Opioids aren't all bad. Of course, the synthetic and recreationally used kinds are highly lethal and causing an epidemic of overdoses across North America, but the ones produced naturally in our own bodies make life awesome, flooding our nervous system with pleasure when we listen to music, have sex, and—as we now know—eat pizza.
This all sounds about right anecdotally, but now there's some brain science from the Turku PET Centre in Finland that will help you to better understand that impulse to grab another feel-good slice.
According to a recent article entitled "Feeding releases endogenous opioids in humans" published in The Journal of Neuroscience, eating food produces "significant" opioid release throughout the brain. That is hardly a groundbreaking finding, but the study gets more interesting when pizza is introduced.
Participants were injected with a radioactive compound that attached itself to opioid receptors in their brains, thus making the levels of pleasure-inducing opioids measurable through a positron emission tomography (PET) camera. Radioactivity was measured after three different stages: after an overnight fast, a tasteless high-calorie nutritional drink, and, finally, pizza. But not just any pizza.
READ MORE: Why Processed Food Is Like Crack
The discerning team of researchers specified that "delicious" pizza was selected to induce opioid release in the brain—and it worked. After crunching some PET data, the Turku team found that "eating a delicious pizza led to significant increase of pleasant feelings," as opposed to the calorie-matched nutritional drink, which did not. Again, not exactly shocking.
But what surprised researchers here was that more opioids were released during consumption of the nutritional drink than during pizza consumption, suggesting that eating triggers opioid release "even in the absence of subjective pleasure associated with feeding." In other words, eating releases opioids (like endorphins), no matter how "delicious" your food is. That might sound like semantics, but it could have a big impact on the study of food disorders.
"It was a surprise that endorphins are released in the entire brain and that the nutritional drink had a larger impact," researcher Jetro Tuulari said in a press statement. "This creates a basis for future research and hopefully we will find ways to study and describe the development and predictors of addiction, obesity, and eating disorders."
"The opioid system regulates eating and appetite, and we have previously found that its dysfunctions are a hallmark of morbid obesity," added co-author Lauri Nummenmaa. "The present results suggest that overeating may continuously overstimulate the opioid system, thus directly contributing to development of obesity. These findings open new opportunities for treating overeating and the development of obesity."
Shutting off opioid receptors can get you to stop liking your favorite song; maybe it can do the same for pizza.