Amazing alkaline lemons?

Tonight on How Not to Get Old (I really shouldn’t have been watching it) I heard the following gem:


Can lemons neutralise acids? (Spoiler: no)

“Lemons neutralise acidity.”

In fact, not only did I hear it, it even flashed up on the screen in a helpful little box. The speaker was Elizabeth Peyton-Jones, who says on the Channel 4 website that she is a “herbalist, naturopath and food and health consultant” and that she has “run a highly successful alternative health clinic in Central London for over a decade.”



A molecule of citric acid. Definitely not an alkali.

Let’s start here: lemons are acidic. Why are they acidic? They contain citric acid, about 5% by weight. Citric acid has the chemical formula C6H8O7, and the catchy systematic name of 2-hydroxypropane-1,2,3-tricarboxylic acid. If you look at the molecule you can see why it’s an acid. See those OH’s that are sitting next to =O’s? Those are acid groups. There are three of them. This is most definitely an acid.

Why do they make it an acid? Or rather, what is an acid? Well there is a bit more to this than I’m about to explain (interested parties could read about Lewis acids) but essentially acids are substances that can release H+ ions (‘hydrogen ions’) when they’re dissolved in water. Those three acid groups in citric acid can, in theory, release three H+ ions per molecule. So you might expect that citric acid is a pretty strong acid.

In fact, it’s not.  It’s actually what chemists call a weak acid, because although it can release three hydrogen ions per molecule it doesn’t really want to that much. It’s a stingy old Scrooge and likes to keep hold of them. But that doesn’t make it somehow not an acid, it still is one. The pH of lemon juice is about 2.

Which brings me to pH. It’s possibly the most abused and misunderstood scale ever. (There are two wonderful blog posts on that very subject, written by Marc Leger, which you really should read, obviously after you’ve finished here.) I’ve even found a school text book, yes honestly a school text book, that said “no one really knows what pH stands for”. Er. What?

Chemists know what it stands for thank you very much (I suspect, or at least hope, that the author of that book was not a chemist). The H stands for, guess what? Yes, the amount of hydrogen ions. The p is a symbol chemists use as shorthand for ‘negative log10‘ (it’s p because it comes from the German word for potency or power, potenz, and this might be why some books claim that pH stands for ‘potential hydrogen’, which it doesn’t really).

Log refers to logarithms. I’m not going to explain those in depth here – if you want to know more, this page has a clear explanation – but you will have come across other log scales. Probably the best-known is the one used to describe earthquakes: the Richter scale. Basically when you go up by a factor of 1 on the scale, it’s actually a power of 10. A major would-seriously-damage-buildings earthquake that measures 7 on the Richter scale is 1000 times more powerful than a light crockery-rattling quake that only measures 4. The pH scale is like this: every point on the scale represents ten times more (or fewer, depending on which way you’re going) hydrogen ions.

Slightly counter-intuitively (but the maths works out, honest) a lower pH means more hydrogen ions. An acidic solution with a pH of 2 has 1000 times more free hydrogen ions than one with a pH of 5. The pH scale goes from 14 down to 0, and actually negative pH values are possible as well. Values above 7 are described as alkaline (or basic), 7 itself is neutral and those below 7 are acidic.

Saying that this or that acid has a pH of a specific number (like I sort of did back up there when talking about lemons, remember I started with lemons?) is a bit of a nonsense, although many authors do it. pH refers to the concentration of hydrogen ions. You could get some hydrochloric acid (the stuff in your stomach) and dilute it, and its pH would actually go up. Really. If you drop a bit of lemon juice in a big glass of water its pH would be closer to neutral (pH 7) than 2. If you think about it you know this: drink neat lemon juice and you’re puckering up your lips in a classic ‘sour’ face. Drink some water with a bit of lemon in and you barely notice it.

Phew. Ok. Back to the frankly silly statement that lemons neutralise acid. We’ve established that lemons contain citric acid, and although citric acid is a weak acid, it still is an acid. It produces hydrogen ions when you put it in water, and for that reason the pH of lemon juice – as it comes out of the lemon – is about 2.

If you want to neutralise an acid, you need an alkali (or, more generally, a base). Alkalis contain OH ions (hydroxide ions) which can react with hydrogen ions and actually remove them from a solution, like this:

H+  +  OH  –>  H2O

Look, that’s water on the right hand side of that slightly-wonky arrow. Pure water has a neutral pH of 7. If you add exactly enough hydroxide ions to join up with all the hydrogen ions, you get water (and a salt, because there will have been some other stuff in there as well).

Once you get this far, it becomes fairly obvious that adding more hydrogen ions to hydrogen ions isn’t going to neutralise anything. It’s like trying to turn your blue paint purple by adding more blue paint.

If anything, adding more acid will make your solution even more acidic (although with a weak acid it may not be quite that simple, is it ever?) Again, experience bears this out. Your stomach contains hydrochloric acid, along with some other stuff, and has a pH of between 1.5 and 3.5. Fortunately your stomach is lined with special cells that protect you from this powerful stuff. Acid indigestion, something many of us have experienced at one time or another, happens (usually) when that stomach acid gets where it shouldn’t be, i.e. into your esophagus, where it burns.

If you have indigestion, do you drink lemon juice? No you do not. Not unless you actively like pain, that is. No, you take an indigestion remedy. Guess what they’re made of? Yes, alkalis, or bases (and sometimes other clever ingredients as well). They really do neutralise the excess acid by way of the equation I wrote up there.

And unless you have indigestion, why would you want to ‘neutralise acidity’ anyway? Stomach acid evolved for a reason. It helps to break down your food, proteins in particular, and it also keeps you safe from lots of bacteria and other nasties which usually don’t like acidic conditions. Once your stomach has done its thing the partially-digested food passes into your small intestine where it gets squirted with bile, which actually does neutralise it so it can pass through your intestines without doing any damage.

Your body has this covered. There really is no need to mess with it, and in any case, you can’t really. At least, not beyond your stomach (and urine, possibly – see my comment at the end). Homeostasis insures that everything stays remarkably consistent, and good thing too. There are lots of chemical reactions going on in your body that keep you alive, whether you realise it or not. If you could actually mess with the pH of your blood (pH 7.35-7.45) you’d be in a whole heap of trouble.

So can lemons neutralise acid? No. Can what you eat ‘alkalize’ your blood? (It’s terrifying just how many websites there are about this.) No. Absolutely not. Under no circumstances. If you were to eat a lot of indigestion tablets they would neutralise the acid in your stomach, but that would have no effect on your blood. Literally no effect.

By all means eat a healthy diet. Fruit and vegetables are definitely good for you. Lemons contain vitamin C (yet another acid: ascorbic acid) which is a vital nutrient. Eating them will certainly do you no harm and might well do you some good. But don’t let anyone tell you they’re anything more than a healthy citrus fruit.

As you can see, this post has generated a lot of comments. Some more scientific than others.  In particular, a lot of them have focused on urine, and the effect lemon juice might or might not have on urine pH. My original post was not about urine, but clearly a lot of people are fascinated by the subject. Who knew?

So here’s a little extra on that topic to save me repeating myself in comments.

It’s well-known that chemical makeup of urine can be affected by what we eat. We’ve probably all experienced the odd effects of asparagus, or beetroot, or even sugar puffs, so the idea that certain dietary substances make their way into urine is nothing particularly new or surprising.

And following from this it IS possible to affect urine pH by eating or drinking certain substances. For example, if you’re a cystitis sufferer, you might have used a sodium citrate-containing product such as Cymalon. During a cystitis attack the urine becomes more acidic. These products work by creating a buffer effect in the bladder, which means they raise the pH slightly towards neutral and, crucially, stabilise it so that it doesn’t drop again (or, indeed, rise).

Lemons contain citric acid, the salt of which is citrate. So it’s possible eating a lot of lemons (or drinking a lot of lemon juice) could have a similar effect. I found a paper on this very topic. The researchers found that drinking lemon juice produced a small increase in urinary pH from about 6.7 to 6.9. So, ok, it went up a tiny bit (remember that pH 7 is neutral) but given that the error in their measurements was +/- 0.1, that’s virtually no change at all.

That said, the main focus of their interest was actually treatment of kidney stones, which are, in some cases, caused by a build-up of calcium oxalate which then forms crystals. The researchers found that the lemon juice helped the body to get rid of oxalate, and they’re not the only ones to draw this conclusion. Magnesium can also help prevent kidney stone formation (magnesium-rich foods include leafy greens, nuts and seeds, oily fish and whole grains – basically all that ‘healthy diet’ stuff, funnily enough).

So in summary (and I stress, I am not a medical doctor and you should take your GP’s advice over that of some blogger on the internet), if you suffer from kidney stones, lemon juice might be helpful. It certainly won’t do you any harm (well, except possibly to your tooth enamel). A generally healthy diet will also, not surprisingly, be beneficial. Lemon juice might have a very tiny effect on urine pH. However if it does, the result is only to raise the pH a tiny bit closer to pH 7 (i.e. neutral). It does not make your urine alkaline.

The topic of gout has also come up. Vitamin C is known to help with gout. Lemons contain a lot of vitamin C (ascorbic acid, not to be confused with citric acid). If you’re a gout sufferer, drinking lemon juice might help. Although taking a vitamin C supplement might be even better.

None of this in any way relates to the blood, or ‘the body’ in general. You cannot, absolutely cannot, affect your blood pH with your diet, and nor would you want to.

Oh, and buffers seem to come up a lot too. To save time I put all of that in a separate blog post: buffers for bluffers.


Note: comments have been closed on this post because I found myself repeatedly refuting the same arguments over and over again. One in particular is the notion that lemon juice somehow becomes alkaline once in the body, and that this is why lemons are considered ‘alkaline’. Lemon juice will certainly be neutralised during the digestive process but there is no mechanism by which it could possibly “become alkaline”. Please don’t post comments on other pages in this site to get around the fact that comments have been closed.


155 thoughts on “Amazing alkaline lemons?

  1. Lemons don’t neutralize acids, agreed. Their constituents support the phosphate-buffering system the body uses to regulate the blood’s pH. Lemons, along with other veggies and some fruits, have an alkaline-forming effect on the body. They promote the formation of alkaline molecules, in other words. Here’s one reference that goes into some detail: Lemons are good for body chemistry any way you want to explain it.


    • I have moved the first part of this comment (with some edits) to its own separate post.

      The idea that any fruit or vegetable “promotes” the formation of “alkaline molecules” is, I’m afraid, just wrong. In particular, as I’ve hopefully just explained [see buffers post] we don’t need extra alkali to regulate the pH in our body. Our body has buffer systems to control pH. Yes, we need a balanced diet to keep those buffer systems working smoothly, but no one particular food is going to make a significant difference. Our bodies have no reason to produce extra ‘alkaline molecules’ from the food we eat (other than for bile, which I mentioned in my article), and mother nature doesn’t generally waste her energy doing things she doesn’t need to.

      There’s no doubt that lemons are good for you. They contain vitamin C, as well as plenty of fibre, and eating them won’t do you any harm. The acid might be quite tough on your tooth enamel though, so maybe hold off on actively chomping on whole ones. But “good for body chemistry”? Well, no better than any other food.

      And by the way, that link you posted… the very first couple of lines say “Is it true that the foods and beverages you consume cause your blood to become more alkaline or acidic? Contrary to popular hype, the answer is: not to any significant degree.”


      • I want to trust your breakdown because you seem extraordinarily educated in the field of chemistry. I however, am not. So I have a few questions:

        1. If lemons or any other food eaten has very little effect effect on the body’s pH levels, why do urine tests show such wildly varied readings? Surely something is happening in the body that affects what is eliminated in the urine.

        2. The claims made by the pH diet people are that you can raise your body’s pH level and make it more alkaline and indeed, after eating and drinking what is suggested, the urine tests indicate less acid and more alkalinity (or rather a series of tests during the day indicate that acidity lessens and alkalinity increases). This is independently verifiable.

        3. If the pH level of urine is not an accurate test of anything happening in the body, why do so many internists/endocrinologists, etc. rely on them to measure bodily functions and problems such as ketoacidosis, protein in the urine, etc. (as I said, I am not a chemist or a scientist). I am curious as I want to understand what is actually happening.

        4. You’re going under the assumption that the ‘pH diet people’ are claiming you can raise or lower BLOOD pH when in fact they don’t. In a few of the articles I’ve read they mention that the blood remains pH balanced. Their claim is that the food we eat has an effect on PH first and that after that, the body uses it’s tissues and organs AFTER to correct pH in the blood, and that it puts stress on the body leading to disease and illness. I am not claiming anything, I am curious. There are many documented cases of people becoming healthy/healthier by eating the foods they claim are alkalizing. If that is not the mechanism, what is? And does it matter if it leads to better health?

        I certainly understand your need to correct the mistakes in chemistry but I wonder if you are going on an incorrect assumption (or if they are too). I respect your knowledge and would be interested to hear your thoughts on this.


      • Ok first of all I should point out that I am not a medical doctor, and I am certainly not an urologist. My original post addressed the nonsensical idea that foods which are blatantly acidic in nature could cause ‘the body’ to somehow become alkaline. Such quackery does frequently refer to ‘the blood’. I did not intend to get into a discussion of what does, and doesn’t, happen to urine. So I fully accept that there might be qualified medical practitioners out there (note that ‘nutritionists‘ are NOT necessarily qualified medical practitioners, so be cautious of those using that term) who know more about this than I do. All that said…

        Urine is a waste product of the body, and contains things the body needs to excrete, either because they could be harmful if allowed to build up or because they’re simply not needed (or both). We’ve probably all experienced the odd effects of asparagus, or beetroot, or even sugar puffs, so the idea that certain dietary substances make their way into urine is nothing particularly new or surprising.

        Healthy urine has a pH in the range 4.5-8 but it’s usually 5.5-6.5, in other words slightly acidic. I am going to stress this: slightly acidic urine is normal and healthy, and nothing to worry about.

        Very acidic urine is a concern, and could be a sign of a medical condition. So could very alkaline urine. It’s one of the many things a doctor may check when testing urine just because if it’s out of the normal range it could indicate a possible problem. They might also look for other things such as traces of protein, and of course traces of glucose (a common sign of diabetes) because excretion of these things in urine is a sign that the body’s systems are not working as they should be.

        It’s true that food can change the pH of urine. In particular, consumption of a lot of acidic fruits like cranberries and lemons will (not surprisingly) lower the pH. Which brings us back to the original post: lemons will not and can not make ‘the body’, blood, or urine alkaline!

        If you eat a heavy meal, particularly a meat-heavy one, it causes first lots of acid to be produced in the stomach, and secondly lots of alkaline bile to be produced in the small intestine (to neutralise the acid). The time the sample is taken is important: soon after the meal it could actually be more alkaline due to the bile production. Also, it’s worth mentioning that the longer you leave a urine sample lying around the higher the pH will become, due to carbon dioxide being lost to the air. So it’s important to be consistent with testing.

        It is also true that animal protein-based diets can cause more acidic urine, whereas plant-based diets do not have this effect. This is not the same thing as saying that fruit and vegetables ‘alkalise’ the urine, or ‘the body’ in general. It’s pretty well-established that eating lots of fruit and vegetables is good for you. Switching to a diet higher in fruit and vegetables and lower in animal protein, particularly processed meat, is probably going to result in a healthier individual for many, many reasons (increased fibre intake, more micronutrients being consumed, reduced salt intake, reduced calorie intake). There may well be documented cases of health improvements but this is almost certainly less about acids and alkalis than the nature of the food being eaten.


      • I highly recommend reading The Ultimate pH Solution by Michelle Schoffro Cook. It certainly changed mine and my mother’s perspective. I have a clinical chemistry and toxicology background and my mom worked as a traditional Registered Dietician, now retired. I am now in the process of getting my nutrition therapy training from Nutrition Therapy Institute in Denver. It’s a crazy, politicized world out there, but I now realize that science/it’s interpretation has also been politicized and tightly controlled. The only way out of this is to read, read, read and question what you hear INCLUDING most historically popular scientific sources.


      • I agree in principle that it is important to question. However it is also important to understand that not all sources of information are equal. Fundamental principles of chemistry are really not up for debate; for starters they are easy to demonstrate experimentally. Always remember that many of the people crying ‘politics’ and ‘conspiracy’ are selling something.

        Michelle Schoffro Cook is a case in point. She’s making an awful lot of money from her books. She has a lot of impressive-sounding qualifications, but look a little deeper: a “doctor of natural medicine”. This is almost certainly not a licensed qualification equivalent to that of an MD. Please read this Wikipedia page which provides some insight into ‘Naturopathy’ and qualifications associated with it. Likewise this page which explains ‘Orthomolecular Medicine’ (the ROHP bit after her name) and this one which clearly explains the difference between nutritionist and dietician (Schoffro Cook identifies herself as a nutritionist).

        Now, I realise you might say, “ah, but Wikipedia is hardly a reliable source!” but in this case the information being presented is well-referenced and unbiased. And I would rather trust a source that is non-profit and which can be (and is) edited by everyone, than one that comes from a single person who sole goal is to make money.

        But just in case that’s not enough, have a look at the PubMed database, which comprises more than 24 million citations for biomedical literature from MEDLINE, life science journals, and online books. If Schoffro Cook were a reputable scientist, she would surely have published peer-reviewed articles, wouldn’t she? If she has genuinely completed a PhD as recognised by most large scientific bodies – which would involve writing a thesis and defending it in an oral examination – she ought to have published at least one scientific paper. Is her name in PubMed? I can’t find it.

        On the other hand, this paper (which I’ve referenced many times before) IS on PubMed, and is well worth reading.


  2. I saw this exact thing promoted in a triathlon clinic I signed up for, for my first tri – lemons as alkalizing for your body. That caused some hilarity among my friends when I told them, but a fitness instructor I know who was present at that bit of laughing got quite defensive about it. If I remember right, fitness instructor also tried the line about citric acid promoting formation of alkaline substances.

    Unfortunately a lot of otherwise healthy activities (gyms, running groups, other physical activity) are targets for all of this nonsense. Those who are doing the physical activity because they want to be healthy, but who don’t have a scientific background, just hear health claims combined with words they vaguely recognize from high school science class and that’s as far as they get.


    • I think that’s a lot of the problem. Plus the internet is awash with inaccurate information and if you don’t have a scientific background, how are you supposed to differentiate? As I was writing this I couldn’t recall the exact name of acidosis, so I searched for “blood too acidic”. The first 4 pages of links were about ‘alkalizing’ foods. Now, I knew to ignore those, but not everyone would. Some of them read fairly convincingly if you don’t know the chemistry. It is tricky. I don’t know what the answer is.


  3. I don’t think anyone is saying the acid in lemons alkalizes, its the minerals, and the weak acid is easy to expel.


    • Are you suggesting there are such things as alkaline minerals in lemons? There are not. You really should read the whole post, and possibly the comments (in particular the one on buffers).


      • Is that what he said. You tactic in dealing with this whole issue is overly- reductive.


      • He said “its the minerals, [which alkalize]”. So, pretty much.

        Frankly I don’t think we need to confuse REDOX with this whole mess as well…. 😉


  4. Thank you for this post. It’s unfortunate that I have heard many of these erroneous claims, especially from the younger crowd who seem very avid about all things health and fitness. They are fast to claim and defend this misinformation without doing proper research. Sad world.


  5. I remember reading something about this in another post which referred to the Krebs’s cycle or the citric acid cycle.

    I read it here
    here is the relevant part of the comment that seemed rather convincing when I read it:

    ” it’s true that lemons, limes, and oranges metabolize to be fairly alkaline. I studied biology in college, but I learned about this (oxidative phosphorylation, the Kreb’s cycle aka the citric acid cycle, glycolysis) in high school when I took advanced/college biology. I remember when our teacher told us about this chemical breakdown. Like you, we needed to know WHY. We were almost sorry we asked, it took several days to explain and then we were tested on all of it. To demystify what we’re talking about, foods you eat either produce free Hydrogen ions (having an acidifying effect on the body), or accept/bind to free Hydrogen ions (having an alkalinizing effect on the body). The human body has a variety of mechanisms that strive to maintain a pH of around 7.4, which is slightly alkaline. I’ve attached a link to the physiology book this explanation came from, and honestly it is widely known and accepted in science and can be found in most college-level biology textbooks. “Whether or not a food has an acidifying or alkalinizing effect depends on whether and how its constituents are metabolized. Cranberry juice has an acidifying effect because of its content of benzoic acid, an acid that cannot be broken down in the body. Orange juice has an alkalinizing effect, despite its acidic pH of about 3.7, because it contains citrate, which is metabolized to HCO3. The citric acid in orange juice is converted to CO2 and water…” Page 445, Medical Physiology: Principles for Clinical Medicine
    In other words, orange juice accepted free Hydrogen ions (H+) that were in your body when it was broken down. This results in an alkalinizing effect on the body. The flaw in your logic regarding acid or base added to water is that when you consume an acidic or alkaline food, it’s not simply being added to water- your body is using energy and systems to alter the chemical composition of these foods, energy and systems that do not exist in water alone.
    I think if more people understood the whole process of ATP synthesis, it would demystify a lot about the digestion process and energy production. “


    • I have a number of problems with this. My biggest is this: what does “an alkalinizing” effect MEAN? And why is it a good thing?

      Research your bodily fluids. With the exception of bile, they are all in the acidic-neutral range. Blood is a tad over 7 at 7.35-7.45, but that’s still essentially neutral. Why, why, and again why, would you want to “alkalinize” your oh-so-carefully and beautifully balanced bodily systems?

      The ONLY genuine health reference I can find is that citrate might help to prevent kidney stone formation, and may possibly help with existing stones. So if you’re a sufferer, there might be an argument for eating foods with citric acid in them. Like lemons, limes and, guess what? Cranberries (which have much more citric acid than benzoic. Huh).

      Again, obviously a diet rich in fruits and vegetables is healthy, but not because of some mysterious “alkalinizing” effect.

      That Google book link is broken, by the way.


      • I actually am a chemist, and it is indeed the metabolites of lemons that reach the urine and they obviously do have an effect on urine pH. You can test this yourself with pH strips or just wait until you are really burning down there and drink half a lemon squeezed into 8oz of water… If what ails you responds to a more alkaline pH, you will find the fire is put out. Irritated urinary tract tissues (especially the urethra) often do better with a higher urine pH (more alkaline). This is why so many people can get quick relief from the burning of a UTI by taking sodium bicarbonate in water (or just dump an alka seltzer packet into the water if preferred). If the microbeastie responsible for the infection has a preference for acidic pH, such measures can actually knock out the infection especially if started early. (Yes, there was medicine before antibiotics).
        Some conditions do better with acidic pH, and sometimes medications intended to treat the urinary tract work better with acidic than with alkaline environments or vice versa. Blood pH is maintained by buffering agents in the blood, but reputable sites with reasonable information don’t claim otherwise. That’s kind of a straw man argument, you can’t extrapolate from foolish statements about blood pH and claim there is therefore no validity to the idea that urine pH is variable and adjustable by diet, since it can be so easily checked and has been many times. But urine pH can definitely be affected by what we eat — but it’s always what reaches the urine that matters (typically breakdown products, i.e. metabolites). Lists of urine alkalizing/acidifying foods can be useful, bearing in mind that individuals vary and the ash method for categorizing isn’t terribly reliable (hence borderline foods put in both categories). Lemons seem to be the superstars of every list I’ve seen, a little goes a long way for a urine alkalizing effect. I guarantee that if you put the recommended half a lemon in a glass of water that you won’t hardly notice it, as you claimed… You must have just experimented with a tiny bit. In any case, what’s in the glass doesn’t matter, it’s what ends up in your urine. Be thankful if you’ve never had to worry about urine pH, but some of us have good reason to experiment.


      • The post was originally about blood pH, urine pH came later in comments.

        I have stated several times that urine pH can be changed by what you eat, but not by a huge amount. If you’re claiming that it can be significantly changed (i.e. more than one pH unit) by consuming lemons/lemon juice then please post a link to a scientific paper. I’ve not seen any such evidence, despite looking for it. “I’ve tried it and tested my urine with pH strips” is not evidence that the lemon did anything, as I can guarantee you didn’t control all the necessary variables.


  6. This was a very good read. After searching many articles online i am glad i came to one with a scientific explanation of their point.

    So after reading your comment from above, you mention lemons do not alkalize your body, but the citric acid in lemons may help in preventing/breaking existing stones in your kidneys. My question is do you think citric acid will help in preventing/breaking uric acid crystals in joints around the body?

    The reason i ask this is because i am currently suffering from Gout and there have visited countless websites stating “alkalizing your blood will help break down the uric acid”. One of the most mention methods of this was to drink lemon water. Your analysis contradicts many of those websites out there so i want to hear your opinion on this.



    • Hm, I should really stress that I am not a medical doctor at this point! I understand that gout is incredibly painful, and I’m sorry to hear you’re suffering from it. As I understand it there have been legitimate studies showing that vitamin C can help prevent attacks, and lemons are certainly high in that. A low-calorie diet is also beneficial. So (and again, not a medical doctor) I think it’s extremely unlikely that lemons will make any difference in terms of a mysterious ‘alkalising’ effect. However the vitamin C might be good for you, and lemon water is virtually calorie-free (so long as you don’t add sugar!) so if you use it to replace some kind of sugary drink that will definitely be a positive. If you like the taste why not drink it? I can’t see that it would do you any harm 🙂 But take your GP’s advice of course.


      • Wow thank you for the fast response.

        I know i may be getting a bit off subject here, but aside of drinking lemon water as a tonic for good health, there are two other ones that are mentioned quite frequently too. They are Baking soda + water and Apple Cider Vinegar + water, and yet again the main thing they stress is that it will help alkalize your body. Can you give me your opinion on this or if you write a future article on them I will read them also 🙂

        Thank you,


      • Yuck, they sound pretty nasty to drink! Here’s the key: nothing you eat or drink is going to change the pH of your blood. At all. It’s fixed. If the argument revolves around that, it’s wrong.

        The pH of urine might be temporarily affected by certain substances, but that’s a special case (and not especially relevant for gout, as far as I know). Generally when things do affect urine pH it’s because they cause a temporary buffer system to occur. It’s not ‘alkalinizing’, more stabilising the pH at something closer to neutral.

        This is not to say that there aren’t dietary changes/additions that help with gout. Just that ‘alkalinization’ is not the reason they make a difference, if they do.

        Best bet is to look for published, peer-reviewed studies. There seem to be quite a few out there involving simple dietary additions (coffee, vitamin C etc) – it’s not all about pharmaceuticals. And of course talk to your GP/specialist because, if they’re doing their job well, they will be familiar with those studies.

        For what it’s worth, I don’t think baking soda or cider vinegar will do anything and they sound pretty nasty to drink, so personally I’d leave it! Unless you like vinegar flavour that is. At least the lemon will taste of, well, lemon.


    • Henry, I’m lucky to have very mild gout, and can feel the onset of pain in my ankle joints. For myself, I habitually do not drink enough water (8 glasses?), so catching up on the water helps to wash out excess uric acid, and may have helped to reduce the uric acid crystallization in the joints. Cherries seems to have a really good reputation for gout.


  7. Nothing will change the ph of the blood because your body will make sure the blood ph remains “normal”. Lemons do not alkalize the body, what they do is help neutralize or counterbalance the effects of our modern day heavily acid diet. Coffee, meats, alcohol, supplements, drugs, etc. Just as coffee, meat etc. cannot change the ph of the blood, neither will lemons change the ph of the blood. In the case of gout, cherry juice extract will help lower the uric acid levels of the body, and also help counterbalance acidity.


    • Have you read the entire article, and comments, particularly then one on buffers? If so, please provide evidence, in the form of a peer-reviewed article, of this counterbalancing effect.


  8. I just use plain common sense. You are proposing that our bodies will “balance” our ph on its own despite our terrible diets, this is only true concerning blood ph. At some point our bodies will not function effectively if we lead an unhealthy lifestyle, coupled with stress, hence the need for pharmaceuticals – including antacids and probiotics. I’m sure in your ideal world no one would need to take antibiotics for infections, pain medicine for aches, and of course, no one will ever suffer an accident. No one will ever develop an illness because our bodies will efficiently and magically take care of itself. If we suffer from our modern day stress, our bodies will magically find a way to balance the effects of stress. If this is what you are proposing, then at the very least, you should be touting the benefits of meditation.


    • I am ‘proposing’ that because it’s true. Exactly which bodily fluid are you contesting will have a permanently maladjusted pH? Obviously a healthy diet is extremely important, I have stated this many times. Lemons might be a part of that diet. They do not, however, have any proven amazing health benefits beyond that of most other other fruits or vegetables.

      I have also said on many occasions that I am not a medical doctor and that anyone with a genuine medical condition should seek medical help, including appropriate medication if advised by a GP or specialist. To the best of my knowledge lemons are not, at present, available on prescription and I don’t know of any doctors that would consider them an appropriate medical intervention. Unless, possibly, you have scurvy.


  9. Pingback: Basic Chemistry | the chronicle flask

    • So one of the comments above clearly states the ‘alkalizing effect’ described is the ability of a food, through the metabolic process, to remove free hydrogen ions from the body. This is not the same as dumping base in acid because the body reacts to an introduced substance with chemical mechanisms the byproduct of which yields less free hydrogen in the body. when you work out the body creates lactic acid which builds in the muscles. the body will work to neutralize the pH through the systems you mention however doing so with no intervention uses substances in the body (cannibalization) just like failure to consume carbs to reload glycogen can cause protein cannibalization (or aerobics lasting longer than 90 minutes without consuming carb/protein in proper ratios). Lemon water trends to encourage quicker safer recovery if you don’t believe it… Experiment and see if what I’m saying doesn’t work.


  10. There is a lot of unproven information. But do you think a chemical or a drug company will pay for a clinical trial like this? Everything is happening no matter if it is scientifically proven or not. This applies to gravity as well. Get used with it.


  11. The lymph fluid is a lipid-based fluid and we all know the effect of citric acid on lipids.
    Drug business is not a myth. Actually it is a billion dollar businesses. Cancer is caused by acids and radiation and we still “cure” cancer with acids and radiation (chemotherapy and radiotherapy) in hospitals. Ever asking why? Ever asking why dairy milk is considered as the healthiest drink you can have despite it is actually a poison and does not have any health benefits?


    • Do we all know the effect of citric acid on lipids? Please enlighten me.

      Dairy milk is not a poison. Cyanide is a poison. You can tell because it comes in bottles with a skull and crossbones on it, whereas milk doesn’t. Honestly.


      • You can check it in your kitchen lab. Doesn’t something which causes diarrhea, obesity, high blood pressure, high cholesterol levels, bone density loss, diabetes, fertilization problems and sterility, allergies, infections, cancer and many others should come with at least tiny skull on the bottle?


      • No. Because you see, the hazard labels are based on the evidence of rigorous scientific testing, whereas what you have just started is conspiratorial nonsense from the dark corners of the internet, based on – if it’s based on anything – the weakest of correlations. Correlation is not causation.

        Now please, go and post on a blog that isn’t written by an actual scientist.


  12. This is what I’ll do next. But my job is done here, I gave you the seed and if you’re wise enough you’ll grow a plant. It was a pleasure for me. Bye.


  13. I’m with keyguy13, very interested to find an actual scientist writing about the subject, and curious for more information. At one point you asked why people would even want to have a more “alakline body” (whatever that means, which I admit, I don’t really know). One of the arguments I have seen is that acid dissolves cells in all kinds of body tissues.

    I’m sure you will ask “what fluids or substances in the body do you claim are becoming acidic?” which is a good question. I have no idea. You would know better than I. But I wonder what you think about this: you agree that many foods we eat do affect our body chemistry – for instance, ones that have vitamins we need to replenish buffers and tissues, and every other body part. Also there are foods that will cause indigestion and ones that give us energy or tire us. Many people claim several different kinds of foods that cause cancer (I don’t know how many of them are proven to have a direct effect).

    So, to my point, it is not proven that an “alkaline body” is beneficial, but is there any room in what we don’t yet know, or what hasn’t been studied, for the possibility of a foreign/unhealthy modern diet (compared to the one our species’ bodies evolved with) causing some part/fluid of the body to become acidic in a way that the body isn’t perfectly designed to balance well enough (like it is with blood)? And is it possible that might make it more likely for tissue to degrade and be more susceptible to disease. If so, what about the possibility that some foods might be able to balance that acidity, such as lemon juice, which, as you pointed out from your additional research into a study, although acidic, does raise the pH of a person’s urine, when consumed… or maybe other foods which are more obviously alkaline.

    I’m very much a believer in science myself, it can benefit us in so many ways to think critically about our actions and their consequences. One of the things I love about science is that people who practice it well are very good at, and unashamed of admitting what they don’t know – like you do about not being a doctor – (as opposed to, say, people who base all their decisions in faith, and then try to make arguments about what is right and wrong for others based on that). But I’m also a believer in faith and tradition, in the sense that there are things science doesn’t tell us, and things we haven’t discovered yet, but which do still affect our decisions, and outcomes. And our only option there (until/unless we can explain them with science) is to use our intuition (which incorporates many things we may not have had the chance to reason about scientifically yet).

    If intuition has revealed for some people that drinking lemon water helps, perhaps it’s placebo. Or perhaps there’s something chemically about it. The trouble comes when people start to make scientific claims like “increases the pH of the blood”, when they have no proof of any such thing. But at least it begins to get at the heart of the matter, since at least that’s a claim that can be challenged and proven wrong. So thank you for that 🙂 Now I’m just curious if there’s any other way it could be helping people chemically. Of course, maybe I’ll have to settle for “I don’t know” if that’s your answer 🙂


    • Thanks for your comment. The fact that what you eat has effects on your body is not controversial. There is plenty of evidence that eating healthily is beneficial. Lemons are a fruit which contain plenty of vitamin C, as well as fibre and a smattering of other nutrients. Drinking lemon juice may well have health benefits, particularly if as a consequence you end up drinking fewer sugar-filled fizzy drinks.

      Does this work by somehow mysteriously changing the pH of your body? No. Not at all.

      There are many explanations for the health benefits of certain diets. They are invariably complicated, involving many interrelated systems and factors. Sometimes it’s not especially well understood but it’s clearly linked to, for example, a particular hormone such as IGF-1. The recent news reports linking high-protein diets to cancer have hinged on this.

      I understand why people want a ‘simple’ explanation such as pH, because acids and alkalis are sort of familiar substances and it’s easy to understand. That doesn’t make it scientifically correct. But yes, eat your fruit and vegetables. They are good for you.


      • Question to tag onto all of the above, I understand that you cannot change the pH of the body. And I also understand what you were saying about the reasons urine will show more alkaline or acidic. My question would be since, as you stated above “Urine is a waste product of the body, and contains things the body needs to excrete, either because they could be harmful if allowed to build up or because they’re simply not needed (or both).” would that be the reason that people claim “alkalinity” is better (even though it does not permanently affect the pH)? Would the process of expelling these unnecessary products cause less stress on the body by being easier to balance one way or the other (specifically alikaline)?
        I hope that makes sense.


      • This just doesn’t make any sense. Other than indigestion tablets, we don’t eat alkalis. Ever. All our food and drink is either acidic (like lemons) or neutral. It may be the case that certain foods provide more minerals than others, and it may even be the case that certain foods can be detrimental to mineral levels in the body. Again, there is no debate that a diet rich in fruit and vegetables is healthier and will put less ‘stress’ on the body, but this has nothing to do with the pH of those foods, or somehow making the body more alkaline.

        In short, stop worrying about acids and alkalis and just eat a healthy diet with lots of plant-based stuff in it. This whole acid/alkali thing adds nothing.


  14. I know anecdotal evidence isn’t actual proof, but I know people who have driven their cancer into remission by merely changing to ‘alkalinizing’ foods. I don’t know if some other mechanism than altering pH is at work. But it is interesting.


  15. Whats up! I simply want to give an enormous thumbs up for the nice info youve got here on this post.
    I will probably be coming back to your blog for more soon.


  16. I agree that lemons do not have an alkalizing effect on the body, but I do however believe that the alkalinity of saliva and urine has an effect on health. Acidic saliva can have a corrosive effect on tooth enamel, for instance. And it’s not just a health issue – sweat with high acid levels can damage or discolor clothing, and guitar players with acidic sweat find that their strings go black very quickly and have to be changed more often.


    • Right. Of course a low pH in the mouth can be damaging to teeth. Eating too many acidic foods could well aggravate this. Like, oh, I don’t know… lemons…


      • Meyer Lemons, possibly a hybrid of a regular lemon and a mandarin orange, are sweeter and SLIGHTLY less acidic than the regular lemon with a pH of 2.
        A friend complained to me that his dentist “had failed to warn” him that he’d lost all the enamel on his teeth. The very next day, I saw him eating one of these Meyer lemons like an orange!! I asked him why in the world he was doing this. He replied that he’d been advised this was a healthy practice, one or more a day for years, as they were milder and sweeter. In fact, their pH is still quite acidic––neutral is 7––and they were of course the cause of his enamel having eroded. Just because a fruit or candy tastes sweet doesn’t mean it isn’t damagingly acidic to your teeth with prolonged exposure. Most people only get one set of healthy adult teeth––and with care they can last a century. This faddishness for undiluted lemons seems foolish in the extreme.


      • Yes I think people massively underestimate the importance of their teeth. Until they’ve done permanent damage to them and have to live with it.


  17. This was a great article , and I appreciate your follow up comments. When someone mentioned this to me, I thought “no way, lemons are 100% acidic”.But then after searching the first few results all support this whole pH diet craze. Was glad to find some real science.


  18. Great post and comments. I admire your patience and am relieved to find a science-backed sensible voice is weighing in on this topic.


  19. After reviewing your post and comments it appears to me you are a young scientist pursuing either a PHD or MD in medicine. The information you provided, the discussion, and the conclusions drawn were both factual and correct concerning pH and body fluids. There is no need for you to further indulge in back and forth mini debates on the subject matter. There will always be people who will argue against the observed facts of natural law. The pH of human blood should never vary much outside of 7.348, PERIOD! This is an established fact of natural law and nature over time has developed energy sources (foods, drinks, etc) that when consumed by man maintains this delicate balance of pH in human beings. Yet, are you aware of your apparent dogmatic reliance on “accepted scientific” positions on what may be real science or not real science? I sense that you don’t question anything if it is accepted as true by the current scientific community. I only raise this issue because I noticed your reference to Wikipedia (as a scientist you can do better than this) and your cynical responses when replying to people who disagree with you. As a research scientist (MS) with almost 30 years experience in pharmaceuticals and chemicals, and now more than 10 years in nutraceuticals R&D work, be careful about discounting research efforts that proposes so-called natural remedies for known health related issues. You can knock-yourself-out with volumes of Peer review research papers on the use of natural remedies in areas of cancer management to controlling neuropathy in diabetics. True, there are established standards and research methods and protocols that are fundamental to proper scientific investigations. Still, my advice to you is to never assume that the outcome of an investigation should follow what is currently accepted. In other words, “I only pursue the path that nature reveals and I do report my findings in a truthful and non-biased fashion even if the truth goes against what I believed or previously accepted. If you accept this way you will be following in the footsteps of giants that have preceded you.


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  21. Great blog post, and well handled responses to those that have ‘drunk the Kool Aid’ (which ironically has a pH of 3 and therefore, no doubt, exhibits an alkalising effect..)
    Will be back to read more 🙂


    • Haha well, yes! Good point. After all if citric acid is alkalising, then surely fizzy drinks that contain citric acid are as well…. And those sour sweets… (better eat more!)


  22. Good work on staving the trolls off, even if they’re probably trolling themselves more than the rest of us. The internet needs more reasonable, polite and thorough writers like you.


  23. I came here by searching how lemon juice could make a body alkaline also cider vinegar. As a chemist I can see your chemistry is correct but our bodies are not as simple as mixing things in water. The pH of our blood changes with the rate we breathe hyperventilation lowers CO2 in blood it is still buffered but moves slightly and this lowers our ability to exchange O2 for CO2 so more O2 in blood makes for less O2 in our cells. This is why we feel light headed when hyperventilating yet fine while breathing pure O2. Off track a bit but trying to show body chemistry is not simple. I will continue to search the original problem, thanks for your posts.


    • Evidently body chemistry is not simple, however lemon juice and cider vinegar categorically do not make the blood or, indeed ‘the body’ more alkaline. Still, feel free to keep looking. Beware, however, of people who simply state it as fact with absolutely nothing to back it up. In much the same way, you will find people who firmly believe they’ve seen Big Foot and the Loch Ness monster, but….


    • Assuming you don’t have scurvy? Probably not. Lemon water is a lot healthier than sugary drinks of course, but, you know, so is plain water.


  24. Thanks katlday.
    This is the most informative thing I have read on this subject. I could never get my head around how
    people could say lemons and cider vinegar are acidic but alkaline at the same time. It never made cents.
    I may be wrong and please correct me if I am, but a PH test on your urine and saliva, may only be an indication of how hard the body has to work to process the food we eat. Eat good food and the body gets what it needs run and don’t have to to hard to get it, so you mite get a alkaline reading in a urine test. But eat bad food,then the body has to so hard to fined anything good that it needs in it. It pushes more wast out so when you test your urine now it is more acidic. That’s it, that’s the test, nothing more to be read into it. Nothing else happens, no big PH swings in your body, It’s just an indication that your body likes or doesn’t like what your eating. This is just a thaw t I had as I was reading through your posts and the comments. I think the PH test it self is a good sound test. We just don’t understand the date-ta the test gives us.


  25. Pingback: The Colours & Chemistry of pH Indicators | Compound Interest

  26. OK – I love your chemist approach. I too LOVE chemistry (took O chem as an elective 🙂 and I’ve been researching this because Lemons, Limes etc have proven to help prevent problems like Kidney stones (experimental proof). There are several kidney stones, but 80% are due to calcium oxalate, which is a crystal. Oxalic acid is, well, an acid. (interestingly, it’s found in heavy concentrations in the skin, so if you have kidney stones, avoid the skin lol)

    I was explained that organic acids, as compared to chemical acids, are broken down in the stomach and the molecule itself changes. The leftover molecules end up having alkalinic properties. The alkalinic properties from the leftover molecules neutralize the oxalic acid and start the process of breaking down the calcium oxalate.

    At least that is how i understand it – haven’t been able to find information on the actual process, but DO KNOW that drinking lime juice WILL break down kindey stones ( huge ones, gone in less than a year). Since the kidney stones are acidic, then logic states that the lemon molecules broken down and absorbed into the bloodstream are alkaline. OR that the acid directly breaks down the crystals? I’m not sure how this would work since it was the “too acidic” “too concentrated” kidney environment that caused the crystals to drop out of solution and crystallize in the first place.

    Lemons also help neutralize uric acid. This is a problem for people who eat too much meat – the body releases huge amounts of uric acid from breaking down the proteins, which can result in gout. It is well known that drinking lime / lemon juice will reduce the crystallization of uric acid in the joints and thus helps prevent gout.

    So drinking lemon juice has the effect that it neutralizes/buffers acids in the bloodstream. I’m trying to understand exactly how that happens 🙂



    • Since I’m in danger of repeating myself on the topic of urine pH, I’ve added an extra bit to the bottom of my original post on the subject.


      • I am not claiming that Lemon will noticeably change the blood pH after a day or even after a month. As you clearly stated, the body has a huge resiliency to pH changes due to a complex relay of buffers. Changes to blood pH take a long time over a sustained poor diet – such as eating way too much protein and not drinking enough water for years and years.

        What i am saying is that lemon removes kidney stones, and I want to understand the chemical process in which an organic acid can dissolve kidney stones that are only soluble in alkaline (:

        as you said:

        “That said, the main focus of their interest was actually treatment of kidney stones, which are, in some cases, caused by a build-up of calcium oxalate which then forms crystals. The researchers found that the lemon juice helped the body to get rid of oxalate, and they’re not the only ones to draw this conclusion”

        My brother removed 3 huge kidney stones in one year drinking lemon juice. It works. It is well known and documented that lemon juice breaks down kidneys tones. The question is how.

        For lemon juice to be effective it MUST be, chemically, alkalinic in the blood. I can think of no other way that lemon juice could dissolve kidney stones. Can you? Kidney stones formed because the kidney environment was too acidic and concentrated – the solutes at that slightly too acidic solution began to precipitate and thus form kidney stones. Kidney stones are not soluble by acids; they are soluble by alkaline compounds.

        Thus, if drinking lemon juice experimentally dissolves kidney stones, then lemon juice must turn alkaline in the bloodstream, and it must do so to a degree sufficient to change kidney stones. Will this change the pH? probably not, because the buffers that keep the blood from being too acidic would be highly saturated (since, by default, a person that has kidney stones has a slighly too acidic blood, thus the buffers must be saturated and unable to keep the blood at optimum pH). The alkaline from the lemon would start ‘helping’ neutralize the acid buffers over a looong time. The buffers will slowly start to be ‘unsaturated’ and the blood will return to optimal pH.

        Think of titrations with buffers. You can keep adding an acid to a buffered solution, and the pH will not change or hardly change at all. Does that mean that the acid is doing nothing? no, it means that the buffers are doing their job and getting saturated. Once the buffer reaches approximate saturation, the pH of the whole solution will change. That’s how the body works. It’s buffered, but only to a certain degree. Eat lots of protein, soda, coffee for a couple years and i will guarantee your blood pH will be more acidic.

        My understanding is that organic acids, or ‘molecules with acidic properties’ CAN be cleaved and modified into molecules with entirely different properties, such as alkaline properties. My hypothesis is that some part of the lemon, likely it’s organic acids are being cleaved or maybe saturated into a molecule with alkaline properties. In the blood, these alkaline molecules then start neutralizing acids, thus being able to break down calcium oxalate.

        Please, you’re a scientist. Don’t just say, “that’s not how it works”. Provide an alternative to how lemon juice dissolves calcium oxalate, which precipitates and crystalizes in acidic environments and dissolves in alkalinic environment. I’m totally fine with being wrong, but if you want to prove me wrong, provide an alternative plausible scientific answer.

        For Science!


      • You know, instead of writing a long post here demanding that I explain everything to you, you could spend that time refreshing your chemistry knowledge, learning a bit of physiology, reading the scientific papers I referenced, and looking up the question for yourself. I’m just saying. I don’t pretend to be a nephrologist; there are specialists out there who’ve devoted years to this research and answering these questions, and any one of their scientific papers would be well worth reading. For example: Citrate, not phosphate, can dissolve calcium oxalate monohydrate crystals and detach these crystals from renal tubular cells.

        I’ve been hunting and I can’t find a lot of evidence that calcium oxalate is soluble in alkaline solutions. It’s pretty insoluble generally (6.7 mg/litre at 20 oC). However citrate can bind to calcium, which makes calcium oxalate more soluble. So, increase the amount of citrate in the bladder and you improve the solubility of the kidney stone, assuming it is an oxalate stone (not all of them are).

        On another note, please stop confusing urine with blood. They’re really not the same thing. Just because something has an effect on urine pH, doesn’t mean it’s going to change blood pH.

        Also, kidney stones often disappear by themselves. Your brother getting rid of three over the course of a year, whilst at the same time drinking lemon juice, is great for him but it’s about as far from scientific evidence as you can get. Unless you’re twins, and you had kidney stones too, and you didn’t drink lemon juice and still have yours?


  27. I’d like to take this opportunity to point out that calcium oxalate and oxalic acid are two different things, which I will call Ca-Ox and H-Ox (to casually shorthand the oxalate part of the molecule). H-Ox is an acid; Ca-Ox is the calcium salt of that acid and is not itself an acid. Much like HCl is an acid, while NaCl is the sodium salt of that acid (or CaCl2 is the calcium salt of HCl); likewise citric acid/sodium citrate or acetic acid/sodium acetate. The properties, including both solution pH and solubility at various pH levels, are different between the acid and the salt. If the salt is soluble, it’s the other half of the buffer system. (Citrates and acetates are both used to buffer foods, which has a preservative effect.) Sometimes the salt is not soluble, as in oxalate type kidney stones. While people usually say gout is caused by uric acid crystals, it’s actually the sodium salt of uric acid, sodium urate, which forms the crystals once the uric acid levels in the body get high enough. Again, the crystals are not the acid.

    Different salts have different solubilities based on both pH and what they’re being dissolved in. Many things are more soluble in acidic solutions than they are in plain water. Calcium salts often are, in my experience. A solution rich in oxalate/oxalic acid will not readily dissolve an oxalate salt because the solution already has a lot of it there. If something removes or otherwise ties up oxalate from solution and thus makes the solution low in oxalate, then an oxalate salt will more easily dissolve to “fill the gap”. Simply drinking more water will dilute urine, which will also lower the concentration of everything in it, and have a similar effect, though not as much of one as a reaction that dramatically reduces oxalate concentrations. Google search term for further reading: le Chatelier’s Principle.


    • Oops, that was meant to be a reply to Miguel Amat y Leon. I guess that’s what happens when you hit the nesting limit…


      • Wow – CC you really did pack a lot of information on this – i read it a couple more times – That’s the process! !

        a follow up Q, if i may – Do you think it’s excess of oxalic acid or perhaps excess of calcium that’s dominating the equilibrium of the precipitation reaction for ca + ox Ca-Ox?

        I checked into oxalic acid, oddly enough i found this:
        “Urinary calcium, the main constituent of renal stones, is increased by a high salt diet and this increases the risk of stones forming” [ ]
        -Made me think, maybe the calcium is leading the reaction?

        Also, do you know why would eating lots of NaCl drain calcium?
        (guess) is it the calcium from used up calcium phosphate buffers / other buffers? (guess) Does the NaCl just drag the Ca2+ along ionically?
        does the calcium come from bone stores i take?

        i’m having trouble finding a chemical explanation to that one.



      • Your reply was also really helpful – the one above – a couple things i had confused – I assumed that an alkaline would dissolve the Ca-Ox. I do need to review my chem!
        Acids, conjugate bases and relative pKa – good stuff. It’s really all a game of h+ potato 🙂


    • Ok, you have made 7 comments in a short space of time, and a lot of what you are posting is not particularly scientific. Please do feel free to start your own blog to discuss this if you wish, but I’d rather not have chunks copy/pasted from dubious websites on mine.

      My final words on the subject:

      Nothing, no thing, that you eat changes your blood pH. It’s impossible. If your blood pH changed every time you ate, you would become seriously ill. And frankly, that would be a bit of an evolutionary dead-end. Buffers do not ‘hide’ pH changes, they prevent them. This is a subtle, but crucial difference.

      It is true that if someone is eating an extremely nutritionally-deficient diet their body can start to leach minerals from their bones (for example, low bone density is a complication for sufferers of anorexia), however this is not a problem for the vast majority of people eating a reasonable, if not perfect, diet. Also, the phosphate buffer system you mention relies on, guess what, phosphate ions. Want to know some foods which are rich in phosphorous? Cheese, fish, shellfish, pork, beef and dairy. Guess where all of those tend to fall on those lists of ‘acid-forming’ and ‘alkaline-forming’ foods? Yup. On the acid side. (I will add here that too much phosphorous may well be harmful, however the reasons for that aren’t at all simple: it’s certainly not just a case of somehow producing extra acid.)

      On the topic of gout, it’s known that consuming coffee, seafood and dairy reduces the risk. Again, categorised as ‘acid-forming’. These lists of ‘acid-forming’ and ‘alkaline-forming’ foods literally make no sense.

      For the record, the phosphate buffer plays a relatively small role in blood pH. The carbonate buffer is much more important. That relies on carbonic acid and bicarbonate. Do you know what you need to do to make sure you ‘get enough’ of these substances? Just keep breathing.


      • “Nothing, no thing, that you eat changes your blood pH. It’s impossible. If your blood pH changed every time you ate, you would become seriously ill. And frankly, that would be a bit of an evolutionary dead-end. Buffers do not ‘hide’ pH changes, they prevent them. This is a subtle, but crucial difference.”

        Damn it i’m not saying it changes blood pH. I am saying foods DO produce alkaline / acidic compounds after they digested IN THE BLOOD and they DO affect your blood buffers. The blood buffers neutralize their acidity or alkalinity. It doesn’t change the pH, but the molecules are STILL THERE. And those molecules DO have an effect.

        The way you write your information you make it sound like the foods DON’T affect the body, but they DO. Especially with things like lemon juice, the alkaline properties do HELP your buffers not work as hard.

        I am not defending the lists of alkaline / acids foods – some things frankly are a wash. But ignoring things like “lemon juice helps prevents kidney stones”.. is bleh.

        Thanks for deleting half my posts. I kinda had a feeling that you were really biased – you’re not looking for the answers.


      • Lemon juice is not alkaline. It does not have ‘alkaline properties’. I have said countless times that eating healthily is important, but the mechanisms are complicated – more complicated than simple ideas of buffers, acids and bases. The posts I removed contained long quotes from, and links to, scientifically dubious websites, and I would rather not send traffic to such sites from here. Now please, go and bother someone else.


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  29. Organic acids have alkali properties when put next to strong acids. It’s relative.

    You have a ton of information about everything BUT how lemon works.

    You’re obsessed with the stance that blood pH doesn’t change,
    and yes it’s absolutely true. I see that now. I came here to learn.

    I learned that, but you stopped there.

    You didn’t keep looking to see what other properties might be occurring.
    You barely mentioned that citric acid actually dissolves kidney stones. “possibly” ? really. It’s documented:

    You don’t explain Ca-Ox either. Basically it’s only, no the blood pH doesn’t change.

    But wait the blood pH CAN change in unhealthy individuals due to poor diets .. seems worth researching?

    What about the minerals from the Lime? maybe the composition has lots of alkali minerals? maybe a possibility? Worth a look i say?

    Can’t organic acids behave like alkaline? pka tables: A weak organic acid can behave like alkaline in acidic environements, such as urine. Urine can range from 6.5 to 8.0 for healthy people, yet for people with poor diets can have a pH below 5.5 – That’s pretty acidic. Anything below 6.0 is not healthy.

    “The most important risk factor for uric acid crystallization and stone formation is a low urine pH (below 5.5), rather than an increased urinary uric acid excretion ”

    Hmm maybe urine pH might be worth researching.

    nono, blood pH doesn’t change!

    Yes i need to brush on chemistry, but clearly this is not the place to do it.



    • No, organic acids cannot behave as alkalis. Ever. You need to understand the difference between an alkali and a base. ‘Alkalis’ are a specific group of chemicals. Weak (actually even strong acids, sometimes) acids can sometimes behave as bases, in the presence of strong(er) acids.

      If you followed the links to the scientific papers I quoted, you will see that actually I have responded to a number of your questions. Or rather, I have linked to researchers who are working on the questions you have raised. Additionally, I added a whole extra section to the bottom of this blog entry on urine pH.


    • I’m curious – where did you get the idea that katlday had any obligation to explain in detail all of the things you don’t understand?


  30. Lol actually i think that’s the answer – Citric acid IS a buffer. Check out the acid dissociation constants for Citric Acid
    pKa1 = 3.14
    pKa2 = 4.75
    pKa3 = 6.39
    When you eat it in foods it’s acid, in the blood (7.41), acid, but put it next to urea and concentrate it in the kidneys, where the pH starts going up, Citric acid, as the pH passes 6.4 it binds with a proton (at 7.41, they would have been dissociated) – thus the citric acid acted as an alkaline molecule / buffer.

    That’s how Citric Acid increases the overall pH of urine, or better said, helps keep it neutral, since it acts more like a buffer. It slows down the H+ buildup in the urine.


    • Correction “…in the kidneys, where the pH starts going *down/ acidic*,.. not “up”


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  33. Dear Doctor (yes, I know it’s a PhD not a medical degree) thank you for your plain language explanation of high school level chemistry. One of my old army mates has been diagnosed with lung cancer (he was a heavy smoker) and is not expected to make it to Christmas. Whilst doctors and orthodox medical experts tell him to “get his affairs in order”, the alternative therapists have flocked to him with the twig of hope. He is convinced that if he can get his urine alkali (by eating more and more lemons) the cancer cells will die because they can’t survive an alkali environment. I suggested he squeeze a lemon onto one of his urine strips to get the real pH of lemon juice (2?) but he clings to the belief that the pH of lemon juice is different in the body (7.5). He keeps quoting Dr. Theodore A. Baroody’s book “Alkalize or Die”. Whilst the alkalizing diet has steered him to a healthier lifestyle, I fear his obsession with alkalizing his urine is cheating him of his last days and closing his eyes to genuine advice. Is there anything that can be done to silence this quackery ?


    • Well, maybe in this case it’s not worth the fight? If the worst that happens is that he eats a healthier diet and feels a little bit more positive in his last few months, perhaps it’d be better to just let it go? Sometimes things just aren’t worth arguing over, particularly when you don’t have a lot of time left either way.


  34. katlday,
    I have been following this post and its off-shoots for their entire length, and I appreciate your efforts to bring the lucidity of fact and reason to a widening audience. I hold my B.S. in chemistry, and I am also dismayed by the existence of nutritional and other pseudoscience.

    I’m curious about your recent choice of article (Diet-induced acidosis: is it real and clinically relevant?, Pizzorno et al., British Journal of Nutrition (2009)) in the “What’s in the water?” post. The article itself doesn’t draw any strong conclusions about the negative effects or the supplemental treatment of a chronic, low-level (but within norms) acidotic state, but it does state:
    “[I]f the duration of the acidosis is prolonged or chronically present, even a low degree of acidosis becomes significant. … Diet’s contribution to an acidotic state is now well documented.”
    It goes on to imply by clinical evidence that a reduced protein (#firstworldproblem) and reduced sodium diet may be the best treatments. It’s bold conclusion is thus:
    “Nonetheless, the available research makes a compelling case that diet-induced acidosis is a real phenomenon, has significant clinical relevance, may largely be prevented through dietary changes, and should be recognized and treated.”

    I love that in using this article (considering it on the whole) you make a subtle but brilliant refutation of the cult of “alkalinizing foods” as a panacea, but you have unintentionally contradicted yourself. Of important note, I also hold skeptical reservations about the motives and rigor of this review because of acknowledged support by pH Sciences of Seattle, WA. So, in the first place, I’m excited that this article contextualizes and puts limits on the question of blood pH as an indicator of overall health. It cuts through the sensationalization of dietary effect by emphasizing the body’s natural, homeostatic control of a narrow blood pH by bicarbonate buffer and renal excretion of excess or by-product acids. However, your expressed inflexibility to admit the primary conclusion of your own citation (vide infra: “Can what you eat ‘alkalize’ your blood? … No. Absolutely not. Under no circumstances.” and “None of this in any way relates to the blood, or ‘the body’ in general. You cannot, absolutely cannot, affect your blood pH with your diet…”) instantiates a rhetoric born of emotional frustration and logical inconsistency, and it obligates that you admit a refinement of your own perspective on this discussion.

    Going back to the elegance of this article, it makes a case for boring, ol’ health recommendations of balanced eating. That means no exclusive diets (*eat this, BUT NOT THAT*) and not really much in the way of supplements either (if it aint broke, don’t fix it). Just don’t over-eat anything, but especially salt (i.e. sodium). To a lesser degree, it implicates eating processed foods in negative health effects.

    I think you’ve done a good job at highlighting and debunking an abuse of medical quackery and capitalist greed which prey upon the ignorant and uninformed. Thank you.


    • Thanks, I think… 😉

      I have stressed several times that there are people out there (not, generally, the ones promoting alkalising diets mind you) who know a lot more about the relevant biological science than me. For me, the key part of this paper was the clear distinction they draw between acidosis and acidaemia, where acidosis refers to the process, or trend toward acidaemia, without necessarily reaching a pH of less than 7·35.

      In other words, my understanding is that if your diet is very poor, your body’s homoeostatic systems (I avoid the eponymous term ‘buffer systems’ deliberately, as it’s more complicated than that) may be having to work fairly hard to maintain blood pH. However, here’s the key, blood pH does not actually change. Now I don’t see anything particularly controversial in this idea. It seems to me not unlike saying that if you eat a lot of salt your kidneys have to work hard, however they will (extreme situations or illness aside) maintain your electrolyte balance nevertheless. You can give your kidneys a rest by drinking more water and cutting out the salted peanuts. Likewise, you will be healthier if you eat a diet that contains plenty of fruit and vegetables and rather less meat. However, drinking lemon juice is not some magic panacea that’s going to cure your health problems by raising your blood pH.

      My point is, and consistently has been, that you cannot ‘alkalise’ your blood. You can’t. I don’t see anything in this paper to contradict this. I also find the term ‘alkalise’ extremely problematic as, to misquote a favourite film of mine, “I do think think it means what [they] think it means”.

      As for the validity of the paper, I wondered about that but I’m not really qualified to comment. I just have to trust the peer review system…


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  37. Will putting baking soda up the wahoo help make a womans vajajay more alkaline? I heard this helps with gender swaying since male sperm like a more alkaline environment. Off the topic, i know but im just curious?


    • It WOULD make the environment more alkaline, but it would also probably be quite irritating. For both partners. Sperm like pHs between about 7 and 8.5. Stuffing random amounts of baking soda where it doesn’t belong might result in a higher pH than that, which would kill the sperm (and no, this doesn’t mean it would make an effective contraceptive, either). In short, this doesn’t sound like a very good idea to me!


  38. I also have another question as ive read that being too acidic can cause cancer, but alkaline foods can help to starve the cells. Is this true??? Im just wondering what causes cancer, maybe body being too acidic..idk


  39. Hello.
    While after a quick research I do not believe that lemon juice is base-forming in our body, there is a possibility (have to research it yet, specialized more in chemistry than biology) that metabolites of some substances can have a drastic pH changing effect (like methyl alcohol – neither acidic nor basic, yet it metabolizes to formic acid, in quantites that depletes the buffers in our body, causing severe acidosis).


  40. Wondering if you’ve ever removed the pH from the lemon juice argument and simply looked at it in terms of anionic or catonic? It is my understanding that lemon juice is anionic (however, after prolonged exposure to oxygen it becomes catonic) which parallels stomach acid, bile and saliva. Drinking lemon water 15-30 minutes prior to a meal helps to ensure that we are properly digesting our food and releasing its energy for our body to use. I am of the understanding that lemons are the only anionic food on the planet.

    Now regarding pH, the argument for wanting to eat foods that are alkaline forming is because foods that are typical in the Western Diet (ie. meat, dairy, sugar, processed and refined foods) are extremely acidic/acid forming and cause hydrogen accumulates in the cells of our body. When the cells in our body become acidic, they become deoxygenated, the mitochondria power down and the cells then become a breeding ground for disease (ie. cancer). Cancer cells are anaerobic and thrive without oxygen.

    My understanding of eating an alkaline diet is to ensure that hydroxide ions (OH-) are provided so that they can enter the cells, combine with hydrogen (H+) to form water and flush the hydrogen (acidity) out of the body so that the cells can properly receive oxygen and other important minerals (ie. potassium and magnesium). Now when I say acidity I’m not talking urine or blood, I’m talking about the acidity of the actual cells of the body.

    Anyway, just wanted to throw out a few things for you to consider. Would appreciate your feedback.


    • What you have just written in 100% nonsense. Sorry. Not sure who told you all this, but it’s completely unscientific. For starters, anions are simply negatively charged particles and cations are positively charged. Table salt, for example, contains positively charged sodium ions (cations) and negative charged chloride ions (anions). All acids contain both types.

      The frustrating thing about this is that you’ve clearly spent time and energy learning something that’s completely wrong. Why? Pick up a GCSE chemistry text book instead.


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  42. Hi. I work a great deal with cancer patients. I have heard a lot of strange things (for good or ill), and alternative methodologies proposed. I have taken these questions seriously, and was a real springboard to start working on a degree in organic chemistry. My question is 2-fold:

    1.) Is is possible that this “myth” was generated by the blood-effects of other components found in citrus fruits that are especially prevalent constituents in the steam-distillates of the bio-mass used (…like limonene, for instance?)

    I ask this because in a research project I am working on, a study was done on how a room diffused with Rosemary oil vapor appeared to increase not only cognitive function in exposed test subjects vs. the control, but also the blood levels of 1,8 Cineol. (source:

    2.) Is it possible that the “myth” has less to do with “alkanization”, but rather on inter-cellular processes that are undergone in metabolization? (Source: “Role of citrus juices and distinctive components in the modulation of degenerative processes: genotoxicity, antigenotoxicity, cytotoxicity, and longevity in Drosophila.
    Fernández-Bedmar Z1, Anter J, de La Cruz-Ares S, Muñoz-Serrano A, Alonso-Moraga A, Pérez-Guisado J.
    Author information
    1Departamento de Genética, Universidad de Córdoba, Córdoba, Spain.)

    Many thanks in advance for your consideration. Thank you for your input and wisdom! 🙂


    • It’s possible. Who knows how these things start? There are some crucial misunderstandings going on, that’s for sure. My suspicion is that no one got as far as scientific papers. I think they just worked on an instinctive ‘feeling’ that lemon juice in water is good for you (well, it is a good source of vitamin C, and it’s better than drinking cola that’s for sure), picked up some half-baked ideas about buffers and citrate, and put something together from there. Not unlike people who read a sentence about quantum mechanics and then use it to ‘explain’ homeopathy.


  43. I don’t believe in the “Ph Diet”. I have read a lot about it. Almost all tout some kind of “green” diet. This drives me nuts because many of us suffering from things like CKD, kidney stones, IC, vulvodynia & other ailments are lacking the enzyme/bacteria that degrades oxalates from plant foods. This oxalate can then bind (or steal) our calcium (which can also cause low bone density & make teeth weaker). Calcium-oxalate crystals can cause the filters in our kidneys to clog (as indicated by a low GFR which can also indicate CKD), cause irritation & burning (IC, vulvodynia) and are well documented to be the cause of 60-80& of kidney stones.

    I know I am one person but decided to decrease fruits & veggie intake & increase meat & dairy. My GFR increased 25 points out of the bad zone! Yes, my cholesterol increased, but is still in the healthy range. When I took in more fruits & veggies (but not as much as I used to) my GFR went down again (as did my cholesterol).

    There is not 1 diet that is right for every person. A vegetarian diet is not right for every one.


  44. Mrs. Katlday, I have read over and over in your posts how you are not a medical doctor, yet you argue the point as if you have ten medical degrees. You keep repeating yourself that blood PH can not be changed and that you are not talking about urine PH. And you keep arguing that a lemon can not be alkalizing because it is an acid. Everything I have read supports that after being metabolized, the chemical makeup changes. But that is not even my point, my point is that the PH diet is about helping your body maintain the proper balance so that it is not pulling valuable nutrients from your bones and organs in its effort to maintain the blood PH of around 7.35 or 7.4. Nobody and I mean NOBODY, in all my research on the PH diet, has said that the diet is meant to CHANGE YOUR BLOOD PH LEVEL. That is not what the diet is about at all, its about eating more foods that support a healthy 7.4 PH level rather than continuing to eat the HIGH ACID diets that we are exposed to this day and age. IT IS NOT ABOUT TRYING TO CHANGE THE PH IN YOUR BLOOD, AND IT NEVER HAS BEEN, It is, however, about being aware of the effects different foods have on your PH level, because if you just eat whatever you want with no concern for your health, your body will take what it needs to maintain the PH level from places you can’t afford to lose it from, such as your bones and organs.


    • Ah yes, a high acid diet. What is that again? A diet containing lots of acid, surely? With acidic foods? Like, ohhh, I don’t know, lots of citrus fruits? Like… lemons? Better not eat those then.

      The most important buffer system in your blood is the carbonic-acid-bicarbonate buffer. That’s what regulates your blood pH. Guess where carbonic acid comes from? It comes from the air, from carbon dioxide. Just keep breathing and you’ll be fine.

      I have stated multiple times that a healthy diet, containing plenty of fruit and vegetables is, of course, sensible. That doesn’t mean that the notion of an ‘alkaline diet’ makes any sense at all. Because it absolutely doesn’t. It exists purely because saying “eat fruit and vegetables” doesn’t make anyone any money.


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