longer lifespan, certainly a longer 'Healthspan'
Newswise, St. Louis, April 2010 — Organisms
from yeast to rodents to humans all benefit
from cutting calories. In less complex
organisms, restricting calories can double
or even triple lifespan.
It’s not yet clear just how much longer
calorie restriction might help humans live,
but those who practice the strict diet hope
to survive past 100 years old.
In a review article in the April 16 edition
of Science, nutrition and longevity
researchers at Washington University School
of Medicine in St. Louis, University College
in London and the Andrus Gerontology Center
at the University of Southern California,
report that calorie restriction influences
the same handful of molecular pathways
related to aging in all the animals that
have been studied.
Aware of the profound influence of calorie
restriction on animals, some people have cut
their calorie intake by 25 percent or more
in hopes of lengthening lifespan.
But first author Luigi Fontana, MD, PhD, is
less interested in calorie restriction for
longer life than in its ability to promote
good health throughout life.
“The focus of my research is not really to
extend lifespan to 120 or 130 years,” says
Fontana, research associate professor of
medicine at Washington University and an
investigator at the Istituto Superiore di
Sanitą in Rome, Italy.
“Right now, the average lifespan in Western
countries is about 80, but there are too
many people who are only healthy until about
want to use the discoveries about calorie
restriction and other related genetic or
pharmacological interventions to close that
30-year gap between lifespan and ‘healthspan.’
However, by extending healthy lifespan,
average lifespan also could increase up to
100 years of age."
Fontana and his co-authors write about how
cutting calorie intake between 10 percent
and 50 percent decreases the activity of
pathways involving insulin-like growth
factor (IGF-1), glucose and TOR (target of
rapamycin), and considerably increases
lifespan in animals.
Genetic mutations involved in those pathways
have the same effect. Those animals have far
fewer problems with diseases related to
aging, such as cancer, cardiovascular
disease and cognitive problems.
“About 30 percent of the animals on calorie
restriction die at an advanced age without
any diseases normally related to aging,”
“In contrast, among animals on a standard
diet, the great majority (94 percent)
develop and die of one or more chronic
diseases such as cancer or heart disease.
In 30 percent to 50 percent of the animals
on calorie restriction, or with genetic
mutations in these aging-related pathways,
healthspan is equal to lifespan. They
eventually die, but they don’t get sick."
Unfortunately, many humans are moving in the
opposite direction. As obesity reaches
epidemic rates in Western countries, Fontana
says rather than closing the 30-year gap
between healthspan and lifespan, the gap is
likely to grow.
It’s even possible lifespan may decrease as
people develop preventable diseases such as
atherosclerosis, type 2 diabetes and certain
forms of cancer.
Those growing rates of obesity are a reason
some scientists think calorie restriction
will never catch on, regardless of its
But, Fontana says, if researchers who study
nutrition and aging can understand how
calorie restriction lengthens life and makes
people healthier, it may be possible to
develop less drastic interventions or
medicines that influence pathways affected
by calorie restriction and help keep people
healthy as they get older.
Among people now practicing calorie
restriction, he says side effects include
reduced libido because calorie restriction
reduces testosterone levels.
They also tend to become cold more quickly
because their thermal regulation changes as
their metabolism slows and their core body
Fontana says as calorie restriction research
advances on many fronts, it’s becoming clear
that dietary advice once based on
epidemiological data now makes sense from a
molecular point of view.
In the past, dietitians might recommend more
fruits and vegetables or less meat and more
whole grains. They based that advice on
studies showing people who ate more
vegetables or fewer animal products tended
to have less cardiovascular disease.
“Now we have moved from epidemiology to
molecular biology,” he says. “We know that
certain nutrients, as well as lower calorie
intake, can influence IGF-1 and other
pathways. Soon we hope to be able to use
that knowledge to help people live longer
and healthier lives.