Dairy: food of the Gods or neolithic agent of disease?

February 8, 2011 in Food & Nutrition by Chris Kresser

One of the most contentious issues in the Paleo nutrition community is whether dairy products are health-promoting or disease-causing.

On one end of the spectrum you have Loren Cordain and his group, who claim that dairy is not fit for human consumption for two reasons: 1) because it’s a neolithic food and not part of our evolutionary heritage, and 2) because of proposed physiological mechanisms by which dairy causes harm when consumed. On the other end of the spectrum you’ve got folks like Kurt Harris, Stephan Guyenet, Chris Masterjohn and the Weston A. Price Foundation who have pointed out the many health benefits of dairy and are generally in favor of its consumption.

My answer to the question of whether dairy is healthy are harmful is, in short: it depends. But before we get into the factors I think the answer depends on, I want to briefly address why I don’t take the evidence against dairy very seriously at this point.

Paleo re-enactment isn’t the goal

I agree with Dr. Kurt Harris on this one. We can look to the Paleo era to determine what was evolutionarily normal for humans, but it doesn’t follow that anything that falls outside of that norm is automatically harmful. The argument that we shouldn’t eat dairy now because we didn’t eat it 2 million years ago – without supporting clinical evidence – is not convincing.

There’s also the inconvenient (for the anti-dairy set) matter of people like the Masai and Loetschental Swiss that Weston A. Price studied, who were free of modern, degenerative disease despite receiving a large percentage of calories from dairy products.

Human evidence is more convincing than proposed mechanisms

Cordain’s group has published and reviewed several papers proposing various physiological mechanisms by which dairy causes harm. One recent example is a paper by Melnik called Milk Signalling in the Pathogenesis of Type 2 Diabetes. The theory presented is that milk consumption beyond the weaning period may overstimulate pancreatic beta-cells and promote beta-cell apoptosis. Since proliferation and apoptosis of beta-cells are hallmarks of type 2 diabetes (T2DM), it follows that milk consumption must contribute to T2DM.

Or does it?

If that theory were true, we might expect to see increased rates of T2DM in people consuming dairy products. But in fact we see just the opposite.

This study looked at serum levels of trans-palmitoleic acid, a fatty acid found in milk, cheese, yogurt and butter, and correlated them with risk factors for diabetes. Here’s what they found:

At baseline, higher circulating levels of trans-palmitoleic acid were associated with healthier levels of blood cholesterol, inflammatory markers, insulin levels, and insulin sensitivity, after adjustment for other risk factors. During follow-up, individuals with higher circulating levels of trans-palmitoleic acid had a much lower risk of developing diabetes, with about a 60% lower risk among participants in the highest quintile (fifth) of trans-palmitoleic acid levels, compared to individuals in the lowest quintile.

Translation: people with the highest trans-palmitoleate levels had 1/3 the risk of developing diabetes over the three years volunteers were followed. Not only that, after adjusting for confounding factors trans-palmitoleate levels were associated with smaller waist circumfrence, lower triglycerides, higher HDL and lower C-reactive protein.

Since trans-palmitoleic acid is a fatty acid found in the – you guessed it – fat of milk, the study also supports the idea that full-fat, whole dairy products are beneficial. This directly contradicts the low-fat hysteria we’ve been brainwashed with for so many years. But I digress.

Stephan Guyenet blogged about this study and re-wrote the authors’ conclusion in more straightforward terms:

Our findings support eating as much butter as possible****. Don’t waste your money on low-fat cream, either (half-n-half). We’re sorry that public health authorities have spent 30 years telling you to eat low-fat dairy when most studies are actually more consistent with the idea that dairy fat reduces the risk obesity and chronic disease.

Since this was an observational study, it doesn’t prove that dairy fat reduces the risk of T2DM. But it does suggest that the converse isn’t true.

Another study found that people with the highest levels of milk fat biomarkers, suggesting they consumed the most dairy fat, were actually at lower risk of heart attack; for women, the risk was reduced by 26 percent, while for men risk was 9 percent lower.

Another study showed that people who ate the most full-fat dairy had a 69% lower risk of cardiovascular death than those who ate the least.

Finally, this literature review of 10 studies found that milk drinking is associated with a small but significant reduction in heart disease and stroke risk.

I could go on, but I think you get the point. Which is this: evidence of what happens when people actually consume dairy products is a lot more convincing to me than proposed mechanisms of how dairy may effect humans.

The problem with isolating certain effects of a nutrient or food, and then making predictions based on those effects, is that we might miss some other quality about that food that negates the proposed effect. That’s a mouthful, so let me explain.

T. Colin Campbell is (in)famous for his research linking casein, a protein in dairy products, with cancer. He then made the huge and unsupportable leap to concluding that all animal proteins cause cancer and should be avoided. Most of you know the rest of that story.

However, what Campbell neglected to notice, or mention, is that whey, another protein found in dairy, has anti-cancer effects that completely cancel out the cancer-promoting effects of casein. Oops! This is why it’s so important to study whole foods, not just nutrients.

So let me finish this section by saying that I believe the weight of the evidence on dairy consumption suggests that it is not only not harmful, but quite beneficial.

When dairy may not be beneficial

However, as in most things, there are exceptions. Many of you reading this are probably sensitive to dairy and don’t tolerate it well. I certainly have patients that this is true for, and it’s not at all uncommon.

What’s the deal? Why does it seem to benefit some, but cause problems for others? In my opinion the answer boils down to the health of the gut. If someone has compromised intestinal permeability, or “leaky gut”, it’s more likely that their immune system will respond to potentially allergenic components in milk such as alpha- and beta-casein, casomorphin and butyrophillin.

This is especially true for people who are gluten intolerant, because it has been shown that milk proteins commonly cross-react with gluten. Put another way, if you react to gluten, it’s more likely that you’ll also react to milk.

Along these same lines, people with small intestine bacterial overgrowth (SIBO) – which is one of the major causes of irritable bowel syndrome (IBS) – may be more likely to react to milk because the bacteria in their small intestine aggressively ferments lactose, the sugar in milk, causing gas, bloating and other G.I. symptoms.

Not all milk is created equal

Something that irritates me is that raw and pasteurized dairy is often discussed as if it’s the same thing. It’s not. Raw dairy is a whole food, and pasteurized dairy is a processed food.

While it’s true that some people (described above) react to the proteins in milk, most who are sensitive are reacting to the sugar in milk: lactose. The enzyme lactase must be present to hydrolyze lactose into its constituent compounds, glucose and galactose. Somewhere between 1% – 95% of people don’t produce lactase on their own, depending on race and ethnicity.

In a sign of nature’s wisdom, raw milk contains lactase, the enzyme needed to digest lactose. Pasteurization, however, kills lactase. So if you don’t produce your own lactase, you’ll have a hard time digesting pasteurized milk. But that doesn’t mean you can’t tolerate raw milk. I can’t tolerate pasteurized dairy myself, but I don’t seem to have any problems with raw dairy.

So the answer to the question I posed in the title of this article isn’t so simple, and it depends on several factors:

• The status of your gut barrier
• Whether or not you have SIBO or IBS
• Whether or not you’re gluten intolerant
• Whether you’re eating raw or pasteurized dairy

If you’re not sure where you stand with dairy, the best approach is to remove it for 30 days and then reintroduce and see what happens. Elimination/reintroduction is still the gold-standard for determining sensitivity to a particular food.

But if you tolerate it well, I haven’t seen any evidence in the literature that convinces me you shouldn’t be eating liberal amounts of full-fat dairy.
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Read Chris Kresser's full article here.

Therapy versus Life

Much in this article by Dr Harris to make you think, evaluate, agree with or not and for sure consider.

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from PāNu Blog by Kurt G. Harris MD



I mean, when did this happen, really? When did our default self-concept make the turn from life to therapy?


I used to think this was a narcissistic "American" trait. Maybe we yanks spread it to the rest of the post-industrial world, but it seems to be everywhere now. And in the nutrition blogosphere I think it is the biggest dividing line - magical (bs) and neurotic yearning for immortality on one hand and the simple desire to live a good life without premature crippling diseases on the other.


We have people who want to eat healthy, and we have people who are living some perpetual existential crisis where they think you can cheat death and all disease if you just get all the numbers right. I confess these latter people drive me nuts. A huge contingent who think there is a "secret" to health and longevity the way there must be a secret to wealth, early retirement, being happy and finding love. They want to believe none of these worthy things are as hard or elusive as thousands of years of history, if not our own lives, have taught us.


These are the people who buy "The Secret" and books by Tim Ferriss. People who fantasize that life is all about "tricks" and "hacks". Perpetual youth and effortless happiness. Little study or real work required. Everyone can outsource everything and no real value need ever be produced.


Go through your blogroll of nutrition websites and books, and for each one, count how many special supplements are recommended. Then add the number of numerical recommendations for dietary parameters (wide ranges don't count) that are presented as if you might come to harm if you don't follow them. Then add the fraction of food items in our environment that are portrayed as being problematic, if not deadly. Then, add up the annual number of laboratory tests that are described as being critical to monitoring your health and square it. Then, add the total number of drugs that are suggested for otherwise healthy people who have never had a heart attack, cancer or a stroke, intended to treat these laboratory numbers as if they were diseases (they are not), and square that.


Then add them up S + DP + % F + Labs*Labs + Drugs*Drugs = TI


We can call this the "therapy index". I suggest that this therapy index will give you a good insight into the way the writer envisions health. A high TI means the writer thinks you are sick. That we are all sick. That anyone who has ever lived is born sick and needs therapy - their therapy - to be fixed. A catalogue of tricks and hacks and supplements and drugs and obsessive monitoring.


The writer has a weltanshaaung - a world view - that is Cartesian and mechanistic in proportion to the TI. Thinking about health like an engineer or keynesian economist instead of a biologist.


Now if the human diet in the 21st century were just fine, then a score of 0 on the TI might be achievable. PaNu certainly makes proscriptions, but the default stance is life, not therapy. You don't need fixing so much as to just stop injuring yourself.


A Cartesian view of the human organism is most opposed to the primary evolutionary assumption that should inform our thinking - the baseline assumption of a biologically informed view of humans. That there is a dietary metabolic milieu that we are adapted to, and the best chance we have of optimizing our health is to try and emulate it, not arbitrarily "improve" it.


The likelihood that we can "improve" upon this EM2 by doing something or adding something that was not a part of it already is similar to the probability that adding novel organic compounds to the gas tank or oil pan of my Porsche will "improve" its performance.


Not bloody likely.


Living in ketosis 24/7 - even though this requires persistent avoidance of starches or peculiar amounts of coconut


Multivitamins - even though you eat real, whole foods


Antioxidants - even though there is not a shred of evidence for a benefit, and some evidence of harm


Prebiotics and Probiotic supplements - even though you already eat real, whole foods


Fish Oil, Krill Oil, or even copious fish - even though a minority of hominin evolution could have had an excess of marine n-3s and grass fed beef fat and butter is all you need if you avoid TemPOs


Iodine - even though humans evolved the capability to live with a huge range of iodine in the diet - a nonsense book by Brownstein claims that 90% of the population is iodine deficient - actual science shows that iodine downregulates thyroid hormone synthesis and can flare Hashimoto's


Eating well beyond satiety - even though you are getting fat and feel like shit, you have been told by someone that this will "heal" your metabolism


Thyroid hormone - You feel fine and have normal thyroid labs but you take thyroid hormone from pigs every day to "improve" your LDL levels


Here is how it works in my world. When you come to me and tell me my car will last longer if I put some new compound in the gas tank, and the engineers in Stuttgart have never heard of it, and the manual tells me the car was not designed for it and doesn't need it, I say "prove it". Don't theorize, actually prove it. The burden of proof is on you to prove your artificial maneuver that defies the design of the car will make it "better". I have no similar burden - you are the one claiming magic, not me.


PaNu is the precise opposite of this totally speculative therapeutic approach. The car comes into the shop. The owner tells us about how it ran fine until he bought some (bs) elixir and started adding it to the gas tank a few years ago. The first thing we do in my shop is stop adding the elixir.


Here is the important part. Even if we stop adding the damaging elixir, and we are still a bit broken, it does not follow that any other (bs) elixir added to the tank will fix any damage. It might, but there is no more evidence for that than there was for adding some (bs) elixir to the car when it ran fine.


Of course, the car metaphor is apt but incomplete. The human body is not a machine, it is self-regulating biological system. So the fact that this is biology means there is even less reason to add unproven nonsense to our tanks.


My car cannot fix itself. The human body often can if we just stop ruining it.


So I would encourage you to ask yourself, what are you looking for? Do you think there is a "secret"? Are you fantasizing about immortality? Is everything a tweak or a hack or a trick? Do you think every problem in your life can be fixed by changing your diet?


Or do you see life as complex and tragic but sweet and rewarding, and are happy just to stack the odds in your favor with diet and then get on about your other business?


You do have other business than obsessing about what you eat, don't you?
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