Dear Mark: Does Dietary Acid/Base Balance Matter?

For today’s Dear Mark, I’m covering just one topic: the relevance of acid/base balance to health. Anyone wading through the morass of Internet diet information has come across the idea than an excess of acidity derived from our diet overloads the body’s ability to balance it with alkalinity. A diverse group invokes it, including strict paleo dieters, vegans grasping for straws to indict meat, and web sites featuring HTML from the 1990s that sell alkalizing water tablets. And because acidity sounds caustic and vaguely negative, lots of people buy into it. So, does it matter?

Let’s go:

I often hear about the acid-alkaline properties of foods in the comments and forums. However, I am not sure if this has any scientific merit. You don’t seem to have any posts about it so would you care to shed some light on the matter?


Human blood likes to have a pH between 7.35 and 7.45, slightly above neutral. If pH dips too low and our blood becomes acidic, our cells stop working. This is called metabolic acidosis, and it comes in two flavors – acute and chronic. Left untreated, acute acidosis will kill you, while chronic acidosis leads to a host of health conditions that will eventually kill you or at least erode your quality of life:

  • Hypothyroidism
  • Muscle wasting
  • Bone loss
  • Glucose intolerance
  • Growth hormone resistance (which can retard growth in kids)

When we metabolize foods and nutrients, some of them produce acids as byproducts. Acid-producing foods include meat, fish, grains, legumes, and dairy. They therefore represent a “high acid load,” and avoiding a high acid load is one of the main reasons many plant-based health types recommend avoiding animal foods. Our bodies, you’ve probably heard, just can’t handle the acidic fallout of all that meat and dairy without falling into metabolic acidosis.

Actually, the body has several ways to maintain the optimal pH range and avoid health problems in the face of acid-forming foods – and they’re extremely effective. If they weren’t, we’d be dead.

One way is through basic respiration – breathing. The lungs monitor the pH of our blood, prompting faster breathing when acidity needs to drop and slower, deeper breathing when acidity needs to rise. By exhaling carbon dioxide, we expel excess acidity. This is the primary way we compensate for fluctuations in pH.

Another way is through the kidneys. When acidity is high, the kidneys excrete more acids and produce bicarbonate, which returns to the blood as a buffering agent. Buffering agents combine with acids in the blood to neutralize them for easier excretion. There are other buffering agents, but bicarbonate is the primary one.

Yes, blood pH is tightly and most importantly unconsciously regulated. As long as your kidneys and lungs are working, the foods you eat will neither lower nor raise the acidity of your blood. What about those urine sticks that measure pH? Altering urinary pH with the food you eat is easy enough, but it doesn’t reflect blood pH. In fact, “acidifying” one’s urine by eating “too much” meat is proof that your kidneys are doing their job and excreting excess acid from the blood.

Thus we invalidate the most drastic claim about pH and health – that an acidic diet promotes acidic blood which promotes cancer. The body’s pH is maintained in a narrow range, regardless of the food you eat. Since its proponents are never able to cite any direct evidence beyond a misinterpreted Otto Warburg quote, I never put much stock in this claim.

But the next claim sounds more plausible: maintaining optimal pH in the face of acid-forming foods requires a calcium buffer that we leach directly from our bones. This leads to osteoporosis and the eventual dissolution of our entire skeletal system until we’re nothing but a disembodied urethra spewing brittle bone paste. Okay, that last part I made up. No one says that (I hope). There is evidence that appears to support the claim, which is why this idea has so much traction. First, consumption of the most acid-forming food of all, protein, does increase calcium excretion in the urine. And second, exposing in vitro bones to a metabolic acidosis test tube environment results in mineral dissolution, calcium loss, and production of the prostaglandins involved in osteoporosis.

Superficially, it’s compelling.

The entire premise falls apart when you look at the actual effects of consuming the most acid-forming food of all – protein – on the bones of real live humans. What happens to your bones when you eat protein? Although eating acid-forming protein often increases urinary calcium, it has an overall beneficial effect on bone metabolism and acid/base balance:

Dietary protein increases intestinal calcium absorption. Maybe it’s because the body “knows” it’s about to consume some bone-destroying acid-forming meat or whatever, but studies consistently show that eating protein also increases the amount of calcium we absorb. This is at least partially due to specific amino acids within the protein. At any rate, with more calcium available to the body, more will be excreted.

Dietary protein has no effect on bone resorption. Bone resorption is the removal of calcium from bone. If acid-forming protein were leaching calcium from your bones, resorption markers should be increasing. They don’t. Studies consistently show that eating protein has no effect on bone resorption.

Dietary protein increases renal function. People with existing renal insufficiency are often advised to lower their protein intake, but in healthy people with normal kidney function, eating sufficient protein is important for maintaining that function. By providing ammonia substrates, protein actually increases the kidney’s capacity to do its job and excrete acids.

The same goes for dairy, another acid-forming food that gets a ton of flack from many online health communities for its supposedly bone-dissolving effects. In truth, dairy is good for bone health. Maybe it’s the phosphate, which has been shown to reduce calcium excretion in the urine and improve calcium balance in the body. Or it could be the vitamin K2, a vital bone nutrient found in whole fat aged cheeses that improves bone mineral density in osteoporotic patients. Maybe it’s the dairy protein, which increases calcium retention and reduces bone calcium resorption while improving bone mineral density. Even when you add acid-forming dairy protein to a diet that’s already replete in acid-forming protein, it has no effect on bone mass or strength. There’s also the calcium to consider, along with the synergy of all the listed nutrients.

So it’s unsurprising that a diet high in meat and other acid-forming foods increases calcium absorption and excretion while lowering parathyroid hormone (a hormone usually elevated in osteoporosis).

If there is a problem with acid load, it’s only in people with renal insufficiency. Outright kidney failure can obviously cause metabolic acidosis, and it’s possible that gradually declining kidney function results in problematic low-level acidity. Kidney function certainly tends to decline with age, while the risk of fractures increases. Despite that weak connection between old age and renal insufficiency, seniors who eat more protein still have better bone calcium retention and absorption.

I’m not arguing that the acid/base balance of our blood isn’t important. It is. I’m arguing that the healthy among us are unable to consciously alter it, whether through the foods we eat or sheer will. And I’m arguing that some of the most acidic foods – meat and dairy – tend to have the most beneficial effects on bone health. Eating a purely acidic diet isn’t a good idea, but that’s because you’d be eliminating a ton of healthy plant matter with important nutrients, not because of the effect it has on your blood acid/base balance.

The weight of the evidence is clear: the acid-load of the diet has no effect on bone health in healthy people.

Thanks for reading, all.

TAGS:  dear mark

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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48 thoughts on “Dear Mark: Does Dietary Acid/Base Balance Matter?”

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  1. Thanks for the prompt answer! I eat a lot of meat and this question was nagging at me for a while.

  2. It’s always amazes me how efficiently our bodies are designed. As you stated, acid/base pH levels are important, but our body does a pretty darn good job regulating it naturally (most of the time and assuming we eat a healthy diet.)

    1. Not only that, but the amount of “alkaline” foods you need to eat to restore pH balance is incredibly small. So even small portions of green foods can raise pH enough to avoid low pH levels.

      Mark this is a good article except the only part I don’t see mentioned is the link between acidity and cancer. It has slightly more scientific merit than some of the other claims about pH but it’s still mistaken, due to the guy you mentioned in your post: Otto Heinrich Warburg.

      He showed that cancer causes acidity, not the other way around.

    1. I’m gonna go out on a limb here and speculate that sugar and the insulin response maintain this mystery acidic environment; and prevent the renal ph balancing acts.

    2. Hey Ben, does ketosis (ketoacidosis) cause metabolic acidosis? if so, a low carb ketogentic diet or even fasting make you “too acidic”, right? let me know what you think, thanks!

  3. It’s funny that everyone who goes about spouting off about balance usually has a very poor definition if any about what that balancing point actually is. The food pyramid (as a balanced diet) turned out to be about as bottom heavy as you can get! Now some folks would have us eat in a way to try to keep our blood levels in the magic PH range that nature takes care of.

  4. Valuable info for me. I am old (71). I have somewhat reduced kidney function. I have diabetes.

    Not too long before going Primal, one of my teeth had to be pulled because my body was sucking the calcium out of it. Every time I went to the dentist, he had to replace fillings that had gotten loose. Now my teeth are good. Vitamin D3 or sunshine, vitamin K2, lots of magnesium. Plenty of protein (but lots of veg too.)

    Thanks, Mark!

  5. I eat quite a bit of animal protein because I just plain feel better on a higher-protein diet. If I don’t get enough I start to crave it. I increased the amount slightly after going Paleo, but not much more than I was already eating. Although I also eat plenty of veggies, I usually eat modest portions of some form of protein with every meal. It doesn’t need to be a big steak–although that’s good too–but I do feel that something is missing if I don’t have any animal protein on my plate.

    A brief stint as a vegetarian years ago left me feeling tired, mentally sluggish, and hypglycemic. I gave it up after only 3 weeks, deciding that anything that makes you feel so lousy can’t be good for you, and I went back to eggs, poultry, fish, and plenty of red meat. I guess I’ve always been a dyed-in-the-wool Primal/Paleo type.

    1. When I became a vegetarian 28 years ago I had the opposite reaction. Meat was a drag on my system and gave me heartburn. Getting rid of the meat worked well. But I didn’t give up eggs (I’ve been eating 4-6 per day my whole life). Giving up on eggs and dairy is actually vegan, not vegetarian. I gave up eggs for a couple of weeks just to see what would happen and I, like you when giving up meat, was not a happy camper. Eggs simply make me feel fantastic. Without them I felt a hole on my diet.

      1. It’s possible you didn’t tolerate the meat well because you have/had low stomach acid and couldn’t digest it properly. I wonder if taking a HCL supplement or simply apple cider vinegar before eating meat could help? I’ve got low stomach acid from using a PPI for a couple of years and when I eat meat without taking acid supplement beforehand, I get gross smelly burps for hours afterward! Not pleasant!

        1. Possibly, but eating vinegar before eating meat to avoid heartburn, when I never even really cared for meat that much in the fist place, is a lot of work. Giving up meat was super easy. I never was into it in the first place. And now, after not eating it for almost 30 years, it really tastes foreign. You don’t know it when you eat it regularly, but meat (not fish though) has a texture that’s very close to rubber bands.The taste is pretty close to rubber bands as well. I didn’t realize how lacking in flavor meat was until I stopped eating it. Not as tasteless as tofu, but pretty close.

        2. Another I noticed when I stopped eating meat was that I actually liked cranberry sauce more than turkey. That I didn’t so much as like ribs as I liked bar-b-q sauce. And what I really liked about hamburgers was the ketchup and mustard. Basically, meat was defined by the condiments I put on them and meat was really just a delivery device for the condiment.

    2. Yeah, same here. I have eaten tons and tons of meat ever since I was a little kid. Tried vegetarianism for a month, and I was constantly hungry and my brain didn’t work right. Paleo felt very very natural for me.

  6. Great article! My boyfriend was recently doing one of those gimmicky cleanses and had taken it upon himself to lecture me about how all the meat I was eating was causing extreme acidity in my system. I just knew there had to be a non-CW explanation for this topic, and here it is!!

    1. Actually, this explanation is pretty much as CW as you can get…

  7. What are the most acidic foods? Grains and meat.

    What are the most counter-acidic foods? Green veggies and grass.

    So what will you make yourself less acidic? Eating more green veggies! And eating less meat and grains of course.

    So just give the cows the green veggies instead of grains and they (like humans) and they will not be acidic anymore but neutral.

    The difference? You are now able to eat their meat, too. The grassfed, not the grain-fed CAFO meat, of course. Life can be so simple!

  8. I guess it’s all those amino and fatty acids , maybe the amino and lipid group are someone protective.

  9. Thanks for covering this! I’ve heard a lot about this stuff in the past, and it always sounded a little hokey to me. I’m really happy to see some intelligent conversation on this topic that makes sense.

  10. Protein, beyond that which is required, is redundant, cannot be stored and increases the body’s (toxic) nitrogen load. Calorically speaking, even human mother’s milk is only 1.6% protein by the 10th day postpartum. We can easily get by on 2.5-5% of calories from protein assuming macronutrient and micronutrient requirements are met. Excessive protein draws on the body’s calcium and phosphorus stores in order to restore proper pH balance in individual tissues.

    1. I’m not sure what your point is. You apparently did not even read the article.

  11. Well, raising ph seem to work out fine as a cancer cure for Vito at at least. Wonder why.

  12. The blood pH may be 7.0 but the cells could be 6.0 which can supposedly set the stage for cancer. I would like to know more about the science behind that.

  13. I figure given that I have replaced all the grains in my diet with veggies even though I eat meat I am probably on more of an alkaline diet than some one that doesn’t eat meat but has a heap of grains. Only eating grains and meat is going to get you into trouble regardless of alkalinity.

  14. OMG, this is medschool 101. That you can alter your blood pH, or any pH in your body, by the foods you eat is just plain wrong. Every proper health care professional knows this, whether they are CW or primal.

    The exception is of course the kidneys and urine, as the kidneys are the organ actually regulation blood pH, hence excess acid or base will be excreted in urine.

    And yes, other areas of our bodies have different pH-values. They are designed so, as they have different functions. The stomach for example has a pH-value of around 2, because this helps it break down food. And yes, our body is so smartly designed and regulated, so that it will not “spill over” and what not.

    1. Amen. As a physician by training, I cringe when I see articles about changing your body’s pH. Blood pH is buffered with a tightly regulated system, unless your kidneys are failing or you have a serious infection, etc.

      That being said, I do appreciate Mark’s candor of dispelling the myth without being accusatory of what others say.

  15. Hi Mark,

    I understand the concept of our Liver and Kidneys removing excess acid so it does not cause an increase in blood acidity. But do we not need to consider the excess stress placed on these organs when our diet is too high in acid?

    Can a highly acidic diet lead to lowered organ function and then increased blood acidity?

  16. Great article, I appreciate the perspective.

    A nutritional instructor in my field raised many of these points, and had a pithy rejoined I’d like to share regarding acid phobia:

    What are proteins made of? Amino acids–not amino alkalines.

    What are fats made of? Fatty acids. Not fatty alkalines.

    If two of the most important and most basic building blocks of life are acids, do you really think that acids can be antithetical to health?

  17. Very clear and concise answer to the question. It has been bugging my for a while, cheers Mark!

  18. You had me at “…we’d be dead otherwise”

    If meat and animal fat were bad for us humans would not be here today.

  19. Nice artical on acid/base ph level of our blood, and how the body compensates one way or the other depending on the foods we eat.
    I was a little surprised in your stance that what we eat does not affect our acid/alkaline ph level of our blood. Of course one meal will not throw things off, but a regular diet of the “SAD” has to have an impact on the body’s ph levels, as does a paleo diet.
    I would be very interested to see if there is any research out there concerning the impact of sugar and grains on the body’s ph levels, which I suspect are far more harmful then a healthy raised piece of meat.
    My understanding of it is warburgh showed cancer can not survive in an alkaline environment, which is why people are so interested in it.
    If diet does not impact the body’s ph levels, what does influence these levels, because that is something many people would be interested in.

    Thanks, always enjoy reading your research and position on topics,


    1. The answer to your question is: nothing influences the ph levels. Per Mark in the above article:

      “I’m not arguing that the acid/base balance of our blood isn’t important. It is. I’m arguing that the healthy among us are unable to consciously alter it, whether through the foods we eat or sheer will.”

      The point of this article, as I understand it, is that our blood acidity remains constant and is not affected by the foods we eat. So whether it’s grains, mean, alkaline, acidic, primal, SAD, etc. doesn’t matter.

      The acid/alkaline nutritional philosophy is junk science, and further research will not yield anything meaningful.

  20. What about taking all of these different protein shakes, are these good for us, or is it better to eat good meats, dairy and eggs?

  21. One Thing I did not see mentioned is ketoacidosis. This is possible with too much alcohol, protein and type 1 diabetes or any combination of thereof. Dehydration, excessive physical activity and lack of available systemic bicarbonate are often triggers. The breakdown of fatty and amino acids produces more ketone bodies than the body can process thus increasing blood acidity. So yes acid can be a problem but in extreme situations.

    Type 1 diabetics, gout sufferers and insulin resistant alcoholic weekend warriors need think petite fillet instead of a double end cut and go big on greens if appetite demands a more substantial meal. Gerolsteiner mineral water is high in bicarbonates and would be a good hydration choice for those concerned about their blood chemistry.

  22. That’s a nice set of links Mark – ya’ll are missing out on the sodium bicarbonate connection though ala Suppversity:

    and the Berkemeyer study Dr. Andro cites in that last post:

    No idea how that applies to a healthy human, or how you’d figure out if you have “latent acidosis”, but if serial loading of sodium bicarbonate can better your endurance and health, I’d say go for it.

  23. What a wonderful article. Thank you for posting and thank you, Hashim, for the question.

    I think what often gets lost is the fact that everyone is unique. Everyone is different. We are ALL different on the outside. Why, in the world, don’t we think we’re different on the inside? We each have a unique biochemical makeup. The body really does an incredible job at regulating pH balance of the blood because, as mentioned, otherwise we’d be dead. Not only do the cells not work properly, but our enzymes need a specific pH level to remain in the same configuration. Without enzymes doing all those chemical reactions in the body, we die.

    My point about being unique has to do with the body’s ability to adapt to changes in your environment (more/less sleep, changing stress levels, immune function, food consumption, toxic load, etc.). If we can understand what reactions our body has to those changes, we can work to balance ourselves.

    For example, allergic rhinitis (seasonal allergies) is due to the body being too ALKALINE (believe it or not). It’s primarily the result of sympathetic nervous system hypo function. And one way to increase sympathetic nervous system function is to create a more acidic environment (which goes against conventional wisdom). So while people are suffering through seasonal allergies, I suggest they increase their ratio of meats and fats to vegetables/fruits. Once the symptoms dissipate (an indication the autonomic nervous system has balanced), they can go back to their normal diet.

    A big Thank You to this community. I LOVE this stuff!!

  24. I have a condition called interstitial cystitis/painful bladder syndrome. Metabolic byproducts of the food you eat can affect the pH of your urine. So those of you that might have this condition, it might be worth altering your diet to make your urine more alkaline. Acidic urine can be painful to someone with IC/PBS.

    So although this article focuses on the acid/alkaline diet with respect to blood pH, those with IC/PBS might consider changing their diet to alter the pH of their urine.

    Chris Kresser has a good article that discusses this issue.

  25. My husband and I just switched from conventional meat to grass-fed beef last week. I’ve always had GERD problems (heartburn and up all night among other things) but I’ve had it under control the last year or so with bouts of severe GERD occurring only once in a blue moon.

    Since I’ve switched to grass-fed beef, I’ve had heartburn every single time I’ve eaten the beef. I’ve had worse things than beef this week (like pizza) and they aren’t giving me heartburn–it’s obviously the beef. Is there a difference between the conventional and gf that would be causing this problem? And what can I do about it (without having to resort to ACV or some supplement)?

  26. This may be true for the *healthy*. I, however, have been suffering from hypothyroidism, reduced bone density, muscle wasting, urinary urgency (caused by the lining of the bladder complaining about low pH), and systemic inflammation (which also causes increased acidity). The kidneys can’t ‘produce’ bicarbonate to buffer the acids unless there is bicarbonate in the diet. While it would clearly be best to get said bicarbonate from plants, Tri-Salts (calcium carbonate, sodium bicarbonate, and potassium bicarbonate) have been working well for me. It’s nice to be able to sleep thru the night without having to get up to pee, be able to think clearly, and have the ability to build muscle thru exercise.

  27. My question is … anything dietary that may relate to a sudden appearance and reoccurance of vaginal yeast infections? Have not changed ANYTHING except my diet. Too much protein, not enough veggies ? Not enough yogurt ,lol ?
    Ideas anyone?

  28. Bhakti,

    it looks like you have candida (a type of yeast) overgrowth called candidiasis. The yeast infection may have reappeared if you changed your diet to Paleo. If you went Paleo, you may need to reverse your proportion of protein to veggies to reduce acidity. There are differing opinions about what one should and should’t eat on candida treatment and maintenance diets. But I’ve never heard of basing the diet on animal meat. It’s just too acidic and stressful on the digestion for someone with candidiasis.

    Vaginal yeast infections originate in the gut. Consider changing your diet and taking the appropriate supplements, including herbal anti-fungals. If you changed your diet to Paleo, it shouldn’t be too difficult for you to follow a candida diet as you have gotten over the hurdle of cutting out/ limiting fruit, grains, beans, dairy and the biggest enemy – sugar!

    If you feel pretty good otherwise, then it’s possible that your case is very mild and it would be best to nip it in the bud before it gets worse. Many people, including myself, have a more advanced case that is difficult to get rid of and keep us from thriving. This page lists the symptoms of mild, moderate and severe candida overgrowth.

    Hope this helps! All my best!

  29. I’m a little perplexed. I’m reading “Primal Blueprint” now and there’s mention of the importance of maintaining and “alkaline environment” in regards to moderating dairy. When I came to this passage I started to lose confidence in the author because I know the acid-ash theory is bunk. This article seems to swing in the other direction. Am I reading an out-of-date version of the book or is there some flip-flopping going on? I am enjoying the book and the benefits of working with the information.

  30. “Left untreated, acute acidosis will kill you, while chronic acidosis leads to a host of health conditions that will eventually kill you or at least erode your quality of life…”

    There’s no such thing as chronic acidosis.