I have no evidence for this hypothesis.

January 4, 2008 5:55 PM

Is it possible that lactose intolerance is correlated in some way with the consumption of pasteurized milk?

Or, maybe with some other feature of modern milk?

posted by clockzero to food & drink (8 comments total)

It's correlated with different populations that were or were not pastoral. The normal state for humans is lactose intolerance. Tolerance is an evolutionary adaptation
posted by Pants! at 6:05 PM on January 4 [1 favorite]

Not a direct answer, but there is study currently underway (not to mention lots of FUD and counter-FUD) as to whether milk types that contain the A1 protein may be linked to a wide range of disease. The FAQ I linked to only mentioned a few disorders, but I think some people suspect other conditions too. I'm not sure if lactose intolerance is suspected, but you could look into that.
It presumably varies by region and industrial practise, but in New Zealand, most milk contains A1, because until now, there has been no reason for it not too, and cow's milk is cow's milk so milk from dairy cows is mixed together and sold as the same product without reference to the particular breed of dairy cow. Breeding trends occurring for other reasons are expected to reduce or eliminate A1 in the next few years. I would expect New Zealand to be ahead of the USA in this matter - Dairy is a major national industry there (and I'd trust the NZFSA about 5000% more than the FDA :-)
posted by -harlequin- at 6:17 PM on January 4

It's been compulsory to pasteurize milk for 70 years, since 1938 or so. So, not very modern milk.
posted by smackfu at 6:30 PM on January 4

Sure, it's possible. Everything's possible. Nothing, however, is likely. This is the central paradox that drives science.

On a more helpful note, I don't think modern milk has been around long enough to cause evolutionary change in the vast majority of humans who are lactose-intolerant in adulthood. We might still implicate it in lactose intolerance among those whose ancestors have been drinking milk forever, but what would be the mechanism? If it's the milk microflora, then some appropriate dose of raw milk should restore lactose tolerance, temporarily at least. If it's the amount of casein stuck to the milkfat (which is really what homogenization is about), then we'd have to put experimental groups on diets with pasteurized homogenized and pasteurized unhomogenized and watch for a change. Harlequin raises the possibility that it might have to do with the breed of the cow or some subtler biochemical quality, the gene for which is new. I've never heard of any research on these things, but those are the basic avenues I'd take.
posted by eritain at 6:32 PM on January 4

Anecdotally, a lot of people I know claim they are lactose intolerant, but can drink raw milk. I'm not sure if there is actual science to back that up...probably not, since most modern milk studies have used pasteurized milk.

But it could be other factors with raw milk ranging from fat content (raw milk is whole milk, whereas the American public typical consumes low-fat milk) and homogenization to the breed of the cow and its feed (many raw milk producers feed their cows differently and raise "heritage" breeds).
posted by melissam at 6:45 PM on January 4

Pants! has it (additionally, this Wikipedia link may be more accessible), but I'd like to point out that -harlequin-'s link has a really good explanation of correlation vs causation.
posted by Pinback at 6:47 PM on January 4 [1 favorite]

Anecdotally, a lot of people I know claim they are lactose intolerant, but can drink raw milk. I'm not sure if there is actual science to back that up...probably not, since most modern milk studies have used pasteurized milk.

Raw milk contains a lot of bacteria, those that can harm you and cause disease, and those that ferment lactose (among others). Those that ferment lactose are called Lactic Acid Bacteria (LAB). LAB can break the bond between the two sugar molecules (glucose and galactose) that make up lactose. People who are lactose intolerant do not have the enzyme (lactase) needed to break that bond. If you give raw milk a day or two before drinking, the LAB will have converted some of the lactose into glucose and galactose rendering it easier to digest by those who are lactose intolerant.
posted by catseatcheese at 12:02 AM on January 5 [1 favorite]

When I had "raw" milk I noticed it tasted funny. Like, really funny. In my case it was raw, unpasteurized, and served out of a giant aluminum pot in the middle of Siberia, so a sort of different case altogether. But it definitely didn't have that smooth slightly sweet taste that normal milk has. I wonder if raw milk doesn't free up as much lactose.

In any case, I am not normally extremely lactose intolerant, and in that instance I was sick on everything else I was eating, so hard to know really.
posted by Deathalicious at 4:36 AM on January 5