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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