- CORVALLIS - Researchers in
the Linus Pauling Institute at Oregon State University and the University
of California at Berkeley have identified a combination of dietary
supplements
that dramatically improves both the activity, energy level and cognitive
function of old rats.
-
- The findings were announced today in three articles in
a professional journal, the Proceedings of the National Academy of
Sciences.
The research is supported by grants from the National Institutes of
Aging.
-
- Small clinical trials are already under way with humans
to determine whether these compounds offer the same benefits to
people.
-
- The studies were done with a combination of two compounds
that occur naturally, acetyl-l-carnitine and an antioxidant, alpha-lipoic
acid. Previous work has shown that either of these compounds may have value
in addressing some of the physical and mental deterioration associated
with aging, but the newest research suggested a combination of the two
works far better than either one separately.
-
- "After just a month, older rats whose diet was
supplemented
with these two compounds were about twice as active as our control rats,
which remained largely inactive," said Tory Hagen, an assistant
professor
in OSU's Linus Pauling Institute. "They also had a much better memory
and cognitive performance, measured by their ability to remember objects
and spatial orientation."
-
- The researchers found that old rats given the dietary
regimen had an activity level about the same as those of middle-aged
rats.
-
- The latest findings build on years of research into the
aging process and these compounds, the scientists said.
-
- There are many cellular changes associated with aging,
and one particularly vulnerable area appears to be the mitochondria where
the cell's energy is generated.
-
- Although there are literally hundreds of theories about
why animals age and eventually die, the OSU and Cal-Berkeley scientists
believe that mitochondria may be an "Achilles heel" for absorbing
age-related damage. And there may be ways to influence that process, Hagen
said.
-
- "It appears that some compounds, including carnitine
and lipoic acid, can mask the metabolic problems caused by cellular aging
and the natural oxidative process," Hagen said. "We're very
excited
about the research. This may have relevance to improving people's quality
of life and health."
-
- Aging is closely related to the major diseases that kill
most people around the world --- heart disease and cancer --- as well as
those that can have severe impacts on quality of life, such as Alzheimer's
disease and Parkinson's disease.
-
- Like many complex metabolic processes there is probably
no single, simple answer to the aging process, Hagen said. Some scientists
believe the process has a hormonal basis, in which cells no longer
"communicate"
with each other properly, and others ascribe a genetic basis to aging in
which cells become "senescent" after a finite number of
programmed
divisions.
-
- But the theory being studied at OSU and Cal-Berkeley
is that aging is at least partly due to the natural process of oxidation
in the body and "free radicals," that cause cellular
damage.
-
- "Oxygen is a double-edged sword," Hagen said.
"We need it to live and it's essential to cell function. But oxygen
can be converted into what we call reactive radical oxygen species, or
free radicals. And they have the potential to mutate DNA and damage lipids
and proteins."
-
- The free radicals that are being produced as a result
of metabolism are actually the same that result from nuclear radiation.
It's as if humans were being irradiated throughout their lives. And this
process is such a natural part of life that cellular repair mechanisms
have evolved to help fix or prevent the damage - not the least of which
are well-known "antioxidants" such as vitamin C.
-
- "These cellular repair processes are not
perfect,"
Hagen said. "Oxidative damage does occur, and we think there's strong
evidence that this contributes to aging and some of the other problems
associated with it, such as cancer, arteriosclerosis or
neurodegeneration."
-
- A particular weak spot in the body may be the
mitochondria
in cells - a quasi-independent structure similar to bacteria with its own
DNA. "Mitochondria are the power plants of our cells, where raw fuels
are converted into usable forms of energy," Hagen said. "Up to
90 percent of the oxygen we breathe is used by the mitochondria, as they
perform many of the roles critical to cell function, such as producing
energy, regulating calcium and even controlling cell life and
death."
-
- But mitochondria, Hagen said, are also the chief source
of free radicals. And since they're right in the neighborhood of the
dangerous
free radicals they just created, they're also often the first
victims.
-
- "This can be a vicious downward cycle, in which
mitochondria create free radicals and then fall victim to them," Hagen
said. "This loss of mitochondrial function and its impact on metabolic
function is at least one part of what we call aging."
-
- In studies of old rats, Hagen's laboratory has documented
a severe decline of mitochondrial function, a slower metabolic rate and
reduced cognitive function. He has shown that the antioxidants that help
protect mitochondria, especially glutathione, an intracellular antioxidant,
decline severely with age. And his studies have shown that the cells of
old rats are far more susceptible to age-related oxidative stress than
those of young animals.
-
- But the newest studies offer hope. Carnitine is an amino
acid that's involved in fatty acid transport into mitochondria. It's a
natural compound produced in the cell and obtained in the diet through
meats and vegetables. Previous research showed that rats fed this compound
had improved mitochondrial function and overall activity level. In studies
done in humans by other researchers, carnitine has been shown to improve
balance and short-term memory, Hagen said. And another strong antioxidant,
lipoic acid, found in green, leafy vegetables, appears to improve
mitochondrial
function.
-
- The new study shows that a combination of these two
compounds
provides all these benefits at even higher levels than either one alone.
"As people age and their mitochondrial function declines, they are
even less able to resist the usual metabolic insults of life, just like
rats," Hagen said. "But we're seeing that an intake of these
nutrients in combination seems to restore the ability of cells and
mitochondria
to deal with environmental stresses, just about as well as they did when
they were young."
-
- "If we can better understand the process of aging
and how to influence it," Hagen said, "we may be able to give
people a way to maintain human health for as long as possible."
-
- ___
-
- Abstracts in the Proceedings of the National Academy
of Sciences
-
- http://www.pnas.org/cgi/content/abstract/99/4/1870
- http://www.pnas.org/cgi/content/abstract/99/4/1876
- http://www.pnas.org/cgi/content/abstract/99/4/2356
-
- David Stauth
- 541-737-0787
- ___________
- Source - Tory Hagen
- 541-737-5083
-
- http://oregonstate.edu
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