April 20, 2007
Dogs Lived 1.8 Years Longer On Low Calorie Diet
Gut Flora May Explain
Findings
Science Daily - Changes caused to bugs in the gut by restricting
calorie
intake may partly explain why dietary restriction can extend
lifespan,
according to new analysis from a life-long project looking at the
effects
of dietary restriction on Labrador Retriever dogs.
Bugs in the gut are known as gut microbes and they live
symbiotically in
human and animal bodies, playing an important role in metabolism.
Abnormalities in some types of gut microbes have recently been
linked to
diseases such as diabetes and obesity.
Today's research, published in the Journal of Proteome
Research, was based
on a study in which 24 dogs were paired, with one dog in each pair
given
25% less food than the other. Those with a restricted intake of
calories
lived, on average, about 1.8 years longer than those with a greater
intake
and they had fewer problems with diseases such as diabetes and
osteoarthritis, plus an older median age for onset of late-life
diseases.
The researchers, from Imperial College London, Nestlé Research
Center
(NRC) and Nestlé-Purina, found long-term differences in the
metabolism of
the dietary-restricted and non-dietary-restricted dogs. Metabolic
profile
plays a key role in determining animals' response to illness and
their
susceptibility to disease.
The scientists believe that differences in the makeup of gut
microbes
between the two sets of dogs could partly explain their metabolic
differences. The dogs that were not on a restricted diet had
increased
levels of potentially unhealthy aliphatic amines in their urine.
These
reflect reduced levels of a nutrient that is essential for
metabolising
fat, known as choline, indicating the presence of a certain makeup
of gut
microbe in the dogs. This makeup of gut microbes has been associated
in
recent studies with the development of insulin resistance and
obesity.
Professor Jeremy Nicholson from Imperial College London said: "This
fascinating study was primarily focused on trying to find optimised
nutritional regimes to keep pet animals such as dogs healthy and as
long-lived as possible. However these types of life-long studies can
help
us understand human diseases and ageing as well, and that is the
added
bonus of being able to do long-term non-invasive metabolic
monitoring."
The researchers suggest that part of the healthier metabolic
profiles of
dogs on a restricted diet is related to their changed gut microbial
activity, which in turn contributes to their generally improved
health and
longer lifespan. However, they also found that the overall effects
of
ageing on restricted and non-restricted animals exerted a greater
effect
on the metabolic profile than dietary restriction. This in itself is
interesting as the lifelong metabolic trajectories of large animals
had
never been studied in this detail before and such information might
be of
relevance to ageing humans and their diseases. The team believes
that one
important outcome of this work will be the ability to improve the
design
of products' nutritional properties that mimic the health benefits
of
dietary restriction in pet dogs.
http://www.sciencedaily.com/releases/2007/04/070419160140.htm
Note: This story has been adapted from a news release issued by the
Imperial College London.
