Biology of Sugar Addiction

Throughout this site, we have addressed the ways in which sugars and high glycemic carbs disrupt metabolism. We have also discussed how these dietary molecules can lead directly to destruction of joint tissue. For many people, cutting down on sugar is a matter of simple discipline. For others, it may be more difficult. The fierce cravings that some people experience around sugary foods are more consistent with those who have an addiction.

But is there such a thing as "sugar addiction" or "carbohydrate addiction?" Most doctors would have thought this question frivilous, until serious researchers, such as those at Princeton, Stanford, and other universities began studying it using classical addiction models.

The Biology of Sugar Addiction (move this to its own menu item)

From: http://www.diabetesincontrol.com/results.php?storyarticle=6330

Type 2 Diabetes An Addiction?

Sugar as addictive as cocaine, heroin, studies suggest. Start your day with protein.

It's one addiction that won't land you in court or an inpatient rehab. But sugar - as anyone who mainlines sweets can attest - can be just as habit-forming as cocaine.

Researchers at Princeton University studying bingeing and dependency in rats have found that when the animals ingest large amounts of sugar, their brains undergo changes similar to the changes in the brains of people who abuse illegal drugs like cocaine and heroin.

"Our evidence from an animal model suggests that bingeing on sugar can act in the brain in ways very similar to drugs of abuse," says lead researcher and Princeton psychology professor Bart Hoebel.

In the studies, he explains, animals that drank large amounts of sugar water when hungry experienced behavioral changes, too, along with signs of withdrawal and even long-lasting effects that resemble cravings.

Some people experience powerful cravings for sweets - internal messages telling them to eat sugar even though they know it's bad for them - says Dr. Louis Aronne, director of the Comprehensive Weight Control Center at N.Y. Presbyterian Hospital/Weill Cornell Medical Center. "These people get strong urges to consume sweets, and these cravings border on addiction," he says. "When they eat sugar, just like when someone ingests cocaine, some people get that feeling of well-being, a rush that makes them feel good for a period of time. When the sweets are taken away, the people just don't feel right."

In the animals studied at Princeton, bingeing released a surge of the neurotransmitter dopamine in the brain. "It's been known that drugs of abuse release or increase the levels of dopamine in that part of the brain," Hoebel said.

After the rats' sugar supply was withdrawn, they became anxious. Their teeth chattered and they grew unwilling to venture into the open arm of their maze. Instead, they stayed in the tunnel of the maze.

Deprived of their sugar, the rats displayed signs of withdrawal similar to the symptoms seen in people when they stop smoking, drinking alcohol, or using drugs.

Just as not everyone has the tendency to become an alcoholic or a drug addict, so not everyone is hard wired to be a sugar-holic, Aronne says. And there is certainly effective treatment for a sweet addiction, though it's not likely to go down easily among those who like their candy and cookies.

"If people eat starch and sugar in the morning, it's very difficult to get their behavior in control and they'll be craving sweets all day," Aronne says. "So we have people start out their day by eating protein and vegetables in the morning, like a broccoli omelet for breakfast.

Physiol Behav. 2008 Jun 9;94(3):309-15. Epub 2008 Jan 16. Links

After daily bingeing on a sucrose solution, food deprivation induces anxiety and accumbens dopamine/acetylcholine imbalance.

Avena NM, Bocarsly ME, Rada P, Kim A, Hoebel BG.

Department of Psychology, Princeton University, Princeton, NJ 08540, USA.

Bingeing on sugar may activate neural pathways in a manner similar to taking drugs of abuse, resulting in related signs of dependence. The present experiments test whether rats that have been bingeing on sucrose and then fasted demonstrate signs of opiate-like withdrawal. Rats were maintained on 12-h deprivation followed by 12-h access to a 10% sucrose solution and chow for 28 days, then fasted for 36 h. These animals spent less time on the exposed arm of an elevated plus-maze compared with a similarly deprived ad libitum chow group, suggesting anxiety. Microdialysis revealed a concomitant increase in extracellular acetylcholine and decrease in dopamine release in the nucleus accumbens shell. These results did not appear to be due to hypoglycemia. The findings suggest that a diet of bingeing on sucrose and chow followed by fasting creates a state that involves anxiety and altered accumbens dopamine and acetylcholine balance. This is similar to the effects of naloxone, suggesting opiate-like withdrawal. This may be a factor in some eating disorders.

Exp Clin Psychopharmacol. 2007 Oct;15(5):481-91. Links

Examining the addictive-like properties of binge eating using an animal model of sugar dependence.

Avena NM.

Department of Psychology, Princeton University, New Jersey, USA. navena@rockefeller.edu

The increase in the incidence of obesity and eating disorders has encouraged research efforts aimed at understanding the etiology of abnormal eating behaviors. Clinical reports have led to the suggestion that some individuals may develop addictive-like behaviors when consuming palatable foods. Binge eating is a behavioral component of bulimia and obesity and has also become increasingly common in nonclinical populations in our society. This review summarizes the behavioral and neurochemical similarities between binge eating of palatable foods and the administration of drugs of abuse. An animal model of bingeing on sugar is used to illustrate behaviors found with some drugs of abuse, such as opiate-like withdrawal signs, enhanced intake following abstinence, and cross-sensitization. Related neurochemical changes commonly observed with drugs of abuse, including changes in dopamine and acetylcholine release in the nucleus accumbens, can also be found with bingeing on sugar. These neurochemical alterations are exacerbated when animals binge on sugar while at a low body weight or when the food they ingest is purged. Drawing on other animal models and the clinical literature, parallels between drug abuse and binge-eating behavior are discussed. (c) 2007 APA