Chocolate may be a guilty pleasure for many, but how its pleasure responses could be measured was unknown to scientists, until now. Researchers from Drexel University have found a way to actually measure pleasure responses associated with chocolate - using a common, low cost ophthalmic tool.
This study, led by Dr Jennifer Nasser, an associate professor at the Drexel University's College of Nursing and Health Professions, tested how electroretinography may indicate the increase in the level of dopamine; a neurotransmitter associated with pleasure, in response to looking at chocolate.
Dopamine, which causes a pleasurable effect in the brain, may now be viewed in the retina of the eye, when it is released in response to light exposure.
This small-scale study involved just 9 participants, none of them suffering from eating disorders.
The electrical signals in the retina went up when the study subjects were exposed to a flash of light and a piece of chocolate (food stimulus) was consumed by them.
This increase in the electrical signals was comparable to that when individuals were subjected to a drug stimulant to initiate a dopamine response, the study further revealed.
"What makes this so exciting is that the eye's dopamine system was considered separate from the rest of the brain's dopamine system," Dr Nasser explained. "So most people- and indeed many retinography experts told me this- would say that tasting a food that stimulates the brain's dopamine system wouldn't have an effect on the eye's dopamine system."
If validated, this study could prove to be beneficial in obesity prevention and decoding food addictions. "My research takes a pharmacology approach to the brain's response to food," Dr Nasser added. "Food is both a nutrient delivery system and a pleasure delivery system, and a 'side effect' is excess calories. I want to maximize the pleasure and nutritional value of food but minimize the side effects. We need more user-friendly tools to do that."
The study is now published in the journal Obesity.
