A piece of anti-milk propaganda featured on the appropriately-named website “iwastesomuchtime.com” has started cropping up here and there. Its basic message is: don’t drink milk – it’s unneeded, unnatural, and bad for you. Naturalistic fallacy aside, the author(s) bring to bear on this message that a large proportion of the world is actually lactose intolerant. But in actual fact, when you look at the evolutionary history of lactose intolerance, this fact actually starts to sound like an argument from the other side of the fence.
Lactose tolerance is overwhelmingly more common in people who have pastoral (cattle-rearing) ancestry; for example, those of north-central European descent. It is rare in people who have non-pastoral ancestry, for example the Chinese. Population genetic studies tell us that the oldest genetic mutations associated with lactase persistence (the retaining of the enzymes necessary for digestion of lactose into adulthood) only reached appreciable levels in human populations in the last ten thousand years – in some populations, the frequency of the genes conferring lactase persistence have taken only 3,000 years to increase from negligible frequency to near-ubiquity. This rapidity, seen alongside other lines of evidence point to strong selection for an ability to digest lactose, and significant survival benefits for those who could do so, compared with those who couldn’t, when milk was available, in recent human evolutionary history. Most Westerners now live in a time of consistent nutritional plenty, so for this sample of the world’s population, generally the ability to digest lactose is no longer a matter of life-or-death. But seen in the light of evolution, the idea that drinking milk is “NOT NATURAL” falls through. And it renders the bulletin’s stats about China vs. Asian-Americans silly, because they correspond exactly to what genes and ancestry predict. Please do take a moment to read about the evolution of lactase persistance, if you are unfamiliar with it. It is a lovely demonstration of gene-culture co-evolution and a striking example of “niche-construction”. See, for example: http://lalandlab.st-andrews.ac.uk/niche/HumanSciences.html
One section in the bulletin reads: “cow’s milk is also the number one cause of food allergies among infants and children.” I’ve been to the source cited as a reference for this fact, and the maker of the anti-milk poster has in my opinion been fairly sneaky in its paraphrasing. The actual stat in the referenced document reads, “eight foods account for 90 percent of all (allergic) reactions: milk, eggs, peanuts, tree nuts, soy, wheat, fish and shellfish”. It doesn’t say that these foods “cause food allergies” in the sense of triggering allergies to other foods, which is what statement printed on the bulletin implies, I would say.
I’ve followed all of the cited references at the bottom of the bulletin and can’t find any source to back up their assertion that 62,200,000 Americans are drinking milk even though they can’t digest it. Perhaps I’m not looking hard enough, or perhaps they got that figure using dodgy calculations. If anyone can shed any light, please do. In any case, it sounds unlikely.
The really irresponsible feature of this meme is the clear-cut picture it presents of milk and disease. It implies that higher milk consumption is known to increase risk of ovarian cancer when in fact the picture is not clear, with some studies finding an association between high milk-(and meat- and cheese-) consumption and increased risk of some cancers, and other studies finding the opposite effect. With complex diseases involving so many variables, it is notoriously difficult to single out individual causal relationships, and it is common for different studies to find conflicting results. A meta-analysis in 2005, which looked at epidemiological studies of ovarian cancer and milk consumption, did not find an association. High milk and/or calcium consumption may increase the risk of prostate cancer, but then, it is also seems to lower the risk of colon cancer. The relationship between diet, lifestyle and cancer is a crucial area of active research. See:http://www.cancerresearchuk.org/cancer-help/about-cancer/cancer-questions/does-milk-cause-cancer
The blue and white poster also implies that high milk consumption is known to increase your risk of type 1 diabetes and heart disease. It has been proposed that early exposure (in infancy) to cow’s milk (or lack of breastfeeding) may increase a child’s risk of developing type 1 diabetes – a disease which in most cases is inherited. But it’s not clear that this extra risk accrues to people without a family history of diabetes.
Various studies have looked at dairy and its relation to heart disease and type 2 diabetes. An overview of the available evidence in 2010 found a *reduced* risk of all-cause deaths, heart disease, stroke and T2D associated with increased consumption of milk and dairy foods. The picture is complicated, unlike the one painted in the bulletin.
Going by the allusions to maltreatment of cows, it seems that really this is an agenda-driven campaign, whose net its author(s) have sought to widen by drawing from nutritional science, being willing to give an unchecked and distorted picture of what the science actually says in the process.
Notice, also, the complete vagueness of equating the saturated fat in “one serving” of milk to “one serving” of fries. How big’s a serving? And is it really all that surprising, and all that worrying, that ounce-for-ounce, milk has “about the same calorie-load as soda”? “Saturated fat” and “calories” are not terms synonymous with “bad”. This poster doesn’t centre around a solid stance or case. Its miscellaneous and dubious contents testify to a lack of quality control in its putting-together. The author(s) have clearly scanned the web for anything that can be framed to fit the anti-milk agenda, and ignored everything else.
Just for the record, I (the UK admin), can really get behind veganism (though this is not necessarily the agenda behind the bulletin) – I think it’s a very worth cause. But the broadcasting of misinformation for promotion purposes it is something that shouldn’t be accepted.