September 21, 2012
Natural Chemical In Our Brains Responsible For Chocolate Cravings
Connie K. Ho for redOrbit.com — Your Universe Online
A new study has revealed that the brain might have chocolate temptations due to the production of a natural chemical that is similar to opium.The researchers looked at a group of rats to better understand the urge to overeat chocolate candies. They injected a drug that sent an artificial boost to the neostriatum, a region in the brain. With the injection, the rats ate more than double the number of M&M chocolates than they would have normally eaten. The researchers also discovered that enkephalin, a naturally produced chemical in the neostriatum, increased when rats ate the sweet treats.
"This means that the brain has more extensive systems to make individuals want to overconsume rewards than previously thought," explained Alexandra DiFeliceantonio, a researcher at the University of Michigan, Ann Arbor, in a prepared statement. "It may be one reason why overconsumption is a problem today."
Based on the findings, the team of investigators stated that the brain releases chemicals that make the rats desirous of chocolate. They also found that the neostriatum is linked to the part of the brain managing movement. The results from the study can help explain some of the reasons as to why humans have temptations for chocolate.
"Chocolate offers sweetness and fattiness–the perfect storm of a stimulus to get the effect we wanted," study author DiFeliceantonio told Scientific American.
According to the Los Angeles Times, the researchers also decided to study this particular area in the brain as it was linked to reward-seeking behavior and could encode how people were supposed to feel when rewarded something. They also probed the question as to whether the injection made the rats want more chocolate or if this part of the brain combined with the drug made the rats feel as though the chocolate tasted sweeter, thus making them crave the sweet treat.
As well, the scientists decided to study the rats´ faces when consuming the chocolate. If there was more enkephalin in the area and rats licked their lips, then it meant that the chocolate tasted better to the rats. However, since the facial expressions of the rats did not change, the researchers took that as a sign that there was more neural motivation behind the desire for chocolate.
The study also showed how that how the neostriatum existed within a circuit and, while it received information from other parts of the brain, it also helped manage motivation and reward. The results displayed how various parts of the brain are involved in changing an individual´s want for food and that there are multiple routes that lead to consumption.
“Opioid circuitry... could in this way participate in normal motivations and perhaps even in generating intense pathological levels of motivation to overconsume reward in binge eating disorders, drug addiction and related compulsive pursuits,” wrote the authors in the paper.
In moving forward, the researchers plan to look at how the brain controls temptations from eating fast food.
"The same brain area we tested here is active when obese people see foods and when drug addicts see drug scenes," commented DiFeliceantonio in the statement. "It seems likely that our enkephalin findings in rats mean that this neurotransmitter may drive some forms of overconsumption and addiction in people."
The findings were recently published in the Cell Press publication Current Biology.