If you love cheese, you might as well be doing crack.
Or at least that’s what you might gather from recent health news vilifying one of America’s favorite fatty foods. MTV news said “Science declares what we all know: Pizza is the most addictive food.” And the LA Times was one of many outlets to claim that “Cheese really is crack.” They cited research from Ashley Gerhardt and colleagues from the University of Michigan concluding that “cheese crack is the real thing. And so is your addiction.” The problem is, the study indicated no such thing.
In Gerhardt’s experiment, participants ranked thirty-five foods on a scale from 1 (not problematic) to 7 (extremely problematic) in difficulty to avoid. Pizza won first place, with an average score of 4.01. Cheese got tenth place, with a score of 3.22. In another experiment, participants who were shown pairs of foods indicated which was more problematic. After comparing all possible combinations of the 35 foods, chocolate came in first place, while cheese trailed behind at sixteenth.
But ranking pizza as more problematic than chocolate (clearly debatable) and cucumbers (obviously) does not prove that it is the most addictive food. Or that it is addictive at all.
Food addiction is a contentious concept with an unclear biological mechanism. Addiction itself has many debated definitions, but usually refers to a change in the “reward-seeking” regions of the brain involving the “feel-good chemical” dopamine. Despite what the news reports implied, Gerhardt’s study made no claims regarding cheese addiction, or regarding cheese at all. Her conclusion? Highly processed foods – those containing artificially high levels of sugar and fats – are potential candidates for food addiction. Cheese is indeed fatty, but was not considered “highly processed” by Gerhardt’s definition.
So where did all this “cheese is crack” business come from?
Dr. Neal Barnard from the Physicians Committee for Responsible Medicine (PCRM) is often quoted calling cheese “dairy crack.” The PCRM is a vegan-diet-promoting organization previously funded by PETA. The PCRM’s article “Three Steps to Fight the Cheese Addiction” provides little scientific explanation of what “the cheese addiction” is, and instead markets vegan products and dairy-free cookbooks.
Barnard rightly mentions that casein – the principle protein component of cheese – breaks apart into fragments called casomorphins (not “queso-morphins”) due to digestive enzymes in the stomach. But facts get shaky when he says that casomorphins activate brain opioid receptors like heroin and morphine do.
If casomorphins in cheese are equivalent to heroin and morphine, we’ve got a huge problem. Either the Drug Enforcement Agency must immediately outlaw cheese products like it does heroin and morphine, as dangerous Schedule I or II substances with a high potential for abuse, or consumers should expect to find drugs like heroin readily available for purchase among the Philadelphia Cream Cheese and Kraft Singles.
Heroin and morphine addiction results from the drugs’ effects on opioid receptors in the brain. But these receptors are found in other places, including the gut. Laboratory studies show that the most important casomorphin, known as BCM7, activates opioid gut receptors, albeit 250 times less powerfully than morphine does. Opioid receptor activation in the gut, part of what’s called the enteric nervous system, does not result in addiction. For cheese to be addictive, the gut would need to absorb BCM7 into the bloodstream and pass it across the blood-brain barrier, and no study to date shows that BCM7 can do that.
Cameron Wells, PCRM’s Associate Director of Clinical Dietetics told me that “looking at cheese under the microscope really takes away from the nutrition component.” And she has a point. Americans are consuming about three times as much cheese as they did in the 1970s. The high levels of saturated fats and cholesterol aren’t helping anybody’s heart health. Cutting down on fatty foods like cheese, as well as processed and red meats, consistently is solid guidance amidst a flurry of seemingly changing health advice.
When pressed for an answer to the literalness of the “cheese addiction” epidemic, Wells did stand by PCRM’s claim that cheese is chemically addictive due to casomorphins. But she was unaware of the European Food Safety Authority’s one-hundred page study concluding no evidence for risk of addiction or any other disease from ingestion of casomorphins.
But what are those opioid receptors doing in the gut anyway? Well, the activation of these receptors slows peristalsis and gastrointestinal transit time. Translation? Constipation. So today when you load your burrito bowl with heaping scoops of queso, shredded cheese, and sour cream, eat merrily, free from fear of addiction. But tomorrow, when you’re in the loo upset from over-activation of your gut opioid receptors, well… you’ve been warned.
Originally written on November 9, 2015
Published on December 28, 2015