My daughter having newly embraced lacto-ovo-vegetarianism, I am researching it, and I ran across this rather startling statement on page 22 of Suzanne Havala’s Being Vegetarian for Dummies.
And then on page 61, there was this equally startling statement:
I had never heard that before. I was aware that your body draws on its calcium reserves in order to keep your cells’ ion balance at the proper levels, but I had never heard anyone say that eating meat messes up your body chemistry.
(She also asserts that the reason NASA astronauts are at risk for developing kidney stones is because of their meat-eating in-flight diet. NASA, however, seems to feel it was due to lack of exercise and limited fluid intake.)
Anyway, so then I was googling around on things like “meat makes body acidic”, and discovered that there is apparently a large and vocal contingent of vegetarians who firmly believe that eating meat makes your blood and body too acidic, which causes you to lose calcium, which leads to bone loss. The biochemistry of this is beyond me. Anybody else got any input?
Also, how could amino acids from a plant have a “different effect” on the body than amino acids from an animal? Methionine is one of the sulfur-containing amino acids found in meat, but is also apparently found in legumes and nuts. So how does the methionine in grain have a “different effect” on your body than the methionine found in beans?
And since methionine is one of the “essential” amino acids that the human body cannot synthesize itself, and you gotta have it, wouldn’t it also cause your blood to become too acidic even if you got it from plant sources?
It all sounds a bit woo–and a trifle preachy–to me. Color me surprised that IDG Books published it like that.
It’s all crap, as has been well pointed out already. There are medical conditions that result in acidosis but since it’s usually a symptom of poisoning, diabetes, kidney failure and other scary things, bone loss and meat consumption are probably pretty low down on the list of things the medical types will be worrying about.
IANANutritionist, but, in my limited experience, it seems that the only reasonable way to read any litereature on vegetarianism is to seperate it from the preaching. Very often, vegetarians come up with bizzare pseudosciene in an effort to biologically justify their ethical position. That section you quoted is all preaching.
This is what biology tells us (and why vegetarians tend to work so hard at refuting it): Humans and pretty much all of the great apes are omnivores. We aren’t ruminants or hind gut fermenters. We don’t have the machienery to run on plants alone unless we are especially watchful of our diet.
If your daughter has decided to never eat meat again, she needs to make sure that she is getting adequate supplies of the vitamins that mostly come in meat (notibly the B vitamins). The fact that she is still eating eggs and dairy products will help. Make sure she keeps her diet varied enough that she doesn’t make herself deficient in any other vitamins or minerals.
And get her talking to someone who actually knows their stuff. Often, the nutrition department of your local university is willing to help or at least set you up with trustworthy information. See if she’d be willing to take a nutrition class at the local Junior College.
You cannot change the acidity of any part of your body except your urine.
Where do you think urine comes from? Stuff that comes out in your urine came from your bloodstream. The acid in your urine was cleared out of your bloodstream by your kidneys. Before it is removed by the kidneys, it is circulating throughout your body.
Your bloodstream and organs control acidity in a very narrow range.
Exactly. But that doesn’t mean that different foods (when digested and absorbed) don’t present different loads on the kidneys. This effect can be directly measured in the urine.
See: Remer and Manz, J. Am Diet Assoc. 95: 791-797, 1995.
I’m certainly not defending vegetarianism (I believe it is a very poor nutritional strategy), but claiming that different foods don’t effect the acid/base maintenence mechanisms of the body in different ways is nonsense. It is also silly to equate the pH of the stomach and the pH of the intestines with the pH of the blood and the acid/base load on the kidneys. The fact is that different foods do present different loads on the kidneys. Make of that what you will, but don’t claim it doesn’t happen.
No, it’s not crap. At least not the physiologic basis behind the assertions. The broad statement that eating meat = osteoporosis is shady. For one thing, there are marked racial differences in the development of osteoporosis. An African-American on the worst possible diet is very likely to have better bone densitity than a Cacausian that has the best.
That “debunking” article higher up the thread is kinda spooky in that the person who wrote that doesn’t appear to understand acid base physiology at all.
One aside - it’s the lack of gravity that causes the severe muscle and bone loss in space. Animal models that try to re-create the effect are done by unloading the skeleton, not by changing the diet.
Dietary anion -cation differences and the chemical composition of foods has been used to affect skeletal mobilization in dairy cattle for many years. It’s catching on in human health as well.
Here’s a crash course on the physiology behind this:
It starts with an understanding of strong ion (or Stewart’s) acid base principles. Bottom line - the old Henderson-Hasselback theory of HCO3 being central to maintaining blood pH is incomplete (it acutally explains a facet of strong ion acid base, so it’s not accurate to say that it’s out and out wrong).
What DOES influence acid base status is the balance between strong anions (negatively charged particles that are completely dissolved in aqueous solutions) and strong cations (positively charged…). For calculation purposes, the strong anions in diet are Sulfer and chloride and the strong cations are sodium and potassium. In fact, other elements contribute too - such as phosphorus (negative), calcium, magnesium (positives).
These minor ions aren’t usually used in calculations because 1) they are not typically consumed in as large amounts and 2) their charge and thus how they contribute to the overall acid-base balance is dependent on their chemical form. HOWEVER - phosphoric acid is quite acid producing and, while it’s not part of a healthy diet, is consumed in mass quantities in people who drink phosphoric acid-containing soda pop.
The mammalian body is set up in a hierarchal fashion - When an evironmental factor causes the body to deviate from steady state, some things are preserved at the expense of others. Here’s an example: Your heart rate is typically 60 beats per minute. When you excercise your tissues become hypoxic (lack oxygen). The body speeds up the heart - altering the heart’s steady state in order to maintain the tissue’s constant supply of oxygen. Of all these things blood pH is maintained more tightly than just about anything else.
So, if a bunch of strong acid gets into your blood stream, the body doesn’t let the blood pH fall - it buffers it and then excretes the excess acid in the urine. Eating an excess of anions won’t change blood pH very much because everything the body does is geared towards keeping blood pH constant- it will change urine pH dramatically because that’s were the excess acid is moved.
One of the blood’s buffers is all the calcium (a cation) in the skeleton. The skelton basically acts as a giant source of cationic buffer that can be used to neutralize excess acid in the system.
Keeping all other things constant - Eating relatively more sulfer increases the acidity of the diet when compared to a diet lower in sulfer. There are more sulfer-containing amino acids in animal-derived proteins. So, yes, a high meat diet adds to the acid load that the body has to deal with - by buffering it and excreting in the urine. One way it can do this is to use the calcium in the skeleton.
Except in extreme circumstances, the body can do this while keeping blood pH pretty much constant.
Thanks for the links, guys. I should have thought of quackwatch myself, but I was distracted by the vision of my daughter thinking that “no meat” means “The Macaroni and Cheese/Iceberg Lettuce Diet”. And yes, I’ve ordered Idiot’s Guide to Being Vegetarian for her, and will be tactfully not-nagging her to balance those amino acids, eat eggs, drink milk, and take vitamins, especially in light of the fact that she’s only 16 and still growing.
Anyway.
I note in passing that John Berardi is overtly anti-vegetarian, and in addition is in the business of pushing books about his own personal system of nutrition. Not a disinterested .edu or .gov bystander, IOW.
He makes a big leap in his article from “scientists can analyze ash and decide whether a food item is base or acid” to, all of a sudden, with no explanation, two guys named Remer and Manz who have apparently arbitrarily assigned values to foods and then announced that if you consume too many of these foods, you will make your body too acidic or too alkaline.
And when I go to their website, lo and behold, right off the bat, I am faced with Primary Woo Technique #1, the sweeping assertion: " It is well established that diet and certain food components have a clear impact on acid-base balance." Um, no, it is NOT well-established, or else I’d have been able to find something on Google besides biased vegetarian websites parroting it.
They go on to admit, right up front:
And then in the very next paragraph they go right on with more sweeping assertions:
Bolding mine.
There are “frequent” cases of “latent acidosis”–but what’s “latent acidosis”? And, those cases of “latent acidosis” are still “within the normal range”? If it’s in the normal range, why should I worry?
Interesting jargon tapdance there, telling you “you’re in danger!” but without saying anything potentially litigious.
Daffyduck, I understand that everything you eat will affect your body and your body chemistry, but the assertion here is that it affects your body chemistry in the long-term, and negatively. I’d like to see a cite for that from somewhere, is what I’m after here. Have you got a cite besides Remer and Manz?
And I read the osteoporosis document, and found this on page 12:
Bolding mine.
And as a matter of fact, the very next paragraph says that while “acidic” diets may theoretically increase urine production and thus the load on the kidneys, still overall extra protein in the diet actually improves BMD and skeletal metabolism in the elderly, and it finishes up with:
This would explain why I, as a 51-year-old female who just finished going through menopause, in all my googling on menopause and osteoporosis over the last couple of years, never heard anyone say that my high-protein “acidic” American diet was putting me at increased risk for osteoporosis. As a matter of fact, the International Osteoporosis Foundation themselves have a “1-minute Risk Test” for women to assess your risk for osteoporosis, and “diet” isn’t even mentioned, only “smoking” and “alcohol use”.
So, “eating meat causes bone loss” is still just a theory, and not even a mainstream theory, if it has eluded the various osteoporosis organizations, and folks like Medline and eMedicine. Thanks, everybody, for helping me get my thinking straight.
And color me even more surprised that IDG Books let it get out the door.
The article was written by Dr. Stephen Barrett, who runs the Quackwatch website, and who is generally considered an authoritative cite. In what way is his analysis incorrect?
I was wondering the same thing. Although I’ve had problems with things written on the site before, and I’m no pathophysiology expert, I’d like to know what makes it apparent that the author doesn’t appear to understand acid base physiology.
I do recognize there’s a lot of proselytizing by all sorts of diet fanatics. As a vegan who is not particularly preachy, I would amend your statement as follows:
“Very often, people who are predisposed to bizzare pseudoscience pick up all sorts of diet fads, vegetarianism among them. Be careful to interpret what you read, whether it’s sales flak from the meat marketing council, an effort to biologically justify a vegan ethical position, or fad diet hype.”
It was my understanding that gorillas and perhaps orangutans are pretty much vegetarian. (I recognize that chimpanzees are not, and that we are essentially mutant chimpanzees, rather than gorillas.)
Gorillas eat insects as well, although by volume or weight, I believe it’s a fairly small percentage of their diet (with an adult male eating something like 50 lbs/22 kg of food a day).
Orangutans are predominantly frugivores (fruit eaters), but have been known to eat:
I recommend finding a good vegetarian cookbook or two, to encourage her to learn to cook (something too many people can’t do these days) and to try a wider variety of vegetarian foods. I like Vegetarian Cooking for Everyone by Deborah Madison, Moosewood Restaurant Low-Fat Favorites, and Moosewood Restaurant Cooks at Home. Those books have good recipes, and little to no preaching or dubious science. How to Cook Everything by Mark Bittman, while not a vegetarian cookbook, does have good information on shopping for and cooking lots of different kinds of vegetables and quite a few vegetarian recipes.
Thanks, I’m not sure she’s ready to start actual “Cooking” with a Capital C yet. So far her cooking interest has tended towards chocolate chip cookies and the occasional microwave scrambled eggs, and actually, she was cooking pots of mac-n-cheese nearly every other night for 3 months and all I thought was, “Oh, good, at least when she’s 18 and has her own apartment she won’t starve–now she knows how to cook three things…” Then of course I finally got the memo, on Thanksgiving Day actually, when she didn’t have any turkey on her plate.
Anyway, I was fascinated to run across the first edition, from 1999, of Idiot’s Guide to Being Vegetarian at the library this morning. The one I ordered for my daughter was the 2nd edition, by someone named Frankie Avalon Wolfe. This 1999 edition is by–Suzanne Favala.
And I was even MORE fascinated to find on pp. 49-50, word-for-word her statements, above, about meat and acidic blood. She evidently simply copy-and-pasted it into her 2001 Being Vegetarian for Dummies.
She also copy-and-pasted word-for-word the remarkable statement, “The countries with the highest intakes of dairy products and animal protein also have the highest rates of hip fracture”, from her 1999 Idiot’s Guide to her 2001 Dummies. Apparently nobody ever told her that correlation is not causation.
So now I’m wondering in fascination if Alpha Books fired her off the 2nd edition of Idiot’s because there’s other non-mainstream and biased stuff in there, so she took it down the street.
Seconded. Obviously learning how to cook is a simple and useful skill. The Moosewood books are a great start, wonderful stuff (I’m not vegetarian but I eat mostly vegetarian food). Any bookstore will be crammed with vegetarian cookbooks.
My cousin is a vegetarian and he cannot cook beyond heating up canned soup and making awful “Minute Rice”.
If you eat a non-standard diet, like a vegetarian or kosher diet, cooking skills are even more helpful than they are for someone who eats a standard diet. Someone who eats a standard diet can get a fairly varied menu from restaurants and prepared foods, but that’s not as true for someone who doesn’t (this varies, depending on where you live- a vegetarian in the Bay Area is going to have a much easier time finding prepared and restaurant food than one in a small Midwestern town).
How to Cook Everything is a good “starter” cookbook. It doesn’t assume much prior knowledge of food or cooking. It has a lot of quick and/or easy vegetarian recipes that are healthier and more interesting than mac & cheese.
At the risk of providing waaaaaaay too much information, here is my problem with the Quackwatch statements.
The author does not appear to understand strong ion acid/base theory. Strong ion difference has been pretty much accepted as the most correct way to interpret and understand acid/base physiology. IT is the ONLY way to understand the role of diet on blood pH balance.
“ Anyone who tells you that certain foods or supplements make your stomach or blood acidic does not understand nutrition.”
Well, either they don’t understand nutrition or they’ve been reading scientific journal articles like the following:
Effect of a metabolically created systemic acidosis on calcium homeostasis and the diurnal variation in urine pH in the non-lactating pregnant dairy cow
By John R Roche, Dawn E Dalley and Frank P O’Mara
J Dairy Res. 2006 Sep 15;:1-6
The article concludes:
“Twice-daily supplementation of anionic salts was sufficient to reduce the pH of blood and increase gastrointestinal Ca absorption.”
In the veterinary and animal science literature there are many papers that show essentially the same thing – altering the dietary acid-base balance by changing the ratio of cations to anions in the diet changes urine pH a lot and blood pH a little. “You should not believe that it matters whether foods are acidic or alkaline, because no foods change the acidity of anything in your body except your urine.”
Here’s where I have a bigger problem with what he wrote – he doesn’t appear to understand the relationship between diet and pH. Compare what happens when someone eats a steak vs. tofu. Eating a steak doesn’t cause more acidic urine because steak has a lower pH than tofu. It has nothing to do with stomach acids or pancreatic neutralization. So even though he’s correct in asserting that “all foods that leave your stomach are acidic. Then they enter your intestines where secretions from your pancreas neutralize the stomach acids. So no matter what you eat, the food in stomach is acidic and the food in the intestines is alkaline” – that’s totally beside the point and has nothing to do with the effect of diet on body pH.
Here’s what IS important: There are 2 major types of acids your body has to get rid of to maintain normal acid base levels – volatile and titrational. The volatile acid is carbonic acid that can be exhaled as carbon dioxide. Because carbonic acid is turned into carbon dioxide very, very quickly and it can be both breathed out of the lungs and urinated out through the kidney, the body has an easy time getting rid of it.
You can ingest some very acidic things – like vinegar, Vit C, etc. – but since they are ultimately broken down into carbonic acid they won’t affect body pH.
The titrational acids are sulphuric and phosphoric acid – they can only be excreted through the kidney. They are the end product of the metabolism of chemicals that contain Sulfur and Phosphorus. When they are consumed in excess they are excreted in excess – and your urine becomes more acidic. Before they leave the body in the urine they are buffered by various body buffering systems, including adding more positive ions to the mix by mobilizing bone.
So steak is acidifying when compared to tofu because the final metabolic pathways of steak produce more sulfuric acid than does tofu. And that’s because steak contains more sulfur-containing amino acids.
*
“An entire bottle of calcium pills or antacids would not change the acidity of your stomach for more than a few minutes.”*
No. 1 – As stated above, stomach acidity has nothing to do with the overall body acid/base
No. 2 - Here’s the tricky part – there’s no strong ion that is alkalinizing or acidifying per se – it’s all about the ratios. So eating lots of calcium in the form of Calcium chloride would have no effect on acid-base because the negative chlorides balance out the positive calcium ions (Since both are strong ions). Eating lots of calcium as calcium carbonate would have an effect because carbonate does not act like a strong anion. Thus the positive calcium cations aren’t balanced by strong anions – this would produce an alkalizing effect overall.
*“You cannot change the acidity of any part of your body except your urine[/I]”.
Sure you can – every time you spring 100 yards or undergo any form of anaerobic exercise you’re doing this. Your blood becomes more acid due to the build up of lactic acid in your system. “ Promoters of these products claim that cancer cells cannot live in an alkaline environment and that is true, but neither can any of the other cells in your body.”
This is a matter of degree. Normal blood pH is 7.4-7.5. A range that’s consistent with life is about 6.8 – 7.9. Your body’s cells can live OK (not great but OK) at a pH of 7. 6. That, by definition, is alkalemia. You probably couldn’t change your blood pH from 7.4 to 7.6 through diet, but you could possibly change it from 7.45 - 7.58. That little change could have a major impact on bone health.
I don’t think that it’s fair to say that this is an inaccurate statement. The snippet you included from the journal article does not state whether or not the supplementation of anionic salts reduced th pH of the blood or gastrointestinal Ca absorption enough to make a difference.
You yourself said basically the same thing: So, if a bunch of strong acid gets into your blood stream, the body doesn’t let the blood pH fall - it buffers it and then excretes the excess acid in the urine. Eating an excess of anions won’t change blood pH very much because everything the body does is geared towards keeping blood pH constant- it will change urine pH dramatically because that’s were the excess acid is moved.
Which is all that he is trying to explain to the layman.
I think it’s fair to assume that he’s talking about matters concerning diet only.
I am no nutrition expert, but I do know a bit about acid-base physiology. It comes up quite a bit in the emergency room.
I can certainly believe that amino acids have the potential to “acidify” the blood. The claim that this causes “bone loss” seems a little disingenuous, though. This is because the amount of acidification is small and easily compensated for.
In short, the body tries hard to keep your blood pH between 7.35 and 7.45. Your blood is “acidotic” if the pH is below 7.35. Acidosis can be caused by things which increase blood acid (metabolic acidosis) – including kidney failure, diabetes, alcoholism, lactic acidosis, aspirin overdose, etc.
Changes in breathing can also affect pH. Respiratory acidosis is when a person breathes too slowly to blow off carbon dioxide produced by the tissues. Breathing quickly makes blood more alkalotic. A mild metabolic acidosis and mild respiratory alkalosis can co-exist, resulting in normal blood pH. In practice, one might consider the balances below, remembering that CO2 by itself is acidic.
H(acid proton) + HCO3(bicarbonate) = CO2(carbon dioxide) + H2O
HA (acid) + HCO3 = CO2 + H2O + A(conjugate base)
The body can compensate for an acidic load by changes in breathing, which happens quickly (breathing faster blows of carbon dioxide and increases blood pH); or slowly (the kidney gets rid of ammonium to generate bicarbonate while clearing acid).
Eating a meat diet does not make your blood terribly acidic – amino acids are not strong acids (unlike your own stomach acid). Your body can easily compensate for this weak acid load using routine lung and kidney compensation. The impact on bone loss is minimal, so the claim is overblown – Chronic metabolic acidosis is associated with bone loss, particularly in the presence of kidney disease. The problem is that most meat eaters are not acidotic. Their lungs and kidneys have already compensated for the weak acid loads using normal buffering mechanisms.
So far her cooking interest has tended towards chocolate chip cookies and the occasional microwave scrambled eggs, and actually, she was cooking pots of mac-n-cheese nearly every other night for 3 months and all I thought was, “Oh, good, at least when she’s 18 and has her own apartment she won’t starve–now she knows how to cook three things…”