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Life
Extension
Science
or Science Fiction?
Explorers once searched
for the fountain of youth, and old legends tell of magic potions
that keep people young. The ancient questions--Why do people grow
old? How can we live longer?--still fascinate people, including
the scientists who study aging (gerontologists). But their most
important question is this: how can people stay healthy and independent
as they grow older?
Recently, researchers
have begun to find certain chemicals in our bodies that may
someday answer these questions. As a result, some stores and
catalogs now sell products that are similar to these chemicals.
However, the advertising claims that these products can extend
life are very much exaggerated. Here are some of the chemicals
being studied and what scientists have learned about them so
far.
Antioxidants.
These are natural substances that may help prevent disease.
Antioxidants fight harmful molecules called oxygen free radicals,
which are created by the body as cells go about their normal
business of producing energy. Free radicals also come from smoking,
radiation, sunlight, and other factors in the environment.
Some antioxidants,
such as the enzyme SOD (superoxide dismutase), are produced
in the body. Others come from food; these include vitamin C,
vitamin E, and beta carotene, which is related to vitamin A.
The body’s antioxidant
defense system prevents most free-radical damage, but not all.
As people grow older, the damage may build-up. According to
one theory of aging, this build-up eventually causes cells,
tissues, and organs to break down.
There is some evidence
to support this theory. For instance, the longer an animal lives,
the more antioxidants it has in its body. Also, some studies
show that antioxidants may help prevent heart disease, some
cancers, cataracts, and other health problems that are more
common as people get older.
Most experts think
that the best way to get these vitamins is by eating fruits
and vegetables (five helpings a day) rather than by taking vitamin
pills. SOD pills have no effect on the body. They are broken
up into different substances during digestion. More research
is needed before specific recommendations can be made.
DNA and RNA.
DNA (deoxyribonucleic acid) is the material in every cell that
holds the genes. Every day some DNA is damaged and most of the
time it is repaired. But more and more damage occurs with age,
and it may be that DNA repair, never 100 percent perfect, falls
further and further behind. If so, the damage that does not
get repaired and builds up could be one of the reasons that
people age.
As a result, pills
containing DNA and RNA (ribonucleic acid, which works with DNA
in the cells to make proteins) are on the market. But DNA and
RNA are like SOD tablets. When they are taken by mouth, they
are broken down into other substances and cannot get to cells
or do any good.
DHEA. Short
for dehydroepiandrosterone, DHEA is a hormone that has turned
back some signs of aging in animals. When given to mice, it
has boosted the immune system and helped prevent some kinds
of cancer.
DHEA travels through
the body in the blood in a special form, called DHEA sulfate,
which turns into DHEA when it enters a cell. Levels of DHEA
sulfate are high in younger people but tend to go down with
age.
Substances labeled
DHEA are being sold as a way to extend life, although no one
knows whether they are effective.
Other Hormones.
In a recent study with a small number of men, injections of
growth hormone boosted the size and strength of the men’s muscles
and seemed to reverse some signs of aging. Now, larger studies
are testing growth hormone and other hormones, such as estrogen
and testosterone, to find out whether they can prevent weakness
and frailty in older people.
However, it is much
too early to know whether any of these hormones will work. There
could be problems. Moreover, the side effects of hormones could
be very serious; high amounts of some hormones have been linked
to cancer.
Ten Tips for
Healthy Aging
No known substance can extend life, but the chances of staying
healthy and living a long time can be improved:
- Eat a balanced
diet, including five helpings of fruits and vegetables a day.
- Exercise regularly
(check with a doctor before starting an exercise program).
- Get regular health
check-ups.
- Don’t smoke (it’s
never too late to quit).
- Practice safety
habits at home to prevent falls and fractures. Always wear
your seatbelt in a car.
- Stay in contact
with family and friends. Stay active through work, play, and
community.
- Avoid overexposure
to the sun and the cold.
- If you drink,
moderation is the key. When you drink, let someone else drive.
- Keep personal
and financial records in order to simplify budgeting and investing.
Plan long-term housing and money needs.
- Keep a positive
attitude toward life. Do things that make you happy.
The Bottom Line
Currently no treatments, drugs, or pills are known to slow aging
or extend life in humans. Check with a doctor before buying
pills or anything else that promises to slow aging, extend life,
or make a big change in the way you look or feel.
Resources
The National Institute on Aging Information Center
P.O. Box 8057
Gaithersburg, MD 20898-8057
1-800-222-2225
1-800-222-4225 (TTY)
National Institute
on Aging
U. S. Department of Health and Human Services
Public Health Service
National Institutes of Health
1994
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