Chocoholism may no longer be a joke. A Princeton University psychologist is today presenting new evidence that sugar can be physically addictive.
Bart Hoebel, whose research focuses on behavior patterns, addiction and the functioning of the nervous system, has been studying the addictive power of sugar in rats for several years. His previous studies have demonstrated in the rodents one of commonly understood component of addiction: a pattern of increased intake followed by signs of withdrawal.
In his latest studies, Hoebel and his colleagues at the Princeton Neuroscience Institute have identified another essential part of the addictive cycle: craving and relapse.
In his most recent experiments, lab rats were allowed to binge on sugar, then denied the sweet substance for a prolonged period. When it was reintroduced into their diet, they ate more sugar than they had before — behavior that will sound familiar to many dieters.
Ominously, the rats increased their consumption of alcohol after their sugar fix was cut off. They also showed extreme sensitivity to a tiny dose of amphetamine. Both findings suggest their bingeing changed the way their brains function – and not in a good way.
“Craving and relapse are critical components of addiction, and we have been able to demonstrate these behaviors in sugar-bingeing rats in a number of ways,” said Hoebel, who is presenting his findings at the annual meeting of the American College of Neuropsychopharmcology in Scottsdale, Ariz. “We have the first set of comprehensive studies showing the strong suggestion of sugar addiction in rats and a mechanism that might underlie it.”
Hoedel’s data is in a paper that has been submitted to the Journal of Nutrition.
His previous research has found that rats that binge on sugar provoke a surge of dopamine in their brains. After about a month, however, their brains begin to adapt to the increased dopamine levels by producing fewer of a certain type of receptor. Thus the animal had to ingest increasing amounts of sugar to get the same feeling of reward or satisfaction – a similar process to that seen in the brains of rats addicted to cocaine and heroin.
If that sounds alarmist, consider that the rats suffering from sugar withdrawal exhibited some of the same behavior as junkies in need of a fix. These include chattering teeth and a tendency to stay in a small tunnel rather than explore their maze, which Hoedel considers a sign of anxiety.
As usual, the research comes with a caveat that it’s too early to fully understand its implications for humans. Our relationship to food – which is simultaneously physical and emotional – is highly complex. Nevertheless, Hoedel notes that “It seems possible that the brain adaptations and behavioral signs seen in rats may occur in some individuals with binge-eating disorder or bulimia.”
In any event, the research is enough to give one pause before reaching for that plate of holiday cookies.