Saturday, April 5, 2008

Does Milk "Do a Body Good?"

Note: Part of my motivation in keeping this blog is to serve as a resource for many food and nutrition issues. Some of you know that I am currently in a Masters program in Nutrition and Health Education, that I am studying in a more formal way what I live and research because it fascinates me--and maybe just because I am driven (or is that led?) to it! Anyway, I regularly have to write on various topics concerning nutrition for my program, from formal research papers to creating client handouts. I will begin sharing some of these writings here, so we can all benefit from this work I am doing (and you help me too: I write more clearly with an audience in mind).

Fair warning, gentle reader: I am very opinionated, and my bias will no doubt be obvious. I will try here to provide links for my assertions--and I will include many sources, even (especially?) some that do disagree with my personal viewpoint.
Please let me know if there are topics you would like me to address, and if there are resources you are wanting to find. And tell me if posting these papers helps you in any way . . .


Is milk "nature's perfect food?" In the USA, we have certainly all been told this many times. But is it true? And which milk are we talking about anyway? This has become a heated issue for some, one that touches on how we feed our most vulnerable citizens, our children (ok, and the rest of us, too). There are now websites on both sides of the issue (see NotMilk for many articles and links against drinking milk, and see RealMilk for argument supporting milk drinking.) There are those who think milk is poison and those who believe it is nectar of the gods . . . I am not sure I can settle the controversy for all, as the food we eat is such a personal decision--and because "milk" is not really one thing. I will try to illuminate what I feel are some major issues.

First, a definition: milk (mlk) n.
1. A whitish liquid containing proteins, fats, lactose, and various vitamins and minerals that is produced by the mammary glands of all mature female mammals after they have given birth and serves as nourishment for their young.
2. The milk of cows, goats, or other animals, used as food by humans.
3. A liquid, such as coconut milk, milkweed sap, plant latex, or various medical emulsions, that is similar to milk in appearance.

Part one hints at one of the foundations of the controversies: Milk's biological purpose is nourishment for the young of a species. Milk, as we generally understand it, is meant as the sole food for mammalian young for a species-specific period of time. Some feel that we humans have no business drinking the milk of other animals, and certainly not past the natural age of weaning of our own species (that--weaning--is a controversy for another day!) On the other hand, many believe that if milk can function as a complete source of nutrients, macro and micro, then it must be an ideal of sorts: "nature's perfect food."

The definition does cover some of the variety we need to address. Most basically in our culture, we are usually referring to mammal milk, especially from cows. Not all cultures depend upon the cow--throughout history, humans have drunk the milks of goats, sheep, water buffalo, horses, reindeer, camels, yak, and others we might find odd or improbable. And we now have commercially available soy, rice, almond, coconut and hemp milks. At home, milks can be made from many nuts and seeds. And yet, are these milks similar in nutritive value? Are they traditional foods? It seems they might not be, though the history is not very clear. Neither is nutritional information on these "alternative" milks easy to come by, perhaps because they are newer (see this link for a comparison of human and some animal milks).

While I was researching this topic I came across numerous comments to the effect that "humans are the only animals that drink the milk of other animals." Curiously, not one of these statements was backed up with a citation. This may be a case of something that we believe to be true because it seems to make sense--but may not actually have science behind it. I did find, on the other hand, accounts and photos of animals being fostered by another species (think Romulus and Remus--but played out in zoos and neighborhoods the world around where babies need a surrogate mama and another willing animal is found). These cases, while isolated, show that animals will do what it takes for survival, and humans drinking other animals' milk may be another example. It seems that humans have been enjoying dairy for at least 8000 years, from archeological evidence in Europe and in the Middle East. There is also evidence of extensive dairying in African history, something that continues today in tribes such as the Maasai. It has been postulated that this was an adaptation humans made in the transition to a more agriculturalist way of life, from a longer history of true hunting and gathering.

So why the controversy, if many humans have adapted over time to milk drinking? Well, being humans, we tend not to leave things as they are. Instead, we create, we innovate. And sometimes we mess with things until they are not at all the same as when they started out. And these altered substances just might not be very healthy. We have done this with the lowly beet, from whence comes that evil, white sugar. We have done this with grains, changing whole grains into things like Twinkies(TM). It may be that this is what we have done with milk, and why there is such confusion and conflicting "evidence." If we are not ingesting the same substance in each study, and if the substance being used in a study is not "the Real Thing" (thanks to CocaCola for their slogan . . .) how can we say it is the real thing causing the trouble? That is, the only real milk is the one straight from the animal (setting aside the issue of plant-based milks, for now) that is eating its natural diet. Anything else is a cultural manipulation.

And yet there are all of these studies that implicate milk in all sorts of illnesses, from cancers to diabetes to heart disease (look at this and this for an overview of some of the health issues that have been associated with milk). Yet what milk was the subject of these studies? Modern commercially produced cow's milk, the kind we buy in supermarkets. And what is commercial milk? Is that all one thing? No, it comes with varying percentages of fat, it might have dried milk added in to thicken it, it is pasteurized and usually homogenized. And it comes from animals raised in confinement, fed grain, cottonseed meal, bakery waste, citrus peel cake, the waste of ethanol production, and so on (see this and this for information on some of these feeding practices). This milk most likely has the residue of antibiotics, hormones and pesticides that were either given directly to the cow or were in the feed the cow ate.

It is true, that milk may indeed be harmful for us all. The studies are there to show problems (see the above links). Many people are indeed sensitive to both the lactose (milk sugar) in the milk and to the casein (milk protein) that is damaged in the pasteurization process. On the other hand, that thing we call milk only bears a visual resemblance to real milk, which comes from cows raised on pasture, and is not treated in any way--just put in clean bottles and consumed locally and in real time, soon after it came from the cow. The milk some are now calling "fresh, unprocessed milk" has all of the nutrition that a cow can glean from grass--its natural food. It has fragile proteins in their natural state. It has many enzymes, including lactase--which helps "digest" lactose, that help our digestion and our health. It has high quality fats, including some EFA's--which carry vital fat soluble vitamins, and these fats naturally separate, allowing us to have cream or butter (or homemade ice-cream, but don't get me going, or I may have to put a recipe in here!)

What of alternative milks? What if we can't drink milk, or don't want to? Are these milks acceptable substitutes for Nature's Perfect Food? It really depends upon what we are looking for in a substitute--an occasional milk-like substance to fill a need in a particular meal (what else goes so well with cookies? and what is a cream soup without cream?) or a daily food, contributing essential major nutrients. If the former is the desire, for sure almond milk or coconut milk would be great--and they are delicious. I have heard that oat sprout milk even tastes much like cow's milk. If we are looking for a nutritional mainstay though, we have to do the same sorts of calculations that vegetarians must do to ensure that complete proteins are being consumed--we have to look at what we would be getting in the cow's milk and try to balance with other foods, or supplements. For example, coconut milk, while full of wonderful fats, including antimicrobial lauric acid (the other main source of this is human milk), has very little calcium, and--especially when diluted to have a similar calorie content as cow's milk--is not a significant source of protein. So, if I wanted to use it regularly as a milk substitute, I would have to make sure that I had other good sources of protein and calcium in my diet, or I could fortify the the milk (as suggested in Eat Fat, Lose Fat) with a calcium source.

Why drink milk at all? In some cultures, it might be the most reliable source of protein and fats (and some carbohydrates--remember this is a "complete" food), especially if there is a religious taboo about the consumption of flesh. In a fascinating interview, anthropologist Marvin Harris goes into great detail not only about the nutritional "choices" made over time, but also about why biological adaptations may have set the stage for varying religious beliefs concerning foods. He also describes why some groups of people are adapted to drinking fresh milk and others to fermented dairy.

Fermented dairy is actually the way most peoples consume "milk." The lactose in the milk is broken down by a culture, making it more digestible, even for those who are not lactose intolerant (see table of sample rates of lactose intolerance by ethnicity.) And, as the pre-refrigeration world discovered, the cultured forms keep instead of spoiling. Each region has a favorite type, ranging from the world's many cheeses, to cultured buttermilk, sour cream, kefir, yoghurt, koumiss (from mare's milk), longfil, piima . . . (See Nourishing Traditions for descriptions and recipes of many types of fermented dairy, as well as further discussion on the consumption of dairy in general.)

Personally, I have experimented with many forms of dairy and dairy alternatives over my life. I enjoy the varied tastes and the qualities of richness and creaminess that dairy can add to food. Like many Americans, I am of mixed ethnicity, though I can trace most of my ancestors to Eastern Europe, where dairy is/was eaten almost exclusively in cultured form. And that is generally what keeps me most healthy, eating yoghurt, kefir, some cheese. I am certain that my forbears did not consume soy or hemp milk. And while they didn't consume coconut either, I do live in Miami and have somewhat adapted to this semi-tropical environment, so I do use coconut milk on occasion, especially when I get fresh, local coconuts.

Choosing a foodway is not something our ancestors had to do. They ate the foods their local environment gave them and they prepared them in the ways of the only culture they knew. We are confronted with many choices about food, and must find a way of navigating the confusion. With milk, as with every other food, we would do well to look to the traditions of the world and to those of our own people for guidance. And then we owe it to ourselves to experiment with an open mind.

Some Further Reading (not exhaustive, but a good start):

Pro Dairy: (has a good resource list)
The Untold Story of Milk, Ron Schmid
The Raw Truth About Milk,William Campbell Douglass

Con: (also has an extensive resource list)
Don't Drink Your Milk, Frank Oski
Milk A-Z, Robert Cohen

Good To Eat, Marvin Harris
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