Addiction to Cheese is Real Thanks to Casomorphins

If you talk to anyone who has recently switched, or is considering a switch, to a plant-based diet, more often than not, they claim that cheese is their weakness. So why is this? After all, doesn’t cheese smell like dirty socks?

The answer is casomorphins—protein fragments, derived from the digestion of the milk protein, Casein. The distinguishing characteristic of casomorphins is that they have an opioid effect. Yup. Opioids are among the world’s oldest known drugs. Dependence can develop with ongoing administration, leading to withdrawal syndromes with abrupt discontinuation. Opioids are well known for their ability to produce a feeling of euphoria, motivating some to recreationally use opioids. But if it’s already a huge part of our diets in America, so who will actually have to experience the uncomfy withdrawl? You guessed it. Those who try to kick dairy to the curb.

Casein is a hot topic for vegans and plant-based eaters because it can be found deceptively listed in the ingredients of certain dairy-free and vegan cheeses. You may be familiar with it in that regard, but the addicting qualities of Casein are somewhat unknown. As Casein breaks down in the stomach producing the peptide, casomorphin (an opioid), it acts as a histamine releaser [1], which is also why so many people are allergic to dairy products; An estimated 70% of the population worldwide!

Ok, back to the opioid effect. It takes 10lbs of milk to make 1 lb of cheese. As milk is turned into cheese, most of its water is removed leaving behind concentrated casein and fat. So, concentrated dairy products, like cheese, have especially high levels of opiates, even morphine.

At this point you might be wondering what the evolutionary basis might be for these opiates to be in a mammal’s milk. Dr. Neal Barnard, founder and president of the Physicians Committee for Responsible Medicine (PCRM), explains that, “It appears that the opiates from mother’s milk produce a calming effect on the infant and, in fact, may be responsible for a good measure of the mother-infant bond. No, it’s not all lullabies and cooing. Psychological bonds always have a physical underpinning. Like it or not, mother’s milk has a drug-like effect on the baby’s brain that ensures that the baby will bond with Mom and continue to nurse and get the nutrients all babies need. Like heroin or codeine, casomorphins slow intestinal movements and have a decided antidiarrheal effect. The opiate effect may be why adults often find that cheese can be constipating, just as opiate painkillers are.”

The European Food Safety Agency, in response to a number of studies and public health concern, did a scientific literature review in 2009 to assess the potential health impact of casomorphins and similar biologically active peptides [2]. Much of the review centers addressing the overarching question (although several avenues were explored in detail): Do casomorphins have potentially deleterious health effects? The concern of course stemming from the addictive capacity of opioid drugs.

The jury on that specific question is still out and a lot of the research is conflicting. There is discussion as to whether or not enough of the casomorphins cross the intestinal wall and get into the blood stream and ultimately cross the blood-brain barrier, etc. It discusses the data implicating this as a factor in Autism, etc.

While, I believe this is great information and I applaud the European Food Safety Agency for looking into it (note: our government has not), I think we are asking the wrong question!

I mean does it really matter “how addicting” it is and in what amounts does are able to get into the bloodstream, etc?

Common sense alone tells us that: We know with opioid drugs, different people react differently to them and different amounts affect people differently. I suspect it isn’t too much of a stretch to conclude that this is also the case for substances that produce an opioid effect. Further, it is generally accepted that binging on drugs on a daily basis is bad for us even in sufficiently small quantities, thus, again consuming highly concentrated forms of analogous substances probably isn’t the best plan either.

The question isn’t whether or not the casomorphins themselves have potentially deleterious health effects, the question is do dairy products on the whole have potentially deleterious health effects!

And that answer is a resounding YES.

The casomorphins only explain why we like cheese so much and why it is so hard to give it up. It’s the sugar (lactose), animal protein and the saturated fat content (which triggers IGF-1 in the body, and is the reason it is now being strongly linked to several cancers) that make it so bad for you.

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Are you, or have you, experienced withdrawal symptoms
from dairy? Share your experiences with us below…
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For more info, check out these related articles:
Why Cheese is Like “Dairy Crack”: Because It’s Got Morphine In It [Food]
Breaking the dairy addiction
Know the Signs of a Milk Allergy


1. Kurek M, Przybilla B, Hermann K, Ring J (1992). “A naturally occurring opioid peptide from cow’s milk, beta-casomorphine-7, is a direct histamine releaser in man”. Int Arch Allergy Immunol 97(2): 115–120. doi:10.1159/000063326. PMID 1374738.

2. Review of the potential health impact of β-casomorphins and related peptides European Food Safety Agency, Scientific Report (2009) 231, 1-107

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  1. Lola

    Can’t wait for the recipe!

  2. Dr. Chris

    It’s been nearly 20 years since I eliminated any significant quantities of milk from my diet, so I don’t recall whether or not I had withdrawl. However, my family, long-term close friends and I are unanimously certain that when I drink milk I get “goofy.” I call it “high” on milk and it happens without fail whenever I consume more than a child sized glass on rare occasions. Furthermore, as near as I can tell, milk tends to prevent my body from taking in nutrients from food in some way. Despite the unusually large quantities of food I ate as a child, I was so thin my mother was worried child services would remove me. Childhood pictures of me show ever single rib and are the subject of laughter today. At the age of 24, while in college, I decided that milk was a luxury and in short order felt “better” in terms of mental clarity and within 6 months I gained 40+ pounds of muscle with such a degree of speed that I still have stretch marks on my arms.

    I never cared if this was a “real” condition or just an allergy peculiar to me, but not that I have 2 1/2 yr old fraternal twin boys, I see a huge difference in behavior in one of my boys when his mother and I substituted soy milk for dairy. Hopefully we’ll see him gain weight now as his slow growth and limited weight gain compared to his brother was beginning to concern us.

  3. When I found out I was lactose intolerant more than 10 years ago, I had no problem giving up milk or ice cream, but to this day I crave cheese. My body can tolerate hard cheeses well, so I use those to satisfy a little craving every once in a while, but whenever I go a stretch without any dairy at all I definitely notice my desire for cheese growing. I always wondered what caused this! Thanks!

  4. Emily Claire

    This is fascinating! I have been off dairy for about a year, and I can very much see the addictive qualities of it. I do think I experienced withdrawl symptoms, but for me it was mostly that I repeatedly sabotaged my efforts to kick it out of my diet. I would try to give it up, and then eat a lot of it all at once! It wasn’t until I had some pretty severe skin issues that I finally found the clarity and willpower to really say no.

    What I will say now is that I practically grew up on dairy. I remember once upon a time thinking that I could never live without cheese and yogurt. Now that it’s been out of my diet, however, it doesn’t even interest me anymore! It’s just not a big deal for me. The only time I have difficultly with it now is in social gatherings when everyone wants to order a pizza or have ice cream. If dairy has such a strong, relaxing effect on the body, it makes sense to me that many social activities have developed around it, just as they have around alcohol, coffee, and other drugs. This article helps me understand the allure of those situations a bit better.

    • Heather Crosby

      So glad you like this article/post Emily. You may enjoy the videos on this page from Neal Barnard (9th down) and Dr. Lisle, too (4th down). xx

  5. Dirtragmike

    I was always suspicious about cheese and thought, I was addicted to it. This confirms that.

    Yet, I must admit, that I personally find yellow (and especially “old”) cheese (Gouda, Emmentaler, Tilsiter, Cheddar etc) is more addictive than white cheese (Feta, Mozzarela, goat cheese), if it were to determine regarding my own cravings. I think, the amount of salt plays a crucial role in this, too.

    I have no problem coldturkeying any food, but I cannot stop eating cheese. I reduced it to a single piece a day (20-50 grams), but that was it. And that piece became a daily ritual.

    I feel like relieved after the first bite, much like other sedatives. After a while, you start seeking this mindset daily.

    • Heather Crosby

      I hear you, not everyone can do cold-turkey. You know what’s happening now when you take that bite or give into the craving——take it one day at a time with that new awareness…H

  6. Liz

    I never knew about this morphine effect until today, and it makes a lot of sense! I went vegetarian but I have been unable to break the cheese and ice cream addiction. I have always loved both, and you’re right – it has a calming, comforting effect! I am now motivated to rid of the dairy.
    I went dairy free for a while once, and cheese actually tasted disgusting when I tried it again after a few months. I’m ready to give it a go again and to kick dairy to the curb.

    • Heather Crosby

      You can do it Liz. Knowing what’s going on in your body when you eat certain foods is very empowering. Now when you eat dairy and you feel that bliss, you know what’s really going on 😉 H

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