Anyone still wondering about the health effects of dairy? Have some lingering questions about whether it’s Paleo or not, even in its raw, grass-fed form? Good news! The Paleo dairy expert himself wrote in to us to explain a few things.
Last week I posted a review on the Ancestral Health Symposium, that intermingling of Paleo people in Los Angeles I went to a couple weekends ago. In the post I said the following about Pedro Bastos, one of the many reputable speakers at the event. He’s a Portuguese researcher who focuses on the effects of dairy on human health:
I got to ask Pedro Bastos, who I think of as the Paleo anti-dairy guy, one of my most burning questions (for real). That is, how can he explain the success of the Maasai people in Africa, who use raw, grass fed cow’s milk as a dietary staple? His answer to my question went something like this:
The hormones (or lack thereof) are different in their cows’ milk. The Maasai have different genes that make them more able to deal with lactose, etc. And their lifestyle is totally different – they get more vitamin D, have less stress, etc. Maybe if you ate like the Maasai your whole life, you would be fine with milk.
Raw milk is different than normal, pasteurized milk for sure. Pasteurization may lead to higher release of peptides from casein which could increase gut permeability. But that’s speculative. Grass fed milk is different – it contains CLA, and has been shown to be anti-carcinogenic in rats. But in the rat studies, the CLA content was way higher than what you’d actually get in milk or cheese.
Update from Pedro Bastos
Over the weekend, Mr. Bastos graciously added a few details to my summation as a comment to the blog post. I’m going to publish it here, too, so it gets the attention it deserves. Thank you, Pedro, for your thorough reply to my brief synopsis of your talk!
Oh, and the video at the top is the actual talk I heard him give. In it, he explains a lot of the topics below in more detail. Enjoy!
Thank you for including my name and my lecture among all the great names and lectures that were part of the AHS, which was a truly a marvelous experience.
If I may, I would just like to have the opportunity to say a few things about your excellent and timely question on the Maasai:
I didn’t say they were very different from us (from a genetic point of view that is), except for adult lactase persistence (ALP). About 60% of them (if memory doesn’t fail me) express ALP, but as far as I know that doesn’t really change the way they would react to milk, except for lactose digestion.
My main point regarding the Maasai and other African traditional pastoralists (the Fulani are another good example of a population who drinks milk and appears to be perfectly healthy, at least according to western standards) is that these populations have a very different diet (at least until a few years ago they didn’t include western foods and we could write a whole book on the adverse effects of isolated sugar, seed oils, grains, etc – all things that you and your readers know very well – perhaps it is not milk, but the lack of other foods that are being replaced by milk that preserves their health) and lifestyle – as you said higher sun exposure and presumably higher vitamin D levels, perhaps less chronic stress, higher physical activity, lengthen period of breastfeeding, hygiene hypothesis (important in allergy and autoimmunity), less exposure to genotoxic substances, etc.
This is very important when we discuss milk, since it is fairly well validated that milk increases IGF-1 more than any other (natural) food.
The problem is that IGF-1 in addition to promoting normal cell proliferation, it promotes tumor cell proliferation as well as it inhibits apoptosis. And it facilitates angiogenesis, malignancy and metastasis. So, if you have suffered either epigenetic modifications or DNA mutations either because of random errors or through exposure to a genotoxic substance (and there are so many in this industrial environment where we live) and if your cell-cycle control and repair mechanisms are not working properly, by chronically increasing your IGF-1 levels you may increase your risk for cancer.
Moreover, indeed raw milk from grass fed cows (which is what those traditional pastoralists drink) contains more CLA (which in rat studies, albeit in higher doses than we would find in dairy, has shown to have anti-carcinogenic effects) and some potentially protective peptides in the whey fraction that increase glutathione (GSH), although the amount of whey in milk is rather small, since caseins represent the biggest protein fraction in milk and the effects upon GSH that I mentioned were achieved with a whey supplement.
Furthermore, as I have presented in my lecture, novel dairying methods have increased the IGF-1 content of milk (although I’m not sure how significant this is, since pasteurization decreases IGF-1), as well (and this is in my view particularly disturbing) the amount of estrogens. The problem with estrogens in milk is that most of them exist in the conjugated form, which we know from hormone replacement therapy drugs that they have high oral bioactivity. And rat studies and one small human study suggest that indeed estrogens in milk are absorbed.
My take on milk and hormones is that chronic intake of industrial dairy (particularly milk) leads to chronic estrogen and IGF-I exposure (or in the case of IGF-1, it may simply be IGF-1 stimulus) that begins in utero. And in adolescence growth and development, I believe industrial milk can indeed lead to problems latter in life, because this is a period of rapid proliferation of undifferentiated (immature) epithelial cells, very sensitive to estrogens and growth factors.
Nevertheless, we must not forget that the purpose of milk is to to be the sole food of infant mammals during the most accelerated growth period in postnatal development when endogenous production of hormones is low! And this function also occurs in raw grass fed milk. That is why traditional Nilotic pastoralist are so tall. And height has been positively associated with a number of epithelial cell cancers (in part for the reasons I have outlined above)
Regarding other potential effects of milk, again one thing is to talk about it in the context of a traditional diet and lifestyle and another it is to talk about in the context of the western diet and lifestyle.
In biology, often 1+1 is not 2. Interaction is more important than isolated variables. As so, we need to always put things into context and my talk and my take on dairy was in the context of the western diet and lifestyle (I have learned to value not only diet but also lifestyle).
Best wishes and sorry for the long post,
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