Written by Slawomir Gromadzki, MPH

amazing benefits of Vitamin B12


Vitamin B12, also called cobalamin, is a water-soluble, largest and most structurally complicated cobalt-based organic vitamin. Cobalamin is such a unique and complex compound that no scientist is able to make it in the lab, and for this reason, it is often referred to as “the Mount Everest of biosynthetic problems.” However, what scientists can’t accomplish a humble bacteria can, as cobalamin can be synthesized (produced) only by certain probiotic bacterial species, especially those that are anaerobic (e.g., able to thrive in environments that lack oxygen such as intestines). Cobalamin synthesis is an extremely complex process which involves over 30 enzymatic steps and scientists still don’t understand many details associated with it.


There are two bacterial species that possess all the genes for Cobalamin synthesis and both are used for the commercial production of vitamin B12. The first one is Lactobacillus reuteri (naturally can be found in intestines of many humans) and the second one is Propionibacterium freudenreichii which is a genetically-engineered strain. Several other probiotic bacterial species especially Lactic-acid bacteria such as Bifidobacterium, Lactobacillus or Propionibacterium species can produce cobalamin as a result of teamwork. Certain Lactobacillus probiotics improved vitamin status (B12, folate, and D3) in human studies. Some other species also produce nutrients like B vitamins and folate.

Daily consumption of L. acidophilus significantly improved vitamin B12 and folate levels in children [>].

L. reuteri isolated from sourdough has been shown to produce cobalamin (vitamin B12) [>]

amazing benefits of Vitamin B12


Vitamin B12 is absolutely critical for good mental and physical health. It is essential for the DNA (contributes to the successful synthesis of the cell’s genetic material) and works with other B vitamins to form all types of blood cells. It helps nerve fibres form and function in our brain, spinal cord and peripheral nerves. It supports brain function (memory & focus), immune system, energy production and metabolism of fats, carbohydrates and proteins. It helps to keep our heart and cardiovascular system on track by maintaining normal homocysteine levels. Vitamin B12 plays an important role in fertility and pregnancy. It is crucial in the maintenance of the nervous system and in preventing damage of the myelin sheaths, the insulating material that surrounds nerve cells. Also children require constant Vitamin B12 supply for the healthy development of the immune and nervous systems and to maintain proper appetite.


Unfortunately, due to many different nutritional, physiological, environmental and lifestyle factors Vitamin B12 deficiency is regarded now as a very common and growing problem even among young people. For example, some sources suggest that almost half of the entire American nation may be affected by B12 deficiency (without knowing about it). The problem is similar in the UK and many other countries due to various common environmental and lifestyle factors. 50% of vegetarians and 70-80% of vegans are deficient in Vitamin B12.


There are two types of anaemia (megaloblastic and pernicious) that involve B12 deficiency. In megaloblastic anaemia, red blood cells are fewer and enlarged especially as a result of vitamin B12 and folic acid deficiency. However, in this case, vitamin B12 deficiency alone will not be able to produce symptoms if there is sufficient amount of folate (folic acid). This is why folic acid supplementation even in the absence of vitamin B12 can prevent megaloblastic anaemia.

The second type of anaemia is called pernicious and it is the most common cause of vitamin B12 deficiency in the UK. In case of pernicious anaemia our immune system attacks and destroys the cells in the stomach that produce the intrinsic factor which is necessary for proper absorption of vitamin B12 from our gastrointestinal tract. As a result, the body is unable to absorb vitamin B12 which leads to anaemia caused by a chronic deficiency of vitamin B12.

Anaemia and any form of chronic vitamin B12 deficiency can be expressed in many different symptoms such as mental fogginess, poor memory and concentration, fatigue, numbness & tingling of fingers or toes, abnormal smoothness of the tongue, dementia, irritation, feelings of apathy and lack of motivation, mood swings, muscle weakness, sleeping problems, loss of appetite, constipation, sores at the corners of the mouth, mood disturbances, personality changes, depression, spasticity (a condition in which muscles are continuously tight or stiff), neurological pain, vision changes, incontinence, spasticity of muscles (shaky movements), low blood pressure, vision problems, delusions, hallucinations, cognitive changes, spinal cord damage, etc.

amazing benefits of Vitamin B12

Lack of this vitamin also contributes to weakened immunity and recurrent infections, damage of the myelin sheaths of the nerve cells, birth defects, or increased homocysteine levels and higher risk of cardiovascular problems. Deficiency of vitamin B12 and folic acid lead to hearing loss. According to Alan Greene, M.D., premature grey hair is caused by vitamin B-12 deficiency. B12 deficiency often affects the lining of the uterus, causing an abnormal pap smear that is often mistaken as pre-cancerous. B12 deficiency can also cause nerve damage in the stomach, which prevents the stomach from emptying properly. This results in symptoms of bloating, heartburn, gastric reflux, nausea, or constipation.

Deficiency leads to the impairment of neurological functions since Vitamin B12 is a compulsory factor needed for the development of neurons. Because of the great variety of possible symptoms vitamin B12 deficiency can mimic many diseases such as depression, psychosis, or even Parkinson’s disease. Vitamin B12 deficiency may also lead to the damage of the myelin sheath which surrounds the nerve fibres; it can also mimic the symptoms of multiple sclerosis (MS). Researchers have reported that these symptoms may sometimes occur even when vitamin B12 levels are just slightly lower than normal.

Initial symptoms such as numbness and tingling of fingers or toes may, without treatment, progress to the instability of gait (deviation from normal walking) or paralysis.

Since the preservation of DNA integrity is dependent on vitamin B12 and folate availability deficiency of both of them has been linked to increased risk of various cancers such as breast cancer.

amazing benefits of Vitamin B12


Facts about vitamin B12 (cobalamin) show that in developed countries the number of people with low vitamin B12 is rampant not only among elderly people, vegans and vegetarians but actually among entire population including younger individuals or those who consume dairy and meat products on a regular basis. According to Dr Jennifer Rooke – Assistant Professor in the Department of Community Health and Preventive Medicine at Morehouse School of Medicine, “Cattle no longer feed on grass and chickens do not peck in the dirt on factory farms. Even if they did, pesticides kill B12 producing bacteria in the soil. Heavy antibiotic use kills B12 producing bacteria in the guts of farm animals.”


Since apart from fortified and animal-based foods the number and vitality of certain strains of B12 manufacturing probiotic bacteria in our intestines is the key source of this vitamin, the following factors can lead to B12 deficiency by damaging intestinal flora balance: Antibiotics (also found in meat, dairy farmed fish, and tap water), laxatives, chlorine (Sucralose, Splenda, tap water, swimming pools, etc.), sodium fluoride (toothpastes, tap water, etc.), caffeine (coffee, tea, cola drinks, green tea), refined sugar, alcoholic beverages, unhealthy eating habits (lack of dietary fibre), stress, anxiety, depression, etc.

Also, celiac disease, IBS, Crohn’s disease, stomach surgery, autoimmune disorders, diabetes and some other conditions may contribute to the deficiency.

The following drugs reduce the absorption of vitamin B12: Metformin (a medication for individuals with type 2 diabetes), nitrous oxide (commonly used anaesthetic), chloramphenicol and neomycin (antibiotics), colchicine (medicine for gout treatment), Proton-pump inhibitors (e.g., omeprazole and lansoprazole), Proton-pump inhibitors, Histamine2 (H2)-receptor antagonists (e.g., cimetidine, famotidine, and ranitidine), cholestyramine (used in the treatment of high cholesterol).

Individuals taking above-mentioned drugs and medications that inhibit gastric acid secretion should consider taking the sublingual methylcobalamin form of vitamin B12.


Studies have noted a link between B12 deficiency and abnormal oestrogenic levels that may interfere with the implantation of the fertilized egg. Dr Michael Bennett describes a connection linking B12 deficiency with not only a failure to get pregnant but also a failure to successfully carry a baby full-term as a lack of this vitamin can lead to neural tube defects in pregnancy. Pregnancy can drastically worsen a pre-existing B12 deficiency because B12 is transferred to the growing foetus throughout pregnancy. Maternal B12 deficiency may also increase a child’s risk of type-2 diabetes.

Pregnant women that are on a vegan diet are recommended to take B12 supplements but since about 40% of those who regularly consume meat products and dairy are deficient in this vitamin it is wise for all pregnant women (regardless of diet) to take B12 supplements (especially the sublingual methylcobalamin).


Because the chemical structure of cobalamin (B12) is extremely complex its proper absorption from animal foods in our body depends on many factors. Proper stomach acidity is required for this vitamin to be properly absorbed later in the intestine. Antacid drugs, therefore, by reducing gastric acid production cause a decrease in vitamin B12 absorption leading to its deficiency. Another factor which may lead to the same problem is age as the older we get the less stomach acid we make.

There are at least seven factors required for proper B12 absorption from food sources and utilization. Among the most important ones (apart from stomach acid) are intrinsic factor and transcobalamin. Unfortunately, the older we get the less of them we produce. The problem starts especially when we are over 50 years old. However, those who are over 70 usually do not make those factors at all! It means they may be completely deprived of vitamin B12 and as a result can easily develop all kinds of symptoms including severe dementia, neurological problems or even Parkinson’s- or MS-like symptoms!

Since due to a common deficiency of one or more of these seven factors elderly people can’t properly digest and absorb cobalamin (vitamin B12) they can get it only in the form of good quality supplements or B12 shots.


Apart from senior citizens, people at higher risk for vitamin B12 deficiency include especially strict vegetarians (vegans), breastfed infants, people with increased vitamin B12 requirements associated with kidney or liver disease, women during pregnancy, those who suffer from haemorrhage, and individuals with malignant cancers.

Also, various prescribed medications such as some diabetes drugs may lead to B12 deficiency. Therefore, even if you are not a vegan you may still need the supplementation as meat and dairy eaters also often experience symptoms of cobalamin (B12) deficiency due to problems with absorption or other factors such as stress, depression, and use of stimulants or laxatives.


Since vitamin B12 deficiency is a very common problem today proper supplementation of this vitamin is very important as it gives many health benefits: It protects nerve and brain cells from free radical damage, and often reduces pain associated with neuropathies (B12 was considered a painkiller in some countries >), contributes to the creation of healthy DNA and RNA, works with other B vitamins to form all types of blood cells, supports immune system health, improves mood and cognitive functions, protects the cardiovascular system, maintains overall energy levels, etc.


Vitamin B12 is an amazingly powerful detoxifying agent, particularly when it’s used in the form of sublingual methylcobalamin. Its power lies in the methyl part of the methylcobalamin as a process known as methylation is one of the most critical processes in the body. B12 (especially methylcobalamin), therefore, is used in our body to remove numerous dangerous substances such as arsenic, mercury, glutamates from artificial sweeteners and MSG, mycotoxins, or cyanide.


Methylcobalamin is absolutely vital in the protection and repair of the nervous system. Its deficiency can lead to peripheral nerve damage (especially in people with chronic high blood sugar levels and those who are on statins and other cholesterol-lowering drugs), brain and spinal cord problems, neural tube defects in pregnancy, or Multiple Sclerosis lesions.

Very few substances have any impact on regenerating damaged nerves in humans. However, a 1994 study in the Journal of Neurological Science (Vol 48) suggested that the methylcobalamin form of vitamin B12 could increase the synthesis of certain proteins that help regenerate nerves. The study showed that extremely high doses of methylcobalamin produced nerve regeneration in rats. A study on the impact of vitamin B12 on the brain found that seniors with the lowest B12 levels had a six times greater rate of brain volume loss compared with those who had the highest levels of B12! Interestingly, none of the participants was actually deficient in vitamin B12 – they just had low levels within a ‘normal’ range! (>).

Also, some individuals with peripheral neuropathy may initially experience worsening of the burning feet but for a short time as it may be just a sign that B12 starts regenerating the damaged nerves thus making them more sensitive.


Vitamin B12 is involved in the production of white blood cells which are responsible to deal with viral infections and many people with inflammations, weak immune system and autoimmune diseases have low levels of this most important vitamin. “Vitamin B12 deficiency is common among both vegans and meat-eaters alike. The Framingham Offspring Study found that not just vegetarians or older people are deficient in vitamin B12. This study showed no difference in the B12 blood levels of younger and older adults. Most interestingly there was no difference between those who ate meat, poultry, or fish and those who did not eat those foods.” (Jennifer Rooke, MD, November 1, 2014) Read a fascinating article on B12 >


There is an extraordinary BBC documentary available on YouTube about a certain British lady by the name Catherine Iceton who was diagnosed with MS and the disease was so advanced that she used a wheelchair as she couldn’t walk because of the severe nerve damage. She also suffered from depression and blurred vision. She was prescribed immune suppressor drugs but they failed to improve her symptoms leading to some bad side effects. Fortunately, her loving husband didn’t give up but took her to an experienced doctor of Indian origin and when that lady with diagnosed MS explained to him all the details about her disease he remembered that before he moved to England and worked as a physician in India he met some vegetarians or vegans with similar symptoms. In their case, however, the problem wasn’t caused by MS but by vitamin B12 deficiency. And when he prescribed them B12 shots they recovered. He, therefore, concluded that also in her case symptoms were caused by chronic and severe B12 deficiency and not by the autoimmune response (MS). And lo and behold, after a series of hydroxocobalamin B12 shots she completely recovered from all her problems! Normally she had to go to bed at half seven to eight o’clock as she couldn’t keep her eyes open. But after the first injection, she wasn’t tired or sleepy even at 9.30 as vitamin B12 greatly increased her energy and alertness. One night she needed to use the bathroom and surprisingly after waking she just got up on her own and walked to the bathroom forgetting about her wheelchair! And only when she was there she realised she did it without a wheelchair! Soon as a result of B12 supplementation, all the symptoms were gone. She described her experience as “waking up from a nightmare.” At the same time, she also recovered from severe depression, muscle cramps and chronic fatigue.


amazing benefits of Vitamin B1, MS, neurological damage


Vitamin B12 (cobalamin) is reported to help insomniacs who have problems falling asleep as its deficiency can be one of the key causes of insomnia. The research indicated that as a result of taking B12 supplementation total length of sleep decreases while the restorativeness of sleep increases. It is also important to know that many people who are B12 deficient never get into deep sleep, although they may have enough of shallow, non-restorative sleep.
Certain middle-aged Indian lady who suffered from insomnia for about three years asked me once how to cope with this problem as well as constant tiredness. Knowing that she was over 60 and was probably deficient in B12 I recommended her sublingual methylcobalamin. In addition, I also encouraged her to take B complex, Magnesium citrate, some herbs known to help relax the nervous system, and lifestyle changes. When I met her again after about one month she informed me her insomnia was gone. She also told me she decided to find out which supplement was most helpful and she discovered that only whenever she stopped taking methylcobalamin she couldn’t sleep again even if she kept on taking B complex and all other supplements and remedies!
But although deficiency of B12 can cause difficulties with falling asleep and therefore supplementation helps to cope with it yet the same B12 can also cause some problems with sleeping as it increases alertness and energy. For this reason, take B12 (sublingual methylcobalamin is the best) only in the morning and try to not overdose it (not more than 2,000mcg per day). Also, any B vitamin, Chlorella, Ginseng, Acetyl L-carnitine, Fumarate or DHEA and many other energy-boosting supplements and herbs should be taken only in the morning as they all are known to increase energy and mental alertness.


Strict vegetarians often think that they can provide sufficient amounts of this vitamin with seaweed such as spirulina or kelp but unfortunately, studies demonstrated that these rich in B12 plant sources do not contain a biologically active form of this vitamin. Vitamin B12 present in spirulina or other seaweeds can even interfere with the active vitamin B12 forms and thus may contribute to the deficiency development! Also, barley grass powder does not supply sufficient amounts of vitamin B12.

Some sources claim Brewer’s and nutritional yeast are good sources of B12 but the truth is they do not naturally contain B-12 unless they are fortified. But even if they are fortified the amount of B12 is too low to provide sufficient levels of this vitamin.

amazing benefits of Vitamin B12


There seems to be only one bioavailable plant source of vitamin B12 and it is Chlorella. According to the Journal of Medicinal Food (2015) “Vitamin B12 in chlorella is bioavailable and such dietary supplementation is a natural way for vegetarians and vegans to get the vitamin B12 they need.” Since we know that only bacteria are capable of producing vitamin B12, it is, therefore, bacteria which grow in symbiosis with Chlorella that make this vitamin. Chlorella only absorbs B12 made by bacteria and stores it. However, not every Chlorella is believed to contain the bioavailable form of vitamin B12. Only chlorella which is exposed to natural sunlight contains vitamin B12 in its active form.

While there are different species of chlorella, it is recommended to use Chlorella pyrenoidosa (sun chlorella strain). Apart from chlorophyll, the most important constituent of chlorella is the Chlorella Growth Factor (C.G.F.), and it is believed that only Chlorella pyrenoidosa (sun chlorella strain) contains it in large quantities. Tank-cultivated chlorella that doesn’t use sunlight are much lower in CGF and in addition, they shouldn’t also contain an active form of vitamin B12. Apart from a large amount of sunlight, proper cultivation of chlorella requires other important elements such as plenty of clean groundwater, low rainfall, clean air or stable temperature. A so-called subtropical region like the Taiwan area or the South China Sea (not far from Taiwan) has one of the best conditions for culturing chlorella.

Chlorella is also recommended for those who are or might be deficient in B12 as it is the best possible food for intestinal bacterial species able to produce this vitamin. Chlorella helps them to multiply and thrive in the GI tract.

Nevertheless, even if chlorella contains active B12 the amount of this vitamin may not be sufficient for every person as even properly cultivated Chlorella contains only about 1 µg of vitamin B12 per gram of dry Chlorella. If you take about 2 heaped tablespoons or about 20 tablets of good quality Chlorella every day on a regular basis then it is possible that it will be able to prevent B12 deficiency. But since no Chlorella is standardised for B12 content and it is difficult to have a guarantee that Chlorella we use actually contains active B12 and whether it is a sufficient dose I believe it is still wise to take 1000 mcg of sublingual methylcobalamin at least 2 or 3 times a week.


The only one type of bacteria that possesses all the genes for cobalamin (B12) synthesis is Lactobacillus reuteri (naturally can be found in the intestines of many most humans). But fortunately, there are also other probiotic bacterial species, especially Lactic-acid bacteria such as Bifidobacterium, Lactobacillus, or Propionibacterium that are able to synthesise this vitamin and other B vitamins by mutual cooperation and by completing each other’s work.

It is therefore very beneficial for those who want to prevent or increase B12 levels to take good quality probiotic supplements containing the above-mentioned strains.


Published in 1999 Australian study of 245 Seventh-day Adventist ministers, who followed a vegan diet, found that 70 per cent of them were deficient in vitamin B-12. 30%, however, had normal levels of this vitamin in spite of a diet which was completely deprived of B12 sources.

In another experiment, Dr Donaldson tested 54 Health Ministers who had been on the 100% plant-based Hallelujah Diet for B12 adequacy after they had been on the diet for a minimum of two years. His finding revealed that about 50% of those who had been on The Hallelujah Diet for two years or longer showed signs of B12 deficiency. However, it is very interesting that the second half of the participants, who also were on the same completely plant-based Hallelujah Diet, showed no B12 deficiency at all! The very important question to answer, therefore, is: Why do some individuals who are deprived of animal foods for years show some signs of B12 deficiency, while others on the same diet are never deficient in this vitamin?

The answer to this question is not difficult to find if we take into consideration the fact that vitamin B12 (cobalamin) can be manufactured only by certain strains of beneficial probiotic bacteria that normally should live in our intestines and that there are many factors which can increase their number or destroy them. It means that those long-term vegans who are not deficient in B12 must have enough B12-manufacturing probiotic bacteria not only in the large intestines, where it can’t be absorbed but also in their small intestines where B12 can be still absorbed and used by the body.

There is enough evidence that in some cases a sufficient amount of B12 may come from the microflora found in the intestines even though the diet is deprived of B12 sources, and no supplements are taken. In one of the studies by Dr Donaldson, vegan volunteers were given probiotics and some of them (not all) had significantly improved B12 levels without using any food sources of B12 or supplements. It means that proper care for gut flora and taking supplements with live probiotic bacteria with the known ability to produce cobalamin can in a certain type of people be a sufficient source of B12.

It is also important to remember that although it is true that there are bacteria in our intestines that synthesize B-12 yet in order for B12 to be absorbed into the bloodstream the bacteria must reside also in the small intestine. Unfortunately, in many people, they live well beyond the part of the intestine where B-12 is absorbed.

However, although it is true there are some lifelong vegans who do not seem to suffer from B12 deficiencies, it is still safer and wise to use B12 supplements (especially in the form of sublingual methylcobalamin) just to avoid any possible and dangerous consequences, in case bacteria in the small intestines do not make enough of this vitamin. Although bacteria present in the small intestine produce some B12 yet experts suggest that this amount does not always appear to be sufficient. Apart from that, vitamin B12 in the form of supplements is safe, strengthens our nervous system and boosts energy as it often helps to effectively cope with fatigue. Almost every day I encourage different individuals to take B12 in the form of sublingual methylcobalamin and personally know many people who shortly after taking it experienced an energy boost and other benefits.

So, yes, it is possible that vegans may not develop vitamin B12 deficiency through sufficient B12 production by bacteria in the small intestine as well as chlorella supplementation. However, some experts suggest this is still regarded as an unusual condition, especially in Western countries, and therefore, should not be relied upon.

We also know that vegans (including myself) have almost always a much lower white blood cell count than meat-eaters. In the past, I believed that it was so because being on a meat-free diet our bodies have a lower concentration of toxins or pathogens and therefore do not require so many leukocytes in the blood. But, although it may be one of the causes of this phenomenon, yet today I believe that the key reason for low white blood cell count among vegans is rather vitamin B12 deficiency as it is required in our body for all blood cell production, including white blood cells.


Unfortunately, encouraging people to consume animal products to prevent B12 deficiency is not a very wise idea as meat and dairy greatly increase the risk of many dangerous health problems. Apart from that, even animal foods (including meat, dairy, eggs or farmed fish) today are often deprived of B12 as animals are fed with antibiotics which destroy probiotic bacteria in their gut. Studies have shown that those who are on a typical animal-based diet actually require more vitamin B12 than vegans. This is because their diet gradually destroys bacterial flora and leads to the deficiency of stomach acid and digestive enzymes.

According to The American Journal of Clinical Nutrition, “Low vitamin B-12 levels don’t just occur in older people. And contrary to current wisdom, meat, poultry, and seafood may not be a good source of the vitamin. A surprising 39 per cent of participants (3,000 men and women aged 26-83) had blood levels below 350 pg/ml, the level at which neurological signs of B-12 deficiency or high homocysteine levels sometimes occur.”

Because vitamin B12 is peptide bound in animal foods and in order to be absorbed must be enzymatically cleaved from peptide bonds, a deficiency of hydrochloric acid, digestive enzymes and other factors such as transcobalamines greatly contribute to B12 deficiency as it can’t be properly extracted from food. On the other hand, healthy vegans (especially those who consume mostly raw plant foods) have a much stronger digestive system, and healthier bacterial flora in their intestines may actually get more vitamin B12 even though they do not consume animal foods. Unfortunately, not all vegans practice healthy diet and lifestyle principles as they consume products high in refined sugar and bad commercial pro-inflammatory oils, mostly refined and cooked products. In this way, they cause dangerous nutritional deficiencies (including B12) and health problems bringing disgrace to proper veganism. Especially dangerous with regards to B12 is refined sugar as its negative influence can be similar to that of antibiotics due to its damaging effect on the intestinal flora. Since heating (cooking) unrefined plant foods such as vegetables also kill probiotic bacteria it is very difficult for vegans who consume mostly cooked foods to maintain healthy bacterial balance in their intestines.

amazing benefits of Vitamin B12


The two known biologically active forms of B12 are methylcobalamin and adenosylcobalamin. Other forms, such as cyanocobalamin or hydroxocobalamin (aquacobalamin) must be first metabolized to either of the two active forms in order to be used in our body.

Some experts maintain that the most common and inexpensive cyanocobalamin (much cheaper than methylcobalamin) is difficult for the body to absorb, and the small amount that is absorbed usually fails to find its way into the cells. As a result, many people who take even large doses of cyanocobalamin may continue to be deficient in B12. I don’t want to suggest that cyanocobalamin doesn’t work at all but that supplementing our body with this form of B12 requires more time and higher doses. In addition, since cyanocobalamin is not a natural form, it has to be converted in our body to the physiological forms (methylcobalamin and adenosylcobalamin), leaving behind the cyanide which has to be removed from the body. However, separating cyanide from cobalamin (B12) and flushing it out of your body requires using methyl groups of molecules that are needed to fight things like homocysteine which greatly increases the risk of heart attacks and strokes. Therefore, taking the cyanocobalamin form of B12, we actually deprive our body of very beneficial methyl groups.

On the other hand, a 2003 study (>) compared 500 µg per day via the sublingual (under the tongue) and oral routes. Sublingual fared no better than oral B12 at raising B12 levels or improving B12 activity (as measured by homocysteine and methylmalonic acid levels). Both routes effectively increased B12 levels (>).

As far as supplements are concerned methylcobalamin is regarded as the final and therefore the most bio-available form of vitamin B12 (cobalamin), and when dissolved under the tongue it is not lost in the digestive process but gets straight into the bloodstream significantly increasing its absorption and effectiveness. Since methylcobalamin can also be absorbed via the oral mucosa, it is available in the form of lozenges, sublingual tablets or drops. Whether this actually has any therapeutic advantages is still to be proven, since the relevant studies have not yet been carried out. However, it is suggested that lozenges or sublingual tablets could be the best form because methylcobalamin may not be chemically stable in the stomach and intestines. Unfortunately, we are no sure as this claim seems to be contradicted by studies which have recorded good absorption of methylcobalamin from the intestines.

Additionally, methylcobalamin plays an important role in detoxifying our body from heavy metals and lowering the homocysteine, which is known to contribute to cardiovascular problems when its levels are too high. In addition, methylcobalamin is the only form of B12 which can directly participate in homocysteine metabolism. Also, converting homocysteine to methionine via methyl B12 increases the supply of SAMe (S-adenosyl methionine), regarded as the body’s most important methyl donor.

Some suggest that the most biologically active form of vitamin B12 is neither cyanocobalamin nor methylcobalamin but hydroxocobalamin because our body can dispose this form of B12 more efficiently. Others, however, oppose this idea by explaining that hydroxocobalamin is completely unstable when put in a tablet or capsule, and can only be taken by injection. This is the reason, they say, why we can’t find hydroxocobalamin in a nutrition supplement made by an honest company.

There is also a notion that methylcobalamin works best for most people but may not work for all possibly because their bodies need two forms of cobalamin – methyl and adenosyl as they aren’t able to convert methyl to adenosyl form of cobalamin.

B-12 is also available in the form of injections but this method requires a trained medical professional, so only few people are willing to pursue this route. Sublingual methylcobalamin, therefore, seems to be the best and most convenient way of dealing with the problem of B12 deficiency.


Some experts who studied the subject for decades suggest that “normal” B12 blood levels is set way too low and should be raised from 150 ng/l to over 350 ng/l. This reasonable advice is based on the fact that symptoms of B12 deficiency often start to appear even when blood levels are way over 150 ng/l or slightly below 300 ng/l!

We also need to take into consideration the fact that pseudo vitamin B12 from spirulina, tempeh, nori, etc. give positive B12 blood test results in spite of active B12 deficiency.

High blood levels of folate (folic acid) can make the complete blood count (CBC) test appear normal even though a B12 deficiency exists.

B12 serum testing can also show falsely elevated results for patients with underlying liver disease, alcoholism, lymphoma or harmful intestinal bacteria overgrowth.


Unfortunately, regular medical tests of B12 levels in the blood can be often inaccurate not only because of wrong norms, which are way too low, but also due to many different possible factors such as high blood levels of folic acid, presence of pseudo forms of B12 (analogues) in the blood (from dietary sources such as spirulina, nori, sea vegetables, etc.) as they can give a falsely high reading of B12 in the blood.

Additionally, increased homocysteine levels, neurological damage and other symptoms can start taking place long before people are diagnosed with anaemia or even if they are told to have normal B12 levels.

The most reliable, therefore, suggested way to find out B12 deficiency is testing the blood homocysteine and MMA (methylmalonic acid) levels as both substances increase when B12 is deficient.


The recommended daily intake for Vitamin B12 for adults is 2.4µg. Knowing that the recommended daily intake for this vitamin is so small (only 2.4µg), many people wonder why the suggested supplemental amount of this vitamin is so high (1000-2000µg per day). It is so because the recommended daily amount of 2.4µg stands for the actually absorbed vitamin B12. However, since only about 1% of this vitamin from supplements is actually absorbed the amount we should take to get enough B12 must be much higher. In addition, only certain percentage of the absorbed amount is usable by the body. And, even if we absorb more than we need, the body will remove the excess with urine without any side effects.


Depending on your diet, lifestyle and all the mentioned above factors which may influence the absorption of vitamin B12 I would recommend taking about 1000 mcg to 2000 mcg of active vitamin B12 supplement (in the form of sublingual methylcobalamin) every day or every other day only after breakfast (all B vitamins should be taken only in the morning as otherwise they may sometimes interfere with sleeping as they increase energy levels for a longer time during the day).

Though RDA for adults is only 2.4 µg of vitamin B12 per day the suggested above amount (1000-2000mcg) is hundreds of times higher because only about 1 per cent of ingested B12 from supplements is absorbed while all the rest is removed with urine. In addition, only certain percentage of the absorbed amount is usable by the body.

Those who are already deficient in this vitamin and experience anaemia and symptoms associated with deficiency should take even higher dosages of about 5,000mcg of sublingual methylcobalamin per day until recovery from symptoms. After that 1,000 to 2,000 mcg per day should be sufficient to prevent deficiency.

B-12 is stored in the liver, blood and muscles. Every day we lose about 0.2% of our cobalamin stores. It means that if we don’t regularly supply our body with this vitamin we will eventually cause deficiency and its consequences.


When high doses of vitamin B12 are given orally, only a small percentage can be absorbed, which may explain extremely low toxicity of this vitamin. Because of the low toxicity of vitamin B12, no tolerable upper intake level has been set by the US Food and Nutrition Board.

In EU countries, the safe upper intake (limit) from supplements is set at 2000mcg per day.


Vitamin B12 supplements are regarded as incredibly safe, even at very high doses. While doctors usually prescribe 0.5 to 1mg, in some studies doses of up to 40 mg per day (40,000 micrograms) were used with no side effects!

Some individuals who overdose vitamin B12 (over 3000 IU daily) for a long time may experience burning feet symptom which should stop 1-3 days after avoiding the supplementation or at least reducing daily doses to 500mcg – 1000mcg daily.

Also, some individuals with peripheral neuropathy may initially experience worsening of the burning feet but for a short time as it may be just a sign that B12 starts regenerating the damaged nerves thus making them more sensitive.


Though it may be cheaper and easier to just take something once a week, some people would rather get into the habit of doing something daily, so they don’t forget. So, how much vitamin B12 would you have to take if you wanted to do it once a day, rather than once a week?

Well, using the formula we just learned, 1.5 plus 0.1 times the quantity (x minus 1.5) equals 4 to 7; solve for x. I’ll wait. Once a day, 250 micrograms or more is all we need. You can put it next to your toothbrush to remind yourself.

The reason we can’t absorb more than about 1.5 at a time directly through our receptors is that they get filled up. But it only takes them about four to six hours to unload their cargo into the body, and then they’re back in business.

So if we got B12 three times a day—breakfast, lunch, and dinner—we could absorb 1.5 each time and end up with 4.5 at the end of the day, which is all we need. And those kind of doses we can get from fortified foods.

The so-called “daily value” on Nutrition Facts labels for B12 is 6 micrograms. So, as long as each serving contains 25% of our daily value, then we can eat a serving of B12-fortified foods at every meal, and we wouldn’t have to take supplements at all!

So, for example, there’s a vitamin B12-fortified nutritional yeast. Two teaspoons counts as a serving, so you could sprinkle that on your meals. But that would cost a few dollars a week, as opposed to just a few pennies a week for B12 supplements.

Whichever path you choose, these are not just recommendations for people eating plant-based diets. They’re for anyone who wants to get a cholesterol-free source of vitamin B12.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the VIDEO >


The cyanocobalamin form of B12 contains traces of cyanide, which is a poisonous substance. Because of this, some concerns have been raised about its possible toxic effects. However, many fruits and vegetables contain these traces, and it is not considered a significant health risk.


Taking B12 supplements remember that you need more potassium as potassium and methylcobalamin are antagonists. More methylcobalamin equals less potassium and vice versa. However, if you consume a big bowl of raw vegetable salad every day the problem of potassium should be solved.

Although vitamin B12 is considered very safe, taking only one of any B vitamins for a long period of time can result in an imbalance of other B vitamins. It is, therefore, recommended to take B12 with a good B complex formula or multivitamins and minerals (such as Healthy Mega) that include all B vitamins.

Also if you take 400-800mcg of folic acid on a regular basis you need to take B12 as high doses of folic acid can mask B12 deficiency.

Because of the potential interactions with medications, you should take B12 supplements only under the supervision of a knowledgeable healthcare provider.

For instance, vitamin B12 should not be taken at the same time as antibiotic tetracycline because it interferes with its absorption and effectiveness. All vitamin B complex supplements act in this way and must be taken at different times than tetracycline.

Normally B12 is very beneficial for maintaining eye health but in people with Leber’s disease (a disease of the eye), B12 supplements can cause damage to the optic nerve.


– Vitamin B12 (Cobalamin) is required by folic acid (B12 deficiency leads to folic acid deficiency). Vitamin B12 is responsible for converting folic acid back into its bioactive form after various reactions – in other words, it reactivates it.

Without vitamin B12, the body quickly suffers a functional folic acid deficiency, since the folic acid is left stuck inside our body in its unusable form. There is clearly enough folic acid present, but it cannot be converted!       

– Supplementing with B12 increases the need for folic acid and vice versa because both play key roles in the methylation cycle.

– B12 requires B6 for absorption.

Vitamin E is required for the conversion of inactive B12 to the active form.

Folic acid masks B12 deficiency (in people who take folic acid supplements and are deficient in B12 it is very difficult to detect B12 deficiency).

More than 1,000 mcg of supplemental folic acid per day can cause symptoms of B12 deficiency.

– In an aqueous solution, vitamin C might degrade B12 especially when B1 and copper are also present.

– B12 in the form of adenosylcobalamin requires biotin for conversion.


Bacteria (living in water, soil, and the digestive tracts of humans and animals), are the only organisms known to manufacture Vitamin B12.

When humans eat animal foods, the B12 present in these foods is bound to protein. When the protein-B12 complex reaches the stomach, the stomach must have enough hydrochloric acid and enzymes to be able to detach the B12 from that protein.

Then, in a process unique to B12, another protein, R-protein (cobalophilin, haptocorrin, and transcobalamin I), found in saliva and stomach, picks up the B12 and transports it through the stomach and into the small intestine.

The stomach cells also produce a protein called intrinsic factor (IF), which travels to the small intestine where it liberates B12 from R-protein complex and carries the cobalamins to the last section of the small intestine, the ileum. The intrinsic factor, apart from transporting B12, also protects it against bacterial and digestive enzyme degradation.

The cells lining the ileum contain receptors for the cobalamin-IF complex where the cobalamin (B12) is finally absorbed into the blood which transports it to various body cells.


In supplements, B12 (cobalamin) is not bound to protein and therefore does not need digestive enzymes or stomach acid to be detached from a protein.

When taken in large enough doses, unbound cobalamin can overcome intrinsic factor defects and deficiency and part of it is absorbed through passive diffusion.


There is evidence that unbound B12, especially when combined with an absorption enhancer, can be directly absorbed through the membranes under the tongue at higher rates than through passive diffusion in the digestive tract. The best example of this kind of sublingual form of Vitamin M12 is Methylcobalamin.


After B12 is absorbed into the intestinal cells, it attaches itself to transcobalamin II, made in the intestinal cells. Transcobalamin II then transports B12 to all body tissues through the blood and cerebrospinal fluid.

Once the B12-Transcobalamin II complexes arrive at the cell, B12 is released from in the form of hydroxocobalamin. It is then converted into methylcobalamin or adenosylcobalamin and used for their respective enzymes.

Transcobalamin II also transports B12 to the liver for storage on transcobalamin III.


Crane et al. (1994) noted that tablets of one vitamin company dissolved slowly in water and acid. They conducted a study to see if vegan patients who hadn’t previously responded to swallowing B12 tablets whole could improve their B12 levels by chewing the tablets. Of 16 participants, 7 chewed tablets of 100 µg once a week for 6 weeks; their average serum B12 levels increased from 86 to 216 pmol/l. Of the 9 who didn’t chew, their serum B12 increased from 91 to only 103 pmol/l. However, a 100 µg dose once a week isn’t much; the more surprising result of this experiment was the large increase in the serum B12 of the 7 people who chewed. Of the 9 who originally didn’t chew, 7 of them then chewed 500 µg/day for 10 days and their levels rose to normal with a final average of 388 ± 174 pmol/l. Three participants couldn’t raise their levels orally and required B12 injections to maintain serum B12 above 222 pmol/l. A 2003 study compared 500 µg per day via the sublingual (under the tongue) and oral routes. Sublingual fared no better than oral B12 at raising B12 levels or improving B12 activity (as measured by homocysteine and methylmalonic acid levels). Both routes effectively increased B12 levels (Sharabi, 2003).





Vitamin B12 Absorption >

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What Every Vegan Should Know about Vitamin B12,

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The more detailed Catherine Iceton experience (mentioned above) >

In a BBC One documentary, ‘Inside Out’, which can be seen on You Tube, Catherine Iceton, of Horden, Britain, had been diagnosed with multiple sclerosis. “I could not see or walk properly,” says the mother of two. “My life had come to a standstill.” Seven years went past.

In August, 2006, she came under the care of the Pala-born Dr. Joseph Chandy Kayalackakom, the general physician in the National Health Service (NHS) at Horden. “As soon as I saw her I knew she had a Vitamin B 12 deficiency,” he says.

A blood test revealed that Catherine had a B 12 level of 175 nanogram per litre (ng/l). This was far lower than the normal 500 to 1000 ng/l. Immediately Dr. Chandy put her on 1000 mg injections every day. Within a matter of weeks, there was an unbelievable impact. Catherine was able to walk, and her eyesight was restored. “The nightmare was over,” she says.

The Vitamin B 12 deficiency is little known. And Dr. Chandy stumbled over it by accident. At the Medical College in Alleppey, in 1966, he came across patients who suffered from multiple sclerosis and other neurological disorders. On a sudden inspiration, he checked their Vitamin B 12 levels and discovered that it was very low. He began giving injections and the patients improved quickly. Interestingly, all the patients were vegetarians, but that did not surprise Dr. Chandy.

The B 12 vitamin can only be obtained from red and white meat, milk, eggs, and fish,” says Dr. Chandy, while on a brief visit to Kochi. “So, there is a strong likelihood that vegetarians could have this deficiency.”

Apart from the drawbacks of a vegetarian diet, many people lack an enzyme in the stomach which helps to absorb the B 12. “It is for this reason that among meat-eating Caucasians, 20 to 40 per cent of the population suffers from a B 12 deficiency,” says Dr. Chandy. The absence of this enzyme can be a genetic trait. “That means that if a mother lacks it, there is a strong possibility that her children will also be B 12 deficient,” he says.

So what are the symptoms of this deficiency? “Tiredness, extreme fatigue, depression, and low moods,” says Dr. Chandy. Other signs include dizziness, hair loss, numbness in the hands and feet, mouth ulcers, palpitations of the heart, diarrhoea and burred vision. “It affects every gland and system,” he says.

Incidentally, 80 per cent of Dr. Chandy’s patients are women. “They have more glands than men,” he says. “They have breasts, ovaries, and the uterus. Women have menstrual periods and menopause, and they go through childbirth. All these adjustments causes disturbance to the metabolism. So they are more vulnerable.”

Meanwhile, not everybody was convinced about this diagnosis of Dr. Chandy. In the NHS the rule is that Vitamin B 12 treatment can be prescribed only if the deficiency is 150 ng/l, but the doctor was treating patients even with a count of 300 ng/l. So, he was barred from administering the B 12 by the Primary Care Trust (which is a part of the NHS). Immediately, some patients, who were suffering from multiple sclerosis, went back to their wheelchairs, because of the lack of the vitamin.

“I would have been sacked a long time ago, but I had kept meticulous records of my patients over the years,” he says. Now, the Primary Care Trust has allowed Dr. Chandy to continue, having realised that there is nothing wrong in the treatment. The doctor says that it is a lack of awareness in the medical fraternity that has caused so much of problems for him. “But my best witnesses are my patients,” he says. “Talk to them and they will vouch for the effectiveness of my treatment.”

In Kochi, Thomas George (name changed) had suffered from a debilitating nerve condition. Thomas had an accidental meeting with Dr. Chandy on a previous visit a few months ago. A blood test revealed a figure of 175 ng/l for B 12. The doctor immediately recommended injections.

“I was sceptical,” says Thomas. But he did a lot of research on the Internet and was finally convinced. After two months of injections, the tremors have stopped. “My health has improved remarkably,” says Thomas.

Now, after 30 years, Dr. Chandy is finally receiving recognition for his work. In September, the India International Friendship Society conferred their ‘Glory of India’ award to Dr. Chandy for his outstanding contribution to Britain.

On November 19, Prime Minister David Cameron invited Dr. Chandy, along with several other prominent Asians, to celebrate Diwali at 10 Downing Street. Dr. Chandy took the opportunity to tell Cameron about the miracle vitamin.




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