It's
never too late to get it back! Aging interrupted
by calorie reduction
Much research has shown that reduced calorie intake can increase health
and longevity. Professor Stephen Spindler
(University of California) and his
collaborators* have discovered that reducing
calorie intake later in life can still induce
many of the health and longevity benefits of
life-long calorie reduction. Importantly, this
also includes anti-cancer effects.
They are using this knowledge to establish a
novel screening technique to find drugs which
mimic this longevity effect.
"Right now, there are no authentic "anti-ageing
drugs" capable of extending the lifespan of
healthy people. The technique we have developed
allows us to screen a relatively large number of
drugs in months rather than years. The hope is
that these drugs will be able to extend the
lifespan of healthy animals, and possibly, after
further testing, healthy humans", says Professor
Spindler who presented his results at the
Society for Experimental Biology's Main Meeting
in Glasgow, 2nd April.
Previous research has show that mice can
live up to 40% longer if they simply consume
fewer calories, but a highly nutritious
diet. Because people are not very good at
dieting, Dr. Spindler and his colleagues
would like to identify drugs which can
produce the same beneficial health and
longevity effects without the low calorie
diet. The problem is to find a way to
rapidly identify these drugs.
Professor Spindler and his colleagues are
examining the gene expression patterns which are
induced by low calorie diets, and looking for
drugs which mimic these changes. They are
searching for drugs which will have these
beneficial effects and slow ageing, even when
they are given late in life. One drug, normally
used to treat diabetic patients, seems to
produce many of the beneficial effects of a low
calorie diet.
However, it is important to be sure that healthy
people will benefit from the drug. A very low
level of toxicity could interfere with the
beneficial effects of such a drug, if it is
taken for a lifetime.
Physiological changes associated with ageing
include cell damage and the emergence of cancer
cells. The most important effects of low calorie
diets and longevity therapeutics given late in
life may not be to prevent this damage, but
instead to stimulate the body to eliminate
damaged cells that may become cancerous, and to
stimulate repair in damaged cells like neurons
and heart cells.
Low calorie diets drive the body to replace and
repair damaged cells. This process usually slows
down as we age, but low calorie diets make the
body re-synthesise and turn over more cells -- a
situation associated with youth and good health.
Dr. Spindler and his colleagues used their
screening method to search for drugs which cause
pre-cancerous and cancerous cells to commit
suicide and to replace those cells with new,
healthy cells.
It is thought that the body does this because it
normally kills some cells like damaged and rogue
cancer cells to provide energy when it is
starving. Then it replaces these cells when a
meal is eaten.
It seems it is the total number of calories
which are consumed, rather than the type of food
which is the key to the effects of low calorie
diets on the ageing process. However, it is
known that vegetarians and fish eaters live
longer than red meat eaters, and that,
generally, the more fruit and vegetables in the
diet, the better your health and longer your
lifespan.
*This work is a collaboration between Professor
Spindler and Dr Joseph Dhahbi (Children's
Hospital Oakland Research Institute).
Published review paper (in press): S. Spindler
and J. Dhahbi. 2007. Conserved and
tissue-specific genic and physiologic responses
to caloric reduction and altered IGF1 signalling
in mitotic and post-mitotic tissues. Annual
Review of Nutrition, 2007.
