Provides information on the dopamine, a neurochemical typically
linked to mood. Role of dopamine in controlling appetite; Link between
dopamine level and obesity; Factors that affect dopamine level.
By
Angela Pirisi, published on July 01, 2001
SELF-CONTROL
THE BRAIN'S PLEASURE CHEMICAL MIGHT BE LINKED TO OVEREATING
Ever hear people threaten to eat an entire cake because they just
can't stop themselves? While that may sound like a feeble excuse to
overindulge, some chronic overeaters may lack control due to a shortage
of a key brain chemical, say researchers from the Brookhaven National
Laboratory in New York.
Dopamine, a neurochemical typically linked to mood, also plays a
role in controlling appetite. It is responsible for transmitting reward
signals within the brain in response to attractive stimuli including
food, drugs and sex. "Obese subjects, however, seem to need to eat lots
more food than a person of normal weight to feel satisfied and full,"
explains lead researcher Gene-Jack Wang, M.D., of Brookhaven Lab, whose
research was recently published in The Lancet.
Using brain imaging, the researchers found that the heavier the
individual, the less dopamine there is in his or her brain. So,
overeating may be a desperate attempt to trigger that pleasurable
sensation that follows a Thanksgiving dinner.
What remains unclear is whether obese people have fewer dopamine
receptors to begin with, or if their brains have shut down some of the
receptors in response to chronic overeating, in an attempt to prevent the
release of excess dopamine. The hope is that the findings may one day
lead to strategies aimed at improving dopamine function. "Right now, it's
just a concept," says Wang. "We have drugs that modulate dopamine, but
the problem is they're addictive." A safer route to go, he says, may be
for people to join an overeaters support group. Or, better yet, to
exercise--luckily, physical activity increases dopamine too.
