Parkinson's risk 'cut by dieting'
December 14, 2004
Eating a low calorie diet may help to reduce the risk
of Parkinson's disease, research suggests.
A team from the US National Institute on Ageing found
a long-term reduction in caloric intake protects rhesus
monkeys from developing the disease.
They believe restricting caloric intake switches on
mechanisms which protect the brain cells lost in people
diagnosed with Parkinson's.
Details are published in Proceedings of the National
Academy of Sciences.
A number of studies have suggested the normal ageing
process causes a loss of brain cells that produce a
key chemical called dopamine in an area of the brain
called the substantia nigra.
It is thought that Parkinson's disease speeds up the
loss of these cells, leading to the problems with movement
associated with the condition.
Limiting the number of calories in the diet has been
shown to have a powerful effect in slowing down the
ageing process.
The US team decided to examine whether it could also
prevent the development of Parkinson's symptoms in monkeys.
For six months monkeys received a diet with 30% fewer
calories than the control diet.
At that point, the monkeys were injected with a toxin
that causes a Parkinson-like disease.
Protective chemical
The calorie-restricted monkeys showed better control
over their movement, and higher levels of dopamine in
their brains.
They also had higher levels of a growth factor, GDNF,
which the researchers believe may protect brain cells
from destruction.
The researchers say their work suggests that long-term
caloric restriction may reduce the risk of developing
Parkinson's by turning on production of this protective
growth factor.
Researcher Professor Mark Mattson said: "The present
findings demonstrate that caloric restriction can protect
brain cells against a toxin that can cause Parkinson's
disease.
"Caloric restriction may stimulate the production
of neurotrophic factors by imposing a mild stress response
in brain cells.
"The cells respond to this mild stress by producing
proteins, such as neurotrophic factors, that help them
cope with more severe stress and resist disease.
"This is analagous to physical exercise which
is a stress on muscle cells. The muscle cells become
stronger for having been forced to deal with the stress
of exercise."
Early stage
The Parkinson's Disease Society said the research was
encouraging, but still at a very early stage.
"The findings are based on an animal study and
it is not yet known if these results would be replicated
with human subjects on a longer term basis.
"There is some existing evidence that individuals
with low calorie, low fat diets maybe at reduced risk
of Parkinson's disease and this study offers support
to this view.
"However, it is clear that further research with
human subjects would be required to increase our understanding
of the mechanisms involved."
Dr Roger Barker, of the Cambridge Centre for Brain
Repair, stressed that translating the findings into
clinical practice could prove difficult.
He said: "The model is a useful one, but is different
from the clinical disorder and so any extrapolation
is not straightforward.
"Also patients with Parkinson's disease often
lose
weight, in part because of their movement disorder
and thus restricting their calorific content may be
detrimental in that respect.
"However, it does once more illustrate that manipulations
of environmental issues, such as diet and exercise,
may help in neurodegenerative disorders."
Source:http://news.bbc.co.uk
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