Within certain sections of the ancestral health community, it’s a fairly common practise to consume significant quantities of dairy products such as cheese, butter, ghee, cream, and yogurt on a regular basis, even though such foods are evolutionarily novel additions to humans’ dietary repertoire. Many of the people who’ve promoted and popularized this nutritional custom argue that it’s not only unproblematic to embrace certain types of dairy foods, but that it’s actually beneficial, from a health perspective, to do so.
Implicit in this notion is the belief that it’s generally better – or at the very least not worse – to consume a dairy-enhanced diet than a more pure hunter-gatherer type diet. I question the merit of this supposition, for a number of reasons, one of this is that the fatty acid profile of dairy products like cheese, butter, yogurt, and ghee differs markedly from that of the foods that we humans have historically derived the majority of our fats from, which are the foods that natural selection would have dovetailed the human genetic-make up with.
Dairy products have an unusual nutritional profile
The most important and dominant source of fat in the typical preagricultural human diet was meat, including insects, organ meats, seafood, and marrow. This can be inferred from reconstructions of the Paleolithic nutritional environment, as well as from studies of contemporary hunter-gatherer communities. One doesn’t even really need to look at science to reach that conclusion, all one has to do is recognize that our primal ancestors ate quite a bit of meat and that plant foods generally contain much less fat than animal source foods. There are some exceptions though, the most obvious one being nuts and seeds, which are rich in fat.
Dairy products such as cheese, butter, and yogurt are obviously also sourced from animals. What’s important to recognize though is that they differ in several important respects from the types of animal source foods that we humans consumed up until the domestication of cattle ensued following the Agricultural Revolution. Not only do they have a very different micronutrient profile, but they contain unique mixtures of proteins, carbohydrates, and fats. No wonder they look and taste very different than meat.
The principle reason dairy products are in a class of their own, close to, but still separated from other animal source foods, is that they are created from a very special type of food, namely mammalian milk (typically cow’s milk), which serves a unique purpose in nature. It’s specifically designed, via natural selection, to promote and support mammalian growth and immune maturation during the early parts of life and contains an extensive list of growth-stimulating and immunoregulatory compounds, including miRNAs. Another reason is that fairly extensive processing procedures go into the production of dairy products such as cheese and ghee. As a result, the nutritional profile of these types of foods deviates substantially from that of unadulterated animal source foods.
When compared with the animal source foods that our primal ancestors ate, dairy products have a skewed fatty acid profile
When the fatty acid configurations of dairy products are viewed against those of animal source foods of non-milk origin, several marked differences present themselves. These differences are particularly profound and apparent when only tissues derived from wild animals are included in the mix. Perhaps the most striking thing is that the fatty acid profile of dairy products looks somewhat skewed when compared with the profile that is characteristic of the types of animal source foods that we’re evolutionarily accustomed to eating. The levels of saturated fatty acids appear markedly heightened, whereas those of unsaturated fatty acids, in particular Polyunsaturated Fatty Acids (PUFAs), seem depressed.
This high level of saturation is a universal characteristic of all dairy products. Take Cheddar cheese for example. It contains about 33 grams of fat per 100 grams, of which 21 grams (!!) is of the saturated kind. That equals to about 63.6% of total fats. Cheddar cheese certainly isn’t an anomaly in this respect. On the contrary, its saturated fat content, as a percentage of total fat, is stereotypical of dairy foods, which isn’t particularly surprising in light of the fact that roughly 65% of the fat in cow’s milk is of the saturated kind.
Is this problematic? If you ask an Atkins devotee, he’ll probably answer no without even pausing to think. Personally, however, I do think it’s a problem. Actually, I think it’s a big one. If you want to find out why I hold that belief, I suggest you dig into the many articles about saturated fat I’ve written here on the site, in which I take an in-depth look at the role that saturated lipids have played in the human diet throughout our evolution, as well as how they affect our health and immune systems.
Moving on from saturated fats to unsaturated ones, we find that dairy products tend to be relatively low in healthful polyunsaturated fatty acids. Butter, for example, only contains 3 grams of PUFAs, although it contains as much as 81 grams of total fat. As a percentage of total fat, that represents a meager 3.7%. Dairy products created on the basis of milk from grass-fed animals is higher in PUFAs than products created from milk produced by grain-fed animals; however, even such products contain relatively little PUFAs as a percentage of total fat (1, 2). This is particularly concerning in light of the fact that we know that PUFAs – in particular long-chain omega-3 fatty acids – of animal origin were essential with respects to the evolution and workings of the big, complex human brain.
From an evolutionary point of view, this high saturated/unsaturated lipid ratio of dairy products is an anomaly, in the sense that the foods that our primal ancestors derived the majority of their fats from generally contained more unsaturated than saturated lipids. This is not only true of fatty plant foods, such as nuts, seeds, and avocados, which are very rich in monounsaturated fats, while low in saturated ones, but it also applies to the animal source foods that have supported the evolution of humanity for millions of years. Wild-caught seafood is obviously rich in PUFAs, but so is wild game meat, which contains a balanced proportion of saturated-, monounsaturated-, and polyunsaturated fatty acids (3, 4, 5). Even marrow, a type of food that’s often brought up in discussions about the role that fat has played in the human diet throughout our evolution, is low in saturated lipids (as a percentage of total fat), when compared with dairy foods (4).
Furthermore, it’s important to note that the relative contribution of each individual fatty acid differs somewhat between dairy products and other types of animal source foods. This is obviously relevant to discussions about optimal human nutrition, as any major alterations of the fatty acid structure of the human diet are going to affect people’s health.
Finally, it needs to be mentioned that many dairy products contain extremely high concentrations of total fat. Butter, ghee, and cheese, for example, are packed with lipids. They contain a lot more fat and calories than almost all of the foods that were continually available throughout our evolution. Two exceptions are marrow and nuts, which are very rich in fat and energy; however, hunter-gatherers have to put in quite a bit of work to gain access to these nutritional resources. In general, the hunter-gatherer diets that contributed to shaping the human genome over millions of years had a low caloric density. The addition of fatty dairy foods to modern renditions of such diets brings about an immediate increase in energy density, which is unfavorable in most situations.
When compared with the types of foods that we humans have historically derived the majority of our fats from and that supported the evolution of the complex human brain over millions of years of evolution, dairy products such as cheese, butter, and cow’s milk have an irregular nutritional profile. Among other things, they contain very high levels of saturated fats, while low levels of unsaturated lipids, in particular polyunsaturated ones. By implication, if you consume significant quantities of dairy products on a regular basis, the fatty acid profile of your diet will be skewed when compared to that of the diet we’re biologically well-suited to eat. This is not to say that it’s very hazardous to one’s health to eat some cheese or drink a glass of milk every now and then; however, there’s no doubt that it’s wise to think twice before one makes such foods a major part of one’s diet.
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