No, milk isn't addictive
Just when you think you've heard it all, the Wellness & Woo world comes up with something even crazier than ever.
You’re probably hearing that milk (specifically, cows’ milk that we drink) has now suddenly been found to be addictive — despite nobody having been addicted to it in the past few thousand years. Just trust me, bro — it’s addictive.
Attend a few snippets from the Interwebs:
By Google Trends, we find that people have been panicking about dairy (both milk and cheese) being dangerously addictive since 2015. That’s when, in February, a study from University of Michigan found that highly-processed foods like pizza cause “addictive-like eating”:
The current study provides preliminary evidence that not all foods are equally implicated in addictive-like eating behavior, and highly processed foods, which may share characteristics with drugs of abuse (e.g. high dose, rapid rate of absorption) appear to be particularly associated with "food addiction."
In October 2015, news agencies picked it up and it went viral. Headlines literally used phrases like “Cheese really is crack,” “Cheese is as addictive as drugs,” and “Dairy crack!”
It actually goes back farther, when a journal article was published in January 2008 discussing the content of β-casomorphin in women’s breast milk. And so this is how popular interest in the subject has manifested in Internet searches:
The University of Michigan immediately tried to correct the media’s misinterpretation of their publication, but to no avail. Nobody cares about that. TIME magazine picked it up, but that’s about it. The sensationalized BS had won.
So here’s what’s basically going on. Dairy — and really all mother’s milk — does contain compounds that produce cravings, which is an evolved trait that gets the baby to want more milk, which totally makes sense. But cravings are not the same as an addiction.
Here’s the hypothesis behind the claims. One of the major proteins in milk is β-casein. When you digest it, it breaks down and releases BCM-7 (β-casomorphin 7, a peptide). The BCM-7 is absorbed through the intestinal barrier and enters the bloodstream, transporting it to the brain. It crosses the blood-brain barrier and binds to μ-opioid receptors in the brain. This triggers the release of dopamine, which creates pleasure responses — just like addictive drugs.
BCM-7 is known to be able to do all of those things, but — and this is the very big BUT — whether a normal amount of dairy consumed by an adult human will do all of those things to a degree that is physiologically relevant is in grave doubt.
The hypothesis proposes a worst-case scenario (or a best-case scenario, if you’re into opioid effects). In reality, the bioavailability of the BCM-7 from ingested β-casein to eventually bind to any meaningful number of μ-opioid receptors has a lot of things working against it. To wit:
A digestive enzyme called DPP-4 has a big problem with BCM-7 and breaks it down very rapidly, preventing most of it from getting to the intestinal barrier.
BCM-7 degrades very rapidly in the presence of blood plasma.
Any BCM-7 peptides that made it this far have another big problem: their exposure to DPP-4 that didn’t kill them probably destroyed the structure that it would use to bond to the μ-opioid receptors. (It’s a thing called the N-terminal tyrosine-proline bond, and that’s exactly what DPP-4 targets.)
And so, although the individual bits of the hypothesis are sound, when they’re all put together in the real world it does not hold up at all. A 2024 study concluded:
Overall, the findings of this study suggest that BCM7 cannot exert systemic effects in humans.
More studies have found the same thing, like this and this and this and this.
And then there’s the final stunt: this beat-up, brutalized peptide crossing the blood brain barrier in order to do its dirty work. It turns out that all the studies that found this is possible used direct injection of BCM-7 into the brain blood, crucially bypassing the entire digestion process! And on top of that, concentrations far, far exceeded what could ever be plausibly achieved through dietary consumption. So it’s a ridiculous and pointless finding.
Translation of all this: consuming dairy doesn’t do anything to your brain.
We see this borne out in real world testing. As far back as 1994, scientists tried to evaluate whether rats were attracted to BCM-7 in the same way they are to morphine, as they claim goes. They placed rats into a controlled environment where they could choose between pairs of two food items: BCM-7, morphine, and water. All 84 of the rats, in six groups, had opportunities to choose between randomized pairs of these three items. The results were that rats always preferred the morphine over the water or the BCM-7, and there was no significant difference between the rats’ preference for BCM-7 or water.
Because consuming dairy doesn’t do anything to your brain.
To this day, the European Food Safety Authority sticks with its 2009 finding:
A cause and effect relationship is not established between the dietary intake of BCM7, related peptides or their possible protein precursors and non-communicable diseases.
So in conclusion, I offer three points:
Dairy products are not biologically addictive to healthy adults.
Casomorphins from dietary sources do not reach the brain in sufficient concentrations to produce opioid-like effects.
Dairy consumption does not meet clinical criteria for substance addiction (tolerance, withdrawal, compulsive use despite harm).
Enjoy your milk and cheese. Ignore the Wellness Wooists.
I think the end game of food woo will be when we're down to only eating sterilized dirt and rocks. Just dirt and rocks.
I'm addicted to milk. I fight it. Glug, glug, glug.