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Eating less results in longer lives, a 14-year CU dog-diet study confirms
From the “Cornell Chronicle”, December 12, 2002 - By Lissa Harris
Seventy years after a classic Cornell nutritional
study showed that cutting rations dramatically
prolongs rats' lives, nutrition scientists have come
up with even more evidence of the benefit of
slender diets: A recently completed 14-year
study found that dogs forced to eat 25
percent less than their littermates of the same
balanced diet lived significantly longer and
suffered fewer canine diseases.
In an age of increasing incidence of obesity
among Americans, "maybe it's time we watched
what the rats and the dogs are eating," advises
George Lust, a Cornell professor of veterinary
medicine and a collaborator in the experiment
with dogs, sponsored by the Nestlé Purina Pet
Care Co.
A specialist in bone and joint diseases in animals,
Lust saw the underfed dogs incurring much less
canine hip dysplasia (CHD) and subsequent
osteoarthritis, compared with dogs that were fed
the portions indicated on the pet food packages.
The dogs on reduced rations also lived nearly
two years longer.
In animal nutritionist Clive McCay's 1930s'
demonstration of the power of portion control on
health, rats on an experimentally reduced diet
lived half again as long as rats on "normal" diets.
His findings with rats are well known to every
nutritionist, but determining the implications for
human health has remained a challenge. The
dog study comes closer, providing the strongest
evidence yet that diet restriction confers benefits
of health and longevity on larger mammals.
While the benefits of diet reduction have been
demonstrated in animals from chickens to singlecelled
organisms, dogs are our closest
evolutionary relatives in which a reduced diet
definitively has been shown to enhance health
and lengthen life.
The ambitious dog study was led by researchers
at Nestlé Purina, and included scientists at
Cornell, the University of Illinois, Michigan State
University and the University of Pennsylvania.
Results of the study were published in the
Journal of the American Veterinary Medical
Association in May. The study also was the focus
of a September symposium in St. Louis,
sponsored by Nestlé Purina, called "Advancing
Life Through Diet Restriction."
In the study, 24 pairs of Labrador retriever
siblings between 6 and 8 weeks of age --
matched by sex and weight-- were selected, with
one of each pair assigned to eat 25 percent less
food than its sibling. The dogs were a part of the
study from the time they were weaned until they
died, and their health was closely monitored
throughout their lives.
The median age of dogs in the reduced-diet
group, the researchers found, was 13 years -- 1.8
years longer than the median age of dogs fed a
normal diet.
As a result of genetic factors, Labradors are
predisposed to develop CHD and osteoarthritis.
Lust, a professor of physiological chemistry at the
James A. Baker Institute for Animal Health at
Cornell, followed the development of the disease
in the 48 dogs in the study. He found striking
effects of diet on the progression of the disease,
even in young animals.
"It was dramatic. In the control group of 24 dogs -
- the well-fed dogs -- 16 had CHD at 2 years of
age, and eight were normal," Lust said. "Of the
24 dogs in the restricted diet group, only eight
had CHD and 16 were normal."
The reduced diet also was found to reduce the
risk of developing osteoarthritis, which generally
results from CHD and is one of the most common
sources of chronic pain treated by veterinarians.
It is also the most common form of arthritis in
humans, affecting over 20 million people in the
United States. Only six dogs on the reduced diet
developed osteoarthritis of the hip by age 10,
while 19 of the dogs in the control group
developed the condition. And for dogs with CHD
and on reduced rations, the diet decreased the
odds of developing osteoarthritis by 57 percent.
Similar studies involving primates are under way
at the University of Wisconsin. Because of the
long life span of monkeys, however, it will be
years before the results of those studies are
known.
From the “Cornell Chronicle”, December 12, 2002 - By Lissa Harris
Seventy years after a classic Cornell nutritional
study showed that cutting rations dramatically
prolongs rats' lives, nutrition scientists have come
up with even more evidence of the benefit of
slender diets: A recently completed 14-year
study found that dogs forced to eat 25
percent less than their littermates of the same
balanced diet lived significantly longer and
suffered fewer canine diseases.
In an age of increasing incidence of obesity
among Americans, "maybe it's time we watched
what the rats and the dogs are eating," advises
George Lust, a Cornell professor of veterinary
medicine and a collaborator in the experiment
with dogs, sponsored by the Nestlé Purina Pet
Care Co.
A specialist in bone and joint diseases in animals,
Lust saw the underfed dogs incurring much less
canine hip dysplasia (CHD) and subsequent
osteoarthritis, compared with dogs that were fed
the portions indicated on the pet food packages.
The dogs on reduced rations also lived nearly
two years longer.
In animal nutritionist Clive McCay's 1930s'
demonstration of the power of portion control on
health, rats on an experimentally reduced diet
lived half again as long as rats on "normal" diets.
His findings with rats are well known to every
nutritionist, but determining the implications for
human health has remained a challenge. The
dog study comes closer, providing the strongest
evidence yet that diet restriction confers benefits
of health and longevity on larger mammals.
While the benefits of diet reduction have been
demonstrated in animals from chickens to singlecelled
organisms, dogs are our closest
evolutionary relatives in which a reduced diet
definitively has been shown to enhance health
and lengthen life.
The ambitious dog study was led by researchers
at Nestlé Purina, and included scientists at
Cornell, the University of Illinois, Michigan State
University and the University of Pennsylvania.
Results of the study were published in the
Journal of the American Veterinary Medical
Association in May. The study also was the focus
of a September symposium in St. Louis,
sponsored by Nestlé Purina, called "Advancing
Life Through Diet Restriction."
In the study, 24 pairs of Labrador retriever
siblings between 6 and 8 weeks of age --
matched by sex and weight-- were selected, with
one of each pair assigned to eat 25 percent less
food than its sibling. The dogs were a part of the
study from the time they were weaned until they
died, and their health was closely monitored
throughout their lives.
The median age of dogs in the reduced-diet
group, the researchers found, was 13 years -- 1.8
years longer than the median age of dogs fed a
normal diet.
As a result of genetic factors, Labradors are
predisposed to develop CHD and osteoarthritis.
Lust, a professor of physiological chemistry at the
James A. Baker Institute for Animal Health at
Cornell, followed the development of the disease
in the 48 dogs in the study. He found striking
effects of diet on the progression of the disease,
even in young animals.
"It was dramatic. In the control group of 24 dogs -
- the well-fed dogs -- 16 had CHD at 2 years of
age, and eight were normal," Lust said. "Of the
24 dogs in the restricted diet group, only eight
had CHD and 16 were normal."
The reduced diet also was found to reduce the
risk of developing osteoarthritis, which generally
results from CHD and is one of the most common
sources of chronic pain treated by veterinarians.
It is also the most common form of arthritis in
humans, affecting over 20 million people in the
United States. Only six dogs on the reduced diet
developed osteoarthritis of the hip by age 10,
while 19 of the dogs in the control group
developed the condition. And for dogs with CHD
and on reduced rations, the diet decreased the
odds of developing osteoarthritis by 57 percent.
Similar studies involving primates are under way
at the University of Wisconsin. Because of the
long life span of monkeys, however, it will be
years before the results of those studies are
known.
