The Plant Rx

If you talk to anyone who has recently switched to a plant-based diet and you ask them what food(s) they miss most, 9 times out of

Bovine Beta-Casomorphin-7 courtesy of Wikipedia

10, they will say cheese! Nope, not chocolate cake or BBQ, it’s cheese.  The same thing is the case if you talk to a vegetarian about completely transitioning to a plant-based diet and omitting dairy from their diet.  The typical response is, ” I would, but I can’t give up cheese”.

So, why is this?  After all, cheese does kind-of smell like dirty socks!

The answer is: Casomorphins.

Ok, well, that’s great – but, 1. What exactly are casomorphins and 2. How do they explain our love obsession with cheese? And, 3. does it even matter?

• 1.  What are “Casomorphins“?

Definition: Casomorphins are peptides, i.e., protein fragments, derived from the digestion of milk protein.

Casein, is the milk protein that makes up 80-86% of the protein content of cow’s milk.  Casein has been documented to break down in the stomach to produce the peptide, casomorphin, an opioid that acts as a histamine releaser. [1]  (Although, not the topic of this blog post, the fact that casomorphins are a direct histamine releaser in humans is why so many people are allergic to dairy products; An estimated 70% of the population worldwide.)

Thus, the distinguishing characteristic of casomorphins is that they have an opioid effect.

• 2.  How do casomorphins explain our love obsession with cheese?

In his book Breaking the Food Seduction, Dr. Neal Barnard discusses the addictive qualities of casein. He uses the example of chocolate to explain how this works:

“University of Michigan researchers showed that chocolate does not merely tickle your taste buds; it actually works inside your brain in much the same way opiate drugs do. The researchers gave 26 volunteers a drug called naloxone, an opiate-blocker used in emergency rooms to stop heroin, morphine, and other narcotics from affecting the brain. It turned out that naloxone blocked much of chocolate’s appeal. When they offered volunteers a tray filled with Snicker’s bars, M & M’s, chocolate chip cookies, and Oreos, chocolate was not much more exciting than a crust of dry bread.

In other words, chocolate’s attraction does not come simply from its creamy texture or deep brown color. It appears to stimulate the same part of the brain that morphine acts on. For all intents and purposes, it is a drug-not necessarily a bad one and not a terribly strong one, but strong enough nonetheless to keep us coming back for more.

As common as chocolate addiction may be, it is by no means the only potentially addictive food, nor is it the most dangerous. In PCRM‘s research studies, when we take people off meat, dairy products, and other unhealthy fare, we often find that the desire for cheese, in particular, lingers on much more strongly than for other foods. While they might like ice cream or yogurt, they describe their feelings for cheese as a deep-seated craving. Could cheese really be addictive?

Well, in 1981, Eli Hazum and his colleagues at Wellcome Research Laboratories in Research Triangle Park, N.C., reported a remarkable discovery. Analyzing samples of cow’s milk, they found traces of a chemical that looked very much like morphine. They put it to one chemical test after another. And, finally, they arrived at the conclusion that, in fact, it is morphine. There is not a lot of it and not every sample had detectable levels. But there is indeed some morphine in both cow’s milk and human milk.

Morphine, of course, is an opiate and is highly addictive. So how did it get into milk? At first, the researchers theorized that it must have come from the cows’ diets. After all, morphine used in hospitals comes from poppies and is also produced naturally by a few other plants that the cows might have been eating. But it turns out that cows actually produce it within their bodies, just as poppies do. Traces of morphine, along with codeine and other opiates, are apparently produced in cows’ livers and can end up in their milk.

But that was only the beginning, as other researchers soon found. 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. A cup of cow’s milk contains about six grams of casein. Skim milk contains a bit more, and casein is concentrated in the production of cheese…

{It takes approximately 10lbs of milk to make 1lb of cheese.  As milk is turned into cheese, most of its water is removed leaving behind concentrated casein and fat.  Thus, concentrated dairy products, like cheese, have especially high levels of opiates}

…When you drink a glass of milk or eat a slice of cheese, stomach acid and intestinal bacteria snip the casein molecular chains into casomorphins of various lengths. One of them, a short string made up of just five amino acids, has about one-tenth the pain-killing potency of 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. Barnard, goes on to explain 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”.

To bring the topic full circle, Dr. Barnard later tells us that in Naloxone tests, the opiate-blocking drug eliminates some of cheese’s appeal, just as it did for chocolate.

• 3.  Does all of this matter?

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 around 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 weather 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?

Sure this is good to know, but 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 bingeing 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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Sources:

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

Related Articles

• Why Cheese is Like “Dairy Crack”: Because It’s Got Morphine In It [Food] (gizmodo.com)
• Lessons Learned: From the participants in the plant-based health study (theplantrx.com)
• Breaking the dairy addiction (soulsearchingvegan.com)
• Know the Signs of a Milk Allergy (everydayhealth.com)

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