of Obese May Crave
Addiction Linked Hormone
YORK (Reuters Health) - A brain chemical linked to drug addiction
may also contribute to obesity, researchers have found. They say
the discovery could lead to new ways to suppress food cravings
in obese individuals.
appear to have fewer brain receptors for dopamine, a chemical
that helps produce feelings of pleasure and satisfaction. This
abnormal brain circuitry has also been found in people addicted
to cocaine, alcohol and other drugs.
The new finding
suggests that, lacking a normal number of dopamine receptors,
obese people may use food to trigger a drug-like effect on the
brain's dopamine ``pleasure'' centers.
system is our reward system,'' Dr. Gene-Jack Wang explained in
an interview with Reuters Health. ``Obese people may use food
to compensate for a dysfunctional dopamine system.''
Wang and his
colleagues at the Brookhaven National Laboratory in Upton, New
York, compared brain scans from 10 obese study participants with
those from 10 normal-weight participants.
found not only that obese people had fewer dopamine receptors,
but also that the heavier the individual, the fewer the receptors.
The findings are published in the February 3rd issue of The Lancet.
The idea that
food and drugs act on the same brain centers is not new. Previous
research has shown that food intake influences dopamine levels,
and addictive drugs are known to boost dopamine concentrations,
creating their characteristic ''high.'' Some scientists believe
the high rate of drug use and smoking among people with eating
disorders can be partly explained by their increased need for
In the case
of obesity, it is unclear whether some people may have a naturally
low number of dopamine receptors that predisposes them to overeating
or if they lose the receptors due to ``chronic overstimulation''
from a lifetime of consuming too much food, Wang said.
It is possible
that obese people's eating patterns may send their dopamine levels
so high that their brains compensate by shutting down receptors.
he and his colleagues are now trying to answer this ``cause-and-effect''
question. If further research confirms this study's findings,
he said, it may be possible to suppress overeating with drugs
that enhance dopamine production.
But a readily
available treatment is that old standby--exercise, which is known
to elevate dopamine levels, Wang said. Moreover, the roots of
obesity are complex, involving a mix of genetic and environmental
factors. Dopamine, according to Wang, is only one potential contributor.
Reference Source 89