Is Chocolate a Drug, an Opiate...like Heroin?
Rats Eating M&M's Faster and Faster Points to Discovery About the Reward Circuitry of the Brain
According to a recent study published in the scientific journal Current Biology, eating chocolate can be compared to consuming opium, or for that matter, perhaps heroin. As reported by LiveScience, chocolate stimulates a peptide called "enkephalin" that activates cerebral opioid receptors. Enkephalin is a "relative" to endorphin. One difference is that enkaphalin is a natural opioid, a drug-like chemical produced in and by the brain that binds to the same receptors as many anaesthetic or psychoactive drugs.
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As reported by TheAtlantic.com, and several other news sources, this study may help scientists figure out why many of us cannot easily stop eating chocolate once we start. The study gets closer to answers about binge eating and addictions that are centered around the compulsive overconsumption of something that triggers the brain's reward center. The study found the natural opiate that contributes to what can be an intense drive to keep eating, and works in a similar way that like narcotics do, to kill pain.
Actually, the surprise of the study, said the study's author, Alexandra DiFeliceantonio, a graduate student in biopsychology at the University of Michigan, as reported by LiveScience, was the brain region where the opium-like chemical acts -- the neostriatum - which sits deep in the forebrain and is responsible for motor movements and habit formation. In movement disorders such as Huntington's or Parkinson's, this is the brain region that gets damaged. But the new study suggests that the neostriatum also plays a role in the reward systems of the brain, too, that are connected to binge eating, and compulsive addictions.
"The same brain area we tested here is active when obese people see foods and when drug addicts see drug scenes," she says. "It seems likely that our enkephalin findings in rats mean that this neurotransmitter may drive some forms of overconsumption and addiction in people."
The Study: Rats were offered M&M chocolates. Who can resist? When they began to gobble them up, the enkephalin surged, and when it was injected into their brain, the rats increased their gobbling rate by over 250 percent, as reported by Antlantic.com. These M&M's were the size that humans eat. So the rats were actually eating the equivalent of a human eating about 6 - 8 pounds of chocolate in an hour. Imagine that!
"Most of rats injected then began to eat more than twice as much candy as before, more than 17 grams--roughly 5 percent of their body weight. For a 150-pound human, this is equivalent to eating roughly 7.5 pounds of M&M's in one sitting. The rats also ate faster than they had before, indicating that enkephalin signals the brain to "eat faster" as well as "eat more."
But what is most interesting? The rats didn't seem to enjoy the M&M's even though they kept eating faster and faster. Scientists can read the facial reactions of the normal vs. the tested rats, measuring their tongue-action -- how much they used their tongues to lick their lips and so forth.)
"They don't really stop eating until you take the food away from them," Alexandra DiFeliceantonio, the author told LiveScience.
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