I'm not a raw milk stan but totally open to the idea that it can both be produced safely and have unique health benefits.
I wrote about the literature on raw milk safety almost a year ago, which I will link to in a follow-up comment, but I think it is also worth looking at the potential benefits.
First, to summarize my prior post, the major routes of milk contamination are environmental contaminants, poor animal health, and unsanitary milking procedures. These issues can be mitigated by hygienic milking practices.
Studies looking at raw milk programs like the German Ferman Vorzugsmilch, The U.S. Raw Milk Institute, and the British Columbia Hershare Association have found that raw milk contains fewer bacterial contaminants than conventional pasteurized (PMID: 32000877).
If the bacteria are the source of infectious disease (which they are), then by pure logic we could speculate that there would be less foodborne illness from high-quality raw milk than low-quality pasteurized conventional milk.
But of course, things can go sideways pretty quickly, and many unregulated farms selling raw milk probably aren't that hygienic and you probably shouldn't drink that stuff. There's also an element of personal responsibility to ensure you store the raw milk appropriately.
Second, raw milk isn't without *any* benefit. Allergies and asthma are the best-researched.
A 2020 meta-analysis out of Germany looking at 8 studies reported that early life (1–5 years old) consumption of raw milk was associated with a 42% lower risk of asthma, 34% lower risk of wheezing, 32% lower risk of hay fever or allergic rhinitis, and 24% lower risk of atopic sensitization (PMID: 31770653).
The effect sizes and confidence intervals were similar between children raised on farms and those who were not, which strongly suggests that it was the milk itself rather than farm life which conferred a benefit.
The authors suggest this benefit could be owed to a variety of factors in raw milk that are reduced with pasteurization and conventional treatment practices, such as bioactive peptides, fat globule structure, prebiotics, probiotics, microRNA, and several cellular structures or fragments.
I'm not going to write about these mechanistic explanations in this post. Too much info there.
I will say, however, that the GABRIELLE study found a protective effect of raw milk but not boiled milk (or pasteurized), and associated it with the bioactive whey peptides (PMID: 21875744).
Also, the PASTURE study found raw milk consumption to associate with a 23% lower risk of respiratory tract infections, which is pretty cool (PMID: 25441645).
Lastly, A pilot study in children allergic to milk found that they could tolerate nearly 6 times more raw milk in a sitting than they could with conventional pasteurized milk (50 mL vs 9 mL) (PMID: 30945370).
The researchers also showed in mice that heated milk abolishes the protective effects of raw milk on acute allergic symptoms, confirming an observation they made in a previous study also in mice (PMID: 28894452).
Many of the mechanisms listed above (particularly bioactive whey peptides and the milk-fat globule membrane) have a good amount of data showing benefits in adult humans, too.