behind the physical
changes that goes on not only inside but outside the body as you
approach your years.
When
your cells finally use up their naturally allotted cell divisions,
the result is death. It is an inevitable occurrence and there’s no
stopping it. There is however a way to retard it though. Recent
research has found a way to give you new hope, a way to rejuvenate
and extend the lifespan of cells.
What causes aging?
Much
of scientific research these days are focused on finding a solution
to aging. The aging process brings with it not only wrinkly skin or
tired joints and muscles. Those can be tolerated. After all, they
are part of the natural cycle of life. But what isn’t natural is
disease. They are disorders – unnatural conditions of the body.
Aging
is caused by harmful molecules called “free radicals.” This was
according to Denham Harman, M.D., Ph.D., who first proposed the
theory in the 1950s. Since then, scientists and researchers have
sought to understand the body’s oxidation process and free radicals
contribute in its acceleration.
There
is growing evidence that the production of reactive oxygen species (ROS),
including free radicals, is behind the aging process and initiation
of age-related disease. The more free radicals you have in your
body, the faster the aging process becomes.
Free radicals
are harmful, unstable substances (rogue oxygen molecules) that
develop after oxidation, which is a naturally occurring process of
the body. Free radicals are not harmful in themselves. In fact, they
can be beneficial. The problem lies in the fact that free radicals
are damaged molecules, which means that they are missing one
electron.
Now,
it is but natural for molecules to want to get their full complement
of electrons, but in order to do that, they would have to “steal”
them from other molecules surrounding them. Free radicals therefore
react with other molecules, leading to the latter’s damage.
Depending on the circumstances, this tendency of free radicals to
react can be good, but only if the molecules they react with are
harmful. The trouble is free radicals do not distinguish between
healthy and harmful molecules so that there is a great possibility
that they would also “attack” your other healthy cells, causing
massive cellular damage, tissue damage, and eventually resulting in
a chronic disease or disorder that includes not only aging, but
something more serious like cancer.
It is
impossible for us to avoid damage by free radicals. Free radicals
arise from sources both inside (endogenous) and outside (exogenous)
our bodies. Oxidants that develop from processes within our bodies
form as a result of normal aerobic respiration, metabolism, and
inflammation. Exogenous free radicals form from environmental
factors such as pollution, sunlight, strenuous exercise, x-rays,
smoking, and alcohol.
The
human immune system and antioxidant activity becomes weaker and less
efficient with age. This reduced effectiveness in turn helps to
explain the rising incidence of cancer and life threatening
infections in older people.
In
their focused attempts to find a solution to aging and other chronic
diseases, scientists have finally made a breakthrough with the
discovery of the anti-aging properties of antioxidants.
What are antioxidants?
Antioxidants
are chemical substances found in nature. They are part of a group of
vitamins, such as vitamin C, vitamin E, vitamin A (beta-carotene),
etc., and nutrients like selenium, lutein, and lycopene.
Functions
Oxygen damage (oxidation) to your cells results when there are too
many free radicals present inside the body. Researchers surmise that
such damage may be partly responsible for the effects of aging and
certain diseases. How then does the human body cope?
The
question led scientists to discover the existence of certain
substances in food that may play a role in protecting against such
damage. By donating electrons to stabilize and, in effect,
neutralize the harmful effects of the free radicals,
antioxidants can block this damage.
How they work:
Ultimately, what antioxidants do is to block the process of
oxidation by neutralizing free radicals. In doing so, the
antioxidants themselves become oxidized. That is why there is a
constant need to replenish our antioxidant resources.
Antioxidants work in a two-way process. First is the
chain-breaking process.
When
a free radical releases or steals an electron, a second radical is
formed. This molecule then turns around and does the same thing to a
third molecule, continuing to generate more unstable products. The
process continues until termination occurs – that is, when either
the radical is stabilized by a chain-breaking antioxidant such as
beta-carotene and vitamins C and E, or it simply decays into a
harmless product.
The
second process is more on the preventive side.
Antioxidant enzymes like superoxide dismutase, catalase, and
glutathione peroxidase prevent oxidation by reducing the rate of
chain initiation. This time, instead of waiting for the free
radicals to make a long chain of free radicals, antioxidants
scavenge initiating radicals and destroy them before oxidation is
set in motion. They can also prevent oxidation by stabilizing
transition metal radicals such as copper and iron.
The
effectiveness of any given antioxidant in the body depends on which
free radical is involved. It may also depend on how and where the
free radical is generated and where the target of damage is. That is
why you may find that some antioxidants work well in one particular
system but may not protect against free radicals in a completely
different system.
Worse
still, an antioxidant may even act as a “pro-oxidant” that
generates toxic oxygen species in certain circumstances.
Types of Antioxidants
There
are several types of antioxidant nutrients that our body needs in
order to control free radical damage in our cells. Each of these
nutrients is unique in terms of its structure and antioxidant
function.
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Vitamin E
is actually a generic term that refers to a group of nutrients
(8 have been found so far). These nutrients all exhibit
biological activity of the isomer tocopherol (NOTE: An
isomer is one of two or more molecules that have the same
chemical formula but different atomic arrangements). |
The
most widely available isomer is alpha-tocopherol. It has the highest
biopotency, or strongest effect in the body. And because it is
fat-solubl
e, it is in a unique position to safeguard cell membranes
– largely composed of fatty acids – from damage by free radicals.
Alpha-tocopherol also protects the fats in low-density lipoproteins
(LDLs, or the “bad” cholesterol) from oxidation.
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Ascorbic acid, also known as Vitamin C, is a
water-soluble vitamin and one of the most commonly found
antioxidants. Its prime function is to scavenge free radicals
that are in an aqueous (watery) environment, such as inside your
cells. Vitamin C has a synergistic effect with Vitamin E, which
means that both work together to quench free radicals. Vitamin C
also regenerates the reduced (stable) form of Vitamin E. |
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Out of the 600 carotenoids identified to date,
Beta-carotene (also known as Vitamin A) is the most
widely studied. As a water soluble vitamin, it is similar to
Vitamin C in that it acts by quenching singlet oxygen (an
energized but uncharged form of oxygen that is toxic to cells).
Beta-carotene is also excellent at scavenging free radicals in
low oxygen concentration. |
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Selenium
is a trace element and a mineral. We only need very small
quantities of selenium, but without it we could not survive.
This is because selenium forms the active site of several
antioxidant enzymes including glutathione peroxidase. |
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Similarly, the minerals Manganese and Zinc
are trace elements that form an essential part of various
antioxidant enzymes. |
Other Antioxidants
In
addition to antioxidants we mentioned above, there appear to be many
other nutrients and compounds that have antioxidant properties.
Among them are the following:
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Superoxide dismutase (SOD), catalase (CAT), and glutathione
peroxidase (GPx), all of which serve as your primary line of
defense in destroying free radicals. |
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Coenzyme Q10 (CoQ10, or ubiquinone) – essential to energy
production and can also protect the body from destructive free
radicals |
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Uric Acid – a product of DNA metabolism that has increasingly
been recognized as a powerful antioxidant |
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Phytochemicals – found in plants with antioxidant properties and
health-promoting potentials |
Proven Key to Long Life
For
the past ten years, since they discovered the link between free
radicals and degenerative diseases such as cancer, researchers have
focused on the beneficial properties of antioxidants and the
important role they play in possibly prolonging human life.
According to US scientists, boosting the body’s levels of natural
antioxidants could be the key to a long life. Numerous studies in
simple organisms, such as yeast, worms, and flies have supported
this theory by showing that enhancing production of natural
antioxidants can extend life. However, evidence that antioxidants
can slow the aging process in mammals has been less convincing.
Of Genes and Mice
To investigate whether increased concentrations of
natural antioxidants give mammals longer lives, Peter S. Rabinovitch
of the University of Washington in Seattle and his colleagues came
up with a study involving genetically engineered mice. The mice were
purposely engineered to over-express a gene responsible for making
the antioxidant called catalase.
Normally, the catalase that a cell makes goes directly into
organelles known as peroxisomes. What Rabinovitch and his
colleagues did was to design a genetic manipulative process so that
in some of the mice, the extra catalase went into its normal
location while in the rest of the mice, the extra catalase went into
the cell nucleus.
A
third group of the engineered mice directed the enzyme into the
mitochondria, the cell’s energy-producing organelles. As a side
effect of converting food into energy, mitochondria produce most of
an organism’s free radicals.
The
study showed no difference in life span between normal animals and
those engineered to keep the extra catalase in the nucleus. And
those mice engineered to direct catalase to its usual place, in
peroxisomes, showed only a modest increase in life span.
Rabinovitch and his colleagues, however, found that animals that
guided catalase to mitochondria lived significantly longer than
normal mice. In fact, the process seemed to add about 5 months to
their normal 3-year life span.
When
the researchers dissected some of the mice, they found early signs
of age-associated disease, such as cataracts and heart disease, at
later ages in the long-lived, engineered mice than in the others.
This showed that mice engineered to produce high levels of an
antioxidant enzyme have a life span that is 20% longer than those of
normal mice.
Results of the study also showed that they had less heart and other
age-related diseases.
If
the same is true among humans, then it’s possible that people could
live beyond 100 years.
The Power of Reishi
In a
thoroughly different study, Reishi, a Chinese mushroom
(also known as Ganoderma lucidum, Lingzhi, or Ling Zhi), was shown
to cause a significant post-ingestion increase in plasma antioxidant
capacity with peak response at 90 minutes. This means that Reishi
can cause increase in urine antioxidant capacity in just 3 hours.
Published in 2004 by the International Journal of Food Sciences and
Nutrition, the results of the study indicate that Reishi intake
causes an acute increase in plasma antioxidant capacity.
Reishi is a powerful antioxidant. In another laboratory study,
Reishi significantly elevated the free radical scavenging ability of
blood and was so strong that even after the Reishi extract was
absorbed and metabolized the scavenging effect still continued.
Dr.
Vladimir Kupin of the Cancer Research Centre in Moscow found a
compound in Reishi called GLB 7 which served as the
main proponent in decreasing the production of oxygen free radicals.
This makes Reishi more effective as a free radical scavenger than
isolated refined compounds.
A
laboratory study with fruit flies also showed just how powerful an
antioxidant Reishi is. The flies, which have a very similar genetic
make up to humans, were used in experiments to prove that Reishi
significantly lengthened the life span of those that had been fed
Reishi compared to controls.
Supplements
Even
though most damage caused by free radicals is repaired, a fraction
may still remain. This is not at all helped when we constantly
expose ourselves to ultraviolet radiation from the sun and airborne
pollutants such as cigarette and smoke.
Eventually, the damage may overwhelm the body’s natural defenses so
that not even intake of antioxidants from our diet can protect
against damages. Soon, our bodies develop reactions that accumulate
overtime, like aging or chronic diseases such as Alzheimer’s
disease, Parkinson’s disease, rheumatoid arthritis, atherosclerosis,
and more. By consuming antioxidant vitamins, these diseases may be
prevented.
How much do you need?
It
should be noted that antioxidant supplements are not cure in
themselves. The American Heart Association, for one, does not
recommend using antioxidant supplements “until more complete data
are in.” Instead, what they suggest is for “people to eat a variety
of foods daily from all of the basic food groups.”
In
April 2000, the Food and Nutrition Board of the Institute of
Medicine, an advisory group that is part of the National Academy of
Sciences, has also reported that Vitamin C, Vitamin E, selenium, and
carotenoids like beta-carotene should come from food, not
supplements, in order to make use of their inherent antioxidant
properties.
Since
1941, the Food and Nutrition Board has established a Recommended
Dietary Allowance (RDA), a daily intake goal for nearly all (98
percent) healthy individuals. It has also developed a “tolerable
upper intake level” (UL), which is the maximum amount of a nutrient
that health individuals can take each day without risking adverse
health effects. The Board does this by determining the types and
quantities of nutrients that are needed for healthy diets through
scientific literature review, disease-protecting nutrients, and data
interpretation on the consumption of these nutrients.
Below
is the Dietary Reference Intakes or DRIs in the 2000 report for
Vitamin C, Vitamin E, Selenium, and Carotenoids:
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Vitamin E
– RDA for adults
is 15 mg; UL for adults is 1,070 mg (natural vitamin E) or 785
mg (synthetic vitamin E) |
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Vitamin C
– RDA for adults
is 75 mg (for women) or 90 mg (for men); UL for adults is 2,000
mg |
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Beta-carotene
– Research indicates that it is not toxic if you consume beyond
what is in a multivitamin and your regular diet. Still, chronic
high doses should be wisely avoided. |
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Selenium
– RDA for adults
is 55 micrograms; UL for adults is 400 micrograms |
Antioxidant supplementation is not a problem in itself. What makes
it potentially dangerous is that if you take more than what is
recommended, there is a chance that you are doing more harm to your
body than good. Just remember that aging is a fact among humans. You
cannot stop yourself from aging. What you can only do is to slow
down the process.
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