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Does Dairy Cause Osteoporosis?


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milk causes osteoporosis, dairy and osteoporosis
Healthy bones are integral to a healthy life. istock.com/feellife

I do a lot of myth-busting around here, and it’s usually conventional wisdom that crumbles in the face of scientific evidence. But this time I’m actually siding with conventional wisdom, and busting a myth that’s common in the alternative health community. I addressed this topic in-depth on a recent podcast, but it’s such a common question that I decided to write an article on it for easy reference.

The myth in question is the idea that dairy foods contribute to osteoporosis by ‘acidifying’ our bodies. This claim is especially common in vegan-oriented alternative health media, but also comes up in other internet realms, including those with a Paleo orientation.

The claim is based on the “acid-ash hypothesis of osteoporosis,” which I addressed extensively in my ‘Acid-Alkaline Myth’ series a couple months ago. (Check out part two as well.)

For those who missed the articles, this hypothesis states that foods high in phosphate leave an ‘acid ash’ after digestion, thereby lowering serum pH. The body supposedly compensates for this and restores normal blood pH by stealing alkaline minerals (such as calcium) from the bones, thus decreasing bone density.

Dairy products and bone health: one thing conventional wisdom gets right. Tweet This

Because of their phosphate content, milk and other dairy products are usually considered ‘acid-producing’ foods under this hypothesis. Thus, proponents claim that even though dairy contains calcium and other nutrients that can be used to build bone, dairy’s acidifying effect on the body outweighs its calcium content and results in a net loss of bone density.

Although I’ve already written about the hypothesis as a whole, I want to specifically address the claims regarding dairy for a few reasons. First, because my readership is acutely aware of how many times conventional wisdom has led us astray, I think we’re all more likely to believe a hypothesis that directly opposes mainstream health claims. In this case, dairy is so heavily advertised as a panacea for healthy bones that it would seem only natural for those claims to be dead wrong. You’ll see that (for once) this is not the case!

Additionally, I came across a 2011 study that specifically addresses the dairy-acid balance-osteoporosis connection. They came to some interesting conclusions that I want to share with you all, and hopefully we can put this issue to rest.

Dairy, Acid Balance, and Osteoporosis: The Real Scoop

In this study, “Milk and acid-base balance: proposed hypothesis vs. scientific evidence,” the authors review both the acid-ash hypothesis as a whole and the specific claim that dairy contributes to osteoporosis. After reviewing the scientific evidence (or lack thereof), they reach the same conclusions that I have: the studies available simply do not support this hypothesis.

First, they emphasize that urine pH is not indicative of systemic pH. In fact, except in cases of serious renal insufficiency, diet does not affect serum pH at all. If it did, we’d be in a lot of trouble! The pH of our blood is maintained in a very tight range, and if it deviates significantly, we will die very quickly. No doubt we can really mess up our health by eating the wrong things, but thankfully our minute-to-minute survival doesn’t hinge on whether we can correctly balance the acidity or alkalinity of the foods we eat.

Further, the bones don’t even come into play in the regulation of our serum pH; that’s our kidneys’ job. Any ‘acid ash’ that is left behind by the foods we eat can be easily dealt with and eliminated in the urine. This is why your urine changes pH depending on what you eat. It’s just a sign that your kidneys are doing their job!

In short, their conclusions simply reiterate the points I made in my Acid-Alkaline series, and demonstrate that the acid-ash hypothesis of osteoporosis has no scientific backing. But perhaps the most interesting thing about this particular study on milk is the authors’ assertion that dairy isn’t even acid-forming in the first place!

The authors cite two studies that indicate that milk actually leaves an alkaline ash as opposed to an acid ash, based on measurements of urine pH and net acid excretion (NAE) following milk ingestion in clinical trials. (Remember, this doesn’t mean that milk raises serum pH. Foods can change urine pH, but not blood pH!)

So not only is the hypothesis itself wrong; the application of the hypothesis is wrong too, at least in the case of dairy. Even if the acid ash hypothesis of osteoporosis were viable, there would still be no mechanism by which dairy would contribute to osteoporosis.

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Dairy Probably Is Good for Your Bones After All

The majority of the evidence indicates that conventional wisdom may actually be right about dairy. Clinical studies have found that drinking milk leads to a positive calcium balance, indicating that more calcium was absorbed than was excreted. (1) Other studies show that phosphate in general – not just from milk – increases calcium retention and improves bone health. (2) Increased dairy consumption is also consistently associated with lower rates of osteoporosis and better bone health. We all know to take observational studies with a grain of salt, but when clinical data backs up their conclusions, they’re significantly more convincing.

For example, an increased dairy intake in postmenopausal Korean women was associated with a decreased risk for osteoporosis. (3) Another study found that in the US, dairy intake was a significant predictor of osteoporosis among postmenopausal women. (4) And in Polish women, higher dairy consumption during childhood and adolescence predicted better bone health as adults. (5)

Although you won’t see me sporting a milk mustache in a “Got Milk?” ad anytime soon, it does appear that dairy can be beneficial for bone health. That’s not to say it’s necessary; after all, we got along just fine without dairy for most of human history! But based on the evidence, it’s safe to say that dairy does not contribute to osteoporosis, and full-fat dairy (preferably raw) can be a beneficial addition to the diet for many people.

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  1. Studies are nice but few, if any, so far have been conclusive. The fact that the Okinawans and Japanese consume about 300mg daily of calcium rather that the recommended 1200 but have strong bones to me outweighs anything said to the contrary here or in studies.
    The fact that all five of the long-living Blue Zones show consumption of whole plant-based food exceeds 80% and little red meat or dairy says it all till there are conclusive studies that prove otherwise.

  2. I think articles like yours can be very dangerous. Humans are only meant to consume dairy in the form of mother’s milk at the beginning of their lives. Then you are done. These are obvious points that have been made many times before, but I will mention them here, again. Name one animal that drinks the milk of another species after weaning. It doesn’t happen, because that is not the way we are built. All countries who consume the most dairy, United States, Finland, the UK, etc., have the highest cases of osteoporosis. Think that is a coincidence.

    And, if we don’t get enough calcium from the plants we eat, how did the cows or goats get their calcium? They don’t have magic calcium making machines in their bodies. They get it from what they eat.

    want to be healthy and have strong bones? Exercise and eat a plant-based diet, and do your own research.

    • Anne, while I think you are very likely right about milk, based on my own many years of reading, I don’t think you give very compelling reasons. One needs more than “here is what other animals do, and so we should do the same”. You do refer to studies of osteoporosis, but while these are noteworthy, the causes are not fully clear, and until they are one does well to be open-minded (perhaps even while avoiding milk personally as you and I evidently both do). Chris gets my respect for attending closely to hard evidence and changes his views when the evidence so indicates.

    • @ Anne,
      You may disagree with the arguments and a lot here do. I myself certainly won’t drink liquid milk ever again in my life, for all the reasons we know. (But I’ll certainly eat again Faisselle and Roquefort, hell yeah).

      However, what truly, unlike this article, is “dangerous”, is the magical and analogical view of the world some people here display, including you.
      How dangerous is it? Answers below.

      “how did the cows or goats get their calcium? They don’t have magic calcium making machines in their bodies.”
      -> True, they don’t.

      “They get it from what they eat.”
      -> Also true. In fact, grass-fed cows easily eat 40 pounds of calcium-rich grass *per day*. Do you? 😀
      And grain-fed cows? Well, they eat calcium supplements (surprise!). Otherwise, they would suffer from what’s called “milk fever”.
      If you don’t eat dairy *at all*, I would urge you to make an Excel spreadsheet to begin tracking down exactly how much calcium you’re consuming every day. You’ll certainly have surprises.

      “Name one animal that drinks the milk of another species after weaning. ”
      -> None does, true again!! Why is that? The reason is not because adults can not digest milk. The (primary) reason is that all animals tend to reduce the amount of metabolic energy they need to function. Making milk is an enormous metabolic burden (see cow milk fever above or ask your young human colleague). It is the adult than *can* digest what the baby can not (solid food), and not the other way round: so mothers simply stop breastfeeding as soon as they can in order to save energy, not because the baby would not be able to digest milk anymore.
      This is why your cat doesn’t throw his milk plate across the room. (Btw, aren’t cats very picky? They seem good at deciding what they can and can not eat. If your magical worldview of a natural order were true, cats would certainly express a global veto over cow milk, and demand cat milk only).

      “It doesn’t happen, because that is not the way we are built.”
      -> Excuse me, do you know the way we are built? No physician on Earth has a claer understanding of how we function. Example, we may indeed have some evidence that dairy/liquid milk is correlated to osteoporosis… but we certainly don’t know for sure WHY and to which extent.
      I sure would be interested by your deeper knowledge.


    • Name another animal that drinks the milk of other species:
      Feral cats steal milk from nursing elephant seals in Baja, as do gulls. There are even videos on YouTube. In Europe, during the time when milk was delivered in foil-topped bottles, several species of birds pecked through the foil and drank the milk. Temple snakes have long been fed milk. Baby mammals will often nurse lactating females of other species – Google “cross-species suckling” or “inter-species suckling”. Some animals will refuse to be weaned, and self-suckling of adult mammals is not unknown. Most animals take to milk readily, even in adulthood.

      I think the major difficulty preventing nonhuman adult animals from drinking milk of other species is difficulty in obtaining it.

    • Cows have 4 stomachs. Cows and goats are ruminant animals, this means they have the ability to ferment the plants they eat before they digest them. They practically chew and rechew their food. Sorry, we cannot be compared with ruminant animals.

  3. Then why do the countries with the highest dairy intake have the highest levels of osteoporosis?

    • The reason is obvious and you already know the answer…dairy is animal protein and excessive animal protein is harmful to the body in more than one way….the bones are just one of them.

      Have to wonder if Chris is not somehow being rewarded by the dairy industry…

      • Richard. I’ve read all your comments on this post. Chris has already spoken at length to every single one of your posts in previous articles, many of his podcasts, and his programs. He frequently makes clear what the evidence suggests. If dairy is all of the following: 1. well tolerated 2. raw and unpasteurized 3. free from hormones and antibiotics 4. from healthy pastured heritage breed cows then it’s a personal choice. He is completely against CAFO dairy, which is the only place that could afford to “reward” anyone.
        Everyone here respects Chris Kresser’s opinion for the fact that he does NOT accept rewards or act on anyone else’s behalf, and only searches for truth and is THE most science based health expert you can find. Making accusations like that here only makes YOU look like the one getting some kind of reward from trying to make him look bad.

        • A comment from the PR department does not change my propensity to lean towards the evidence.

          I did not make an accusation but said “have to wonder” nor do I find him to be a science based health expert but thanks for your effort in replying and expressing your opinions.

          • He doesn’t have a pr department or need one; another jab from you. I’m just someone trying to get information to improve my own health and prevent disease for my own family. If you are suspicious that the information he presents ins’t fully honest, then go somewhere else and find what agrees with your existing beliefs 100% and wonder all you like about that. Good day.

      • Galatians from Galatia, region in Asia Minor, from Greek Galatia, based on Gaul, in reference to the Gaulish people who conquered the region and settled there 3c. B.C.E.

        From the Greek word Gala meaning milk. These people lived and survived off real dairy.

        The real problem lies else where.

  4. It seems that even after all these years scientific research has not really closed the loop on milk or more importantly animal products.

    Maybe milk is good for bones but there is evidence out there that excessive animal protein causes problems unrelated to bones….for example, cancer. There is at least one study that concluded large quantities of milk increases risk of prostrate cancer.

    There are so many additives in meat or animal feed that it is difficult to justify eating very much red meat, chicken or even dairy. What may have been safe one week ago maybe no longer be safe because of something new in the industry thanks to some chemical company.

    Even organic almond milk can contain carrageenan which is a questionable substance.

    Bottom line is maybe we were better off 100 years ago before all this chemical progress…

  5. I’d like to see the pH test done on the blood serum of long term Raw Fruitarian diet and Cooked Meat and Potato diet groups an hour or so after a meal. I’d bet the farm the results would be quite different from the posted narrow range spoken of above.

  6. It’s strange that otherwise intelligent human beings need to be informed of this obvious fact, but: You are not a baby cow.

    Cows produce milk to feed their babies. There is no reason for adult humans to drink breast milk from another animal. It’s illogical, unhealthy, and, frankly, weird.

    The human body is not designed to consume the breast milk of another animal. The healthiest form of breast milk for humans is from our own species. But we tend to leave that for the babies. So let’s offer other animals the same decency.

    Plant milk is healthier, and there is no confusion about whether or not it’s good for us. Almond milk, hemp milk, rice milk, organic soy milk… the options are numerous and provide higher levels of essential vitamins than cow milk.

    • Careful about that almond and soy milk, there are many companies adding unhealthy ingredients beyond sugar.

  7. Something that’s almost nearly always missing in the analysis of dairy, is whether the good outweighs the bad.

    I used to love dairy. I delivered it, I drank litres of it every day, and I had lots of health problems. I gave it up, and the health problems went away. I started researching.

    The good? It’s got some nutrients, but because it’s pasteurised, they’re mostly gone. It’s got calcium, but we just don’t need much calcium – that’s a push from the dairy industry because our bones are largely calcium – a very weak connection. It’s got protein, but really unless we’re doing resistance training we don’t need much of that either. So yeah, there’s some good stuff.

    The bad? Oh man, the list is endless. So many links to things like osteoporosis, cancer, arteriosclerosis, asthma, acne, diabetes, hypothyroidism, calcium deposits in joints and organs.. seriously, there’s just so much bad news for dairy, that you’re playing Russian Roulette.

    Good luck in your choices.

    • I realize the focus of this article is on bones but the evidence against a large quantity of daily milk is much stronger for the link with prostate cancer.

  8. Remember Weston Price found populations that consumed lots of dairy and no ill health was noted (quite the opposite). This was raw dairy of course from healthy ruminants. Whatever ills can be blamed on dairy I think tie in with its adulteration. Homogenization creates abnormally small fat molecules that some speculate can bypass gut barriers. Pasteurization of course destroys fragile components, especially ultra-pasteurized, which Mark MacAfee then calls the milk ‘paint thinner’…ever notice the shelf life of ultra pasteurized milk products? And of course added hormones and antibiotics and grain fed/sickly cattle no doubt create more issues still.

    Try some raw Jersey cow milk and take note of your body’s response (start slow if you have been off dairy).

    • Jersey cow’s milk is a good suggestion as it is very likely free from the mutation found in some European breeds such as Friesian/Holstein or Ayrshire cows – Alpha 1 Beta Casomorphin. This ‘devil in the milk’ is a real trouble-maker, implicated in heart disease, autoimmune disease and plenty of other ills.

      • I’m surprised everyone is talking about different kinds of cow’s milk: I find ewe’s milk yoghourt and cheese (Spanish Manchego, for instance) much better for me than cow’s milk of any sort. This is not from the point of view of osteoporosis but to avoid overproduction of mucus as a singer.

    • If you wish to place you health in the hands of 1930’s research that is questionable that is up to you but I like to react to research done in the last ten to twenty years which includes much better methodologies.
      I suggest for openers you might look into the Blue Zones and see how those cultures did on their specific diets.

    • There are studies that provide strong evidence of a high risk of prostate cancer with two or more servings of milk daily.

      Again, the Asians consume little milk and the men have much lower rates of prostate cancer.

      There are safer alternatives that will result in strong bones without the risks of prostate cancer…

  9. I found all of the information very interesting. I can tell you I feel better on a low acid diet, but I have to agree. I my blood is acidic. Dr. did not seem to care. It does worry me as to why that has not changed.

  10. “Other studies show that phosphate in general – not just from milk – increases calcium retention and improves bone health. (2) Increased dairy consumption is also consistently associated with lower rates of osteoporosis and better bone health.”

    The study says that more calcium was excreted, not retained, with milk. And what are the studies that consistently associate dairy consumption with lower rates of osteoporosis?

  11. But aren’t the countries with the highest per capita rate of dairy consumption also the ones with the highest rate of osteoporosis?

  12. My mother had Osteoporosis, and because I have it in my lower back (I am in my 60’s) I have been advised to take calcium citrate supplements every day. Is this counter productive, bearing in mind previous comments? If so, what would you advise?

  13. What about the effects of pasteurization on the absorbability of calcium from dairy? My understanding is that a substance is formed from the high heat pasteurization that binds the calcium, preventing its absorption. A frequent comment is that North Americans have the highest consumption of dairy and the highest rates of osteoporosis in the world. Is this true, and can it be linked to the heating of the milk?

    Obviously, raw is the ideal way around this, but not everyone is willing to go raw or has access to it.

  14. So the video that has been going around where the milk is poured into the coca-cola bottle and shows what it looks like after a couple hours, it was like sand/dirt at the bottom of the bottle and a clear yellowish liquid at top separate from the sediment….What does that mean….?There was no article ,if I remember correctly, to explain what your seeing. So I wonder what it means?

  15. Dairy is tolerated well by those who are a blood type B ….. I know from own personal health issues that eating any dairy I immediately develop mucus and inflamation in the bones of my hands and feet l am an O blood type and dairy is a killer for blood type A people
    See Dr Peter D’Adamo’s books EAT RITE FOR YOUR BLOOD TYPE … A blood types should be vegetarians ……… it works !!!! no trial and error using this system !!!!!!

    • Enough with this blood types nonsense.

      It is based on the sole unfounded assumption that one should eat the same regimen as when the blood gene mutation occured. Then if I’m blue eyed should I eat dairy and meat because this mutation appeared at a certain time in northern Europe and blah blah blah?
      And if I’m black I suppose I should only be feeding on bananas and manioc?

      This is all complete pseudoscience bullshit. So stop spreading it. Thanks.

      • Funnily enough, Manioc comes from South America. It is very bad for depleting soil and incredibly easy to grow. It needs a lot of processing such as fermenting or soaking to render it safe to eat.

  16. I am always seeking to keep my knowledge base up-to-date with regards to nutrition. I used to teach college nutrition and I am personally passionate about it. Thankfully, there is more impetus now to research nutrition, which many lay people do not realize is an incredibly complex science.

    Here is my thought on milk. I think if we are to consume dairy, typically a fermented form is better for us than drinking lots of milk. A huge portion of our population is intolerant to milk (but not always intolerant to fermented sources of dairy). In reference to milk NOT being the ideal bone building food we all have been told it was as kids (i.e. possib;e contributor to osteoporosis), the 12 year Harvard nurses study actually showed a slight increase of hip fractures in heavy milk drinkers compared to those who were not. Now here is my thought, high levels of consumed animal protein can lead to calcium reduction in the bones. Since milk is a source of animal protein, it may contribute to bone loss when a person’s diet is excessively high in animal protein overall. But given that so many people are intolerant of milk, evolutionarily, we are provided with a large assortment of non animal high calcium foods. Some studies show that vitamin D is a much more important factor than consuming large amounts of calcium. So again I think we the key ideas of moderation (e.g. meat/dairy) and ensuring we get sun and vit D as well as increased physical activity, eating lots of dark leafy greens – not necessarily drinking lots of milk, are key factors in bone strength.


  17. I’m not so sure that Chris didn’t drop the ball in this article. I believe that even though the article may be “technically” correct, it is somewhat misleading or inconclusive.

    First off, whenever people talk about “milk” they automatically refer to pasteurized milk. And, from everything I have read (from many, many different sources), it appears that pasteurized milk has no important health benefits at all. And, even if it were to have some unnamed benefit, the drawback are so many they overshadow any potential benefit from the calcium it contains.

    I’m not arguing that commercial milk (pasteurized, homogenized from cows fed grains, bgh, and antibiotics) leads to osteoporosis, I’m simply challenging the claim that “dairy probably is good for your bones after all” (unless we are discussing raw milk coming from pastured cows).

    Once again the food industry has turned a healthy food into an unhealthy product (for the sake of profit).

    Most milk comes from cows that are fed genetically modified soybean meal and growth hormones to increase production. Both increase a cow’s risk of developing mastitis, liver problems, and pituitary gland problems, leading to frequent doses of antibiotics to curb the subsequent infections.

    Then, the milk is pasteurized which destroys many vitamins, healthy bacteria, and denatures many proteins. Pasteurization also destroys enzymes which enable the body to digest the milk and absorb the calcium.

    Then, for good measure, the milk is homogenized which allows a protein enzyme called xanthine oxidase to be absorbed directly into the blood stream. There is some very compelling research demonstrating clear associations with this absorbed enzyme and increased risks of heart disease.

    Cow’s milk is the number one allergic food in this country. It has been well documented as a cause in diarrhea, cramps, bloating, gas, gastrointestinal bleeding, iron-deficiency anemia, skin rashes, atherosclerosis, and acne.
    It is the primary cause of recurrent ear infections in children. It has also been linked to insulin dependent diabetes, rheumatoid arthritis, infertility, and leukemia.
    Most of these ill effects are the result of the “processing”, not milk (in itself). Still, when someone considers that most milk sold/consumed in this country has been through this unhealthy processing, I’m not sure they could claim claim that dairy is probably good for you bones.

  18. It’s all very interesting, but there are so many factors, is it not important to remember not to ‘micro manage’ our nutrition or ‘micro investigate’ these things in isolation? The fact to remember is that we are the only species to consume milk from another species and the only species to consume it into adulthood. Milk is designed to give nutrition to babies/young of the SAME species. It is known to cause allergies and a host of other human symptoms are associated with it, which were not seen it the San Bushman style Paleo eaters… (who were designed to eat honey for example but only 4lbs a YEAR … ref comment earlier saying if milk is for babies then honey is for bees ….. not!) Which must make you go “Hmmmm….” and would save us all a lot of breath! xx