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A Silent Epidemic with Serious Consequences—What You Need to Know about B12 Deficiency


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Reviewed by Chris Masterjohn, PhD

This tired man rubbing his eyes may be experiencing B12 deficiency.
Fatigue is a common symptom of B12 deficiency.

What do all of these chronic diseases have in common?

  • Alzheimer’s, dementia, cognitive decline, and memory loss (collectively referred to as “aging”)
  • Multiple sclerosis (MS) and other neurological disorders
  • Mental illnesses like depression, anxiety, bipolar disorder, and psychosis
  • Cardiovascular disease
  • Learning or developmental disorders in kids
  • Autism spectrum disorder
  • Autoimmune disease and immune dysregulation
  • Cancer
  • Male and female infertility

Answer: Their signs and symptoms can all be mimicked by a vitamin B12 deficiency.

An Invisible Epidemic

B12 deficiency isn’t a bizarre, mysterious disease. It’s written about in every medical textbook, and its causes and effects are well-established in the scientific literature.

However, the condition is far more common than most healthcare practitioners and the general public realize. Data from a Tufts University study suggests that 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range—a range at which many experience neurological symptoms. Nine percent had an outright nutrient deficiency, and 16 percent exhibited “near deficiency.” Most surprising to the researchers was the fact that low B12 levels were as common in younger people as they were in the elderly. (1)

That said, this type of deficiency has been estimated to affect about 40 percent of people over 60 years of age. It’s entirely possible that at least some of the symptoms we attribute to “normal” aging—such as memory loss, cognitive decline, and decreased mobility—are at least in part caused by a deficiency.

Why Is It Underdiagnosed?

B12 deficiency is significantly underdiagnosed for two reasons. First, it’s not routinely tested by most physicians. Second, the low end of the laboratory reference range is too low.

This is why most studies underestimate true levels of deficiency. Many deficient people have so-called “normal” levels of B12.

Yet, it is well-established in the scientific literature that people with B12 levels between 200 pg/mL and 350 pg/mL—levels considered “normal” in the U.S.—have clear vitamin deficiency symptoms. (2) Experts who specialize in the diagnosis and treatment of a deficiency, like Sally Pacholok, R.N., and Jeffrey Stuart, D.O., suggest treating all patients that are symptomatic and have B12 levels less than 450 pg/mL. (3) They also recommend treating patients who show normal B12 levels but also have elevated urinary methylmalonic acid (MMA), homocysteine, or holotranscobalamin, which are other markers of a deficiency in vitamin B12.

B12 deficiency can mimic the signs of Alzheimer’s, dementia, multiple sclerosis, and several mental illnesses. Find out what this vitamin does and learn how to treat a deficiency. #B12 #B12deficiency #cognitivedecline

In Japan and Europe, the lower limit for B12 is between 500 and 550 pg/mL. Those levels are associated with psychological and behavioral symptoms, such as:

  • Cognitive decline
  • Dementia
  • Memory loss (4)

Some experts have speculated that the acceptance of higher levels as normal in Japan and the willingness to treat levels considered “normal” in the U.S. explain the low rates of Alzheimer’s and dementia in that country.

What Is Vitamin B12 and Why Do You Need It?

Vitamin B12 works together with folate in the synthesis of DNA and red blood cells. It’s also involved in the production of the myelin sheath around the nerves and the conduction of nerve impulses. You can think of the brain and the nervous system as a big tangle of wires. Myelin is the insulation that protects those wires and helps them to conduct messages.

Severe B12 deficiency in conditions like pernicious anemia (an autoimmune condition where the body destroys intrinsic factor, a protein necessary for the absorption of the vitamin) used to be fatal until scientists figured out death could be prevented by feeding patients raw liver, which contains high amounts of B12. But anemia is the final stage of a deficiency. Long before anemia sets in, deficient patients will experience several other problems, including fatigue, lethargy, weakness, memory loss, and neurological and psychiatric problems.

The Stages of a Deficiency

B12 deficiency occurs in four stages, beginning with declining blood levels of the vitamin (stage I), progressing to low cellular concentrations of the vitamin (stage II), an increased blood level of homocysteine and a decreased rate of DNA synthesis (stage III), and finally, macrocytic anemia (stage IV). (5)

Common B12 Deficiency Symptoms

The signs can look like the symptoms of several other serious disorders, and the neurological effects of low B12 can be especially troubling.

Here are some of the most common vitamin B12 deficiency symptoms:

  • Tingling or numbness in the hands and feet
  • Brain fog, confusion, and memory problems
  • Depression
  • Premature aging
  • Cognitive decline
  • Anemia
  • Weakness
  • Fatigue
  • Reduced appetite and weight loss
  • Constipation
  • Trouble balancing (6)

Children can also show symptoms, including developmental issues and learning disabilities if their B12 levels are too low.

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Why Is It So Common?

The absorption of B12 is complex and involves several steps—any of which can go wrong. Any of the following can cause B12 malabsorption:

  • Intestinal dysbiosis
  • Leaky gut and gut inflammation
  • Atrophic gastritis or hypochlorhydria, or low stomach acid
  • Pernicious anemia
  • Medications, especially proton pump inhibitors (PPIs) and other acid-suppressing drugs
  • Alcohol
  • Exposure to nitrous oxide, during either surgery or recreational use

This explains why a deficiency can occur even in people eating large amounts of B12-containing animal products. In fact, many of my patients that are B12 deficient are following a Paleo diet where they eat meat two or three times daily.

Who Is at Risk for a Deficiency?

In general, the following groups are at greatest risk for a deficiency:

  • Vegetarians and vegans
  • People aged 60 or over
  • People who regularly use PPIs or acid-suppressing drugs
  • People on diabetes drugs like metformin
  • People with Crohn’s disease, ulcerative colitis, celiac, or IBS
  • Women with a history of infertility and miscarriage

Note to Vegetarians and Vegans: B12 Is Found Only in Animal Products

You cannot get B12 from plant-based sources. This vitamin is only found in animal products. That’s why vegetarians and vegans need to know the signs of deficiency—and the steps necessary to fix the problem.

B12 is the only vitamin that contains a trace element (cobalt), which is why it’s called cobalamin. Cobalamin is produced in the gut of animals. It’s the only vitamin we can’t obtain from plants or sunlight. Plants don’t need B12, so they don’t store it.

A common myth among vegetarians and vegans is that it’s possible to get B12 from plant sources like:

  • Fermented soy
  • Spirulina
  • Brewers yeast

However, plant foods said to contain B12 actually contain B12 analogs called cobamides that block the intake of and increase the need for true B12. (7) That explains why studies consistently demonstrate that up to 50 percent of long-term vegetarians and 80 percent of vegans are deficient in B12. (8, 9)

Seaweed is another commonly cited plant source of B12, but this idea is controversial. Research indicates that there may be important differences in dried versus raw purple nori; namely, raw nori may be a good source of B12, while dried nori may not be. One study indicated that the drying process used for seaweed creates B12 analogs, making it a poor source of the vitamin, while animal research suggests that dried nori can correct a B12 deficiency. (10, 11) Seaweed may provide B12, but it’s not clear if those benefits are negated when that seaweed is dried. I recommend caution for that reason.

The Impact of a Deficiency on Children

The effects of B12 deficiency on kids are especially alarming. Studies have shown that kids raised until age six on a vegan diet are still B12 deficient even years after they start eating at least some animal products. In one study, the researchers found an association between a child’s B12 status and their performance on testing measuring:

  • Spatial ability
  • Fluid intelligence
  • Short-term memory

Researchers found that formerly vegan children scored lower than their omnivorous counterparts in each area. (12)

The deficit in fluid intelligence is particularly troubling, the researchers said, because this area impacts a child’s ability to reason, work through complex problems, learn, and engage in abstract thinking. Defects in any of these areas could have long-term consequences for kids.

I recognize that there are many reasons why people choose to eat the way they do, and I respect people’s right to make their own choices. I also know that, like all parents, vegetarians and vegans want the best for their children. This is why it’s absolutely crucial for those that abstain from animal products to understand that there are no plant sources of B12 and that all vegans and most vegetarians should supplement with B12.

This is especially important for vegetarian or vegan children or pregnant women, whose need for B12 is even greater. If you’re not willing to take a dietary supplement, it may be time to think twice about your vegetarian or vegan diet.

How to Treat a Deficiency

One of the greatest tragedies of the B12 epidemic is that diagnosis and treatment are relatively easy and cheap—especially when compared to the treatment patients will need if they’re in a late stage of deficiency. A B12 test can be performed by any laboratory, and it should be covered by insurance. If you don’t have insurance, you can order it yourself from a lab like DirectLabs.com.

As always, adequate treatment depends on the underlying mechanism causing the problem. People with pernicious anemia or inflammatory gut disorders like Crohn’s disease are likely to have impaired absorption for their entire lives and will likely require B12 injections or high-dose oral cobalamin indefinitely. This may also be true for those with a severe deficiency that’s causing neurological symptoms.

Typically in the past, most B12 experts recommended injections over high-dose oral cobalamin for people with pernicious anemia and an advanced deficiency involving neurological symptoms. However, recent studies have suggested that high-dose oral or nasal administration may be as effective as injections for those with B12 malabsorption problems. (13, 14)

Try Supplementing

Cyanocobalamin is the most frequently used form of B12 supplementation in the U.S. But recent evidence suggests that hydroxocobalamin (frequently used in Europe) is superior to cyanocobalamin, and methylcobalamin may be superior to both—especially for neurological disease.

Japanese studies indicate that methylcobalamin is even more effective in treating neurological symptoms and that it may be better absorbed because it bypasses several potential problems in the B12 absorption cycle. (15, 16) On top of that, methylcobalamin provides the body with methyl groups that play a role in various biological processes important to overall health.

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Chris Kresser in kitchen

Change Your Diet

Nourishing your body through whole food is the best way to get the vitamins and nutrients you need. If you’re low on B12, try eating some vitamin-rich foods like:

Eating other kinds of seafood, like octopus, fish eggs, lobster, and crab, can also help you attain normal B12 levels. If you’re seafood-averse, you can also get this vitamin from:

  • Lamb
  • Beef
  • Eggs
  • Cheese

It’s important to note, though, that the amount of B12 in these foods is nowhere near as high as the levels in shellfish and organ meats.

What to Do if You’re Experiencing Vitamin B12 Deficiency Symptoms

If you suspect you have a deficiency, the first step is to get tested. You need an accurate baseline to work from.

If you are B12 deficient, the next step is to identify the mechanism causing the deficiency. You’ll probably need help from a medical practitioner for this part. Once the mechanism is identified, the appropriate form (injection, oral, sublingual, or nasal) of supplementation, the dose, and the length of treatment can be selected.

So, next time you or someone you know is “having a senior moment,” remember: It might not be “just aging.” It could be B12 deficiency.

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  1. It’s a stunning article that tells the advantages of taking pharmaceutical as well as aiding in curing different serious ailments. This is really extremely educational and accommodating to patients. In the event that you need to take in more about this or anything than this plzz visit here:-

  2. Has anyone had Joint pain taking the B-12?..
    I know it is supposed to help with joint pain, but I have started having severe pain in my wrist and shoulders since starting the B-12 shots…

    • Yes, Vicki I had my first injection yesterday morning. I went to work but by the time I got home I had abdominal pain and severe joint pain. I have been trying to find out how long this will last and if this will always be the reaction I get.

      • I had my first injection this week and my arms ,shoulders and legs have been in pain . I am having 6 injections over this next two weeks and i cant wait to have more energy . I have to keep lying down as i feel so lathargic . Do u know when i will feel the benefit ?

        • Let me start out by saying that I am not a doctor. You should feel positive effects from a B12 injection almost immediately (within minutes). And I’ve just got to wonder why doctors prescribe B12 injections; oral B12 (preferably in methyl form if you can tolerate it) works just fine and costs much less than injections. Someone is paying after all (even if it isn’t you).

  3. interesting article … I was diagnosed with a low b12 level of 22 about a year ago … I got pretty sick like most folks who suffer from low levels, couldn’t stand, couldn’t walk, numb legs/feet, numb arms/hands, couldn’t eat and lost weight, lethargic and generally tired, really bad brain fogs, actually forgot which toothbrush was mine and also forgot my name … doctor was pretty shocked at the results … have monthly b12 shots [methyl] and have improved immensely … still have the odd down day, but largely feeling pretty good now … i’m a fairly active 55yo male
    I found using oral sprays and sub-lingual tablets actually seemed to make the brain fogs worse during the early days when I tried to supplement the injections … would this be because of the different type of b12 or just the timing was wrong?

  4. My sister is a gastric bypass patient (15 years) and is now suffering from severe peripheral neuropathy. She can hardly walk and is pretty much disabled. I keep telling the doctors she needs B12 as her body doesn’t absorb it. Finally after 9 months and 5 doctors, one of them finally diagnosed her with pernicious anemia. He says she should take B12 but didn’t order the injectable! How much should she take and for how long? I pray someone out there knows.

    • I started taking 2000mcg per day (1000mcg after waking and 1000mcd near bedtime) maybe 3 weeks ago and noticed cognitive improvements, improved energy, reduced anxiety and depression, improved mental focus, reduced irritability and anger. I read several articles saying to take somewhere around 1000-2000mcg per day so I decided on 2000mcg since my symptoms were severe and impacting my emotional and cognitive state that it was impacting my personal life and work.


    • I take all of my B12 after breakfast. I take 400mcg of folate and 4000mcg of methylcobalamin and 4000mcg of adenosylcobalamin. The folate I just swallow, the 2 forms of B12 I take as sublingual tablets; I place them along my gum line on both sides of my lower jaw between my gums and cheek, and let them dissolve until they are gone, it takes a little over an hour. This works for me. The methylB12 I use is Enzymatic Therapy B12 Infusion off Amazon.

      • Molly could you explain to me why you take two types of B-12. And what does the folate do?
        I take methylcobalmin lozenges and Methy B-12 shots, But if I can improve on that I would like too

        • I use Dibencozide, by Source Naturals. I read that adenosylcobalamin is preferred by the mitochondria, so I use both forms. I use half a tablet per day because the dose is nice and high at 8.6mg.

          Just so you know, I am still working on my low B12 issues, they are not fully resolved. I hope they will be, but I don’t know; they are at least improved so it’s possible that I need more than I am taking.

        • Ack, I forgot to add this, it’s from another commenter here, John Macgregor:
          “…methyl & adenosyl B12 are crucial to the methylation system, but often can’t work well without cofactors such as each other, & methylfolate & carnitine (which crank up ATP).”
          Adenosylcobalamin Catalyzes Nitrous Oxide

          Another good reason to use adoB12 with (simultaneously) methylB12.
          Best wishes to all in their healing journey.

  5. Great article! As I was reading, a pop-up displayed offering a free eBook on Vitamin B12 deficiency. I clicked on it, but got the message the page wouldn’t display. I’ve tried several times, even shutting down my computer and starting it again, and I get the same thing. Is the link broken?

  6. Hello Team,.

    I have bee facing extreme fatigue and great pain in my legs and thigh since three months but this problem was started 2 years back and I didn’t realize this would be very dangerous.

    A month back I went to the doctor and after doing whole blood check we found B12 (104) and D3 (19) deficiency . I am taking methylcobalamin 1500mcg with mulivitamins since one month but getting no benefits.

    I have few questions from the experts:
    -Should I take injection instead of tablet as I am having IBS that may be causing medicine to not go in to the blood strem ?
    -How much time would it take to recover extreme pain from legs and thigh ?
    -Is there any nerve damage in my case as I am afraid after reading information about b12 deficency ?

    Asif Khan

    • 1500 mcg is nothing when you are deficient. If unable to get shots you should try megadosing with 5,000 mcg SUBLINGUAL tablets. When I first started self treating, I started at 60 tablets a day which matches two shots a week-loading doses are necessary to start out. After a month or so, I brought that dosage down to 30 a day, after another month or so down to 15, and I am now taking 6-7 per day which if you put it on a conversion chart, matches a shot a month. I went from extreme fatigue, brain fog/dementia/ neuropathy etc, etc. to being extremely healthy and feeling fantastic. The difference is incredible. The first day that I figured out what to do, after getting no help from doctors, I dissolved 5 sublingual (under the tongue) tablets at 5,000 mcg every hour, and the fifth hour (25 tablets later) I stood straight up, woke up, felt normal-no brain fog, pain or headaches-for the first time in months, I felt like me again…Hope this helps you…

      • Hi Kymm,

        I have 10,000 mcg methyl b12 coming in today to start taking, I am beyond excited, hoping that I will have the same results as many of you. I am not sure how many tablets to take in the beginning though…were you taking 60 of the 5,000 mcg?

        • Hi, yes I was taking 60 at 5,000 mcg, sublingually: 5 under my tongue every hour for 12 hours a day. You may want to start lower at first and increase as needed. I was pretty bad off at the time, I’m not sure what your symptoms are/how deficient you are. I could barely stand, stay awake, etc., etc. Maybe try 2 or 3 per hour at first and see how you feel by end of day. You have to play with the dosage to see what works for you. Keep me posted if you will. I sure hope this helps. If you are deficient, it certainly should!

          • PLEASE PLEASE PLEASE DO NOT ‘MEGADOSE’ on vitamin B12. If you have a balanced diet you will be sufficient for vitamin b12 unless you have a malabsoprtion disease such as ceoliacs.

            You can overdose on vitamin B12. Also keep in mind you have stores of B12 that will last you three years as it is essential for life…you wouldn’t last very long if you were completely deficient as your blood cells REQUIRE it to form and survive properly.


            FYI: For older children and adults, the ideal vitamin B12 dosage should be 2.4 mcg DAILY.

            • The vitamin B12 is water soluble. Excess is excreted in urine. This article is accurate. Biochemist Clinical is not accurate.

                • B12 is also stored in the liver, and if you are not replete, most of the B12 will be stored there. A bit different than most B vitamins.

              • Biochemist Clinical, why are you ignoring the fact that Nitrous oxide anaesthesia can impair cellular absorption of b12? Staff in OR and Dentistry inhaling vagabond nitrous can/may suffer from impaired cellular absorption. Patients who have had multiple surgeries, births, dental work OR recreational users may/can suffer impairment.

    • I found I was deficient for B12, and I started taking 5mg twice per day for a month, and now I take 1mg. I also started taking D3 since I was deficient for that vitamin as well; I take 5,000iu per day. Both levels are now OK (though it took a while for D to get to a good level).

    • Magnesium helps me significantly with my joint pain. When I don’t take it, I can really tell. Magnesium Citrate is most easily absorbed, but be care with your IBS as it can have laxative effects.

      • If you take the Magnesium L-Threonate, it is the most absorbable and does not affect the IBS at all. Mercola.com carries it.

      • Andrea: B12 helped alleviate my hip and shoulder pain. Apparently the Bursa sacs are dependant on good b12 levels. I thought I was headed for hip replacement and am now pain free. It was even hard to turn in bed or get out of bed because of the hip and opposite shoulder acting up.
        I carry magnesium to relieve leg cramping and chest pain which was used in ER pre the introduction of Nitro. It is also used by IV for severe asthma attacks. It is a muscle relaxant. My leg cramping has diminished greatly since i started supplementing with Ribose recently.

    • I have been told i must take an oral spray under the tongue as I’m not absorbing b12 with diet so taking a vitamin tablet is a waste and i found some good oral b12 sprays on iherb and am waiting for my order.

      • B12 is a large molecule, and I doubt it’s possible to absorb it sublingually. You probably end up just absorbing it through the digestive tract. With high dose oral forms, enough B12 gets absorbed through your digestive tract via diffusion even if your stomach doesn’t produce enough acid or intrinsic factor. For this to work though, you need to use the methyl form (disclaimer: I am not a doctor).

        • Yes, it is a large molecule, but the people on the Phoenixrising site would heartily disagree with you. Take a look, not all sublingual supplements work, but Freddd in particular has tested many out and found some that work very well.

          • It’s all going to go down to your stomach if it isn’t absorbed sublingually anyway (and it works that way just fine).

  7. Why are doctors reluctant to treat vitamin b12 deficiency? I have celiac disease and even though I follow a strict GF diet I have had consistently low vitamin b12, D and iron levels. My b12 was recently at 70 and vitamin d was at 48 I was getting heart palpitations and felt awful. When I asked the doctor if it could be my low vitamin levels he said no and told me I just must be stressed. I said I did. It feel a great deal of stress. He sent me for an EKG, stress test, and several other tests but was so dismissive of something that is simple and inexpensive to treat. B12 has also been something that I have responded well to in the past. I then was able to get a few B12 injections and things have improved significantly. I just don’t understand why they don’t treat something so simple.

    • Find a different doctor. My doctor was the one who suggested I have my B12 and vitamin D levels checked.

    • Jill, the American Medical Association (in the past, not sure if the teaching has changed) labelled Vitamin Therapy as Medical Heresy. Dr. Russel Blaylock who treated babies suffering Infantile Apnea (often resulting in crib death) with mega doses of B1 was threatened to have his medical license revoked. That motivated the beginning of the Integrative Medicine Group.

      Ref: [PDF]
      Is There a Conspiracy? – Orthomolecular.org
      by A Hoffer – Related articles
      root out these heretics because they and their principles have … activity of the American Medical Association in trying to destroy … critiques of vitamin therapy appeared. They were ….. They were incensed by a report I had published called.

      Blaylock has called the American medical system ‘collectivist’ and has …. naturopathy, vitamin therapy, alternative cancer and arthritis treatments and even books … Beasley’s Betrayal of Health, Mendelsohn’s Confessions of a Medical Heretic, …

      Diseases caused by medical treatment are called iatrogenic diseases. …. Dr Weston Price (19), a former Director of Research for the American Dental Association, observed that …. by greatly increasing our levels of vitamin D with suitable foods, supplements, and …. (2) Mendelsohn, R.S. Confessions of a Medical Heretic.

  8. I suffered terrible dysphagia (difficulty swallowing) for two years and also bursitis (inflammation of my hip) for seven years, after stumbling on an old B12 protocol devised by a doctor in the 1950’s I eventually managed to convince my doctor to give me an injection. The next day I could swallow normally for the first time in two years and my hip got a little better, I was not able to convince my doctor to give me more than a second shot, so I had to come up with a new plan. The information I found here on Chris’ site was phenomenal and as a result of the complete resolution of both of these health issues I started blogging in the hope that others with dysphagia and/or bursitis could find this awesome information and heal themselves too. Chris is right sublingual methylated B12 is the way forward and much better than the injections anyway, if anyone had told me before that a simple deficiency like B12 could have the impact it had on my life and that I could completely get my life back through just adding this mighty supplement, I would have thought them mad. But its true! All the best to others on this journey who have found Chris and his awesome information.

    • Di, Thank you for mentioning the difficulty swallowing. That was happening to me lately which was worrisome as i was exposed to Neurotoxins. I also thought i was headed for a hip replacement with shoulder symptoms also. My brother suggested i increase my b12 intake as the Bursa sacs are dependant on b12, and all the pains issues vanished in my hip and shoulder. Will monitor for the swallowing issue.

  9. I was diagnosed with paranoid delusion , depression ocd and was on antiphyscotic. Seeing this my doctor suggested for b12 and d Vitamin test serum. Which turned out to be 105 and 10 respectively. It took nearly 20 years for me to figure out the problem. In the year 2014 I started taking b12 and d supplements which almost success rate of 99%. Now my b12. Level is 1850 and d is sufficient. This makes me very happy and I am pink in my health.

        • I have to say something here about vitamin D. I too fell for the fallacy that we all need vitamin D. Please go to http://www.thepeopleschemist.com and read what is there about vitamin D and other fallacies. I think this is important. Taking supplements that have been popularized and touted as absolutely necessary might be very dangerous. Educate yourself is the best policy, I think.

    • Hi, my husband has the same as May described, but he has them every two weeks. He had bariatric surgery long time ago, but discontinued to take big vitamins, prescribed for that. He has B12 injection every month. So is that a possibility, that he is normal two weeks after the injection, and kind of confused, euphoric, irritable, the other two weeks, when B12 is less in his blood. Please, what do you think? We are going through such circles for two years. I was thinking that it was Gabapentin, he had for pain in the back, he discontinued, but his symptom returned in two weeks, I thought adverse effect of Oxycodone, also I made him stop it, but it did not work. Today I found this discussion and I think maybe my husband needs more B12, since he can absorb it? His symptoms are euphoric, too full of energy, sometimes angry, paranoid, psychotic, annoying, he has red eyes, scratch himself all the time, can’t sleep in the night, cough a lot only on these days, eats too much, but in three days he will fall asleep and almost will not eat . I don’t know what to do, please help me!

      • I feel for your husband Angela. He is struggling big time and it is also very difficult for you too. I have read about difficulties for people after the surgery to absorb nutrition so his issue may not be just B12. Here is a medical article concerning B12 deficiency after bariatric surgery https://www.ncbi.nlm.nih.gov/pubmed/24091055

        I wonder though he may be deficient in other nutrients too. I think a physician that can take a holistic view of his health is advisable. Depending on his age maybe but I’m no expert he might need many nutrients such as https://www.thorne.com/products/dp/al-s-formula-reg

        I like Thorne’s products because they typically use natural forms of nutrients rather than synthetic which may be better for absorption and more gentle on his body.

      • If he wanted to get a constant dosing of B12, with a steadier delivery, and near-maximum uptake, he could try the transdermal B12 oils developed in Australia: http://www.b12oils.com/

        (I am a customer, but have no financial interest in the company.)

        Sublingual tablets yield about 5% uptake, oral (swallowed) 1% – but the transdermal oils yield about 80%.

  10. Hi,

    I am 28 years old and I’ve been a vegetarian since the past 22 years.
    The symptoms are pretty much similar to what is covered in the above article.
    My current d3 level is 4.83 ng/mL and b12 level is 134 pg/m
    The physician has prescribed 3 injections of D3 and B12 every 10 days for a month. I have taken 2 already but dont see much improvement.
    I am ok turning into a non-veg and plan to start with Tuna fish which has 2.5μg of B12 normal daily intake being 2.4μg
    I am keen to know how much time would it take for recovery with the activation of Tuna in my daily diet?

    • Diet has little to do with it, even though he said vegetarians are most at risk. If less than 1% of the population follow a vegan diet, then why are 40% are sub-optimal levels? Again, best way to get your b12 is through supplementation or b12 shots. I found Jarrow methyl b12, 1000 mcg online for very cheap.

      Same is true for vitamin D, unless you live in a warm, sunny climate. Still, how well your body absorbs it is another issue. Always test annually for these and supplement if needed.

    • A suggestion- find out if the injection of B12 you are getting is the methylcoblin form, rather than the cheaper, synthetic cyanocobalamin form. Your body has to covert cyano into the methyl form. Some people, like me can’t metabolize the cyanocobalamin form. If your doctor is using cyan, ask if he will switch to the methylcobalamin form…

        • You ask your Dr. to switch you and see if there are almost immediate noticeable improvements. That’s the easy, quick way. Apparently thete are also tests to check, but I forgot what they are, and good luck talking doctors into doing specific tests anyway, at least that’s an issue where I live!

      • I finally convinced my dads doctor to give him some B12 jabs, 5 injections over 2 weeks then once every three months.
        I asked dad to check which B12 they were using in the injection, the nurse had no idea!!! She apparently looked on her screen and couldn’t tell which one it was!! Is this possible!??
        He has had no improvement after the first 3 injections yet, suffering with deep depression, anxiety, insomnia and panic so having to do everything immediately to get it done and out of the way (even eating a meal in a pub!)
        Should he have seen any improvement yet with a blood result of 400 before the injections were started or should I try to get another B12 type injected instead to try to help

    • I have been taking 5000mcg per day, and firemen exposed to toxic smoke take this amount twice in a 20 minute period with no ill effects. There are no reported cases of over dose of B12.

  11. Sometime, last year, I think, I asked for help because I had mucous that would trap food. Someone said his wife suffered from this, and was helped by apple cider vinegar. It did help, but I could not stick with it. I then had a very embarrassing episode at a family function, after which, I mentioned the food getting stuck to another doctor, and he tested me for thyroid problems. I was HYPERTHYROID! Since taking my thyroid meds, I am not nearly as mucousy, and food doesn’t fight with me because I want it to stay in, but it wants out!

    I couldn’t find the original entry here, but I wanted to give that guy and his wife, and anyone else with that problem a heads up — have your thyroid checked.

    • Hi there,

      I have been having this mucous issue for almost 2 years. My TSH has been around .4 but my doctors say it is fine because it’s at low end of range, even though I have all hyperthyroid symptoms. What was your TSH? Can you tell me which medication you are taking for this so that I can push the issue with them or a new doctor and hopefully get some relief? Any other advice would be appreciated. Thank you!!

      • Have your doctor test free T3 if you are concerned about hyperthyroid. FT3 is the active hormone.

      • Hi, this sounds crazy but I have been on synthroid since having my thyroid removed. I have felt terrible for years and told my doctor the meds must not be working but like you I was told the test showed my levels were good!
        My condition declined to the point that I couldn’t walk, had trouble breathing and didn’t have the energy to get out of bed and my memory was pathetic. I was so worn down and weak that I ended up in bed for at least 18 hours a day.
        Finally a new doctor checked my B12 because I had symptoms of Rheumatoid Arthritis, heart problems and nerve damage.
        B12 anemia was the cause of everything! Get your levels checked……feel better!

        • Wanda, I am beyond Happy for you!
          Love & Unstoppable Confident Energy Each & All!

  12. Hi!

    Does it actually work if you take ONLY Methylcobalamin to treat b12 deficiency or do you also need other forms like adenosylcobalamin (or can Methylcobalamin get converted into adenosylcobalamin)?
    And if you corrected high MMA and homocystein via Methylcobalamin is then a potential adenosylcobalamin deficiency ruled out?

    thank you

  13. Hi Chris,
    I was identified with GERD (Grade A) in August 2015. My Gastro prescribed PPI for 8 weeks but I didn’t take the same. Thanks to your articles !!

    Been on Ayurvedic medication since then. The heartburn has been under control but I lost almost 14 kg in last 8 months. in fact last 6 weeks I am experiencing high levels of fatigue. I checked out the Vitamin D and B12. My results shows Vitamin D levels as 19 and B12 as 268. The endocrinologist who checked my results told me to take B12 shots and Vitamin D3 (60000 IU every week). I heard Vitamin D can aggravate the heart burn. Please advise if I can take B12 and vitamin D shots same week? will it aggravate the reflux.

    Thanks for your time.

      • Hi Ann,
        Thanks for the reply.
        In fact my gastroenterologist has done a Serum TSH (ECLIA) to figure out symptoms of a thyroid disorder. The result was normal (1.580 micIU/mLa).
        In fact later my endocrinologist has done a Plasma Cortisol, which looks like within normal range (442 nmo1/L).

    • Also, was Heartburn your GERD complaint to begin with, or was it something else? For example, I had a cough, and without testing anything, the doctor prescribed 2 kinds of acid reducers. In a way it was good, because it led me to discover my pre-existing B12 deficiency, but the lack of testing was ridiculous, and the reason for my cough was the Amlodipine I was taking for my high blood pressure. I am very suspicious of all these GERD pills they hand out like candy now.

      FYI, if I can, any pills that gives me heartburn, I take with milk. D3 used to make me feel terrible until I started taking Vitafusion gummies. My practically negative D level is now excellent.

    • Hello Faizel,
      I take daily: 10,000IU vitamin D3 along with 6mg (that’s 6,000mcg) B12 tablets dissolved over an hour along the gum line – no problems at all for me, but I don’t have any heartburn issues.
      Sometimes the best we can do is experiment and find out what works for us after learning all that we can about our issue(s). Best of luck.

          • Thanks Daniel, I didn’t see this until just now.

            Erika, here’s the math:
            1mg = 1,000mcg = 1,000µg(for physicists and chemists)
            Therefore, 6mg = 6,000mcg.

            It is correct, but I’m glad you checked it for me, even scientists and mathematicians make mistakes, especially with brain fog!

  14. Yes, vegetarians suffer from decreased cognitive ability. Albert Einstein, Nikola Tesla, Leonardo Da Vinci, Socrates were obviously all suffering from decreased mental capacity. This article is anti-vegetarian propaganda. Granted we need B-12 more than average, there are many other sources it can be obtained from. I feel sorry for anyone who allows themselves to become fearful based on this mis-information.

    • First of all, vegetarianism is hardly the focus of this article. “anti-vegetarian propaganda”???

      Secondly, if you are so sensitive, why are you on Chris Kresser’s website?

    • The author actually never mentions in his article that one should not be vegetarian. All he says is that if you are, then you should supplement with B12. They only thing he refuted is the myth that you can get it from plant foods. So if you have any concern get tested, as he recommends, and see if you are deficient. If you’re vegetarian and you’re not deficient then fine but if you are then supplement. How is this anti-vegetarian?

    • I have been vegan for the last three years. Seemingly, very healthy and eating all the right things. However, I have managed to become severely deficient in B12. Although veganism is not the only cause by a long shot – I know it has not helped my condition and made it much worse. I have unknowingly become more tired, weak and worn out over the last few years. I thought I had ME. Been to doctor a few times and they tested me but all came back normal and they kept telling me to take antidressants as they thought it was all symptoms of depression. I knew it wasn’t, but finally took action to get some private bloodwork done to find that my B12 level was 140! No wonder I have felt so rubbish over the last few years. Wish I had found out sooner as I thought I was going to be like this for the rest of my life. My GP for some reason decides not to test for this. I am now waiting to see how my body responds to the high dose B12 I am now taking.

      • Hi Joseph,

        What’s the dose of B12 you are now taking? What form is it in. There are guidelines for supplementation doctors are now supposed to follow in the US and the UK if a patient even just shows signs of B12 deficiency; however, most of them never even heard of B12, kit seems. The Pernicious Anemia Society probably have links. You could then print them out to show your doctor.

    • Ian,

      Everyone needs more B12 than average. Though there are B12 vitamins that are made from non-animal sources, there are hardly many sources of B12. If you are privy to such sources, how about being specific.

      Eat meat or don’t, but don’t make vague statements. Being B12 deficient has really taken a toll on me. I did not know I was deficient until everything started going…I could not think, remember anything, walk without sever pain, or see straight. I could not walk without bumping into walls and felt dizzy all the time. Now I have uncontrolled blood pressure, asthma and a hyperactive thyroid, and I wonder if it is because of being low on B12 for years. It’s real, not propaganda.

  15. I notice from my recent testing that B12 is now being measured in total and ACTIVE form. If my TOTAL B12 is very low but ACTIVe B12c is low-normal, what is that telling me? I’m totally confused but I definitely am suffering from several symptoms of deficiency.

  16. Red Star nutritional yeast T-6635 is a Vegan source of B12, 1 Tablespoon supplies the adult RDA. I have been Vegan for 11 years, and DO NOT have a deficiency. This makes me wonder about the data presented.

    • It’s great that the nutritional yeast works for you. That may be an excellent choice, and much less expensive, I might add. Yeast, however, can be allergenic for people with mold sensitivities. Also, some people with gut problems are quite sensitive to yeast products. My allergies to mold and yeast came well before the low b12. As healthy as yeast products are for many people, I wouldn’t take a chance. The methyl B12 shots work for me.

    • Hm, I have to agree with you here. I was intrigued by the info until I read that, which I happen to know is not true. Is it that I am learning new things from this article, or learning fake things?

      Please, not trying to be a hard time and correct me if I am wrong, but I believe that the reason animal products have B12, is because they eat grass and soil contaminated with the micro organisms.. So vegans can also get from the same sources, but not already digested once over…

    • Stephen,

      The USRDA for B12 would not keep a flea alive. If vegan and yeast work for you, that’s great, but I also find stories all over the place of vegans that had to return to meat for health reasons. For me, I have to take 15,000 mcg just to keep most of my symptoms at bay. The FDA recommends 2.5 mcg.

      There are a few B12 supplements, though, that say that they are good for vegans (because of not using animal sources, not just because vegans should supplement B12), so vegans should look around.

  17. I am in early 30’s & having B12 deficiency, lots of relief after started taking needles or methylcobalamin supplements. It took 7 years for me to figure out the root cause for daily suffering. From few years I am pushing hardly to fullfil daily activities.The symptoms are crystal clear, pains all over body, fatigue, needles pains, sometimes headaches, mucus filled throat, gut problems. when you woke up & get ready to go work you feel very tired & will push yourself. slowly the day will be better & again feel fatigue from evenings. I feel light headed ,no more body pains feeling lot better now. Symptoms mimic lots of other dangerous diseases which you feel like you have all of them when you google them & ask doctor to do all those tests. All results will get normal as usual at this young age. but still suffering will be there. It seems like a growing problem.

    • Hi you sound like me I to have suffered from b12 deficiency all my life and had injections in the past but I would like to know what the count should be as I have just been to my doctor and she wouldn’t do the blood test as the last time I had a test was last year sometime so I am going to ask her for a print out so I will know if it’s low or not and if it’s only a little bit down it still makes a big difference on how you feel they don’t seem to understand this so please can you help me thank you

  18. My 2 year old boy has about 1500 b12 and 56 vit d…I am really worried.Should he eat less meat and more greens?Is too much meat elevating b12 levels?

  19. I was diagnosed with low b12. I started to have vold sensations in my legs, i had nentioned to my gp pteviously that i could become very tired. I have been diagnosed with IBS msny years ago and had two premature borths. Any way i came down with a cold and had balance problems, flushes, sinus, blinding headaches. My b12 was low so im having 2weeks of injections but further tests have indicated that the intrinsic tests have come back normal. My level for b12 is 161 which apparentlyis to low. Im struggling tp go to work, concentrate, im feeling extremely tired, emotional. Really fed up as whatever it is its effecting me and i just dont feel normal. Im worried now that further tests are normal they will not treat the b12. Any advice would be great.