February 15

Folic acid and cognitive impairment


Folic acid is a nutrient generally thought to be good for brain health and better thinking, but new research indicates that too much folic acid in people who are deficient in vitamin B-12 can cause just the opposite.
Researchers at Tufts University in Boston using data from the two most recent National Health and Nutrition Examination Survey that had measured cognitive status, anemia, and vitamin B-12 and folate levels found that subjects (aged 60 and older) who had the highest levels of folate were protected against cognitive impairment, but those with low levels of vitamin B-12 and high levels of folate were 2.6 times more likely to show signs of cognitive impairment. And, surprisingly, anemia was 3.1 times greater in the low B-12, high folate group. The results of this study were published in the January American Journal of Clinical Nutrition (AJCN).
How did these subjects who had low vitamin B-12 levels and high folate levels end up with so much folate? In large part, thanks to the efforts of our government.
Over the years there have been a handful of studies showing that pregnant women who take folic acid early in their pregnancies markedly decrease the risk that their babies will be born with a neural tube defect (NTD). Several years back homocysteine was fingered as a risk factor for heart disease; folic acid, along with vitamin B-12 drives blood levels of homocysteine lower. As a consequence, in 1998 the US Food and Drug Administration (FDA) mandated that flour products in this country be fortified with folic acid (actually, pteroylglutamic acid, an extremely minor component of the folates in unfortified food). The thinking of the bureaucrats in the FDA was that since flour is a primary component of the American diet, fortifying cereals, breads, and other flour products would ensure that all Americans got plenty of folic acid whether they wanted it or not. The desired outcome would be a drop in the number of babies born with NTDs and the incidence of heart disease would decrease. As an editorial accompanying the AJCN article points out that

The consequence was, however, that for each NTD prevented, several hundred thousand people were to be exposed, without choice, to extra folic acid. Despite this concern, no studies have been carried out in nonchildbearing subsets of the population to see whether they might also benefit from, or could even be harmed by, exposure to folic acid. The prevailing view was that it must be “a good thing” to give extra folic acid, not only to prevent NTDs but also to lower plasma homocysteine concentrations and perhaps prevent cardiovascular disease. Although folic acid fortification has reduced the number of NTDs, recent trials suggest a limited effect, or no effect, of folic acid intervention on cardiovascular disease, although the outcome may not be entirely negative.

So, once again, the law of unintended consequences asserts itself. In an effort to reduce NTDs and heart disease, the government has spawned what could be an epidemic of slow thinking in the population of folks over 60, the very people who are already worried about Alzheimer’s. And the very same folks who are worried about their cholesterol, and who, thanks to the government food pyramid, have been scared off of eating meat.
Since MD and I and most readers of this blog follow low-carb diets, all the folic acid added to flour-based products shouldn’t affect us. If we’re following a good-quality, whole-food, low-carb diet, we should be getting plenty of green leafy and colorful vegetables, all of which contain folic acid. If we’re really good, we eat liver – a great source of folic acid – from time to time. And since the vast majority of us eat a fair amount of meat, we all will have plenty of vitamin B-12 – which is only found in foods of animal origin, primarily meat. (There is some in eggs and dairy, but not nearly as much as in meat.)
We low-carbers will have good levels of vitamin B-12 and good levels of folate, so we should be well armed to maintain our ability to think well into our dotage.
Given the results of this study, a mystery that I have posted about several times lately can finally be solved.
Let’s look at a list of foods other than liver (which I’ve discovered from many commenters that very few people eat) that contain high levels of folic acid:
Fortified breakfast cereals
Bread, pasta and other whole wheat products
Green leafy vegetables
Cantaloupe and other melons
Now let’s look at the list of foods that contain high levels of vitamin B-12:
The above study showed that high levels of folic acid combined with low levels of vitamin B-12 leads to cognitive impairment. Given this fact, looking at the above lists of foods, it’s pretty easy to connect the dots and suddenly realize why members of PETA are so stupid. They can’t help it. They all have too much folic acid and not enough vitamin B-12.
Readers of this blog who eat primarily meat (but who don’t like liver) and who eat few vegetables might want to consider a folic acid supplement. See my previous post on the best folic acid supplement.

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  1. Given this fact, looking at the above lists of foods, it’s pretty easy to connect the dots and suddenly realize why members of PETA are so stupid. They can’t help it. They all have too much folic acid and not enough vitamin B-12.

    Looks like a cheap shot, but I think it is not. Never try to argue with vegans, they are the most obnoxious people around.
    Hi gallier2–
    Agreed, they are totally obnoxious.
    There is plenty of scientific evidence that low-fat diets decrease reaction time, and now we have this evidence about the folic acid and vitamin B-12 causing cognitive impairment–I am absolutely serious.  I think vegetarians (vegans in particular) are a little slow.  Now we know the reason. 

  2. MRE,
    When you use the word meat in this blog, do you include fish? Or does fish have less B-12 than red or white meat?
    Hi nate–
    I do indeed include fish.  Some fish–trout and salmon, for example–contain more vitamin B-12 than beef.

  3. I take a B-100 supplement with 400 mcg of folic acid and 100 mcg of B12 as cobalamin. Now I’m wondering. Do you supplement the B vitamins broadly or take just B12 or leave it to your wise food selection to cover your needs?
    Hi Blaise–
    I try to get most of my vitamins via food. I take a few extra, however. Some lipoic acid, CoQ10, vitamin E, vitamin D, a methyl folate once in a while, and a few others. I get all my B vits from food.

  4. how much liver would one have to eat per week to be covered, and does it matter if it’s chicken or beef? i don’t really want to take another pill. my ‘food-based’ multi has folate in it which i assume would be pretty bioavailable, but i was thinking of dropping it because it is ‘cultured in soy.’ currently, i eat 4 oz of chicken liver a week. it’s good pan fried with olive oil & oregano.
    Hi susan–
    Both chicken and beef liver will work.  Once or twice a week should be fine.  The best folic acid supplement is methylfolate, which has just become available in the last couple of years.  I take one every now and then when I think of it.  I get most of mine from liver and green leafy vegetables.

  5. My thoughts exactly! I have always wondered how anyone could seriously follow people like McDougall (starch-based ultra low fat). It has to be cognitive impairment.
    Hi Connie–
    There is no other reason I can fathom.

  6. Hi Mike;
    Just yesterday I read that since the Folic Acid Fortification Program began, the incidence of Spina Bifida had fallen by 19%. Looking at the big picture teaches us that consuming white flour “enriched” with iron, b1, b2, and b3 and folic acid you’ll also get plenty of the antinutrient called phytate, which prevents the absorption of the above.
    Reading your post, it seems reasonable that by eating the way we (your readers)do, we get enough of all the above mentioned nutrients we need, without the antinutrients and unintended consequences (such as blatant stupidity!)
    Your writings are a public service. Please keep it coming. Possibly more on other antinutrients and their sources?
    Hi Kev–
    Thanks for the kind words.
    You’re exactly right about the phytate in the foods you mentioned.  It does prevent the absorption of all kinds of good things.  That’s one of the problems with plant foods: although plant foods contain many nutrients, there is no guarantee because of the antinutrients that these good things will be absorbed.  Humans can absorb ALL the nutrients from meat.

  7. Good thing I eat chicken liver three times a week.
    Hi Lyndsey–
    A very good thing.  You’re getting a lot of both folate and B-12 as well as copper, vitamin A, and a host of other good nutrients.

  8. Sir any inspired thoughts on veganism and smell please ?
    Wifey saw a programme the other day about a Vegan lass who stunk to high heaven. She said she smelt like dead fish and ate only..well vegan shite.
    Any ideas ?
    Always a wonderful blog. If you have to stop replying then please do but don’t stop the eclectic mix of topics..at your peril me ol china !
    Hi Simon–
    I suspect that said lass smelled as she did because she was just a little too close to the earth and maybe had a fear of bathwater.  I don’t know of any reason vegetarians would smell.  Maybe some other readers will shed some light on the subject.
    I’ll cast your vote with those wanting to keep the blog the same.

  9. This is neither new nor surprising. When I started teaching natural childbirth classes back in the 70’s, the problem was getting enough folic acid, even with supplements. The reason? The government restricted the amount of folic acid in any one supplement BECAUSE it was well known that too much folic acid in folks with B12 deficiency (vegans) caused anemia. And the cycle continues…
    Hi Martha–
    Your tax dollars at work. That’s why the government shouldn’t be in the nutrition business.


  10. Dr. Mike,
    The scope of this problem is greater than even you have indicated. You do not give an indication of the numbers of people that may be Vitamin b-12 deficient and for whom high folic acid supplementation would be deleterious. I believe however it would be in the multiple millions. See the website for Norman Clinical whose business is testing for b-12 deficiency. It gives some percentages of people who are b-12 deficient. Depending on your standards anywhere from 5 to 15% of seniors (> 65) may be b-12 deficient. I have seen statistics saying that approximately 13% of the US Population is over 65 and there are about 300 million people, so this would give 2 to 6 million people that are b-12 deficient.
    It is not only vegans or seniors. It is more common in older people though and becomes more frequent with age as the digestion process becomes more impaired. My sister who is 52 and her husband who both eat plenty of meat including liver, both take b-12 shots. For them it is miraculous. When they get a shot it is like the Wizard of Oz when the picture changes from black and white to color.
    Hi Porter–
    Thanks for bringing this up.  You are right.  Thanks to a decrease in stomach acid production in older adults, some can’t produce a factor necessary in the absorption of vitamin B-12.  Many elderly people – and younger ones, too – respond almost miraculously to B-12 shots.  Problem is that many of the newer physicians consider B-12 shots nothing but a placebo and so won’t give them.  Nothing could be further from the truth.  Right now many seniors are wasting away in nursing homes with diagnoses of Alzheimer’s or other forms of dementia when all they have is B-12 deficiency.  Most young physicians don’t realize that the neurological problems caused by B-12 deficiency can become permanent if left untreated.


  11. Off the top of my head, I think there’s stuff in Anthony Colpo’s book about low fat intake and increased aggression.
    Hi Neil–
    If you want proof, drive in Boulder, Colorado, the veggie capitol of the world.  I’ve never seen such road rage.

  12. This isn’t really relevant to this post, but there was an excellent article in the Guardian today about the increasing intake of sugar in the British diet, even in things like bread, cheese and Pringles….
    I’ve linked to it and written about it here.
    Hi Chris–
    Interesting.  Thanks for the link.

  13. I just have to chuckle reading your blog. What a refreshing change from the mainstream media coverage of “limit meat, eat a lot of soy, etc., etc.”
    Thanks for your blog Dr. Mike!
    Hi Amy–
    Thanks for the kind words.  I really appreciate them.

  14. So just where do vegans get B12? Or do they get none? Given that it’s only in meat, and they won’t even eat products made from animals, they get none???
    I have asked this question on several vegetarian and vegan boards and have yet to get an answer. So I guess they get none??
    Hi Cindy–
    If they eat no foods of animal origin, they get none from food.  I imagine most of them take vitamin B-12 supplements, which give them a little. Oral vitamin B-12 supplements do not absorb particularly well.  New ones are being made as sub lingual sprays that are better.


  15. I take a couple of B-50 supplements each day. I have more energy and feel better taking them.
    I hope my sis is getting enough B-12. She does a low-fat, high-carb (though low GI, at least) diet and just got preggers. She’s on a prenatal vitamin.
    Hi Victoria–
    Sis is probably getting some with her prenatal vitamin.  I’m sure she’s getting enough folate.  It wouldn’t hurt her to eat a little meat to feed the growing infant.

  16. The people not eating liver are missing out. I try to eat it once a week. Sometimes I have kidney instead. But liver (no breading) and onions fried up in some palm oil with garlic is delightful. As for fortification, it’s only necessary because people refuse to eat the right stuff. I can’t count the number of times I’ve heard “But this bread has 20% of my iron”…yeah, but it’s synthetic!
    Hi Scott–
    You’re on the money.  I love liver and onions, and I really love steak and kidney pie (I don’t eat the crust).  We have trouble finding kidneys in our part of the world, but whenever I’m in the UK, I eat steak and kidney pie every chance I get.  I’ve always wanted to eat a fried kidney since I read the chapter in Joyce’s Ulysses about Leopold Bloom frying the pork kidney, but have never done so. 
    The form of iron in fortified bread is absorbed no matter what and can lead to iron overload, whereas the body has the ability to decide whether or not to absorb heme iron (the kind found in meat) depending upon the body’s iron stores.  It just more data showing that we cut our evolutionary teeth on a meat diet.

  17. HaHa! When Anthony Colpo still had his website active, he posted a letter to a vegetarian who had come to his website to berate him. He told her to eat some meat, get some creatine, and feel better about the world! I remember I laughed out loud because I was googling about meat and its nutrients at that time and finding out some really good things. Meat is a mood enhancer among many other things, because of substances like B12 and creatine.
    I find that a good number of vegetarians are grumpy and exasperated all the time.
    I know that for myself, since increasing my meat intake, I react calmly in all sorts of business and social situations–and it really points out the difference.
    And there’s a question I have for vegetarian men. HOW can you do this? Long term, a vegetarian, and especially a vegan diet is feminizing. Especially if soy is a major part of the diet. Soy is estrogenic, and without certain components in meat, hormones such as testosterone aren’t created in the body the way they should be.
    Years ago, vegetarians were claiming that fermented soy products such as miso were sources of B12. Google ‘miso B12’ and you will find websites that inform you that B12 can’t be found in an absorbable form in vegetable matter. When vegetarians google for B12 info, don’t they run across the same things? Jeesh!
    Hi LC–
    Vegetarians want to fool themselves into believing that some soy products and sesame (I think) and a few other plant products provide vitamin B-12, but they are mistaken.  It comes from foods of animal origin only. If vegetarians eat eggs and dairy, then they get some.  If they’re vegans they don’t unless they supplement.  If they’re what I call beady-eyed vegetarians, they do fine.  (Beady-eyed vegetarians are those who will eat meat from animals with beady eyes, i.e. fish and chicken, but eschew meat from non-beady eyed sources, i.e. cows and sheep.)

  18. Did you really mean what you said (in comment no 1) about low fat diets decreasing reaction time? ie those on low fat diets react faster?
    I’m a liver eater, too. And sweetbreads. And andouillettes (French tripe sausages). And I had some fried calves brains recently in a restaurant, but haven’t ever cooked them at home! The liver’s the only one that’s really regular – but I haven’t persuaded my husband to eat it yet.
    Hi Janet–
    I absolutely meant what I wrote about fats and reaction times.  A wealth of medical literature shows that decreasing fat intake leads to slower reaction times.  From the sounds of your diet as you describe it, your reaction times should be lightning fast.

  19. I love liver (both chicken and beef) as my mom made it really well when I was a kid. Hubby, however, won’t touch it with a ten-foot pole thanks to the way his mom cooked it and he doesn’t even want to smell it in the house so there’s no hope of me even making it for myself. I compensate by eating goose/duck liver pate instead. Does this work as far as getting proper amounts of folic acid? I also adore fresh asparagus and eat it whenever I can. Fortunately, I’ve managed to turn hubby onto it and eradicate the memories of the horror that passed for it on his childhood dinner plate (MIL took canned asparagus and boiled the heck out of it.) At any rate it sounds like my favorite dinner of asparagus and steak balance off each other nicely.
    Simon’s comment about diet and body odor reminded me of these little gems (both short reads):
    I really got a huge laugh at the time I read them.
    BTW, what’s even more heinious about certain vegans/vegatarians to me are the ones that try to turn cats (who are obligate carnivores) into vegans. That just burns me. Don’t try tell me how much you love animals if you can’t respect who they are and try to turn them into something they are not. That’s just abuse in my book. You know, it occured to me a long time ago the reason we even have all this dietary nonsense is because we live in the land of plenty. You can bet that if these folks ever lived on the edge of starvation, they’d be eating whatever they could get their hands on, even if it meant killing an animal to do so.
    Hi Esther–
    Yep, the goose and duck liver pates will give you plenty of folate. The fresh asparagus will help add a lot as well.
    The two links are indeed hilarious. Goes to show that true ill-informed idiots can get press jobs in which they disseminate their idiocy. His comment about the fact that bacteria in the armits and other locations don’t cause body odor is really hilarious because that’s exactly what does cause body odor; the elimination of toxins (the last refuge of scientific idiots for everything they don’t understand) has very little to do with it.

  20. If low fat diets slow down reactions, then surely that’s an increase in reaction times, not a decrease? Sorry if I’m being slow here!
    Hi Janet–
    You’re not being slow, I am.  Low-fat diets increase reaction times, making them slower.  Higher fat diets decrease reaction times, making them faster.
    Thanks for pointing that out.

  21. Kidneys Sir..yaroo. You must inflect the word twds the end and say it thus KIDDLIES.
    GENTLY grilled with some toms and a coupla fried eggs.
    Fookin hell am salivating.
    Also get yoursel some kiddlies and make a casserole with bacon , kiddlies, carrots, onions etc.
    ‘Rart bleedin narce’
    Bon w/e
    Hey Simon–
    Kiddlies it is.  What are toms?

  22. There are certain foods that cause odor, like garlic and other spices because certain chemicals they contain do come through your pores, but fresh red meat or fish is not going to! I can’t stand the half-assed research that someone like the author of the articles upthread indulge in just to try to justify their veganism. Brown rice protein over “odor producing” whey protein? PLEASE.
    Hi LC–
    I don’t think the research is half-assed, I think it doesn’t exist. 

  23. Toms are those red things that came from the New World which most everyone associates with the Old World….meant to be marginally good for one even !
    …… and don’t let me mention,oops, the Hunt family whom i had the misfortune to spend a night with…well one arm of them. Awful awful vegetarian bad ass Buddhist neurotic phuqers.
    I couldnt get oot of there fast enough.
    Lovely house mind !
    Now read this from todays Telegraph about fat and the healing of the heart.
    Hi Simon–
    Toms…tomatoes.  I get it.  I love tomatoes, and although they’re a new world food, they taste much better when grown in the old world.  Something in the soil I guess.  I love gazpacho as made in Andalucia.  I got a recipe and tried to make it in the US when we got home (actually, MD tried) and it tasted nothing like the Spanish variety.  We asked a friend of ours from Spain who is a chef how to make it.  He told us that it would never taste the same made with tomatoes grown in the US.  Spanish tomatoes, said he, make all the difference.  He fooled with our recipe and made some changes that made the soup taste like the Andalucian variety despite the American tomatoes.

  24. Well, this pertains to cats, but perhaps it relates to humans somehow, too. When we took our cats off commercial food (no dry kibble or canned grain-free meat & vegetable) and put them on raw ground whole chickens (supplemented with E, Bs, salmon oil, egg yolks, chicken hearts & chicken livers, etc., to make it more like a rodent’s nutritional profile), one of the first thing we noticed was a complete absence of feces odor in their litter boxes. The urine still has a smell, of course (if it isn’t tended to), but the cats’ feces are like coyote skat, lightweight, dry as a bone in about 5 minutes, and completely free of smell, sort of like owl pellets. Amazing, yet it completely makes sense.
    When we have fed canned again (due to my bad timing with the chicken grinding), the feces again stink until they are back on the raw chicken.
    BTW, am about halfway through the UK doctor’s Great Cholesterol Con book (started yesterday) and find it very entertaining (my mind adds a John Cleese-ian delivery to the text for better or worse, but he does have a humorous style to sucha serious topic).
    So for those who would find Colpo’s book of the same title, or Ravnskov’s Cholesterol Myths too daunting with all the facts, figures, and endless studies and statistics or small text, this new book might be just ticket. I mean the book starts out with a Dalek-inspired (Dr. Who robot) quote, “Instatinate, instatinate!” Whats not to like? And I’m not even a Dr. Who fan.
    For those who have read the other two books I mentioned, it is a breeze to skim through.
    Hi Anna–
    Though I’m not a connoisseur of cat feces, your description makes sense.   I’m sure it is the grain in the canned foods that triggers the odor, since a carnivore’s gut is not designed to digest such.

  25. Two comments on comments: First, LCForevah, #17: yep, not only are they often grumpy, uptight, petty, micromanager types, but every vegetarian and every person on a low-fat diet that I know seems to always be getting a cold, have a cold, or be getting over a cold. They also always seem to look washed out and have dull, lifeless hair.
    And #19, Esther: Agree with you totally on the wrongness of manipulating pets’ diets. A few years ago I started adding meat scraps to my dog’s dry food. He loves this, of course, but the vet reacted in horror, saying I needed to watch his fat intake. And watch it I do… go right down his delighted gullet. And here’s the interesting part: The dog had this terrible arthritis problem, limping noticeably, and was on a daily medication. I started feeding him delicious meat fat, scraps, and greasy juice from roasts mixed in with his dry food. Now his coat is shiny again and he acts like a younger dog, and I don’t give him the medication anymore. What is in dog food, even the “science” brands? Lots o’ grain! Dogs are carnivores!

  26. When eating liver I heard that one should freeze it for a while then thaw it out and then eat it. This gets rid of any toxins. Is this correct?
    Hi Sue–
    This is the first I’ve ever heard of this idea.  It doesn’t make much sense to me.  I’ve eaten fresh liver a zillion times and, as far as I can tell, have never had a problem.  I don’t know what the toxins would be in liver, anyway.

  27. The “feces odor” thing does not apply only to animals. It works also on humans. What a relief for my family since I low-carb 😉
    Hi gallier2–
    You are right.  I’ve got an entire post sort of ready in my head on this very issue.  I just need to get it down on electrons.

  28. Hi Mike–can’t wait to read that post! Seriously, one of the nicest surprises about going low carb is how, um, manageable one’s bathroom habits become.
    Hi Paul–
    It is indeed nice.  I’ll post it as soon as I can.  The blogworthy material is stacking up.

  29. Dr. Mike,
    On #29 Sue’s comment. I believe Sallie Fallon recommends raw meat/fish dishes and she says that freezing the food first for a number of days will kill any parasites that they may contain.
    Hi Porter–
    I don’t know if I agree with that or not.  I need to look into it when I get some time.  I know freezing doesn’t kill all parasites, but I don’t know whether or not it kills all parasites that one might find in liver.


  30. Dear Mike,
    In follow up to comment #32, Sallie Fallon in her book, Nourishing Traditions 2d ed has a chapter on “Raw Meat Appetizers” and she states on page 231, “The problem of parasites in beef or lamb is easily solved. Simply freeze the meat for 14 days. According to the United States Department of Agriculture, this will kill off all parasites.” She also states that parasitic infections are common in Japanese and Koreans who frequently eat raw fish, so parasitic infection from raw flesh must be taken seriously and then because fish flesh texture does not handle freezing well she recommends to prevent parasite infection from fish, “to marinate or ferment fish in an acid solution of lemon juice, lime juice or whey. This will effectively kill off all parasites and pathogens and will serve to predigest the fish as well.”
    Hi Porter–
    Makes sense.  I had just never heard of it.  I do know that some parasites have a cystic stage that is very difficult to kill, even by freezing.


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