Pig study sheds new light on sugar's addictive impacts on the brain
Much research has helped paint a picture of the relationship between sugar and our brain's reward system, though there remains many blanks to be filled. Scientists in Denmark have now offered further insights into how the sweet stuff reshapes our brain chemistry, by performing experiments on pigs and taking note of how the reward circuitry lights up after consumption.
The research was carried out by scientists at Denmark's Aarhus University, who say the use of pigs rather than more conventional animal models was key to advancing their understanding of sugar and the brain. It was also useful in avoiding a range of other factors that can activate the brain's reward systems and cause wild fluctuations in data, such as playing video games, sex, romance or other things we eat.
"The pig is a good alternative because its brain is more complex than a rodent and gyrated like human and large enough for imaging deep brain structures using human brain scanners," says study author Michael Winterdahl. "The current study in mini-pigs introduced a well-controlled set-up with the only variable being the absence or presence of sugar in the diet."
Experiments were carried out on seven pigs, which were fed two liters (0.5 gal) of sugar water a day over a 12-day period. The scientists imaged their brains beforehand, after the first day, and then after the 12th day to observe any changes.
"After just 12 days of sugar intake, we could see major changes in the brain's dopamine and opioid systems," says Winterdahl. "In fact, the opioid system, which is that part of the brain's chemistry that is associated with well-being and pleasure, was already activated after the very first intake,"
This echoes findings from previous studies on sugar intake and neurotransmitters like dopamine, which the brain releases in response to rewarding experiences or consumption of addictive drugs like cocaine. The influence sugar appears to have on this kind of brain circuitry has long been likened to the effects of addictive drugs, and the scientists new analysis on pig brains has led them to a similar conclusion.
"If sugar can change the brain's reward system after only 12 days, as we saw in the case of the pigs, you can imagine that natural stimuli such as learning or social interaction are pushed into the background and replaced by sugar and/or other 'artificial' stimuli," says Winterdahl. "We're all looking for the rush from dopamine, and if something gives us a better or bigger kick, then that's what we choose."
The team's research was published in the journal Scientific Reports.