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Vitamin B12

Vitamin B12 is not a cofactor of Vitamin D, but it is often needed with Vitamin D
Surfing the web finds

  • B12 deficiency increases with age
  • B12 appears to have no toxic upper limit
  • Some people get frequent B12 injections or I.V, to restore levels
    • Injection may not be needed
  • Only a small portion of B12 taken orally gets into the bloodstream
    • Sublingual B12 may not have that problem
  • B12 is stored in the liver – half-life of > 2 years - But. Dr. Greger says to take it weekly or daily
  • B12 deficiency symptoms include poor gut - which can reduce uptake of Vitamin D
    • unless use gut-friendly forms of Vitamin D, including topical
  • B12 can be supplemented via pills, sublingual, transdermal patch, injection, emulsion, and spray
    • As with Vitamin D, a massive (loading) dose can restore levels quickly
    • Nano forms of B12 are more bio-available - as with many other supplements
57 items in Vitamin B12 category on Vitamin D Life

Table of contents

Summary of this page by Claude-2 - A Large Language Model (AI) Aug 2023

Vitamin B12, also known as cobalamin, is an essential nutrient that plays important roles in red blood cell formation, cell metabolism, nerve function, and DNA synthesis. The PDF provides an overview of vitamin B12 including deficiency symptoms, optimal dosages, dietary sources, reasons people may need supplementation, and more.

  • Vitamin B12 deficiency is common, affecting up to 40% of adults. Symptoms include fatigue, neurological problems like numbness and walking difficulties, psychiatric issues like depression, and cognitive decline.
  • Older adults, vegans/vegetarians, and those with absorption issues are at highest risk of deficiency. Taking metformin and acid-reducing medications can also deplete B12 levels.
  • Animal foods like meat, fish, eggs and dairy are the main natural sources of B12. Nutritional yeast and fortified foods can provide some B12 for vegetarians.
  • Daily supplementation with 2,500 mcg per week is recommended for adults under 50 to prevent deficiency.
    • Higher doses may be needed for the elderly and those with absorption issues.
  • Sublingual, oral spray, and injectable B12 are better absorbed than standard oral tablets. Methylcobalamin may be preferable to cyanocobalamin.
  • High dose oral B12 around 1,000 mcg provides little added benefit due to absorption limits. However, megadoses via injection can help rebuild stores.
  • Vitamin B12 blood testing can screen for deficiency. Levels below 300 pg/mL indicate a deficiency. Low-normal levels may still cause symptoms in some.
  • Treatment with B12 supplements or injections can reverse deficiency symptoms like cognitive decline and neuropathy, especially if caught early.

Asked: Apparently, there are two forms of Vitamin B-12. How are they different (Perplexity AI April 2024)

Vitamin B12 is available in several forms, with methylcobalamin and cyanocobalamin being two of the most commonly discussed. These forms differ in their composition, bioavailability, and how they are processed by the body.

Methylcobalamin is a naturally occurring form of Vitamin B12 that is found in animal-based foods. It contains a methyl group (consisting of carbon and hydrogen), making it the most bioavailable form of Vitamin B12. This means it is the most readily absorbed by the body. Methylcobalamin is particularly important for nervous system health, brain function, and the synthesis of melatonin, which can affect sleep patterns and circadian rhythms. It also plays a crucial role in converting homocysteine to methionine, a process that can reduce vascular strain and support heart health. Research has shown that methylcobalamin can significantly improve visual accommodation, unlike cyanocobalamin, which appears to be ineffective in this regard .

Cyanocobalamin, on the other hand, is a synthetic form of Vitamin B12. It contains a cyanide molecule, which, although present in small, non-harmful amounts, must be removed and converted into methylcobalamin by the body for use. This conversion process indicates that cyanocobalamin is not as readily available for biological use as methylcobalamin. Cyanocobalamin is the most commonly supplemented form of Vitamin B12 due to its lower cost and chemical stability. However, its absorption rate is considered poorer compared to methylcobalamin, and it may be less effective for certain physiological functions, such as supporting nervous system health and improving visual accommodation.

In summary, the key differences between methylcobalamin and cyanocobalamin lie in their source (natural vs. synthetic), bioavailability, and how they are utilized by the body. Methylcobalamin is generally considered superior in terms of absorption and physiological benefits, particularly for nervous system health and visual function. Cyanocobalamin, while more cost-effective and stable, requires conversion by the body into a usable form, which may make it less efficient for certain health outcomes

Click here for references etc.

Founder of Vitamin D Life was noticing low energy, B-12 helped a lot - Aug 2023

Age 77, primarily vegetarian. 1000 mcg sublingual helped in an hour
Have ordered for 5,000 mcg sublinqual, $15 for 360 capsules
Many sources recommend need only take Vitamin B12 once a week, so $15 bottle will last 360 weeks = 1/2 cent per day

WARNING: Combined B12 & B6 found to increase risk of hip fracture by 47 percent - 2019

Association of High Intakes of Vitamins B6 and B12 From Food and Supplements With Risk of Hip Fracture Among Postmenopausal Women in the Nurses’ Health Study - May 2019
Combination of B6 >35 mg/d and B12 >20 micrograms/d increased hip fracture risk 47%
Note: My wife had been taking Life Force supplements for decades and got a hip fracture
The recommended daily serving of 4 tablets contains 48 mg of B6 and 200 micrograms of B12
No data in the study, but perhaps this much of B6 and B12 might increase the risk of hip fracture by > 2X
 Download the Study PDF from Vitamin D Life
Details on Vitamin D Life at Warning - High intake of Vitamin B12 and B6 found to increase risk of hip fracture by 47 percent - 2019

Here are the 57 Vitamin B12 articles in Vitamin D Life

Vitamin B12 on the web

Content of B-12 etc in Nutrional Yeast - 2020

Not Created Equal: Which nutritional yeast delivers the vitamin B12 you need?
A few rows of table

B12 blood tests: at home, blood test services: sometimes combined with Vitamin D test

Test at Home and mail in

Blood Test Services - typically also provide Vitamin D tests

47 Vitamin B12 videos by Dr. Greger (typically 5 minutes, with transcripts & references)

Dr. Greger

Also: The 411 on Vitamin B12 Dec 2023

The Symptoms of Vitamin B12 Deficiency and Optimal Dosage for Adults - Dr. Greger - Aug 2023

Dr. Greger

  • ..."crucial for anyone on a plant-based diet"
  • "Vitamin B12 is not made by plants. It’s not made by animals either, but rather microbes that blanket the earth"
  • "The “Many Faces” of B12 deficiency include neurologic symptoms such as numbness and tingling in the hands and feet, muscle cramps, dizziness, cognitive disturbances, difficulty walking, erectile dysfunction, as well as fatigue and psychiatric symptoms like depression and even psychosis."
  • "Now, it’s not just those eating plant-based that should be concerned about getting enough B12. About one in three nonvegetarians aren’t getting enough for optimal health, and that may exceed half in women, especially when they’re pregnant. "
  • "For those with normal absorption capacity, meaning being under age 50 with an intact gastrointestinal system and without diseases like pernicious anemia, we normally lose about one microgram of vitamin B12 a day; so, that’s how much we have to replace, on average, every day"
  • Weekly 2,500 micrograms

B12 infographic - Dr. Greger Oct 2021

Updated Vitamin B12 Recommendations Infographic includes link to his $20 B12 video

Lower 30% of range of B12 blood test can hide big problems - Dr. Greger Aug 2020

How to Test for Functional Vitamin B12 Deficiency 5 minute Video

  • "Most physicians tend to assume that if the B12 level in your blood is “normal”, there is no problem. But, within the lower range of normal, 30% of patients could have metabolic B12 deficiency, with high homocysteine levels."
  • "...10%-40% of the general population, and more than 40% in vegetarians..."

About 1,000 micrograms of B12 =little change in Cognition, Depression, Fatigue - Meta-analysis March 2021

Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression
 Download the PDF from Vitamin D Life

B12 supplementation improved cognition (MMSE) in 3 months - Feb 2020

Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia
Cureus, 12 (2), e6976 2020 Feb 13, DOI: 10.7759/cureus.6976
Shazia Jatoi 1, Abdul Hafeez 2, Syeda Urooj Riaz 3, Aijaz Ali 1, Muhammad Ishaq Ghauri 3, Maham Zehra 1

Background Vitamin B12 deficiency is linked to impaired cognition and memory along with a sensation of tingling and numbness, an outcome of poor myelination. Elevated methylmalonic acid and serum homocysteine levels are markers of Vitamin B12 deficiency. Elevated homocysteine levels are also often associated with Alzheimer's disease and stroke. We conducted this study to determine the effect of vitamin B12 replacement therapy on vitamin B12-deficient patients with noted cognitive impairment.

Methods We conducted a cross-sectional, multicenter study of patients with minimal cognitive impairment (MCI) to assess for Vitamin B12 and homocysteine levels. All patients found to be deficient in vitamin B12 underwent replacement therapy and were assessed again after three months via the Mini-Mental State Examination (MMSE) and a review of symptoms.

Results A total of 202 patients were included in the study. Of those, 171 (84%) patients reported marked symptomatic improvement after vitamin B12 replacement while MMSE scores improved in 158 (78%) patients. Of the remaining 44 patients who reported no symptomatic improvement, MMSE scores improved in 26 while 18 patients showed no MMSE score improvements.

Conclusions Vitamin B12 deficiency is linked to cognition, and replacement therapy may be an option to improve patient cognition outcomes. Further studies are needed to confirm and refine the observed associations over a larger scale and to determine whether these findings will translate to a reduction in cognitive decline.
 Download the PDF from Vitamin D Life
Conclusions from the end of the PDF
We found a clear association between low vitamin B12 levels and progressive cognitive
impairment; therefore, further studies are needed to confirm and refine the observed
associations over a larger scale and to determine whether this change will translate to a
reduction in cognitive decline. Moreover, we are in favor of screening for vitamin B12
deficiency, at least in the elderly population, to find and prevent the possible causes of this
deficiency state, as this can be an easily preventable cause of impending dementia before the
cognitive decline becomes irreversible.

5X difference in B-12 bioavailability (emulsion best)

Note: Does not appear to mention sub-lingual form
 Download the PDF from Vitamin D Life

B12 use both before and during Breast Cancer chemotherapy DECREASED survival by 1.8 X - 2019

Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221)

11 symptoms of B12 deficiency - Jan 2019

__MedNewsToday has detailed description
1. Tingling hands or feet
2. Trouble walking
3. Pale skin
4. Fatigue
5. Fast heart rate
6. Shortness of breath
7. Mouth pain
8. Problems thinking or reasoning
9. Irritability
10. Nausea, vomiting, and diarrhea
11. Decreased appetite and weight loss

Brain Shrinkage 6X more likely if low B-12 - 2008

Vitamin B12 status and rate of brain volume loss in community-dwelling elderly.
doi: 10.1212/01.wnl.0000325581.26991.f2

Misconceptions about a B12 deficiency - 2017?

Misconceptions about a B12 deficiency
Summary points
1. Serum B12 is a conclusive test
2. A B12 deficiency always causes anemia
3. A B12 deficiency is rare and only occurs in older people
4. There is only one cause for a B12 deficiency, auto-immune pernicious anemia.
5. Serum B12 can be used to monitor treatment:
6. B12 can be toxic in high doses

Seniors needed 1000 ug of B12 tablet form (which is the least bio-available) - 2005

Older Adults May Need B12 Dose More Than 200 Times the RDA to Normalize Mild Vitamin Deficiency Medscape 2005

  • Randomized Controlled trial using 2.5, 100, 250, 500, and 1,000 µg
  • “To achieve 80% to 90% of the estimated maximum reduction in the plasma methylmalonic acid concentration, daily doses of 647 to 1,032 µg of cyanocobalamin were required”



B12 - a huge resource of information

Anyone, at any age, can become B12 deficient. However, certain people are at an elevated risk

  • that are vegetarians, vegans, and people on macrobiotic diets
  • aged fifty and over
  • who've undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (gastric bypass)
  • who regularly use proton-pump inhibitors, H2 blockers, antacids, Metformin and related diabetes drugs, or other medication which can interfere with B12 absorption
  • Nitrous oxide administration or abuse
  • with a history of eating disorders (anorexia or bulimia)
  • with a history of alcoholism
  • with a family history of pernicious anemia
  • diagnosed with anemia (including iron deficiency anemia, sickle cell anemia, and thalassemia)
  • with Crohn's disease, ulcerative colitis, irritable bowel syndrome, coeliac disease, or any other disease that causes malabsorption of nutrients
  • with autoimmune disorders (especially thyroid disorders such as Hashimoto's thyroiditis and Graves' disease), type 1 diabetes, vitiligo, lupus, Addison's disease, ulcerative colitis, rheumatoid arthritis, acquired agammaglobulinemia, or a family history of these disorders
  • with neurologic or motor symptoms
  • with Downs syndrome
  • with Phenylketonuria (PKU)
  • with psychiatric disorders, including depression, bipolar etc
  • with elevated MCV (mean corpuscular volume)
  • with occlusive vascular disorders (MI, CVA, DVT, PE)
  • Orthostatic hypotension / Postural hypotension
  • Transient ischemic attacks (TIAs, or 'mini stroke')
  • Cerebral vascular accident (CVA or 'stroke')
  • Myocardial infarction ('heart attack')
  • DVT - Deep vein thrombosis (blood clot to the leg or arm)
  • with Gastroesophageal reflux disease (GERD)
  • who've undergone neck or back surgery
  • Who've undergone Chemo or radiation therapy

Women . . .

  • with a history or infertility or multiple miscarriages
  • with postnatal depression
  • Nitrous oxide administration (laughing gas)

Infants . . .

  • born to and/or breastfed by women who are symptomatic or are at risk for B12 deficiency
  • Infants and children with developmental delay


B12 Deficiency

B12 infographics from the web


A Proven Sign Of Vitamin B12 Deficiency June 2019


  • "Around one-quarter of people may have a vitamin B12 deficiency."
  • "One study of Colombian children found that children deficient in vitamin B12 were at more than twice the risk of repeating a grade"
    • "Deficient children were also almost twice as likely to be absent from school as those who were not" 10.1016/j.jsbmb.2018.09.005

Low B12 in 55% of Diabetics getting Metformin - 2018

B12 supplementation may treat T2 Diabetes - Oct 2022

The efficacy of vitamin B12 supplementation for treating vitamin B12 deficiency and peripheral neuropathy in metformin-treated type 2 diabetes mellitus patients: A systematic review https://doi.org/10.1016/j.dsx.2022.102634

B12 oral seems as good as an injection, and much lower cost - Cochraine March 2018

Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency 10.1002/14651858.CD004655.pub3 PDF

B12. - March 2018

Adv Food Nutr Res. 2018;83:215-279. doi: 10.1016/bs.afnr.2017.11.005
Smith AD1, Warren MJ2, Refsum H3.

The biosynthesis of B12, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B12, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome of pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B12 deficiency.
However, there is no sharp cutoff for B12 deficiency; rather, there is a continuous inverse relationship between serum B12 and a variety of undesirable outcomes, including

  • neural tube defects,
  • stroke, and
  • dementia.

The brain is particularly vulnerable; in children, inadequate B12 stunts brain and intellectual development.
Suboptimal B12 status (serum B12<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in pregnant women and in less-developed countries. Thus, many tens of millions of people in the world may suffer harm from having a poor B12 status. Public health steps are urgently needed to correct this inadequacy.

3X as many headaches in children with low B12 - March 2018

The association between serum vitamin B12 deficiency and tension-type headache in Turkish children.
24% vs 8% were < 200 pg/ml

Singers believe B12 reduces voice tremors - Jan 2018

The Singer's and the Clinician's Perspective on Vitamin B12 Treatment for Vocal Benefits
but laryngologists have not seen any studies

Nineteen B12 genes - Feb 2018

An update on vitamin B12-related gene polymorphisms and B12 status

5 co-factors or regulators for the transport of vitamin B12
1 Membrane transporters
3 Involved in the catalysis of enzymatic reactions
1 Involved in cell cycle regulation
3 Mitochondrial proteins
4 unknown function

 Download the PDF from Vitamin D Life

B12 deficiency - from Pintrest


B12 injections increase acne

Why Most People Need Vitamin B12 Supplementation - 3 Mercola items

Why Most People Need Vitamin B12 Supplementation April 2018, 50-minute video

  • 40 % have marginal vitamin B12, 9 % are deficient
  • "Animal foods have become a questionable source of B12 thanks to modern farming practices ..."
  • "B12 Deficiency Mimics Many Serious Neurological Disorders and Diseases"
    such as multiple sclerosis, Alzheimer’s disease and autism
  • "Low B12 Implicated in Migraines"
  • especially for "Adults over 50, because as you grow older, your ability to produce intrinsic factor decreases."
  • also "People who have taken antibiotics, as these drugs have been shown to induce vitamin B12 deficiency.26"
  • Methylcobalamin is more absorbable than the cyanocobalamin form of B12

Vitamin B12 Deficiency Symptoms Mercola July 2021

Vitamin B12 Is Key for Optimal Tissue Regeneration Dec 2023
 Download the PDF from Vitamin D Life

Tested German pregnancies for 27 deficiencies, B-12 deficiency was found most frequently - June 2018

High incidence of maternal vitamin B12 deficiency detected by newborn screening: first results from a study for the evaluation of 26 additional target disorders for the German newborn screening panel.
DOI: 10.1007/s12519-018-0159-1

80 % of those within neurological abnormalities were B12 deficient - June 2018

Vitamin B12 deficiency neuropathy: A clinical and electrophysiological study
Neurophysiologie Clinique. Volume 48, Issue 3, June 2018, Page 130. https://doi.org/10.1016/j.neucli.2018.05.00

Vitamin B12 deficiency is a metabolic disorder with many causes. The neurological features of vitamin B12 deficiency are heterogeneous [2]. Peripheral neuropathy often described [3], but its frequency and its type is controversial [1[]. The present study was conducted to describe electro-clinical presentations of peripheral neuropathy in patients with vitamin B12 deficiency.

A Retrospective review of 32 subjects with neurological abnormalities due to vitamin B12 deficiency, were subjected to a detailed motor and sensory nerve conduction studies of median, ulnar, external popliteal sciatic, internal popliteal sciatic and sural nerves. Patients that have another reason for neuropathy or another disease that can affect nerve conduction studies were excluded.

The median age of the patients was 51 (± 16.57) years old, (range 18–84 years old), sex ratio (M/F) was 1.66 (20/12).
Clinical features of neuropathy:

  • paraesthesia,
  • hyporeflexia
  • ataxia and limb weakness

were present in 20 (62.5%) patients.
Electromyography showed abnormal nerve conduction in

  • 25 (78.12%) patients and it was normal in 7 (21.88%) patients.

On nerve conduction study: 16 (50%) had axonal impairment, 3 (9.3%) had demyelinating neuropathy and 6 (18.75%) had mixed features. Eleven patients (34.37%) presented a pure sensory impairment and 14 (43.75%) presented mixed pattern sensory and motor impairment.
All cases underwent treatment with intramuscular hydroxocobalamin treatment (daily injection of 1000 μg cyanocobalamin for 4 weeks, followed by injections of 1000 μg each month) with marked clinical and haematological improvement.

Conclusion: We conclude that nearly 80% patients with neurologic manifestations of vitamin B12 deficiency had evidence of peripheral neuropathy which is mainly axonal with some demyelinating features.
Sensory and motor nerve conduction were affected.
Evolution is generally good if the treatment was initiated early.

Images from the web


Evolutionary Quirk- Discover Magazine Aug 2018

The Evolutionary Quirk That Made Vitamin B12 Part of Our Diet
B12 made in the human gut is further down than it can be absorbed

Vitamin B-12 – little extra benefit if more than 5 micrograms at a time (orally)

  • I had been taking 50,000 micrograms every couple of days – in the form of a little pill
  • I just learned that the gut become far less efficient at taking in more than about 5 micrograms at a time.
  • So I had been supplementing with about 1,000 X more than could be absorbed
  • I have been taking many of my supplements in bulk form
    This greatly reduces the cost and the number of pills I take weekly.
  • Bulk Vitamin B12 costs only $18 for 500,000 micrograms Amazon
  • I will be adding 5 micrograms of B-12 to my daily bulk supplements – at a cost of $0.0002 per day
    B-12 Had cost $0.06/day so the bulk form will be 300 X lower cost
  • I am unaware of any limitation on daily intake of Vitamin D by any form nor of Vitamin B-12 by injection

How common is vitamin B-12 deficiency? - 2009

Am J Clin Nutr 2009;89(suppl):693S-6S. Printed in USA. © 2009 American Society for Nutrition
Lindsay H Allen
In considering the vitamin B-12 fortification of flour, it is important to know who is at risk of vitamin B-12 deficiency and whether those individuals would benefit from flour fortification. This article reviews current knowledge of the prevalence and causes of vitamin B-12 deficiency and considers whether fortification would improve the status of deficient subgroups of the population.
In large surveys in the United States and the United Kingdom, '6% of those aged >60 y are vitamin B-12 deficient (plasma vitamin B-12 < 148 pmol/L), with the prevalence of deficiency increasing with age.
Closer to 20% have marginal status (plasma vitamin B-12: 148-221 pmol/L) in later life.
In developing countries, deficiency is much more common, starting in early life and persisting across the life span. Inadequate intake, due to low consumption of animal-source foods, is the main cause of low serum vitamin B-12 in younger adults and likely the main cause in poor populations worldwide; in most studies, serum vitamin B-12 concentration is correlated with intake of this vitamin. In older persons, food-bound cobalamin malabsorption becomes the predominant cause of deficiency, at least in part due to gastric atrophy, but it is likely that most elderly can absorb the vitamin from fortified food. Fortification of flour with vitamin B-12 is likely to improve the status of most persons with low stores of this vitamin. However, intervention studies are still needed to assess efficacy and functional benefits of increasing intake of the amounts likely to be consumed in flour, including in elderly persons with varying degrees of gastric atrophy.
 Download the PDF from Vitamin D Life

From PDF

  • “Although >70% of the vitamin is absorbed when intake is in the range of 0.1-0.5 ug, the ileal receptors for the vitamin B-12-intrinsic factor complex become saturated with higher intakes such that absorption falls to '50% of a 1-ug dose, 15% of a 10-ug dose, and 3% of a 25-50-ug dose”


3 out of 4 Vegans are deficient, 1 out of 4 elderly


Very large doses do result in more getting into the blood

   Source of chart

Females may have less B12 if older than 12 years, especially Black females

   Buce Aimes

B-12 and Vitamin D reduce cardiovascular mortality - Dec 2018

Recent Insights into the Role of Vitamin B12 and Vitamin D upon Cardiovascular Mortality: A Systematic Review
 Download the PDF from Vitamin D Life

Oral B12 was 1.8X better than Injection - Jan 2019


B12 needed to fight pathogens (in roundworms) March 2019

Rice University Press Release
Roundworms and humans both need B-12 in diet, both suffer from the same pathogen
Will soon be at PLOSONE

B12 eliminated canker sores in 74% of people - RCT 2009

Effectiveness of Vitamin B12 in Treating Recurrent Aphthous Stomatitis: A Randomized, Double-Blind, Placebo-Controlled Trial
sublingual 1000 mcg of vitamin B12 for 6 months
Google Scolar - 119 citations of this study as of Feb 2019
 Download the PDF from Vitamin D Life

B12 deficiency and clinical laboratory: Lessons revisited and clarified in seven questions - Sept 2017

 Download the PDF from Vitamin D Life

5 5 minute B12 videos by Dr. Greger Oct 2020

B12 deficiency is sometimes associated with poor cognition, taking B12 reduced their cognitive problems - Feb 2021

Medical Journal Armed Forces India https://doi.org/10.1016/j.mjafi.2020.11.003

Vitamin B12 deficiency is an easily treatable cause of reversible dementia. It is likely to be more common in Indian population due to the traditionally vegetarian culture. This study was conducted to estimate the prevalence of Vitamin B12 deficiency in elderly patients (>60 years) with dementia attending the outpatient department.

This study was conducted in two phases. The first phase was a cross sectional observational study to estimate the prevalence of Vitamin B12 deficiency in the elderly population with dementia. The second phase was a pilot study done in subjects with Vitamin B12 deficiency to assess the change in cognition following Vitamin B12 supplementation.

Out of 2920 study eligible subjects, 200 were diagnosed as dementia with Mini Mental Status Examination (MMSE) score of ≤ 24. Vitamin B12 deficiency was seen in 7.5% of patients. Vitamin B12 deficiency was associated with shorter and more severe dementia. Macrocytosis was more common in Vitamin B12 deficiency (p value < 0.001) where as vegetarian diet did not show significant correlation (p value 0.69). There was a significant improvement in the median MMSE score in the intervention group with increase in MMSE by 2 points at 6-8 weeks and 3 points at 12 weeks (p value 0.009 and 0.003 by Mann Whitney test).

Prevalence of Vitamin B12 deficiency in dementia was 7.5%. It was associated with macrocytosis, shorter duration and more severe dementia. There was a significant improvement in median MMSE score at 6 weeks and 12 weeks following Vitamin B12 supplementation.

Some additional studies of low B12 and poor cognition

Metformin (oral glucose-lowering drug) causes B12 deficiency - July 2021

Long-term metformin therapy and vitamin B12 deficiency: An association to bear in mind
DOI: 10.4239/wjd.v12.i7.916 FREE PDF

Unraveling The Complexity Of Vitamin B12 Diseases - Jan 2022

ScienceBlog Baylor University
Tackling the complexity of two inherited vitamin B12 diseases

Vitamin B-12 and the Gastrointestinal Microbiome - March 2022

A Systematic Review behind paywall https://doi.org/10.1093/advances/nmab123
Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences. Emerging evidence suggests that vitamin B-12 may have an important role in other aspects of human health, including the composition and function of the gastrointestinal (gut) microbiome. Vitamin B-12 is synthesized and utilized by bacteria in the human gut microbiome and is required for over a dozen enzymes in bacteria, compared to only 2 in humans. However, the impact of vitamin B-12 on the gut microbiome has not been established. This systematic review was conducted to examine the evidence that links vitamin B-12 and the gut microbiome. A structured search strategy was used to identify in vitro, animal, and human studies that assessed vitamin B-12 status, dietary intake, or supplementation, and the gut microbiome using culture-independent techniques. A total of 22 studies (3 in vitro, 8 animal, 11 human observational studies) were included. Nineteen studies reported that vitamin B-12 intake, status, or supplementation was associated with gut microbiome outcomes, including beta-diversity, alpha-diversity, relative abundance of bacteria, functional capacity, or short-chain fatty acids (SCFA) production. Evidence suggests that vitamin B-12 may be associated with changes in bacterial abundance. While results from in vitro studies suggest that vitamin B-12 may increase alpha-diversity and shift gut microbiome composition (beta-diversity), findings from animal studies and observational human studies were heterogeneous. Based on evidence from in vitro and animal studies, microbiome outcomes may differ by cobalamin form and co-intervention. To date, few prospective observational studies and no randomized trials have been conducted to examine the effects of vitamin B-12 on the human gut microbiome. The impact of vitamin B-12 on the gut microbiome needs to be elucidated to inform screening and public health interventions.

VitaminDwiki – Comparing High-dose vitamin D therapies includes B-12 and other B vitamins

Dr. Coimbra
books 2018 2016
Dr. Somerville
Optimal Dose
Dr. GominakMr. BatchellerDr. Bredsen
End of Alz.
Health problem Multiple Sclerosis
autoimmune, PD
sleep, flu, pain,
obesity, etc.
SleepCluster, Migraine
Park. being added
Number of people
by 2022
5,000 5,000 8,000
>1,000 ?
Vitamin D targetPTH is target
typ: 150ng of D
100-140+ ng 60-80 ngPTH is target
typ: 80 ng of D
40-60 ng
Vitamin D daily dose
(K = 1,000 IU)
20K - 200K
1,000 IU/kg
30K 2K + monthly
test increasing
dose until goal
4K - 40K
110 IU/kg
Omega-3 * O-3 O-3- - - O-3O-3
Magnesium *MgMg - - - Mg (400 mg) -
Vitamin K2 K2 (no longer?) K2 - - -K2 -
Vitamin B...B2, B9, B12 B3 B50-B100
3 months
Zinc *Zn - - - Zn -
Boron *? B - - - B -
Minimize rock-based Ca
Decrease Ca - - -Ca-
Vitamin A
avoid extremes
avoid A avoid A - - - A-
Co-Q 10
- - - Co-Q 10-
Loading dose
Days instead of months
- - - - - - - - - Loading
"Cluster Balm"

Other B Vitamins

B Vitamins at Mercola Sept 2018

“The Power of Bioavailable B Vitamins – What Could Your Life Look Like If You Had More?”

B Vitamin Recommended Adult Daily Intake Susceptibility to damage during processing and storage Important Functions
Thiamine (Vitamin B1) 1.2 mg; 1.4 mg (pregnant and lactating women) Sensitive to heat, oxygen, humidity, and light, and very sensitive to alkaline pH Essential for metabolism of fats and carbohydrates, energy metabolism for the nervous system and muscles*
Riboflavin (Vitamin B2) 1.3 mg; 1.6 mg (pregnant and lactating women) Sensitive to humidity and light Essential for growth and muscle development, eye health, and healthy skin*
Niacin (Vitamin B3) 16 mg; 18 mg (pregnant and lactating women) Stable Essential for the proper function of enzymes and a healthy nervous system, skin, nails and GI function*
Pantothenic Acid (Vitamin B5) 5 mg; 7 mg (pregnant and lactating women) Sensitive to heat and humidity A structural element of many coenzymes, plays a central role in energy metabolism and the synthesis of sex hormones*
Pyridoxine (Vitamin B6) 1.7 mg; 2 mg (pregnant and lactating women) Very sensitive to heat, and sensitive to humidity, light and acid pH Essential for the body’s utilization of protein and the synthesis of neurotransmitters*
Folate (Vitamin B9) 400 mcg; 600 mcg (pregnant and lactating women) Very sensitive to heat, acid pH and light, and sensitive to humidity Required for the production of red blood cells in bone marrow*
Biotin 30 mcg; 35 (pregnant and lactating women) Sensitive to humidity and light Supports healthy normal growth, digestion, muscle function, healthy skin and hair, and cellular health*
Cobalamin (Vitamin B12) 2.4 mcg; 2.8 mcg (pregnant and lactating women) Sensitive to heat, oxygen, humidity, and contact with iron or copper Supports protein, carbohydrate and fat metabolism, GI and nervous system health, immune function and the healthy production of red blood cells*

Prescribing vitamin B complex: Need for reassessment - June 2021

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20432 Mercola Dec 2023_CompressPdf.pdf admin 04 Dec, 2023 122.68 Kb 66
17886 Oral vitamin B12 versus intramuscular vitamin B12.pdf admin 16 Jun, 2022 681.79 Kb 1648
17771 Prescribing_vitamin_B_complex__Need_for.5.pdf admin 07 Jun, 2022 502.52 Kb 289
16359 B12-Infographic Greger-min.jpg admin 05 Oct, 2021 481.10 Kb 2131
15525 N yeast.jpg admin 29 Apr, 2021 99.86 Kb 12145
15242 B12meta -analysis.pdf admin 12 Mar, 2021 1.69 Mb 592
14710 B12 COVID-19.pdf admin 12 Dec, 2020 580.06 Kb 634
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12862 5X difference in B12 response.jpg admin 25 Oct, 2019 47.29 Kb 3881
12861 B12 types.pdf admin 25 Oct, 2019 1.62 Mb 1230
12860 B12 7 questions.pdf admin 25 Oct, 2019 624.97 Kb 1057
11965 Excess B12 and B6 increases risk of hip fracture by 50 percent.pdf admin 16 May, 2019 861.78 Kb 1154
11426 canker sores 2009.pdf admin 18 Feb, 2019 123.21 Kb 3517
10945 ASPS-02-0173.pdf admin 01 Dec, 2018 290.74 Kb 1324
10629 female deficiency.jpg admin 30 Sep, 2018 12.87 Kb 5040
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10626 B12 vegan elderly.jpg admin 30 Sep, 2018 22.67 Kb 5512
10625 B12 lifetime.jpg admin 30 Sep, 2018 14.58 Kb 6855
10494 How common is vitamin B-12 deficiency.pdf admin 06 Sep, 2018 138.13 Kb 1261
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10104 B12 symptoms.jpg admin 03 Jul, 2018 44.50 Kb 4758
9547 B12 genes.pdf admin 19 Mar, 2018 1.07 Mb 1599
9470 B12 warning signs.jpg admin 09 Mar, 2018 52.59 Kb 17937