Excess fat affects your brain
2008-04-30 12:04
New York - Middle-aged people who are
overweight or obese have lower levels of certain brain
chemicals that signal good brain health and function, according
to a new study using high-tech brain scans.
The findings suggest that excess body fat may speed the
brain ageing process, which could put people at greater risk of
developing age-related diseases of the brain, such as
Alzheimer's disease, Dr Stefan Gazdzinski of the San Francisco VA Medical Centre and colleagues say.
The researchers looked at magnetic resonance imaging (MRI)
brain scans from 50 healthy middle-aged men and women,
measuring amounts of a variety of chemicals in the white and
grey matter of the brain. Grey matter consists of the bodies of
nerve cells, while white matter is made up of the connections
between these cells.
Five of the study participants were obese, 15 were
overweight, and the remaining 30 were normal weight.
The higher a person's body mass index (BMI), the ratio of
body height to weight, the lower the concentration of
N-acetyl-aspartate (NAA), a brain chemical that serves several
functions and also acts as a marker for overall brain health,
in the white matter of the brain's frontal, temporal and
parietal regions.
Heavier people also had less NAA in their
frontal grey matter, and lower concentrations of
choline-containing metabolite - substances key to the
formation of cell membranes - in their frontal white matter.
The strongest relationship between BMI and brain chemistry
was seen in the white matter of the frontal region, which is
believed to be particularly vulnerable to ageing-related damage,
the researchers note.
It's possible that being heavy accelerates brain ageing, or
that being overweight or obese in childhood affects brain
development, the researchers note.
The data didn't allow them to determine if the brain
abnormalities might be related to body fat alone or if it
suggests other health problems, nutrition, or sedentary living,
they add.
But if other research that does address these factors
confirms the current findings, the researchers say, the results
could provide important clues to changes in the brain that
might precede dementia.
- Reuters