One thing that sets the Primal way of eating apart from other ancestral health approaches is our acceptance of dairy fat. Obviously, those people who can’t tolerate dairy shouldn’t eat it, but in my experience a significant portion of the community can handle high-quality, full-fat dairy, especially butter, yogurt, and cheese. We like these foods for many reasons. They’re delicious. They make vegetables more appealing and nutritious. They’re inherently nutritious themselves, containing fat-soluble vitamins and important minerals, while the potentially problematic components of dairy – the whey, casein, and lactose – are either absent or mitigated by fermentation. Fermented dairy is a good source of probiotics, too. All in all, dairy is worth including if you can do it.

The rest of the nutritional world seem to be catching up with us on this. Recent years have seen a rash of meta-analyses, epidemiological studies, and clinical trials that question the assumption that low-fat dairy is healthier than full-fat dairy. Even Harvard’s Walter Willett, that seed oil-loving silver fox with the voluminous mustache, has come out in tepid support of full-fat dairy. Official recommendations lag, as they always do, but it’s changing. Just check out some of the studies. They don’t just exonerate dairy fat. They increasingly and repeatedly find connections between dairy fat and improved health.

• A recent study entitled “Milk in the diet: good or bad for vascular disease?” found that the evidence “indicates that increased consumption of milk does not result in increased CVD risk and may give some long-term benefits” including reduced blood pressure and body weight, and that the “SFA in dairy may be less of a risk factor than previously thought.”
• In women, a recent study found that the effect of dairy on cardiovascular disease depends entirely on the type of dairy consumed. Cheese consumption was inversely associated with risk of heart attack, while butter used on bread increased the risk. Awesomely and unsurprisingly, butter used for cooking did not increase the risk.
• According to another review of the influence of milk fat on CVD risk, the “majority of observational studies have failed to find an association between the intake of dairy products and increased risk of CVD, coronary heart disease, and stroke, regardless of milk fat levels.” While butter and other sources of milk fat may increase LDL-C “when substituted for carbohydrates or unsaturated fatty acids,” they also increase HDL and may even improve the HDL:total cholesterol ratio.
• Another study found that neither low-fat dairy nor full-fat dairy were associated with cardiovascular disease. However, full-fat fermented dairy was protective against CVD.

Many of those studies are based on dietary recall, which is notoriously unreliable. Can you remember how much dairy fat you ate five years ago? Five months ago? Five days ago? It’s more accurate to look at how biomarkers of dairy fat consumption, specific fatty acids or nutrients unique to dairy (or at least uncommon in other foods) that signify dairy fat intake when they show up in tissue or blood, relate to health conditions:

• In overweight teens, levels of the dairy-specific saturated fats pentadecanoic acid and heptadecanoic acid in the blood were associated with lower inflammatory markers, even after controlling for calcium, vitamin D, protein, and omega-3 intake (all dairy components that may influence health).
• Higher levels of trans-palmitoleic acid (a dairy fat) were associated with lower insulin resistance, dyslipidemia, and diabetes risk.
• Although higher circulating trans-palmitoleic acid meant higher LDL-C, it also meant lower triglycerides, improved blood pressure, and less diabetes in a cohort of white, black, Latino, and Chinese Americans. Circulating pentadecanoic acid was also linked to reduced cardiovascular disease in that same cohort. I’ll take the higher LDL-C if I get all the other stuff.
• Dietary intake of menaquinones (vitamin K2), “which is highly determined by the intake of [full-fat] cheese,” was associated with a reduced risk of incident and fatal cancer.

Dairy fat contains over 400 of these fatty acid “species,” making it the most complex natural fat. Not all of those species have been studied – 400 is a tall order – but there is evidence that at least a couple of them exert beneficial effects:

Conjugated Linoleic Acid

You know CLA by now. It’s the “good trans-fat,” the one that causes feverish vegans to point and scream about dairy “having trans-fats!” until you calmly explain the difference between manmade trans-fats in partially hydrogenated vegetable oils and beneficial trans-fats produced in the rumens of cattle and sheep.

I covered CLA a few years ago, focusing especially on the differences between supplemental CLA (often mostly trans-10, cis-12) and naturally occurring CLA (90% cis-9, trans-11), so I won’t go too much into it. Suffice it to say, supplemental CLA is a different beast altogether whose effects cannot be extrapolated out to dairy containing CLA. The dose is larger and the structure is different. That said, dairy naturally rich in cis-9, trans-11 CLA has been shown to be beneficial in trials. In a 2010 trial, pecorino romano (a raw sheep cheese high in CLA that I highly recommend) improved markers of inflammation and atherosclerosis in human subjects compared to a control cheese low in CLA.

Butyric Acid

Butyric acid is a short chain fatty acid produced in the guts of mammals by fermentation of fiber by gut bacteria. Since ruminants like cows are processing tons of fibrous plant matter, they make a lot of butyric acid which ends up in their dairy fat. Most research has focused on the benefits of endogenous production of butyric acid in the colon, but one human study suggests that oral butyric acid in the amounts we could expect to get from dairy fat can also have beneficial effects on our health.

However, it was an enteric-coated oral butyric acid supplement that helped 53% of subjects with “mild to moderate” Crohn’s disease go into remission and 16% have partial improvement, not a mouthful of butter. Enteric coatings allow supplements to make it into the colon whereas butter will be digested before making it. I suppose it’s possible that poor digestion could allow for some butter (and butyric acid) to make it down to the colon, but that’s not a desirable condition. The results of this study may not be applicable to butter consumption.

Milk Fat Globule Membrane

Dairy fat is encapsulated in a “milk fat globule membrane” that also includes various other bioactive compounds that seem to exert beneficial effects. Indeed, consumption of buttermilk, which is rich in MFGM, has been shown to reduce blood pressure in human subjects. Another study showed reductions in cholesterol, especially triglycerides, with buttermilk consumption.

What about low-fat dairy?

Low-fat dairy doesn’t seem to help with blood pressure or adiposity. It either has no effect on or increases a certain marker of inflammation, while eating butter, cream, or cheese has either a beneficial or no effect on inflammation. And although milk is often implicated in cancer, that’s only true for low-fat and skim milk; full-fat milk appears to be protective.

For all the potential benefits of these dairy-specific fatty acid species, I’m hesitant to elevate any one of them. Dairy is a whole food, and it’s likely the entire package that’s responsible for the effects. Plus, it’s difficult, if not impossible, to disentangle the fatty acid components from the other nutrients in dairy. CLA comes with calcium comes with milk fat globule membranes come with vitamin K2 comes with potassium comes with protein, and so on. And even if we could isolate the effects of various dairy nutrients and study them, that goes out the window we eat the stuff. When we bite down on a slab of aged gouda or toss a pat of grass-fed butter over some steamed broccoli or quaff a flagon of kefir, the myriad components of dairy are mingling in our mouths and our guts and being incorporated into and used by our tissues. We can’t disentangle dairy nutrients in the real world. Why would we want to? If we do, we end up with CLA supplements that don’t work quite as well as grass-fed dairy. Just eat the dairy. Studies – and millennia of tradition across dozens of cultures – support this practice.

Whatever’s doing it, something in the full-fat dairy is improving our health over and above low-fat dairy – and that’s what matters most. Choose your fancy. Raw milk? Drink it if you got and want it. Aged sheep cheese? Enjoy. Yogurt? Do it. They all seem to be associated with good health, protection from CVD and diabetes and obesity. Since the healthy user effect doesn’t really apply to full-fat dairy (since “everyone knows” full-fat dairy is bad for you), I’m cautiously optimistic that it’s actually exerting beneficial effects on people who eat it.

What does this mean in the big picture? Is full-fat dairy unabashedly Primal? If you’re tolerant of it, then yes, I suppose it is.

In a future post, I’ll explain how you can figure out if you’re dairy intolerant.

Thanks for reading, everyone. Take care and be sure to leave a comment!

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