Cheese Addiction?

It is common to hear claims in the vegan community that milk & cheese are literally addictive and contain a morphine-like substance, for many this factoid has become so ubiquitous  that it is generally taken as an accepted scientific truth. But what is the actual evidence for this claim?

One of the main proponents of this claim is Dr Neal Barnard who heads up the Physicians Committee for Responsible Medicine (PCRM). Barnard has gone so far as to claim that cheese “can be as addictive as morphine” and referred to it as “dairy crack”. Barnard’s premise in Breaking the Food Seduction is that not only is the food addiction model correct (still a contentious issue in itself) but that it is not, as hypothesized, merely due to endogenous biochemicals acting on reward pathways in the brain but also due to the fact that many foods such as dairy, chocolate, and meat contain addictive chemicals themselves and can induce food-specific addictions, such as a “cheese addiction”. As evidence of the addictive potential of cheese Barnard cites the presence of exogenous opioid peptides, or exorphins,

“Cow’s milk-or the milk of any other species, for that matter-contains a protein, called casein, that breaks apart during digestion to release a whole host of opiates, called casomorphins.”

To demonstrate the addictive power of food Barnard cites research in which Naloxone, an opioid antagonist, caused a loss of interest in the food being studied. Bardnard would like us to believe that “cheese’s popularity may have less to do with its meltability and mouth-feel and more to do with its addictive qualities.” Unfortunately for him the Naloxone research he cites contradicts this claim. The studies most cited were investigating chocolate, sweets, and fats and opioid antagonists like Naloxone reduce cravings for all of these. Far from establishing the role of casomorphin in the appeal of cheese, studies done with Naloxone point more to the importance of general palatability. In other words it may not be the presence of specific psychoactive chemicals that we find so compelling about certain foods but rather the overall sensory appeal of the food.

Placebo controlled research on chocolate addiction for example found “no role for pharmacological effects in the satisfaction of chocolate craving”, rather it found that sensory aspects were more likely the primary factor. Research on casomophin also found that it did not demonstrate “reinforcing properties similar to those of morphine” and concluded that “beta-casomorphin is not likely to become the focus of an addiction.” While there is evidence that the endogenous opioid system plays some role in food intake and craving, the problem comes in when people such as Barnard try to make it appear that it is more due to the effects of specific exogenous opioids rather than the complex interactions of mostly endogenous biochemicals and when the case is overstated with extreme claims and hyperbole.

Dairy isn’t the only source of exogenous opioid peptides however. There are a variety of other opioid peptides in various foods such as hemorphins derived from hemoglobin (a component of blood), gluteomorphin from gluten, rubiscolin derived from spinach, and even soymorphins derived from soy. One study even found that soymorphins “showed opioid activity more potent than human beta-casomorphins”, at least on guinea pig ileum. If Barnard’s theory is true we might expect similar addiction patterns for these foods. While there are claims among some that products containing gluten are addictive, this is also still scientifically controversial and is even approached warily by other anti-wheat writers. One would also expect that if gluten does have this effect that vegans would be a high risk population as they are the most likely to consume relatively large amounts concentrated gluten in the form of seitan. While seitan is quite yummy when prepared well, I don’t think many would describe it as literally addictive. The case of soymorphin is also quite interesting, these peptides should be ubiquitous in the diets of many vegans, though there is still little concern over a tofu addiction. Perhaps casomorphin does have an effect that would elicit casein-specific cravings, however it appears from the current research that if this effect does exist that it is so far indistinguishable from food cravings for any other high preference food.

Further Reading:
Is cheese really addictive? by Diana of The Vegan Option
Vegan Cheese: Casein, Casomorphins, and the Daiya Redwoods Vegusto Taste Test on The Vegan Option podcast
Review of the potential health impact of β-casomorphins and related peptides European Food Safety Agency (2009)
Chocolate: The news you wanted to hear by Glenn Cardwell
The plausibility of sugar addiction and its role in obesity and eating disorders.

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13 Responses to “Cheese Addiction?”

  1. Andy Says:

    Exactly the sort of information needed to keep hyperbolic rhetoric in perspective. Thank you for looking into this.

    The fact that cheese is comforting, pleasurable, and familiar seems to be no more significant than the similar qualities I’m sure you’ll find in your own favorite foods. I for example like to douse all sorts of foods in Vegenaise, nutritional yeast and Sri Racha. Does this place me on a higher plane than my cheese pizza-gobbling neighbor? Ethically, perhaps; gustatorily speaking, no. The mature response is to focus on the ethical benefits, keep looking for better cheese substitutes, and keep promoting the ones we’ve got. (An upside to all this for vegan recruiters is that cheese withdrawal effects are probably also overblown, although the post doesn’t directly address that issue as far as I can see.)

  2. Jonathan Hussain Says:

    Well done! It’s good to see another unsubstantiated and superfluous factoid openly discredited.

  3. It’s Not Easy Being Cheesy « Value Time Says:

    […] Skeptical Vegan tackles the question of whether cheese addiction exists–and don’t miss the picture illustrating his blog post! Share […]

  4. Chelsar Says:

    I really enjoyed this post and will refer it to people in the future! Really great information. Jack Norris spoke on this issue briefly and people were literally leaving mumbling “well I don’t believe that part.”


  5. Dasa Says:

    Food is addictive according to calorie density.

    The more calories per bite the more addictive the food is.

  6. Fred Says:

    Food may be addictive. In my forty-six years, I haven’t been able to stop eating yet.

  7. Cody Yelton Says:

    Dr. Barnard isn’t the only expert with this view point, lots of leading health professionals and studies agree. Unfortunately, it seems like now a days we can find others to agree with our opinions no matter which view we have. While you have a point of other foods being addictive, cheese is different as it is concentrated milk. Mammal milk is designed to be addictive to keep the baby wanting more and growing big fast! Seems illogical it wouldn’t have a similar effect on humans consuming it in mass quantities.

  8. About Me | ahimsatoday Says:

    […] looking for a web page explaining this, but to my surprise, I found instead compelling evidence to the contrary. Nonetheless, there is something about cheese that makes it very hard to give up.) During my […]

  9. johnfmayer Says:

    Thanks, Skeptical Vegan; I was afraid I’d have a hard time finding opposing comment to this view, the more sensationalistic claims usually commanding far more webspace (as they do in this case). Glad you’re here.

  10. Obscure Thing Says:

    Reblogged this on Dragon Mother and commented:
    In light of recent research published on the addictive qualities of cheese (casomorphin) I think this article highlights how addictive many other foods might also be. From personal experience, however, I found cheese the hardest thing to crack (pardon the pun) when going vegan. It took me two weeks to stop craving cheese! I genuinely craved that stuff.

    Maybe casseine is designed to be addictive to baby cows to encourage them to feed. Maybe adult humans are weaned and should not be drinking the baby milk of another species. Just a suggestion.

    • Kristen Says:

      Humans are not made to consume cows milk. Think about it, that milk feeds a calf. The calf grows big, and strong and a fast amount of time. It is meant for that purpose.

  11. skepticalvegan Says:

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