|
Pros and Cons of Raw Milk: Part Deux
A follow-up on our first raw milk article, where we covered the infectious disease aspect.
So you’ve decided to brave the chance of contracting Listeria, E. coli, Salmonella and Campylobacter and find yourself some raw milk. But what are the real health benefits of drinking this unprocessed bovine beverage? In general, the benefits of raw milk break down into two camps: the real ones that that FDA and CDC would like you to ignore and the no-so-true ones advanced by a slightly zealous raw milk lobby.
Let’s start with the best documented of the raw milk health benefits: preventing allergies. For decades researchers had noted that kids who grew up on farms or had regular contact with farms were less likely to develop allergies. This observation falls in line with the “hygiene hypothesis” of allergy development – whereby our immune systems become bored and overactive in reaction to the “too-clean” modern environment, devoid of many of our healthy parasites and bacteria. Farms (with all their dirt and animals) are a rich sources of microbes that keep the immune system on track and steer it clear of allergies.
The same seems to hold true for just drinking raw milk. For example a 2007 study led by Marco Waser at the University of Basel in Switzerland found that European kids who drank raw milk early in life show decreased levels of asthma, sniffling, sneezing and watery eyes (rhinoconjunctivitis), food allergies, pollen allergies and horse allergies. This was independent of farm exposure.
Non-Industrial Farming Practices = Better
Raw milk is also often produced by grass-fed cows. Milk (and meat) from grass-fed cows contains more omega-3 fatty acids - health boon for heart, brain and belly. It also has higher levels of conjugated linoelic acid (CLA). CLA is a type of fatty acid found in milk and meat products that has been shown - in clinical trials and animal experiments – to aid weight loss (it’s a popular dietary supplement, but watch those side effects, eh?), protect against diabetes and heart disease and fight various forms of cancer. Good stuff here. But again, this is a function of what the cows eat and heat processing milk already high in CLA does not affect levels. Raw milk producers also often stick to the organic system, too.
More of the Good Stuff that Makes Kids Grow?
Heating milk may also reduce the amount of some vitamin and minerals - although the actual dietary significance can be hard to determine. For example, one 1939 by Warren Woessner at the University of Madison, Wisconsin found that pasteurized milk sometimes had less than 50% of the vitamin C of particularly rich raw milk samples. Indeed the pasteurization of milk is generally believed to be responsible for the emergence of infantile scurvy (check this 2001 review from Kumaravel Rajakumar at the University of Pittsburgh School of Medicine). However, other than infants no one relies on milk as their major food source, and few rely on it as their major vitamin C source (the richest sources from the above paper averaged about 25 mg/liter of milk. So I’d have to drink 3 liters of milk daily to get my 75 mg of recommended vitamin C. Or one cup of orange juice).
Heat processing may also affect the bioavailability of some other vitamins, but I haven’t seen any papers that blow my socks off. Likewise there is little evidence to suggest that heated milk has less calcium or less bioavailable calcium. For example a 1978 study on raw versus boiled human breast milk found that underweight babies grew fatter faster on raw milk and absorbed more nitrogen but not more calcium.
Yet raw milk might just be better in terms of general growth and goodness. For example, in 1931 a study of 17,000 Lanarkshire children conducted for the Department of Health for Scotland and published in Nature found that children given a 3/4 of a pint of raw milk daily grew slight more in weight and height than that the kids given pasteurized milk (both did much better than the control kids given no milk). For example, boys aged 5-11 gained an average of 12.81 ounces on pasteurized milk and 13.88 ounces on raw milk over the study months. Boys grew 0.79 inches on pasteurized milk and 0.83 on raw. Of course they don’t include any statistical tests, so I can’t really tell you how significant these differences are (if I had the raw data, I’d t-test it for you).
Now one could argue that you can get the same health benefits of raw milk (with fewer risks) by drinking milk from an organic dairy that only grass-feeds its cows, while also taking a multivitamin and forcing your kids to spend a shite load of time at the petting zoo in the first years of their life. Of course that’s your call.
Not So Real Raw Milk Benefits
Now let’s briefly turn our attention to the health claims that are NOT generally supported by medical evidence, just to clear up a few misconceptions. As a starter, let me quote you a passage from an oft-cited source. It’s from the May 8th 1937 issue of the Lancet, from their political discourse sections. While it’s clear that some of observations below are likely grounded in real mechanisms, you must remember that this is not a study. This is not a controlled trial. And this matters. For your reading pleasure:
“The Diseases of Animals Committee said that if vitamin C was destroyed it could be returned by giving the children lime-juice or orange-juice. Did their lordships think that in the poorer parts of our great cities the children were going to get orange juice or lime-juice whenever they got a glass of milk ? The loss in the milk through pasteurisation was first in vitamin C, the loss of which caused scurvy, and secondly, in vitamin D, a loss which caused rickets. The chief medical officer of Dr. Barnardo’s Homes, Dr. A. H. Macdonald, had made an exhaustive study of this subject and had come to the following conclusions: (a) The child on raw milk is very fit. (b) Chilblains are practically eliminated. (c) The teeth are less likely to decay. (d) The resistance to tuberculosis and other infections is raised. (e) In one of his homes containing 750 delicate boys who were fed on raw milk for five years, only one case of non-pulmonary tuberculosis occurred, while in the preceding five years with similar types of children fed on pasteurised milk fourteen cases of nonpulmonary tuberculosis occurred.”
Another old study (and here the age shows in its inaccuracies) is the cat feeding trials of one Dr. Francis Pottenger, a TB doctor working in Southern California. In 1932, after noticing the health problems of many of the cats donated to his hospital for research and hormone extraction, Pottenger decided to do a series of controlled feeding trials testing the difference between raw and cooked milk/meat diets. He found that cats given cooked milk and meat (in various proportions) suffered gravely from many illnesses including visual deficits, lower survival and weight of kittens, higher numbers of stillbirths, neurological problems and abnormal limb development. Those on the all raw diet (also the only of the 5 diets to have more meat than milk) did grand.
However, these are all likely signs of taurine deficiency as described by this 1986 paper. Unlike humans, cats are obligate carnivores. They cannot synthesize the amino acid taurine, which is degraded when meat is cooked. Humans can. This was not known at the time of Pottenger’s study and thus he concluded that cats should only eat raw food and suggested that humans do likewise. In fact, he fed his tuberculosis patients lots of healthy, raw, fresh foods at his sanatorium in Monrovia, which probably did them much good. Ironically, TB is one of the diseases that humans can catch from drinking raw milk and indeed one child died recently via that route.
Various advocates claim that raw milk can cure cancer, heart disease and joint stiffness (based on a 1944 study comparing raw and heated cream in guinea pigs...). Hmm, okay sure. Many raw milk supporters still refer to the 1970s studies of Kurt Oster who suggested that homogenization breaks apart the enzyme xanthine oxidase (XO) into smaller particles that can be absorbed through the intestinal wall and invade arteries and cause heart disease. This was later disproved.
A Problem of All Milk, Hot or Not
Eliminating milk proteins (such as casein) might help calm symptoms of autism according to a 2004 paper from the Cochrane Database Review. However, there is no research implicating the pasteurization process itself. If anything, different genetic variants of beta-casein have been linked to heart disease, autism and schizophrenia, but there is little consensus in the research community about these.
Pasteurized milk is often suggested to be “more allergenic.” While, as mentioned above, raw milk might help stave off allergies, heated or homogenized milk has never been shown to be more allergenic in itself.
Deeper Milky Thoughts
It’s pretty clear that drinking raw milk carries some elevated risk of serious infection. It’s also clear that raw milk is somewhat, if not a lot, better for you [though I might argue that the greatest improvements lie in the fact that raw milk producers also tend to be organic and only grass-feed their cows]. The problem lies in exactly HOW risky and exactly HOW much healthier is the milk, thereby allowing us to decide whether to drink it, or the government to decide whether to allow us to drink it.
To me, the evidence certainly suggests that raw milk shouldn’t be banned. But I do worry that the current craze for raw milk, and the underground nature of its sales, could reduce quality standards. Raw milk supporters often claim that pasteurization is just an excuse for dirty dairy practices. Fair enough. But when demands for raw milk reach mainstream, will all the raw milkers be able to keep their growing herds so clean and healthy?
