I just found out why KKD donuts is going up so much -->
Monday June 18 2:17 PM ET
Rat Studies Show Evidence of 'Sugar
Dependence'
By E. J. Mundell
TORONTO (Reuters Health) - Could many of us be slaves to our
sweet tooth? New research in rats suggests that the brain can become
dependent, if not outright addicted, to sugars in food.
``The brain has opioid compounds and they seem to be released by
palatable tastes such as sugar, fat, ice cream, cake,'' explained Dr. Bart
Hoebel, a researcher at Princeton University specializing in the
neuroscience of addiction. He presented his findings Saturday at the
annual meeting of the American Psychological Society.
Numerous studies have shown that the activity of the nucleus
accumbens, an area in the forefront of the brain, is key to the ``high''
sought by abusers of cocaine, amphetamines, nicotine and other
addictive substances. Drug intake stimulates receptors in the nucleus
accumbens to release high levels of opioids as well as dopamine, the
neurochemical thought to be a driving force behind drug-seeking
behavior.
Because the nucleus accumbens is also involved in regulating normal
feeding, Hoebel's team theorized that food might induce similar
behavioral responses.
In their investigation, researchers fed rats a sugary solution for 12-hour
periods over a number of weeks, then either abruptly cut off the rodents'
supply of the sweet treat or gave them a drug that blocked the brain's
opioid receptors.
The result? Compared with rats fed regular chow, sugar-fed rats
developed ``mild'' symptoms indicative of withdrawal, such as
teeth-chattering, an increased frequency of high-pitched crying and
anxiety. And when researchers allowed these rats renewed access to
sugar they ``binged''--consuming up to 30% of their daily sugar intake
within the first hour of re-introduction.
Subsequent laboratory investigation of the brains of sugar-fed rats
showed an accelerated growth of dopamine receptors in the nucleus
accumbens, indicative of a growing dependence on sugar.
The behavior of the rats in the study is similar to patterns seen in drug
abuse and withdrawal. Bingeing, especially, ``is very important,'' Hoebel
noted. ``If you take in a lot of food at once you're going to get a lot of
dopamine and opioids all at once--that's a little like getting a small shot
of amphetamine and morphine.''
Taste, rather than calories, seems to trigger this neuro-behavorial
process. Rats fed saccharin displayed similar dependent behaviors to
those fed sugars, even though saccharine contains no calories. ``The
evidence so far is that if it tastes good, it should work,'' he said, although
he speculates that the addition of calories may enhance the effect.
Hoebel stressed that, right now, ``we haven't shown sugar addiction, but
for the experts who define these words, we have shown sugar
dependence.'' In dependence, individuals still maintain some control
over their cravings for a particular substance, but they lose this control
when dependence turns into addiction. Genetics could play a strong role
in the process, Hoebel said, leading some individuals to be more prone
than others to what he called ``food abuse.''
Future studies in humans are planned to assess whether an actual
addiction to foods could help drive eating disorders such as binge eating
or bulimia, where individuals lose that vital sense of control. ``We've
seen that drugs of abuse act, in part, via the feeding system,'' Hoebel
said, ``and many scientists have gone to great lengths to show that that
system is involved in addiction. Therefore, maybe food itself could be
addictive. Maybe this is a system that evolved to be addictive.'' |
