Published October 15. 2013 1:00PM Updated October 15. 2013 6:47PM
New London — How does a rat eat an Oreo? It breaks it apart and eats the middle first, just like most humans do.
That’s what Connecticut College students and a professor of neuroscience found in a research study they conducted on the potential addictiveness of high-fat/high-sugar foods.
Their conclusion? Anyone with a weakness for junk food already knows the answer. Oreos are just as addictive as cocaine — at least for lab rats.
Professor Joseph Schroeder and his students found rats formed an equally strong association between the pleasurable effects of eating Oreos and a specific environment as they did between cocaine or morphine and a specific environment. They also found that eating cookies activated more neurons in the brain’s “pleasure center” than exposure to drugs of abuse.
Schroeder, an assistant professor of neuroscience at Connecticut College, will present the research next month at the Society for Neuroscience conference in San Diego, Calif.
“Our research supports the theory that high-fat/high-sugar foods stimulate the brain in the same way that drugs do,” Schroeder said. “It may explain why some people can’t resist these foods despite the fact that they know they are bad for them.”
Schroeder said he and his students chose to feed the rats Oreos because they wanted a food that is palatable to humans and contributes to obesity in the same way cocaine is pleasurable and addictive to humans.
The research was the brainchild of neuroscience major Jamie Honohan, who graduated in May. She worked with Schroeder and several other students last year to measure the association between “drug” and environment.
On one side of a maze, they would give hungry rats Oreos and on the other, they would give them a control — in this case, rice cakes. Then, they would give the rats the option of spending time on either side of the maze and measure how long they would spend on the side where they were typically fed Oreos.
They compared the results of the Oreo and rice cake test with results from rats that were given an injection of cocaine or morphine, known addictive substances, on one side of the maze and a shot of saline on the other.
Schroeder is licensed by the U.S. Drug Enforcement Administration to purchase and use controlled substances for research.
The research showed the rats conditioned with Oreos spent as much time on the “drug” side of the maze as the rats conditioned with cocaine or morphine.
Schroeder and his students then used immunohistochemistry to measure the expression of a protein called c-Fos, a marker of neuronal activation, in the nucleus accumbens, or the brain’s “pleasure center.”
They found that the Oreos activated significantly more neurons than cocaine or morphine.
“This correlated well with our behavioral results and lends support to the hypothesis that high-fat/high-sugar foods are addictive,” Schroeder said.