Raw Milk

[kmcolo]

Hi everyone,

 

In the next few weeks (months?) I will be looking to the question of raw milk. If my learning experience and investigation is of any interest to you then please join in the conversation. I will warn here (as I do in my first post on the subject) that I will bias against raw milk so if a challenge to your understanding of raw milk does not sound attractive, this series of posts will not likely appeal to you.

 

Health Points

[Queso]

cow milk is so gross!

[Monomer]

It's an interesting topic. I don't drink cows milk, but if I did I'd rather have it pasteurised than raw because I wouldn't want to take the chance that it's contaminated.

 

Here's some interesting sites I've found:

 

Raw Milk Safety

PDF: http://www.safefood.qld.gov.au/docs/fs%20-%20raw%20milk%20pathogens%20141003.pdf

Got Milk? Make Sure It's Pasteurized

[CraigD]

I think it’s accurate to conclude that “raw” (unprocessed whole milk) is safe for use if consumed or shortly (within a day, or a few days if kept chilled) after being milked from the cow, goat, etc. If brought in contact with many containers, bottled/packaged, and transported uncertain distances, possibly at various temperatures, pasteurization, irradiation, or other techniques to assure that it does not become contaminated with disease pathogens is prudent.

 

Although raw milk has a unique taste that many people find pleasant (I’ve never had it, but my wife, who grew up in a rural household that had a milk cow, has, and says the taste is very distinct and delicious), I’m unaware of any health or nutrition benefits it offers that pasteurized milk does not. Completely unprocessed whole milk, which has not been skimmed of its cream, has a very high fat content, and is likely to be unhealthy if consumed frequently in typical amounts (.25 litres or more per day), though this can easily be improved by skimming the cream, which is then useful for making butter of various kinds. Like commercially available skimmed milk, manually skimmed milk has only trace amount of fat.

 

In summary, I think that people wanting to drink and process raw milk should own, have access to, or obtain it from a trusted person with a cow. For the large majority of people for whom this is impractical, unpasteurized milk is likely to be dangerous, and should be avoided.

 

In addition to the milk, owning and caring for a cow can be rewarding, though, as with any domestic animal, should not be undertaken lightly (or by people with small yards! ). Surprisingly, it can be done in many places not ordinarily considered farms – my wife’s childhood cows pastured within a few hundred meters of a gas station, office building, grocery store, motel, K-12 school, and within a kilometer of a college campus. Local ordinances for my present neighborhood, “inside the beltway” of the US capitol, Washington DC, permit cows and most other farm animals – though it would be necessary to combine the yards of many neighbors to have enough pasture for a single cow, and be more work than I, personally, would be willing to assume. For aspiring “rustic suburbanites”, a goat seem a better choice (and, IMHO, have better personalities :lol: ).

[kmcolo]

I think it’s accurate to conclude that “raw” (unprocessed whole milk) is safe for use if consumed or shortly (within a day, or a few days if kept chilled) after being milked from the cow, goat, etc. If brought in contact with many containers, bottled/packaged, and transported uncertain distances, possibly at various temperatures, pasteurization, irradiation, or other techniques to assure that it does not become contaminated with disease pathogens is prudent.

 

This is generally true though contamination of the cows udder or teat is not uncommon so it does require human inspection and work for raw milk to be safe (thus introducing all too ubiquitous human error) and some infections (rare) infections are found within the udder and are undetectable to the human eye. [1]

 

Although raw milk has a unique taste that many people find pleasant (I’ve never had it, but my wife, who grew up in a rural household that had a milk cow, has, and says the taste is very distinct and delicious), I’m unaware of any health or nutrition benefits it offers that pasteurized milk does not. Completely unprocessed whole milk, which has not been skimmed of its cream, has a very high fat content, and is likely to be unhealthy if consumed frequently in typical amounts (.25 litres or more per day), though this can easily be improved by skimming the cream, which is then useful for making butter of various kinds. Like commercially available skimmed milk, manually skimmed milk has only trace amount of fat.

 

In summary, I think that people wanting to drink and process raw milk should own, have access to, or obtain it from a trusted person with a cow. For the large majority of people for whom this is impractical, unpasteurized milk is likely to be dangerous, and should be avoided.

 

I'd agree on a first order review. But there are those that are quite certain that there are health benefits (of course there are those that are quite certain of a lot of things that are not all the certain) which is why I am doing a further investigation for my own interest. One possible benefit from raw milk might be from higher levels of omega-3 fatty acids. Primarily those that drink raw milk look to dairies whose cattle are only grass fed. There has been evidence to suggest that grass fed animals have higher levels of omega-3s in their tissues and in their milk [2]. Omega-3s are also heat sensitive and thus in the pasteurization process some portion would be destroyed. Advocates claim there are also benefits from enzymes and antimicrobial agents within the raw milk but so far I find those claims dubious.

[maikeru]

One possible benefit from raw milk might be from higher levels of omega-3 fatty acids. Primarily those that drink raw milk look to dairies whose cattle are only grass fed. There has been evidence to suggest that grass fed animals have higher levels of omega-3s in their tissues and in their milk [2]. Omega-3s are also heat sensitive and thus in the pasteurization process some portion would be destroyed. Advocates claim there are also benefits from enzymes and antimicrobial agents within the raw milk but so far I find those claims dubious.

 

Antioxidants present in the milk from the grass or feed may help prevent a larger portion of the omega-3 fatty acids from being destroyed (oxidized) by pasteurization, so your worries could be unfounded. As I understand it, the reason why grass-fed animals have higher levels of omega-3 in their bodies has to do with grass being rich in alpha-linolenic acid (ALA), some of which is then converted to DHA and EPA (the more important omega-3s) in the cow.

 

I find the risk of mycobacterium, campylobacter, or listeria infections to be worrisome, so I would not recommend drinking raw milk solely for its health benefits when pasteurized organic milk or milk from grass-fed cows could provide similar or comparable benefits. Locally, there have been several people who've come down sick with Campylobacter jejuni recently after drinking raw milk:

 

ksl.com - Utah County Issues Health Warning After Severe Food-borne Illness Outbreak

 

For me organic whole milk works just fine, as long as I drink a little (so I don't die from heart disease). It has a better flavor than regular, cheap milk which tastes like water. There are plenty of sources of omega-3s besides raw or whole milk. Seafood, nuts, soy, flaxseed, and leafy green vegetables. You needn't rely on raw milk or milk at all for them.

[kmcolo]

Antioxidants present in the milk from the grass or feed may help prevent a larger portion of the omega-3 fatty acids from being destroyed (oxidized) by pasteurization, so your worries could be unfounded. As I understand it, the reason why grass-fed animals have higher levels of omega-3 in their bodies has to do with grass being rich in alpha-linolenic acid (ALA), some of which is then converted to DHA and EPA (the more important omega-3s) in the cow.

 

Yes, this is my understanding as well but the heat of pasteurization would impact (lower, not eliminate) the levels of omega-3s.

 

I find the risk of mycobacterium, campylobacter, or listeria infections to be worrisome, so I would not recommend drinking raw milk solely for its health benefits when pasteurized organic milk or milk from grass-fed cows could provide similar or comparable benefits.

 

I agree and my present stance is - do not drink raw milk - that said I am doing further research to see if there might be something to what the proponents of raw milk are saying. To that end I have another post on raw milk on my health points blog. Please read and critique as any added constructive input is helpful.

 

Locally, there have been several people who've come down sick with Campylobacter jejuni recently after drinking raw milk:

 

ksl.com - Utah County Issues Health Warning After Severe Food-borne Illness Outbreak

 

I followed this story as well. As it turns out just yesterday it was reported that the dairy is likely not responsible: Payson dairy's milk OK, tests show.

 

For me organic whole milk works just fine, as long as I drink a little (so I don't die from heart disease). It has a better flavor than regular, cheap milk which tastes like water. There are plenty of sources of omega-3s besides raw or whole milk. Seafood, nuts, soy, flaxseed, and leafy green vegetables. You needn't rely on raw milk or milk at all for them.

 

Agreed, if omega-3s are the only factor in favor of raw milk then it is a no brainer. Avoid raw milk. But proponents say there is something else going on here. And to their credit so far I did find some evidence for proteins in raw milk that boost immune response that are likely greatly reduced in effectiveness in pasteurization due to their functionality being dependent on their tertiary structure. But it is so far scant evidence and not anything approaching proof.

 

Thanks for the replies everyone!

 

Ken

[maikeru]

Yes, this is my understanding as well but the heat of pasteurization would impact (lower, not eliminate) the levels of omega-3s.

 

Yes, it would probably. Omega-3 fatty acids oxidize much faster in the presence of heat and light.

 

I agree and my present stance is - do not drink raw milk - that said I am doing further research to see if there might be something to what the proponents of raw milk are saying. To that end I have another post on raw milk on my health points blog. Please read and critique as any added constructive input is helpful.

 

You have a lovely blog, and I've bookmarked it. I'll add my thoughts on the components from the Biodefenses article. I cannot provide medical or expert advice (nor can I read much in the way of pdf articles at the moment, technical difficulties with my old comp), but I've studied a bit about the immune system. Had a few classes on it.

 

Immunoglobulins: There could be something to these, because I think it's likely they're mostly IgA molecules, which are secreted in the milk of mammals and would be resistant to proteolysis by digestive enzymes. In a neonate, they coat the digestive system and provide the first line of defense against any potential pathogens. But I wonder if this protective effect would be limited somewhat, since the specificity of the IgA molecules might be directed at mostly bovine pathogenic antigens rather ones which humans might be commonly exposed to. I.e., if the IgAs aren't specific for human pathogenic antigens, the IgAs might not help coat, alert, or start any helpful immune reaction.

 

Maybe it could be argued that exposure to pathogens, including those like mycobacteria or listeria, can help prime the immune system of healthy individuals. The levels might be lower than necessary for successful infection. I believe the M cells of the intestines are very sensitive even to micromolar concentrations of antigens. The IgAs could also provide a sort of first line immunity to these bovine pathogens if encountered elsewhere or in other foods. Or if they coat the pathogens and allow the immune system to process the antigens and develop an immune reaction, this could help prime the adaptive immune system with specific antibodies and T cells or larger numbers of cells. But...immunity may not be guaranteed or achieved.

 

I looked up the other components on Wiki, Google, etc., and they seem to be bacteriostatic, bacteriocidal, or antimicrobial in general. All of those, including the IgAs, would probably be affected by heat and I don't know if they would regain their conformation. Probably not. Thus, they'd be non-functional and lose their defensive capabilities.

 

I'd need to do some more searching on Google Scholar, the univ. library, etc. to get a better feel for the pros and cons. Still, the list of possible bacterial contaminants, including the nasty ones like mycobacteria, listeria, etc., really takes my enthusiasm down a notch.

 

I followed this story as well. As it turns out just yesterday it was reported that the dairy is likely not responsible: Payson dairy's milk OK, tests show.

 

That's good to hear. I think some of my neighbors buy raw milk, so they'll be more happy than me about this.

 

Agreed, if omega-3s are the only factor in favor of raw milk then it is a no brainer. Avoid raw milk. But proponents say there is something else going on here. And to their credit so far I did find some evidence for proteins in raw milk that boost immune response that are likely greatly reduced in effectiveness in pasteurization due to their functionality being dependent on their tertiary structure. But it is so far scant evidence and not anything approaching proof.

 

Well, my biochem teacher did always say that for proteins "shape is the key to function." So we definitely agree there. Most of the protective ability of milk seems due to the proteins.

 

Actually, one more thing comes to mind. It could be that raw milk, excluding pathogenic contamination, contains chemicals which specifically act as antigens to prime immune cells against common or pathogenic microbes. Chemicals which may be similar to or the same as common microbial metabolites or antigens recognized by the body. I thought of tea, which contain chemicals broken down in the body into alkylamines, that act to prime gamma delta T cells and cause their rapid proliferation. In the case of tea, some theanine is converted to ethylamine in the liver, and it's believed this ethylamine helps to stimulate the proliferation of those T cells in the body and makes the innate immune system, and possibly the adaptive immune system, more flexible and quicker to respond.

 

Theanine:

Theanine - Wikipedia, the free encyclopedia

Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses -- Kamath et al. 100 (10): 6009 -- Proceedings of the National Academy of Sciences

Is the Increase in {gamma}{delta} T Cell Priming by Dietary Alkylamines Sufficient to Prevent Cancer? What Other Components of the Diet Prime {gamma}{delta} T Cells? -- Bukowski 135 (12): 2911S -- Journal of Nutrition

 

Would similar "immuno-priming" chemicals exist in raw milk or pasteurized milk? Or would they be the result of the microbial content of milk, dead or alive?

[kmcolo]

Thanks for the great research and ideas! I will try to digest (pardon me, I couldn’t help myself) this information with what limited time I have. I hope to have more up at the blog by mid-week next week.

[kmcolo]

"I hope to have more up at the blog by mid-week next week."

 

And will certainly cite your post when I do so.

[maikeru]

I'm glad I could be of some assistance. Ken, do you mind if I ask what scientific field you study and work in?

[kmcolo]

I'm glad I could be of some assistance. Ken, do you mind if I ask what scientific field you study and work in?

 

Not at all. I am a chemist. My recent work has been atmospheric chemistry focusing on the methane cycle. I am also well steeped in climate science.

[maikeru]

Very cool. I have very little experience in climate science, but I hope to learn more gradually. My background is mostly microbiology, cancer, and immunology as an undergrad.

[kmcolo]

If you are interested in learning more about climate science I can certainly help. You have been more than helpful with your knowledge of microbiology and immunology. Also, I've posted a reply to your comment on omega-3s on my blog (http://healthpoints.blogspot.com). Would you be interested in becoming a columnist for Health Points? Nothing too serious, just a place to explore hot topics and see what the science might have to say.