I used to be one of those folks who thought he was being coy when he joked with others about how he was addicted to cheese. It was just so damn tasty that I couldn’t imagine enjoying food without it.

Now that I know much more about nutritional biochemistry I realize my snarky remarks had a hint of truth to them. Cheese really can have an addictive effect on people!

Casomorphins: Dairy’s Opiate

If the above picture makes your mouth salivate and a tingly feeling goes off in your brain, it’s important to understand the biological reason why this happens.

Casein is the name of a family of proteins commonly found in mammalian milk, especially in the milk of a cow. When your body digests casein it gets broken up into fragments, and inside the gut one of the peptide fragments that’s formed is beta-casomorphin-7. 

And yes, I mean that morphine. Beta-casomorphin-7 is a naturally occurring opiate, which is a compound that creates euphoria and is the basis for drugs like morphine, codeine, and oxycodone.  Cheese is essentially a lot of milk that’s been condensed and bacterially cultured to taste yummy. It takes about 10 lbs of milk to make 1 lb of cheese, and during the process most of the water is sucked out leaving a condensed mixture of casein peptides and fats.  Fats create a euphoric effect unique to themselves, and the body also gets a shot of casomorphins which bind to opiate receptors in the brain, which make you feel happy and glowy, and that feeling of “my god, I love cheese so much!” propagates and grows a little bit stronger.

So yeah, you kind of can be addicted to cheese.

Woah! So Is Cheese Dangerous?

Like anything in toxicology, the discussion of health effects can only be truthfully considered when you account for dosage. And no,  eating cheese does not have the same effect on the body as shooting up with heroin, so there’s no need to get carried away. But it is the same thing going on, just to a much lesser degree.

Casomorphins actually play a useful role in infant nutrition (the only time you’re actually meant to drink milk), which is why they’re there in the first place.

The long term health effects of a diet that’s high in casomorphins is not entirely clear, but there are some disturbing signs. The key is how much gets out of your gut and into your bloodstream, where the casomorphins can “swim upstream” into other parts of your body, bind with opiate receptors, and wreak havoc.  Casomorphins that run amok have been linked to brain disorders in the central nervous system, formation of LDL cholesterol (the bad kind), sleep apnea, respiration disorders, and autism.  And cheese addiction, of course.

It’s hard to quantify how much casomorphins are ingested because their presence is not specifically tested for, and the variability of the casomorphin content in food is very high. Small details in the manufacturing process, storage conditions, and your own genetics can all have large effects.

Why Would Mother Nature Put An Opiate In Your Food?

An interesting question is why an analogue of morphine would naturally occur in the first place. It’s actually quite fascinating.

Like I said before, all mammalian milk naturally contains casein, so all infants naturally ingest some casomorphine and benefit from its opioid-like effects.

So why would a baby need opium?

For one, opiods have a calming, euphoric effect.  This calming effect can appease infants who are typically irritable and cranky.  Think about how a baby  quiets down after you give it milk.  And think about how the baby learns to crave milk shortly after its born. Milk provides all sorts of vital nutrients to infants and casomorphins may be nature’s way of giving infants the hook they need to always desire it.

Casomorphins may also be the physiological reason behind the mother-infant bond itself. The brain and body are extremely developmentally sensitive in its early years, and the combination of physical contact, feeding, and casomorphins tells the baby “Hey! I really need this stuff and this is the only place to get it!”

Sources of Casomorphins in the Diet

Casein comes from milk. Milk does not naturally contain a lot of casomorphins, but various manufacturing and fermenting processes either increase the peptide concentration in dairy products or breakdown elongated proteins into casomorphin fragments.  Cheese is by far the biggest culprit.

There’s no definitive way to measure how much beta-casomorphin-7 you’re getting in your diet, but a paper here studied BCM7 content in different types of cheeses. It found that that soft cheeses like brie had a higher casomorphin content than hard cheeses like gouda and cheddar.

Take it for what it’s worth.

The implications of this post are interesting to say the least, but it’s also important not to get carried away. Eating cheese isn’t really like taking codeine, BUT there’s a reason only suckling infants drink milk. Just sayin’.

Research, Stories, and References on Cheese Addiction, Beta-Casomorphin-7 and Its Health Effects:

Cass, H. et. al. “Absence of Urinary Opioid Peptides in Children With Autism”  Arch. Dis. Child.  August, 2008.  pgs. 745-750

URL:  http://www.autisme-gestion.fr/IMG/pdf/745.pdf

De Noni, I, et. al. “Review of the Potential Health Impact of Beta-Casomorphins and Related Peptides” European Food Safety Authority. January 2009.

URL: http://www.efsa.europa.eu/en/efsajournal/doc/231r.pdf

Taylor, Jenna. “Addiction to Cheese is Real Thanks To Casomorphins” Yum Universe. August 25, 2011

URL:  http://www.yumuniverse.com/2011/04/25/dr-jenna-taylor-addiction-to-cheese-is-real-thanks-to-casomorphins/

Sienkiewicz-Sz?apka, E, et. al. “Contents of Agonistic and Antagonistic Opioid Peptides In Different Cheese Varieties” International Dairy Journal. April 2009, pgs. 258-263.