Study: Obesity Associated With Brain's 'Reward Chemical'

October 25, 2007 11:21 a.m. EST

Upton, NY (AHN) - A new study has tagged a brain chemical associated with motivation, reward, pleasure and movement to be playing a role in obesity.

The chemical is called dopamin, which researchers at the U.S. government's Brookhaven National Laboratory in Upton, New York found to be related to food intake.

In a prepared statement, Brookhaven neuroscientist Panayotis (Peter) Thanos, said "This research corroborates brain-imaging studies conducted at Brookhaven that found decreased levels of dopamine D2 receptors in obese people compared with normal-weight people."

Thanos is also the lead author of the research.

Genetically obese rats, as found by Brookhaven researchers, have lower levels of dopamine D2 receptors on brain cells as compared to rats that are lean. Restricting food intake, according to the study, can also increase the number of D2 receptors in brain cells.

Thanos said, "This study also provides further evidence for the interplay of genetic factors with the environment in the development of obesity in our society."

However, Thanos said it is unclear whether or not obesity is the cause or result of reduced dopamine D2 receptor levels.

He said a chronic reduction in receptor levels may be caused by overeating that in the long run contribute to obesity.

Thanos however said a person may overeat in an attempt to mimic a "blunted" reward system.

Nevertheless, he said increasing dopamine D2 receptor levels by limiting the intake of food may be an effective way of preventing obesity.

Thanos said, "Consuming fewer calories is obviously important for people trying to lose weight, plus improving the brain's ability to respond to rewards other than food may help prevent overeating."

Obesity is fast becoming a health concern all over the world. Obese people have a higher risk of heart disease, Type 2 diabetes and other diseases including some cancers.

In eastern Asia, only 7% of the population are obese, in stark contrast to 36% of people seeing their physicians in Canada, 38% of women in Middle Eastern countries and 40% in South Africa.

Recent studies place South Africa and Canada to lead the world in terms of the percentage of overweight people in their populations. The study did not include the U.S.