B12
Very low B12 intakes can cause anaemia and nervous system damage.

The only reliable vegan sources of B12 are foods fortified with B12 (including some plant milks, some soy products and some breakfast cereals) and B12 supplements. Vitamin B12, whether in supplements, fortified foods, or animal products, comes from micro-organisms.

Most vegans consume enough B12 to avoid anaemia and nervous system damage, but many do not get enough to minimise potential risk of heart disease or pregnancy complications.

•eat fortified foods two or three times a day to get at least three micrograms (μg or mcg) of B12 a day or
•take one B12 supplement daily providing at least 10 micrograms or
•take a weekly B12 supplement providing at least 2000 micrograms.

If relying on fortified foods check the labels carefully to make sure you are getting enough B12. For example, if a fortified plant milk contains 1 microgram of B12 per serving then consuming three servings a day will provide adequate vitamin B12. Others may find the use of B12 supplements more convenient and economical.

The less frequently you obtain B12 the more B12 you need to take, as B12 is best absorbed in small amounts. The recommendations above take full account of this. There is no harm in exceeding the recommended amounts or combining more than one option.

Good information supports vegan health, pass it around.

If you don't read another word about B12 you already know all you need to know. If you want to know more, read on.

This information was prepared by Stephen Walsh, a UK Vegan Society trustee, and other members of the International Vegetarian Union science group (IVU-SCI), in October 2001. This information may be freely reproduced but only in its entirety (list of endorsers may be omitted).

Endorsers

Note for participants in the King's College study


Vitamin B12 and vegan diets
Lessons from history
B12 is an exceptional vitamin. It is required in smaller amounts than any other known vitamin. Ten micrograms of�� B12 spread over a day appears to supply as much as the body can use. In the absence of any apparent dietary supply, deficiency symptoms usually take five years or more to develop in adults, though some people experience problems within a year. A very small number of individuals with no obvious reliable source appear to avoid clinical deficiency symptoms for twenty years or more. B12 is the only vitamin that is not recognised as being reliably supplied from a varied wholefood, plant-based diet with plenty of fruit and vegetables, together with exposure to sun. Many herbivorous mammals, including cattle and sheep, absorb B12 produced by bacteria in their own digestive system. B12 is found to some extent in soil and plants. These observations have led some vegans to suggest that B12 was an issue requiring no special attention, or even an elaborate hoax. Others have proposed specific foods, including spirulina, nori, tempeh, and barley grass, as suitable non-animal sources of B12. Such claims have not stood the test of time.

In over 60 years of vegan experimentation only B12 fortified foods and B12 supplements have proven themselves as reliable sources of B12, capable of supporting optimal health. It is very important that all vegans ensure they have an adequate intake of B12, from fortified foods or supplements. This will benefit our health and help to attract others to veganism through our example.


Getting an adequate amount of B12
National recommendations for B12 intakes vary significantly from country to country. The US recommended intake is 2.4 ��gs a day for ordinary adults rising to 2.8 ��gs for nursing mothers. The German recommendation is 3 ��gs a day.�� Recommended intakes are usually based on 50% absorption, as this is typical for small amounts from foods. To meet the US and German recommendations you need to obtain sufficient B12 to absorb 1.5 ��gs per day on average. This amount should be sufficient to avoid even the initial signs of inadequate B12 intake, such as slightly elevated homocysteine and MMA levels, in most people. Even slightly elevated homocysteine is associated with increased risk of many health problems including heart disease in adults, preeclampsia during pregnancy and neural tube defects in babies.

Achieving an adequate B12 intake is easy and there are several methods to suit individual preferences. Absorption of B12 varies from about 50%, if about 1 ��g or less is consumed, to about 0.5% for doses of 1000 ��gs (1 mg) or above. So the less frequently you consume B12, the higher the total amount needs to be to give the desired absorbed amount.

Frequent use of foods fortified with B12 so that about one microgram of B12 is consumed three times a day with a few hours in between will provide an adequate amount. Availability of fortified foods varies from country to country and amounts of B12 vary from brand to brand, so ensuring an adequate B12 supply from fortified foods requires some label reading and thought to work out an adequate pattern to suit individual tastes and local products.

Taking a B12 supplement containing ten ��gs or more daily provides a similar absorbed amount to consuming one ��g on three occasions through the day. This may be the most economical method as a single high potency tablet can be consumed bit by bit. 2000 ��gs of B12 consumed once a week would also provide an adequate intake.�� Any B12 supplement tablet should be chewed or allowed to dissolve in the mouth to enhance absorption. Tablets should be kept in an opaque container. As with any supplement it is prudent not to take more than is required for maximum benefit, so intakes above 5000 ��g per week should be avoided despite lack of evidence for toxicity from higher amounts.

All three options above should meet the needs of the vast majority of people with normal B12 metabolism. Individuals with impaired B12 absorption may find that the third method, 2000��g once a week, works best as it does not rely on normal intrinsic factor in the gut. There are other, very rare, metabolic defects that require completely different approaches to meeting B12 requirements. If you have any reason to suspect a serious health problem seek medical advice promptly.

Symptoms of B12 deficiency
Clinical deficiency can cause anaemia or nervous system damage. Most vegans consume enough B12 to avoid clinical deficiency. Two subgroups of vegans are at particular risk of B12 deficiency: long-term vegans who avoid common fortified foods (such as raw food vegans or macrobiotic vegans) and breastfed infants of vegan mothers whose own intake of B12 is low.

In adults typical deficiency symptoms include loss of energy, tingling, numbness, reduced sensitivity to pain or pressure, blurred vision, abnormal gait, sore tongue, poor memory, confusion, hallucinations and personality changes. Often these symptoms develop gradually over several months to a year before being recognised as being due to B12 deficiency and they are usually reversible on administration of B12. There is however no entirely consistent and reliable set of symptoms and there are cases of permanent damage in adults from B12 deficiency. If you suspect a problem then get a skilled diagnosis from a medical practitioner as each of these symptoms can also be caused by problems other than B12 deficiency.

Infants typically show more rapid onset of symptoms than adults. B12 deficiency may lead to loss of energy and appetite and failure to thrive. If not promptly corrected this can progress to coma or death. Again there is no entirely consistent pattern of symptoms. Infants are more vulnerable to permanent damage than adults. Some make a full recovery, but others show retarded development.

The risk to these groups alone is reason enough to call on all vegans to give a consistent message as to the importance of B12 and to set a positive example. Every case of B12 deficiency in a vegan infant or an ill informed adult is a tragedy and brings veganism into disrepute.

The homocysteine connection
This is not however the end of the story. Most vegans show adequate B12 levels to make clinical deficiency unlikely but nonetheless show restricted activity of B12 related enzymes, leading to elevated homocysteine levels. Strong evidence has been gathered over the past decade that even slightly elevated homocysteine levels increase risk of heart disease and stroke and pregnancy complications. Homocysteine levels are also affected by other nutrients, most notably folate. General recommendations for increased intakes of folate are aimed at reducing levels of homocysteine and avoiding these risks. Vegan intakes of folate are generally good, particularly if plenty of green vegetables are eaten. However, repeated observations of elevated homocysteine in vegans, and to a lesser extent in other vegetarians, show conclusively that B12 intake needs to be adequate as well to avoid unnecessary risk.

Testing B12 status
A blood B12 level measurement is a very unreliable test for vegans, particularly for vegans using any form of algae. �� Algae and some other plant foods contain B12-analogues (false B12) that can imitate true B12 in blood tests while actually interfering with B12 metabolism. Blood counts are also unreliable as high folate intakes suppress the anaemia symptoms of B12 deficiency that can be detected by blood counts. Blood homocysteine testing is more reliable, with levels less than 10 mmol/litre being desirable. �� The most specific test for B12 status is methylmalonic acid (MMA) testing. If this is in the�� normal range in blood (<370 nmol/L) or urine (less than 4 mg /mg creatinine) then your body has enough B12. Many doctors still rely on blood B12 levels and blood counts. These are not adequate, especially in vegans.

Is there a vegan alternative to B12-fortified foods and supplements?
If for any reason you choose not to use fortified foods or supplements you should recognise that you are carrying out a dangerous experiment - one that many have tried before with consistently low levels of success. If you are an adult who is neither breast-feeding an infant, pregnant nor seeking to become pregnant, and wish to test a potential B12 source that has not already been shown to be inadequate, then this can be a reasonable course of action with appropriate precautions. For your own protection, you should arrange to have your B12 status checked annually. If homocysteine or MMA is even modestly elevated then you are endangering your health if you persist.

If you are breast feeding an infant, pregnant or seeking to become pregnant or are an adult contemplating carrying out such an experiment on a child, then don't take the risk. It is simply unjustifiable.

Claimed sources of B12 that have been shown through direct studies of vegans to be inadequate include human gut bacteria, spirulina, dried nori, barley grass and most other seaweeds. Several studies of raw food vegans have shown that raw food offers no special protection.

Reports that B12 has been measured in a food are not enough to qualify that food as a reliable B12 source. It is difficult to distinguish true B12 from analogues that can disrupt B12 metabolism. Even if true B12 is present in a food, it may be rendered ineffective if analogues are present in comparable amounts to the true B12. There is only one reliable test for a B12 source - does it consistently prevent and correct deficiency? Anyone proposing a particular food as a B12 source should be challenged to present such evidence.

A natural, healthy and compassionate diet
To be truly healthful, a diet must be best not just for individuals in isolation but must allow all six billion people to thrive and achieve a sustainable coexistence with the many other species that form the "living earth". From this standpoint the natural adaptation for most (possibly all) humans in the modern world is a vegan diet. There is nothing natural about the abomination of modern factory farming and its attempt to reduce living, feeling beings to machines. In choosing to use fortified foods or B12 supplements, vegans are taking their B12 from the same source as every other animal on the planet - micro-organisms - without causing suffering to any sentient being or causing environmental damage.

Vegans using adequate amounts of fortified foods or B12 supplements are much less likely to suffer from B12 deficiency than the typical meat eater. The Institute of Medicine, in setting the US recommended intakes for B12 makes this very clear. "Because 10 to 30 percent of older people may be unable to absorb naturally occurring vitamin B12, it is advisable for those older than 50 years to meet their RDA mainly by consuming foods fortified with vitamin B12 or a vitamin B12-containing supplement." Vegans should take this advice about 50 years younger, to the benefit of both themselves and the animals. B12 need never be a problem for well-informed vegans.

Vegans and the Vitamin B12 Deficiency Myth
Last updated 2008

It seems there's always at least one tired old myth making the rounds about vegetarianism. Twenty years ago when I switched, it was the "protein deficiency" myth. Now that the protein myth has been completely discredited (human breast milk is only 5% protein, and it is estimated that adult humans only need 2-3% protein in their daily diet), these days the vitamin B12 myth occasionally surfaces. Usually it's only preached in places like very old doctors' offices or talk radio shows dominated by heavy recommendations for drugs and dairy products, but the question still comes up. Of the thousands of people who visit this web site every month, a few always find me with the search string "vegans B12 deficiency". (The sickle cell anemia page mentions B12 in its title.)

Deficiencies at Large
A small number of people develop B12 deficiencies, most of them not vegans, just like people with deficiencies in every other type of vitamin and mineral. Ever heard a dieter say that his or her hair fell out while dieting? That's borderline scurvy, a Vitamin C deficiency. Any friends or relatives have white hair, wrinkles, maybe an aneurysm? That's copper deficiency. Know anyone with cystic fibrosis (CF)? His or her mother suffered a selenium deficiency before and/or during their pregnancy. Vitamin deficiencies are as common as bad health in general; in fact, they cause a good chunk of the bad health these days.

B12 Deficiency: A Lengthy Process
B12 (also called cobalamin due to its central cobalt atom) is a water-soluble vitamin with a very low recommended daily intake requirement, about 2-3 micrograms per day. That's MICROgrams, not milligrams. In addition to having extremely low intake requirements, Vitamin B12 is stored in the liver, kidneys, and muscle tissue, and most B12 (65-75%) is reabsorbed by the body instead of excreted. A deficiency could take from 5 to 20 years of inadequate intake to develop. The deficiency could be masked by adequate folic acid intake, as the two vitamins work together, but only temporarily. Eventually a B12 deficiency manifests as nerve damage and pernicious anemia, a very serious type of anemia where red blood cells are improperly formed and white blood cell count is low.

Bacteria: Myth vs. Reality
So how could anyone develop pernicious anemia when B12 intake requirements are so low, and when the liver stores so much that it takes years for a deficiency to develop? The reason touted for the B12 myth is that B12 is found primarily in animal foods. Very few plant foods provide good sources of B12, they say. In a way that's true, but only because the source of B12 is not plants OR animals; neither manufacture their own B12. In the B12 reality, Bacteria are the B12 producers on which both plants and animals rely. And in humans, that bacteria doesn't necessarily come from plants -- the mouth, upper intestine, and lower intestine all contain bacteria that produce B12. However, it's unknown if enough B12 to meet the daily requirement comes from internal sources of B12. More likely, they produce some, and the rest comes in with food and water consumed.

All of the Vitamin B12 in the world ultimately comes from bacteria. Neither plants nor animals can synthesize it. But plants can be contaminated with B12 when they come in contact with soil bacteria that produce it. Animal foods are rich in B12 only because animals eat foods that are contaminated with it or because bacteria living in an animal's intestines make it.
-- From The Vegetarian Way: Total Health for You and Your Family (1996), Virginia Messina, MPH, RD, & Mark Messina, PhD p. 102

The Causes
Most people with B12 deficiencies and/or pernicious anemia are NOT vegans. Very few vegans have pernicious anemia. B12 deficiencies occur primarily when:
1.) Something is competing for your B12 (like parasites);
2.) Something is destroying your B12 (like cyanide in cigarettes); or
3.) Something is preventing the proper absorption of B12 (like inadequate production of intrinsic factor).

It's possible that vegans may be more susceptible to these three factors, as vegans don't consume huge quantities of B12 to counteract such problems (unless they use vitamin supplements). I assume it's also possible that any depletion of intestinal bacteria, for example from lengthy courses of antibiotics, might lead to a drop in B12 production, although I haven't yet found any other author mentioning this as a contributing factor. However, even with these factors present in vegans as well as the population at large, very few vegans develop B12 deficiencies. Most recent books I've found refer to parasites and intrinsic factor (IF) production problems as the common culprits.

1. Competition (Parasites)
Hulda Clark, the famous research scientist who uses radio resonance in vivo to determine microorganisms involved in cancer, AIDS, and other diseases, finds the parasite Ascaris (a worm-like parasite) is usually involved in cases of pernicious anemia:

Each red blood cell is shaped like a doughnut without the hole. This fits a lot more oxygen, O2, than round balls would. Yet, if there isn't enough vitamin B12, the dimple isn't put into them to make them doughnut shaped. This reduces the body's oxygen supply and the disorder is called "pernicious" anemia. The changed shape of the red blood cells is reflected in a bigger volume called mean cell volume (MCV). The correct volume for red blood cells is about 90 cubic microns. Many elderly persons have a MCV over 100!

I have seen pernicious anemia to be associated with Ascaris infestation. Kill Ascaris on a frequency generator (408 KHz) or zap. The source of Ascaris is usually a pet, owned in the past. Once infected, the tiny worms do not leave your body on their own. The infestation may date back to childhood. What a relief for the bone marrow whose job it is to make red blood cells to have enough vitamin B12 again! What does Ascaris do with your B12? B12 is a beautiful rose colored vitamin. Some worms are actually pink from absorbing your B12! Giving B12 shots is the current clinical treatment for B12 deficiency. Killing Ascaris twice a week by zapping and taking B12 lozenges is a better solution.
-- From The Cure for All Diseases (1995), Hulda Clark, PhD, ND, p. 285

One thing to note about Hulda Clark is that she is NOT an advocate for vegetarianism (although she does concede that meat carries far more parasites and bacteria than vegetable matter). If Clark thought veganism was involved in pernicious anemia, or that people need to eat meat products to avoid it, she would have said so.


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2. Destruction
Another cause of B12 deficiency could be destruction of the Vitamin due to dietary or environmental factors. For example, smoking, high protein diets, alcohol consumption, chlorinated water (disruption by chloroform), and diarrhea may deplete B12.

3. Absorption Problems
Other than parasites, the most common cause of B12 deficiency is absorption problems. In order to properly absorb B12, the stomach produces a special "intrinsic factor" that, with adequate calcium, promotes the absorption of B12 in the small intestine. Intrinsic factor production problems are often related to stomach problems in the elderly.

The Cautious Path
So what's a vegan to do for B12? Less rinsing of fruits and vegetables is a bad idea. Bacterial food poisoning is much less common with vegetables than meat, but it can still occur with vegetables. The body might produce enough B12 from its own bacteria and naturally-occuring bacteria on food (rinsing doesn't remove all of it), but I like to play it safe. Personally, I believe in vitamin supplementation for a number of reasons. In their book Rare Earths, Forbidden Cures, Joel Wallach, DVM, ND and Ma Lan, MD, MS cover the uneven distribution of minerals in the earth's crust. Wallach and Lan believe that mineral supplementation is absolutely necessary, as even pristine farmland usually doesn't contain all the needed minerals.

I take an occasional multi-vitamin -- a GOOD multi-vitamin that's bought at a health food store or mail-ordered, with plenty of colloidal or chelated minerals. Although I'm not the best at taking pills (sometimes I don't take my vitamins more than a few times a month), I eat a lot of organic fruits, vegetables, legumes, nuts, etc. Not all vegans make the effort to eat healthy. Vegans who eat a lot of processed, nutrient-poor foods and take no vitamins put themselves at risk for a number of deficiency diseases.

Personal Experience
One of these days, I want to start a "Pam the Lab Rat" series, where I describe alternative medicine I've tried on myself and how it worked for me, like the Hulda Clark-style Zapper (an excellent device). In the meantime, I'll cover how my limited vitamins and good diet work out for me in relation to any B12 deficiency:

I didn't go completely vegan until early 1997. Until that time, for years all I'd eat in the way of animal products was "a little cream in my coffee". It's now 2003, 6 years later, and my only health problems are leftovers from physical accidents -- a trip-and-fall, and two auto accidents (1998 and 2002). In 1999, a physician treating me for the 1998 auto accident couldn't believe that some of my neurological symptoms weren't caused by a B12 deficiency. Somehow she believed that all vegans had B12 deficiencies. So she ordered a full, very expensive liver panel on me. The readings all came back perfect, of course. Then several months later, a chiropractor fixed up 100% of my symptoms in question with chiropractic adjustments, and with only a few visits! That's the problem with traditional doctors -- they know almost nothing about nutrition. (A vegan's been in an auto accident, therefore her injuries must be from vegetarianism? What kind of logic is that?) From what's been written about medical education, sometimes MDs might be offered an *optional* class on nutrition in medical school, but they often don't attend, because that's a lowly nutritionist's job...

B12 Facts
Here are a few functions of Vitamin B12: proper formation of red blood cells, manufacture of DNA, formation of fatty insulation surrounding nerve cells, detoxification of cyanide from cigarettes and food, cancer prevention, nervous system health, proper growth, prevention of PMS, posture and balance, memory and concentration, proper cell division, sperm production and motility.

Some B12 deficiency symptoms: pernicious anemia, diarrhea, fatigue, nerve damage, depression, PMS, heart disease, trembling, low sperm count or poor sperm motility, and a sore red tongue.

What If?
The above functions and symptoms of B12 are only partial lists. If you suspect you may have a B12 deficiency, it's best to consult both reference materials and your doctor, as doctors are often poor sources on nutritional deficiencies. A doctor, however, can determine whether your symptoms are actually a B12 deficiency or a different disorder.


Special note
PAM's RESPONSE TO READER FEEDBACK, 22 November 2008: Over the years, less than a dozen people have written to me, convinced that their pernicious anemia (or a loved one's) was due to being vegan. This was either something that their doctor had told them, or an idea they had formed on their own. I always ask the same question -- did your/her doctor test for PARASITES? So far, the answer has always been "no." I don't want to tell people who they should see for a doctor, or call anyone's doctor a quack. But if your doctor diagnoses pernicious anemia and doesn't even test for parasites, then he or she is unfamiliar with the number one cause of pernicious anemia according to the literature in his or her own field. That's reason enough to seek a second opinion. Furthermore, I belong to several very large vegetarian/vegan groups, and so far have only met one person with pernicious anemia (and no, her doctor DIDN'T test for parasites or even mention them).

Personally, I've been a vegetarian for more than 20 years, and vegan for more than ten. I have never been diagnosed with pernicious anemia, and only one doctor even tested for it (due to dizziness after an auto accident -- the results came back normal, of course). I don't mean to be rude, but the facts were clear -- that particular doctor wasn't very good, and wasn't my doctor for long. I had dizziness after an auto accident, with many other accident-related symptoms, and she thought dizziness was due to B-12 deficiency? It was tragic, so much time being wasted by this nonsense while I suffered and was unable to work. Months later, a chiropractor re-ordered my neck x-rays and the radiologist found a healed (by that time) neck fracture. That's right, a neck fracture can cause dizziness.

Although I've never had pernicious anemia, it should be noted that I cleanse for parasites at least once every two years (although this didn't start until the year 2001, and I was fine until then, too). I use either a Clark zapper (see clark.pamrotella.com) or an herbal parasite cleanse from Hulda Clark's book "The Cure for All Diseases." So parasites aren't going to be eating my B-12, at least not for long! However, I don't mean to imply that parasite cleanses are absolutely necessary to prevent pernicious anemia. Many vegans never cleanse for parasites, and never have such extreme B-12 deficiency. It's really up to individuals to monitor their own health, and make decisions based on their own personal situation.


Sources:
Hulda Regehr Clark, PhD, ND. The Cure for All Diseases. Chula Vista, California: New Century Press, 1995.

H. Winter Griffith, MD. Vitamins, Herbs, Minerals, & Supplements. USA: Fisher Books, 1998.

Virginia Messina, MPH, RD, & Mark Messina, PhD. The Vegetarian Way New York: Three Rivers Press, 1996.

Denise Mortimore. The Complete Illustrated Guide to Vitamins and Minerals. London: Element [imprint of Harper Collins Publishers], 2001.

Rachel's Environmental & Health Weekly. Dangers Of Chlorinated Water; RACHEL'S ENVIRONMENT & HEALTH NEWS. Annapolis, MD: Environmental Research Foundation. Published on Gary Null's web site at http://www.garynull.com/Documents/erf/d ... _water.htm

Nicola Reavley. The New Encyclopedia of Vitamins, Minerals, Supplements, & Herbs. New York: M. Evans and Company, Inc. (Bookman Press), 1998.

Joel D. Wallach, DVM, ND, and Ma Lan, MD, MS. Rare Earths, Forbidden Cures. Bonita, California: Double Happiness Publishing Co., 1994.

Cyanocobalamin is the most commonly supplemented form of vitamin B12, but you might be surprised to discover that this form of vitamin B12 does not actually occur in plants or animal tissues. In other words, outside of the chemically synthesized cyanocobalamin that you encounter as B12 in most vitamin supplements, you would be extremely hard pressed to find this compound in nature (in fact you would not be able to find it). As the name implies, cyanocobalamin contains a cyanide molecule. Most people are familiar with cyanide as a poisonous substance. Although the amount of cyanide in a normal B12 supplement is small and from a toxicology point, viewed as insignificant, your body will still need to remove and eliminate this compound. This removal is accomplished through your detoxification systems with substances like glutathione being very important for the elimination of the cyanide.

Compared with cyanocobalamin, it appears that methylcobalamin is better absorbed and retained in higher amounts within your tissues. In simple terms, they are used much more effectively. In general, methylcobalamin is used primarily in your liver, brain and nervous system.

Methylcobalamin is the specific form of B12 needed for nervous system health. Because of this it should be the first form of this vitamin thought of when interested in attempting to optimize the health of the nervous system with vitamin supplementation. Indications of a potential deficiency of B12 in the nervous system might include numbness, tingling, loss of feeling sensation, burning sensations, muscle cramps, nerve pain and slowness of reflexes.

Because of methylcobalamin's importance in nervous system health, it is also an important nutrient for vision. In fact, continued visual work (like work on a computer) often leads to a reduction in something called "visual accommodation". Methylcobalamin can significantly improve visual accommodation, while cyanocobalamin appears to be ineffective.

An elevated level of homocysteine is a metabolic indication of decreased levels of the coenzyme forms of vitamin B12, especially methylcobalamin. Homocysteine has received a tremendous amount of emphasis in the scientific literature because of its associations with heart disease and a variety of other specific health conditions. I have even seen advertisements on television promoting folic acid, as a vitamin needed to lower homocysteine. While this is true, and folic acid does lower homocysteine levels, the combination of methylcobalamin and folic acid appears to work much better.

The most well studied use of methylcobalamin has to do with sleep. Although the exact mechanism of action is not yet clear, it is possible that methylcobalamin is needed for the synthesis of melatonin. Available information indicates that methylcobalamin can modulate melatonin secretion, enhance light-sensitivity, and normalize circadian rhythm (your 24-hour clock). Because of this, individuals supplementing this form of B12 often have improved quality of sleep, often will require slightly less sleep, and will not uncommonly report that they feel a bit more refreshed when waking in the morning. Methylcobalamin is particularly effective when your 24-hour clock is not running smoothly. This may be indicated by a need for excessive sleep, changing sleep-wake cycles, or a tendency to have altered sleep wake patterns. As examples, you might require 10-12 hours of sleep, or you might not feel tired until 2-3 am and you might wake at noon, or you might find that you wake a bit later every day and go to be a bit later every night. Under all of these circumstances the combination of methylcobalamin (about 3000 mcg daily) and exposure to bright light in the morning can help reestablish your 24-hour clock.

Because of methylcobalamin's impact on 24-hour clock and the cycles that feed of this, it is also an important vitamin to regulate your 24-hour release of the stress hormone cortisol. This seems to be particularly important for blood types A and AB. Methylcobalamin also seems to result in a better 24-hour maintenance of body temperature. Typically individuals supplementing this coenzyme form of B12 have higher temperatures in the later hours of the daytime. This usually corresponds with improved alertness at the same time of the day. While this can be of importance to all blood types, low body temperatures seems to be an area of greater challenge for A's and B's.