Al-Huda
Foundation, NJ U. S. A
the Message Continues ... 11/97
Newsletter for September 2009
Article 1 - Article 2 - Article 3 - Article 4 - Article 5 - Article 6 - Article 7 - Article 8 - Article 9 - Article 10 - Article 11 - Article 12
Eat Less, Live
Healthier and
Longer,
but Preserve the
Meaning of Life
and Death
Calorie
restriction,
involves eating
about 30 percent
fewer calories
than normal
while still
getting adequate
amounts of
vitamins,
minerals and
other nutrients.
Aside from
direct genetic
manipulation,
calorie
restriction is
the only
strategy known
to extend life
consistently in
a variety of
animal species
In the last
year,
calorie-restricted
diets have been
shown in various
animals to
affect molecular
pathways likely
to be involved
in the
progression of
Alzheimer's
disease,
diabetes, heart
disease,
Parkinson's
disease and
cancer. Earlier
this year,
researchers
studying dietary
effects on
humans went so
far as to claim
that calorie
restriction may
be more
effective than
exercise at
preventing
age-related
diseases.
The findings
cast doubt on
long-held
scientific and
cultural beliefs
regarding the
inevitability of
the body's
decline. They
also suggest
that other
interventions,
which include
new drugs, may
retard aging
even if the diet
itself should
prove
ineffective in
humans. One
leading
candidate, a
newly
synthesized form
of resveratrol
-- an
antioxidant
present in large
amounts in red
wine -- is
already being
tested in
patients. It may
eventually be
the first of a
new class of
anti-aging
drugs.
Extrapolating
from recent
animal findings,
Dr. Richard A.
Miller, a
pathologist at
the University
of Michigan,
estimated that a
pill mimicking
the effects of
calorie
restriction
might increase
human life span
to about 112
healthy years,
with the
occasional
senior living
until 140,
though some
experts view
that projection
as overly
optimistic.
In almost
every instance,
the subjects on
low-calorie
diets have
proven to be not
just longer
lived, but also
more resistant
to age-related
ailments.
"In mice, calorie restriction doesn't just extend life span," said Leonard P. Guarente, professor of biology at the Massachusetts Institute of Technology. "It mitigates many diseases of aging: cancer, cardiovascular disease, neurodegenerative disease. The gain is just enormous."
Researchers
at Louisiana
State University
reported in
April in The
Journal of the
American Medical
Association that
patients on an
experimental
low-calorie diet
had lower
insulin levels
and body
temperatures,
both possible
markers of
longevity, and
fewer signs of
the chromosomal
damage typically
associated with
aging.
These studies and others have led many scientists to believe they have stumbled onto a central determinant of natural life span. Animals on restricted diets seem particularly resistant to environmental stresses like oxidation and heat, perhaps even radiation. "It is a very deep, very important function," Dr. Miller said. Experts theorize that limited access to energy alarms the body, so to speak, activating a cascade of biochemical signals that tell each cell to direct energy away from reproductive functions, toward repair and maintenance. The calorie-restricted organism is stronger, according to this hypothesis, because individual cells are more efficiently repairing mutations, using energy, defending themselves and mopping up harmful byproducts like free radicals. "The stressed cell is really pulling out all the stops" to preserve itself, said Dr. Cynthia Kenyon, a molecular biologist at the University of California, San Francisco. "This system could have evolved as a way of letting animals take a timeout from reproduction when times are harsh." In a series of studies, Dr. Kenyon, of the University of California, San Francisco, has created mutant roundworms that live six times longer than normal, largely because of a mutation in a single gene called daf-2. The gene encodes a receptor on the surface of cells similar to a receptor in humans that responds to two important hormones, insulin and the insulin-like growth factor 1 or IGF-1. Insulin is necessary for the body to transport glucose into cells to fuel their operations. Dr. Kenyon and other researchers suggest that worm cells with mutated receptors may be "tricked" into sensing that nutrients are not available, even when they are. With its maintenance machinery thereby turned on high, each worm cell lives far longer -- and so does the worm. Many experts are now convinced that the energy-signaling pathways that employ insulin and IGF-1 are very involved in fixing an organism's life span. Some researchers have even described Type 2 diabetes, which is marked by insensitivity to the hormone insulin, as simply an accelerated form of aging. In yeast, scientists have discovered a gene similar to daf-2 called SIR2, that also helps to coordinate the cell's defensive response once activated by calorie restriction or another external stressor. The genes encode proteins called sirtuins, which are found in both plants and animals. A mammalian version of the SIR2 gene, called SIRT1, has been shown to regulate a number of processes necessary for long-term survival in calorie-restricted mice. Scientists are now trying to develop synthetic compounds that affect the genes daf-2 and SIRT1. Several candidate drugs designed to prevent age-related diseases, particularly diabetes, are on the drawing boards at biotech companies. Sirtris Pharmaceuticals, in Boston, already has begun testing a new drug in patients with Type 2 diabetes that acts on SIRT1 to improve the functioning of mitochondria, the cell's energy factories. While an anti-aging pill may be the next big blockbuster, some ethicists believe that the all-out determination to extend life span is veined with arrogance. As appointments with death are postponed, says Dr. Leon R. Kass, former chairman of the President's Council on Bioethics, human lives may become less engaging, less meaningful, even less beautiful. Dr. Kass recently wrote. "Mortality makes life matter." Courtesy: Dr. Robert D. Crane |
HOME - NEWSLETTERS - BOOKS - ARTICLES - CONTACT - FEEDBACK - UP
DISCLAIMER:
All material published by Al-Huda.com / And the Message Continues is the sole responsibility of its author's).
The opinions and/or assertions contained therein do not necessarily reflect the editorial views of this site,
nor of Al-Huda and its officers.