Some people's brain chemistry may make them more likely to notice food.
Research to be presented at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB) looked at how having a certain type of brain chemistry can tempt people to overeat, even if they were not overweight.
Dopamine in the striatum (a region of the brain linked to food reward) was found to be involved in how quickly young men noticed food pictures hidden among more neutral ones; men who noticed these pictures more quickly also tended to eat more. Mouse models have also demonstrated a link between eating habits and dopamine in the striatum.
"We do know that in human obesity the striatal dopamine system is affected, but interesting enough we know little about the striatal dopamine system of young, healthy individuals and how it relates to the motivation to eat" said Susanne la Fleur from the Academic Medical Center in Amsterdam, who directed the study linking dopamine, attention to food, and eating."
In most cases dopamine is stopped during a rewarding activity when it is re-absorbed into the cells it emerged from; this uptake process requires brain chemical known of as a "dopamine transporter" (DAT). Lower levels of DAT causes dopamine to be reabsorbed more slowly, allowing it to affect the brain for longer periods of time.
The research team used brain scans to determine DAT levels in non-obese young men; they found those with lower DAT levels (meaning higher dopamine activity) showed a stronger visual bias towards food.
"We could speculate that in healthy humans dopamine does motivate eating, however although we did observe a correlation between striatal dopamine transporter binding and the visual attention bias for food; and between visual attention bias for food and actual food intake, we did not observe a correlation between striatal dopamine transporter binding and actual food intake. Thus, a factor in addition to dopamine must be involved in going from being motivated to actual eating", la Fleur concluded.
