The new low cost ophthalmological tool could be used for clinical applications in obesity prevention and addiction to foods.
The study, published in the journal Obesity, was led by Dr. Jennifer Nasser, an associate professor in the department of Nutrition Sciences in Drexel University’s College of Nursing and Health Professions.
She used electroretinography (ERG) to observe neurotransmitter dopamine located in the retina.
As a simple organic chemical that functions as a neurotransmitter dopamine is linked to a number of pleasure-related effects in the brain.
Dopamine is released in the eye’s retina when the optical nerve activates in response to light exposure.
Electrical signals in the retina responded to light when a small piece of food was given to the patients. The researchers found that the dopamine response was as great as when they received the stimulant drug called methyphenidate.
The response to food was also significantly higher than the control substance – water.
“What makes this so exciting is that the eye’s dopamine system was considered separate from the rest of the brain’s dopamine system. 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.”
The small study only included nine participants who didn’t eat for four hours prior to the testing. Nasser believes that the technique needs to be validated through larger studies with more participants.
The findings could provide very valuable insight into food addiction. Just the sight or smell of foods triggers a spike in dopamine among certain people, which may play a role in triggering compulsive overeating, according to a previous study published in Obesity
Scientists at the Wellcome Trust Centre for Neuroimaging at UCL (University College London) showed that increased levels of dopamine make us more likely to opt for instant gratification, rather than waiting for a more beneficial reward – this affects our willpower and makes us act impulsively. Their findings were published in the Journal of Neuroscience.
Just the sight of food can trigger a very strong dopamine response in some people.
“My research takes a pharmacology approach to the brain’s response to food. 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.”
It is a low cost and fast method, says, Nasser. Medicare reimbursement cost is only $150 per session compared to methods that measure dopamine in the brain that cost around $2,000 and take much longer to give results.
Written by Joseph Nordqvist