Do you suffer from any of the following symptoms?
- Weakness, tiredness, or light-headedness
- Rapid heartbeat or difficulty breathing
- Poor memory or difficulty concentrating
- Depression, anxiety, mania
- Numbness and tingling of hands or feet
- Difficulty with balance, poor coordination
- Pale skin
- Sore tongue
- Easy bruising or bleeding gums
- Upset stomach or weight loss
- Diarrhea or constipation
- Depression, irritability, paranoia, mania, hallucinations
If you answered “yes” to any of the above, it may be time to get tested for B12 deficiency.
Vitamin B12 is a water-soluble vitamin that is crucial to normal neurologic function, red blood cell production, and DNA synthesis. It cannot be manufactured in human beings must be regularly obtained from the ingestion of animal proteins or fortified food products. Hydrochloric acid in the stomach liberates vitamin B12 from animal proteins. It then combines with intrinsic factor produced by gastric parietal cells and is absorbed in the terminal ileum.
Vitamin B12 is essential to several enzymatic processes:
- Conversion of homocysteine to methionine
- Conversion of methylmalonic acid to succinyl coenzyme
- Conversion of 5-MTHF (methyltetrahydrofolat) to tetrahydrofolate (required for DNA Synthesis and RBC production)
How common is vitamin B12 deficiency?
B12 deficiency is common and reported to affect up to 25% of the U.S. population. Up to 20% of people over the age of 60 years old show marginal B12 status. The CDC reports, one out of every 31 Americans over 50 are B12 deficient. Sadly the current lab values of serum B12 grossly underestimate the incidence by using a cut-off range far too low. The current ranges for a common commercial laboratory, which I use are 211-946 pg/ml. Many researchers propose that we raise the lower limit of normal to 550pg/ml, above which is optimal. In my clinical practice, I have seen many patients who have significant symptoms of low intracellular B12 and they still show “within normal range” on serum lab values. Serum homocysteine and methylmalonic acid are much more sensitive markers as they may show a deficiency earlier than serum B12.
So what causes B12 deficiency?
The main causes of B12 deficiency include inadequate dietary intake and malabsorption issues. Vitamin B12 deficiency may occur if you have certain conditions, such as:
- Pernicious anemia, which makes it hard for your body to absorb vitamin B12 (characterized by a lack of intrinsic factor – individuals cannot properly absorb vitamin B12 in the gastrointestinal tract)
- Atrophic gastritis or inadequate production of stomach acid (occurs in 10-30% of older adults!)
- Helicobacter pylori infection in the stomach
- Surgery that removed part of your stomach or small intestine including bariatric surgery (Surgical procedures in the gastrointestinal tract, such as weight loss surgery often result in a loss of cells that secrete hydrochloric acid and intrinsic factor)
- Conditions that affect the small bowel, such as
- Crohn’s disease
- Celiac disease (11-41% of patients with celiac will have B12 deficiency)
- Small intestinal bacterial overgrowth (SIBO)
- Parasite infections, such as giardia, tapeworm
- Chronic pancreatitis
- Heavy alcohol use or advanced liver disease
- Autoimmune conditions, such as Grave’s disease, Lupus
- Malnutrition or eating disorders
- Long term use of medications
- Proton pump inhibitors
- H2 blockers
- Certain antibiotics
Who should be tested for B12 deficiency?
- Anemia with elevated MCV (mean corpuscular volume)
- Neurological symptoms, such as numbness, tingling, difficulty with walking or balance issues
- Changes in mental status, confusion, or disorientation
- Dementia or Alzheimer’s disease
- Bipolar, mania, or schizophrenia
- Gastrointestinal disorders with malabsorption, like pancreatic insufficieny
- Patients who have had gastrointestinal surgeries or gastric bypass
- Anyone over age 60 years old
- Restricted diets: vegans, vegetarians, macrobiotic diets
- Autoimmune disorders
- Children with autism spectrum disorders or developmental delay
- Breast fed infants of mothers at risk
- Eating disorders
- Family history of pernicious anemia
- Chronic use of PPI medications (Nexium, Prilosec, prevacid, etc) or Metformin
- Occlusive vascular disorders (heart attack, stroke, blood clots)
Children may present differently from adults and should be tested if any of the following symptoms occur
- Developmental delay or regression
- Apathy or irritability
- Lack of coordination
- Lack of appetite or failure to thrive
- Poor socialization or poor motor skills
- Speech problems or language delay
You can request following blood tests from your doctor to determine if you are deficient:
- Serum B12
- Methylmalonic acid
- Complete blood counts
So what if I do have a B12 deficiency?
B12 is nontoxic and water soluble so if you are deficient the good news is it is easy to replace! Traditionally B12 has been given in the form of intramuscular injections to ensure absorption but studies have shown that sublingual forms may be equally effective. B12 may come in the form of cyanocobalamin, methylcobalamin, hydroxycobalamin, and adenoxylcobalamin. You can discuss with your doctor which form is best for you. I typically start patients with sublingual methylcobalamin in lozengers or drops at 1000-5000mcg daily. Some patients require subcutaneous or intramuscular injections, which can be taught in the office and given by the patient at home. Depending on how severe the deficiency, I will typically prescribe 5000mcg from once per month to 2-3X per week initially. Liver stores of B12 are usually repleted with a half a dozen or so doses but full repletion may take up to 20 doses. Once a patient’s symptoms are improving, maintenance of B12 may occur with as little as one injection every 2-4 weeks. There are now forms of B12 available in oral, sublingual, intranasal, transdermal and injectable forms.
Vitamin B12 can be found in large quantities in animal products, including meat, poultry, fish, seafood, eggs, and dairy products; and the consumption of these products is the most longstanding method by which human beings have taken vitamin B12 into their systems.
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* These statements have not been evaluated by the Food and Drug Administration. The product mentioned in this article are not intended to diagnose, treat, cure, or prevent any disease. The information in this article is not intended to replace any recommendations or relationship with your physician. Please review references sited at end of article for scientific support of any claims made.
My medical practitioner has prescribed methylcobalamin 1000MCG/ML injections, subcutaneously, 3 times a week. But now I’ve developed a reaction at the injection site. About 12-24 hours post injection, I develop a very red, extremely itchy patch about 2-3″ in diameter. Pharmacist recommends using ice packs or cool clothes to relieve the itch. My Dr. is unavailable for another week. I am not experiencing any itching in my throat or shortness of breath. Any ideas? Pharmacist predicts that the reaction will stop after a while.. I started injections on June 6 and had no reactions for the first 3 1/2 weeks. Thank you. I have found your website, blog and Facebook pages very helpful.
You should check with your compounding pharmacist to find out what preservative they are using in the methylcobalamin preparation. While it is unlikely that you are reacting to the methylcobalamin, you very well could have a sensitivity to the preservative used. I often compound the B12 “without preservative” for this reason but it will need to be compounded in individual dose vials.
Thanks so much. I will contact them tomorrow.
What is the ideal range for B12? Mine just came back at 1489. Is this too high? I eat a lot of animal products and take an organic whole-food multivitamin daily that has 30mcg (says 500% DV) B12. Thank you!!
Hi Breann, I prefer serum B12 be above 550pg/ml. Higher than normal levels may indicate a block in MTR/MTRR enzyme pathways and this would need further testing and consultation with a functional medicine doctor to evaluate.
Thank you so much for your response, it was an answered prayer :). When you said further testing would be needed…. would the genetic profile test from 23andme show any blocks in MTR/MTRR enzyme pathways, or were you referring to different types of tests? Thank you!!
Love these posts but for some reason am unable to Pin them to keep in my files. Is that fixable on your end?
I’ll try to get that fixed, Nanci!
What is your opinion on b12 vitamins that you can buy at any health food store? Are they effective? Is it ok to take them without being tested for deficiency? I have a hard time getting my doctor to test for anything that isn’t mainstream and I seem to have more energy when I take a capsule. I also have hoshimotos.
Thanks for listening!
B12 is water soluble so safe for most folks… I still recommend checking with your doctor before starting new supplements. My favorite brand is Prothera Methyl-B12 lozenges. which you can order online using physician code 618
Hello Dr. Jill, I am a 36 year old healthy male. In the past year I have had weird symptoms from numb toes, heart palpitations, chest pain, fatigue, brain fog and vision changes. My MD can’t seem to find any issues. However the 4 blood tests I had all showed low RBC HG and HCT. The highest levels in the 4 tests were 4.6 RBC 140 HG and .42 HCT the rest of the tests were all below that. They only tested b12 once and it was 145 PMOL/L.
She said not to worry about it, however I am. I started taking sublingual methyl B12 5000mcg per day for a week, and felt alot better, however I broke out in a itchy rash so I stopped taking it. 2 weeks later the itch is better but still there. I’m sure B12 is part of my issues however I can’t handle the rash. I was taking Natural Factors B12, ingredient list below.
Lactose, microcrystalline cellulose, croscarmellose sodium, vegetable grade magnesium stearate (lubricant).
I don’t know what to do next. Can you recommend anything for me.
Many people are sensitive to lactose, so I recommend buying one, like Prothera Methyl-B12 lozenges without lactose. You can order online with physician code 618 if you like.
If you are regularly taking B-12 sublingual, 5,000 per day, and your B-12 is still low, does that mean the only way to raise are injections?
yes, you may need IM injections to raise B12
Hi, I was diagnosed with pernicious anemia at 40, right after childbirth and two boob infections while breastfeeding. I can’t stop wondering if the antibiotics did me in?! I now get biweekly injections of b12. Please tell me if there is anything I can eat, drink, supplement that would help my stomach lining from thining? Thank you kindly. Oh I am 55 now.
I mentioned this to Heidee above as well; not sure if this helps or if you are interested but I recently heard about a new oral prescription alternative to the injections called Eligen B12. I recently read that it works even if you don’t have intrinsic factor (so even if you don’t have normal gut absorption). Apparently it came out a month or two ago
Hello. I have recently been told I have partial deafness in both ears due to nerve damage. GP (in the UK) ordered a range of bloods in response. Almost all results were ‘normal’. I have yet to obtain a copy of the actual levels. B12 serum was very high (1500 ng/L), folic acid was high ( don’t have number yet). Amongst other things, I inject 5mg of methylcobalamin each week and take a multivitamin daily which contains 400 mcg folic acid and 30 mcg B12 hydroxycobalamine and GP has advised to stop the injections before I get nerve damage. I asked about nerve damage affecting hearing and he said it was not related. I asked about issues regards utilisation of B12 to the cells and was told this is not relevant as my blood cells were not enlarged. Oh and almost forgot! I was diagnosed CFS/ME three years ago. What would you suggest I investigate next? I have access to a functional medicine doctor.
Serum b12 is not an accurate marker of intracellular levels. I would have your functional doc order MMA for more specific assessment of your B12 status, which may actually be low, even in face of high serum B12 according to this study – http://www.ncbi.nlm.nih.gov/pubmed/25563739. I have never heard of B12 causing hearing loss.
I am homozygous for The C mutation of MTHFR. Taking methlfolate has helped my energy levels, but if I take methylated b12 I have symptoms of a racing heart, more palpitations and anxiety. I’m not quite sure what to try or if I should text for some other mutation? I cannot seem to tolerate any b12 supplementation not can my brother, actually.
There are many reasons why someone may not tolerate methyl-B12. Without doing the testing, I cannot tell you why it is in your case but it could be related to deficiencies of other B vitamins, COMT or other genetic mutations, low lithium levels or other factors.
I was diagnosed with small fiber neuropathy about a year and it was confirmed with a skin biopsy. I’ve had many blood tests and EMG/NCV, MRI, but all are normal. I’ve been urged by some online folks on a health forum I’m a part of to investigate my B12 levels. My number is 381 pg/mL.
Can you please reply with your thoughts re: my number. I have read that you believe the normal range should be 550pg/mL. According to that information, mine would be low. Could this be the cause of my SFN? I’m considered idiopathic so I’m just checking into things.
What should I do?
I hope to hear from you! Thank you!
They could certainly be connected. Have your doctor check urine or serum MMA which is a more sensitive marker of B12
Hi Dr Jill
I read your article & a glimmer of hope appears!
I have multiple autoimmune issues including Hashimotos disease & pernicious anemia. In February this year my serum B12 was just 124 with a GP who refused to treat anything above 100. I subsequently moved GPs & have been having IM Tx with hydroxy B12. We did the alternative days for 5 doses then she gave me 9 vials to have injected as I felt I needed it. I have a very good grasp on my body so this was as key indicators showed such as slurred speech or intolerance to certain noises etc.
Over the last 3 months the frequency has increased to now being weekly & my GP has said she’s unhappy with this. We retested serum levels which came back at 1100 6 days post Tx. Any suggestions why I’m still experiencing the symptoms? I suspect being under treated for the last 6yrs I have lasting damage to the cognitive function of my brain.
I appreciate any advise you may offer
Serum B12 may not accurately reflect intracellular B12 levels. I suggest using MMA as a better marker
It never occurred to me that Vit B12 deficiency could be linked to a child’s developmental delay! One of my children is a slower developer, shorter and delayed with her language, and motor skills compared to my other children. We all eat the same, so I wonder why she may be deficient and they are possibly not? I’ve been considering doing some tests for her to look at her nutritional status perhaps. What tests should I do for her? She is 6. it gets confusing to know where to start. The other week I was reading that a chiropractor or Rolfing technique could sort out similar issues for children that you wrote about (her posture is naturally not as good as my other childrens).
Hi Dr. Jill,
I’m having a lot of health problems and I’m struggling to get better. I am deficient in a lot of nutrients like iron and B12. I was exhausted and sleeping all the time and could barely move. So then I started taking a multivitamin that includes B12, iron, and all the other B vitamins. I have seen a lot of positive changes and I’m certainly not complaining about having energy, but I feel revved up and keep staying up till 6am, nauseous, and my weight problem that’s already bad has gotten worse. I struggle to gain weight for some reason and ever since I started taking the multivitamin, it’s been even more of a struggle even after all the Thanksgiving food when I should have gained weight. I looked it up and it acted like certain vitamins including iron increase metabolism. Well how am I supposed to get my nutrients up if iron and certain B vitamins increase metabolism? I just want my natural energy back. Do you have any suggestions? I would really appreciate it.
That is not the right vitamin for you… you may have methylation issues or other reasons that you do not tolerate the b vitamins. I suggest trying an individual vitamin, like methylcobalamin to see if you can isolate the problem
Hi I noticed in this article you use 560 for optimal levels of B12. But my B12 has been up to 712 in the past and I had a lot more energy. My doctor says it should be around 800. Are you saying it should be at least 560 or is it too much B12 if it’s greater than that?
Optimal is not 560. Optimal is well above that…
I was wondering if you have any advice for me? I am suffering from chronically low ferritin and B12 levels with no explanation. I am not a vegetarian or vegan. I eat turkey and beef regularly. My periods are very light. And iron and B12 supplements are barely bringing up my numbers. After supplementing with B12 for 2 months, it went from 400 to 414. And after supplementing iron for 2 months, my ferritin went from 4 to 9 and then fell back down to 6 and I was supplementing the whole time, even when it fell back down. I have old B12 test results and the results were in the high 500’s and low 700’s and that was diet alone, no supplements. Now I’m supplementing and have been supplementing and I’m only at 414. I don’t know what’s wrong. I have been checked for Celiac with the antibody blood test twice and it’s negative. Doctors aren’t sure what else it could be.
You likely have some form of dysbiosis, like SIBO or villous atrophy affecting absorption of both B12 and iron. Treat the gut and you may be able to restore levels. Other inflammatory conditions may also cause low iron.
Had my B12 checked by my doctor came back at 395 wondering if that’s low different websites say different things
I consider that level quite low from a functional perspective. Checking MMA is much more accurate than serum B12
Hi I am a male ,85 yrs old , healthy otherwise until now. I have been recently been diagnosed with vitamin b12 deficiency, blood test reading about 200…therapy 5000 mcg of cianocobalamina injections, one same day and
then one every month for one year….my question is: is that the right dosage? I have been feeling weak, always tired
and with memory problems…should not my case require a more aggressive therapy, such as the same amount but spaced to at much shorter interval , say 5 or 7 days?
Much obliged dr.Jill , may God bless you. C.Tucci
I often dose 5000mcg of methyl-B12 2 X weekly… best to discuss with your physician and if possible get the compounded form of active B12 – methylcobalamin.
What are the causes for normal/high plasma levels of B12 but low intracellular B12 levels? I’ve been trying to find the answer to this but have had no luck. What are the usual solutions?
Hi Dr. Jill –
I saw in an above post that you like B-12 optimally to be above 550pg/ml. Could a 344 be low enough for muscle weakness, heavy legs, difficulty with normal gait, some numbness/tingling, balance isssues?
yes, absolutely Lisa!
My current B12 value is 185.00 pg/ml.
Can u please suggest is this a normal value should a person have.
This is quite low… I generally treat < 500
3 to 4 months back, I felt the symptoms of vitamin b12 deficiency and through the consultation with a family doctor, I went for a test where my vitamin b12 level was only 131 and I think it should be more than 200. He suggests me to inject b12 lipotropic injections but it doesn’t have good results. Then, I got to know about Super MIC B12 shots from my colleague which doesn’t require any doctor prescription to buy and reviews are ultimately positive so I have purchased this oral shots. After 1 or 2 weeks I saw there is an increase in my energy level and day-by-day I am feeling better. So can you please suggest how long I can take this B12 mic oral injections being an experienced doctor you can give me a better suggestion. If you want product details you can visit the website: https://buymicb12.com/
Sublingual or intranasal B12 are safe ways to increase your levels. You can theoretically take this vitamin long-term since it is water soluble and non-toxic