The Ultimate Guide to Vitamin B12

It’s the stuff of spy movies. When about to be caught, with no way out, the spy bites on a cyanide pill, causing death to come quickly. Yet despite its toxicity, cyanide is found in most vitamin B12 supplements on the market today!

It’s a tiny amount, won’t cause any harm, and superior forms are available, so don’t let that put you off taking supplements. B12 has a boatload of functions, is needed by every cell, and plays crucial roles in many body processes.

Despite its importance, deficiency is surprisingly common, not just among those on plant-based diets but even among meat eaters, for reasons we’ll explain.

What’s shocking is that the medical authorities still have out-of-date views on what B12 deficiency looks like, so many people remain undiagnosed, leaving them at risk of irreversible harm and without hope of recovery.

It’s vital to understand the importance of B12 and the symptoms of deficiency so you can take charge of your health and aren’t failed by the medical system.

Key Takeaways

• Vitamin B12 plays crucial roles in many cellular functions, including producing healthy blood cells, DNA synthesis, energy production, and more. Untreated deficiencies can lead to severe health problems, while improving insufficient levels of B12 can increase energy, improve the functioning of the nervous system, support brain health, and help prevent heart disease.
• B12 deficiency is widespread and mostly undetected. It can occur at any age but is more prevalent in seniors, even among meat eaters, because its absorption and utilization by body cells is a multistep, delicate, and complex process that’s easily disrupted.
• Blood tests used to detect deficiency are unreliable, and experts consider the cut-off point to provide a diagnosis too low. This means many people with B12 deficiency remain untreated, risking their health.

What is Vitamin B12?

Vitamin B12 is an essential nutrient that can’t be made by the body so must come from the diet.

It’s one of eight members of the vitamin B group, which are all water soluble, allowing them to dissolve in water, travel through the bloodstream and be peed out of the body if there’s too much in the blood.

Not only is B12 the largest and most chemically complex of all vitamins, but it’s unique because it’s joined to a metal – cobalt, which is why B12 is also called cobalamin. In the body B12 appears in the active chemical form of methylcobalamin-- the methylated form-- or adenosylcobalamin. More on the different forms in a minute...

B12 is needed by every cell in the body and plays crucial roles in a vast number of cellular functions. It’s involved in the manufacture and normal functioning of blood cells, DNA formation, gene expression, nerve function, energy production, toxin removal, the metabolism of lipids (fats) and the production of the essential amino acid, methionine.

It’s essential for healthy nerves and glands, digestion, cognition and mood, blood formation, immunity, skin and mucous membranes, bones, and pregnancy. In other words, there’s almost no aspect of the body that doesn’t need B12 to function normally.

Let’s look at the role of B12 in more detail.

Health Benefits of Vitamin B12

Improves Energy and Endurance

In the form of adenosylcobalamin, B12 is needed by the mitochondria, the cell’s major energy producers. Any shortfall can cause fatigue, low energy, lethargy and exhaustion.

Historically, before B12 was discovered, severe deficiency showed up as a blood disorder where red blood cells don’t form properly. They become distorted and enlarged (megaloblastic anemia) and this was given the name, pernicious anemia. These impaired blood cells had reduced ability to carry oxygen leading to the typical symptoms of anemia which includes weakness and fatigue.

Today, megaloblastic anemia is differentiated from pernicious anemia. The former can be caused by any of many conditions that disrupt B12 absorption, whereas the latter is an autoimmune disease.

In the pernicious form the body either attacks its own stomach cells to prevent B12 being separated from food, or it attacks cells that secrete intrinsic factor -  a sugar/protein molecule produced by the stomach that’s needed for B12 absorption. Pernicious anemia is usually seen in older people but there’s also a juvenile form affecting children under ten.

Since fatigue is an early symptom of B12 deficiency, if diagnosed and B12 is supplemented, fatigue lessens in a day or so and general tiredness lifts after a few weeks after which energy and endurance are restored.

Encourages Nervous System Health

The nervous system needs B12 to function normally. It’s used to produce fatty acids that are incorporated into the myelin sheath that surrounds nerves. A damaged myelin sheath will disrupt and impair signaling between brain cells. B12 is also needed to produce proteins and neurotransmitters in the central and peripheral nervous system.

According to the late Dr. Joseph Chandy, a British general practitioner (primary care physician) and B12 specialist, “neurological and neuropsychiatric signs and symptoms are the most frequently encountered presentations of vitamin B12 deficiency today” and are seen in three-quarters of patients with B12 deficiency. [1]

If left untreated, and severe deficiency develops, it can cause a devastating condition called sub-acute combined degeneration of the spinal cord (SACD). Symptoms include tingling and numbness, weak limbs, difficulty walking, vision problems, depression, low attention span and memory loss.

Anemia doesn’t always accompany SACD and since physicians rely on blood tests for B12 deficiency and signs of anemia, the condition is often misdiagnosed as chronic fatigue syndrome (CFS), myalgic encephalomyelitis (ME) and especially multiple sclerosis (MS), which has a very similar set of symptoms.

In fact, a recent study described a novel molecular link between vitamin B12 and MS that takes place in specialized brain cells called astrocytes. The authors recommend supplementing B12 to nourish these cells. [2]

Dr. Chandy helped many people misdiagnosed with such conditions regain their health. One was a patient who had trouble walking, often needing to use a mobility scooter, until she took B12.

Another was a 17-year-old with aches and pains all over the body and dependent on crutches or a wheelchair. After her neurologist dismissed her as an attention-seeker and thought the condition was all in her mind, she consulted Dr. Chandy who diagnosed B12 deficiency. After one month the pain had greatly diminished and she was able to walk without crutches.

Promotes a Sharper, Clearer Memory

B12 is vitally important to the health of the brain with deficiency causing a wide range of neuropsychiatric symptoms. Anemia itself, whether caused by B12 deficiency or for other reasons, puts people, especially seniors, at greater risk of dementia.

Over a century ago, nervous and mental symptoms were linked to pernicious anemia and in 1988 researchers reported that 28% of 141 consecutive patients with B12 deficiency - yet without anemia or any red blood cell anomalies - had neurological symptoms. [3] That bears repeating: The science shows that you don't have to be anemic to experience the negative effects of B12 deficiency.

And according to the Institute of Medicine, 75%–90% of people with clinically relevant B12 deficiency have neurological disorders that include dementia. In fact, there are many similarities between dementia and B12 deficiency. Both:

• increase with age
• affect the central nervous system
• promote inflammation
• have a genetic component in many instances
• cause loss of short-term memory, impaired cognitive function and confusion

The kind of symptoms seen with B12 deficiency are confusion, fogginess, irritability, apathy, depression, psychosis, impaired judgment, memory loss, mild cognitive impairment and dementia.

Not only can deficiency cause brain dysfunction but also brain shrinkage and structural damage, leading German scientists to urge clinicians “to accurately diagnose and treat early vitamin B12 deficiency to prevent irreversible structural brain damage.” [4]

An international research team found B12 levels in the brains of otherwise healthy people aged 61 to 80 were only a third as much as seen in younger adults. This means age-related cognitive and memory decline could be linked to poor uptake of B12 in some cases.

Richard Deth, who led the team said: "These are particularly significant findings because the differences we found in brain B12 with [normal] aging…are not seen in the blood, which is where B12 levels are usually measured." [5]

One reason low B12 and dementia are linked is because deficiency leads to excess homocysteine.

Essential to Lower Homocysteine

Homocysteine is an amino acid made from the essential amino acid methionine which we ingest from foods containing protein. Without enough B12, homocysteine rises too high, and this negatively impacts brain function.

In 2018 a team of expert scientists produced a paper called “Homocysteine and Dementia: An International Consensus Statement.” In it they wrote that elevated homocysteine is a risk factor for cognitive decline, dementia, and Alzheimer’s disease.

“Intervention trials in elderly with cognitive impairment” they wrote, “show that homocysteine-lowering treatment with B vitamins markedly slows the rate of whole and regional brain atrophy and also slows cognitive decline.” [6]

Nutrients that lower homocysteine are mainly vitamin B12 and B9 (folate) with the help of vitamin B6, so if we want to keep our minds sharp and memories unfaltering, this is one simple strategy for doing so.

B12 and homocysteine are also linked to heart and circulatory disorders.

Supports a Healthy Heart

The American Heart Association accepts that excess homocysteine is linked to a greater risk of stroke and other blood vessel disorders.

A study that pooled the results of twelve previous studies involving over 23,000 adults found that as homocysteine levels rose so did the risk of cardiovascular death. Compared to adults with the lowest levels of homocysteine, those with the highest levels, had a 68% increased risk of death from cardiovascular disease. [7]

In a recently published study containing 5,200 participants, scientists reported “solid evidence” that heart disease mortality increases in line with rising homocysteine levels. [8]

One would think supplementing with B12 and other B vitamins would therefore lower the risk, yet most intervention trials found that while supplementation reduced the risk of stroke by a small amount, it didn’t reduce the risk of a heart attack. The reason for this was suggested in a recent scientific review. Researchers pointed to the “substantial limitations” in trials assessing B vitamins and their role in heart disease prevention and treatment.

In the scientists’ assessment, B vitamins had their greatest cardiac benefit in people with normal kidney function, without unstable angina, and who haven’t had a type of heart attack called non-ST-elevation. So while B12, folate and B6 will help the vast majority of people, their research suggests those with these complaints may not experience dramatic benefits [9]

The role of B12 goes beyond its effect on homocysteine. It’s necessary for various metabolic processes and contributes to DNA synthesis. If these are disrupted because B12 is in short supply, cardiovascular diseases and other illnesses can result.

So, what can you do?

Increasing Your Intake of Vitamin B12

Food Sources

Vitamin B12 doesn't come from food exactly. Believe it or not, vitamin B12 is made by microbes in the digestive tract of animals and then distributed throughout the animal's tissues. That's why meat is the main source of vitamin B12. However, those on a plant based diet can also obtain B12 from fortified foods. For example:

Animal sources:

• Meats of all kinds
• Liver
• Fish
• Shellfish
• Eggs
• Milk
• Yogurt
• Cheese

Plant sources:

• Seaweed – some species
• Silk® organic unsweet soymilk
• Fortified breakfast cereals
• Fortified nutritional yeast
• Fortified soy products
• Enriched plant milks

Dietary Supplements

Since B12 plays so many essential roles in the brain and body, many people choose to take B12 supplements. This is especially important for those of us who eat only plant foods.

In fact, the Vegan Society recommends eating either fortified foods two or three times a day, or taking a one a day vitamin B12 supplement providing at least 10 micrograms or a weekly vitamin B12 supplement providing at least 2000 micrograms. [10] You can also self-administer vitamin B12 shots with the help of a functional medical doctor.

Forms of Vitamin B12

When you're shopping for vitamin B12 supplements, you'll encounter two main categories:

1. Nature's Own: These are the ready-to-use forms your body prefers - methylcobalamin and adenosylcobalamin. Think of them as pre-assembled furniture, ready to be placed in your home immediately.
2. Lab-Created Helpers: Then there are cyanocobalamin and hydroxocobalamin. These are synthetic versions, like flat-pack furniture that needs some assembly. Once inside your body, these forms undergo a transformation process, eventually becoming the same active forms as their natural counterparts.

Both types can support your B12 needs, but they take slightly different routes to get there. The natural forms are immediately recognized and put to work, while the synthetic forms require a bit of processing by your body first.

Cyanocobalamin

Cyanocobalamin combines cobalamin with cyanide and is the cheapest form of B12.  Uptake isn’t optimal as it’s lost from the body very quickly. This is because the body recognizes cyanide as a poison and rapidly excretes it through the kidneys, so you won’t be harmed from taking B12 in this synthetic form. In fact, in cases of cyanide poisoning, cobalamin is used to flush it out of the body!

Even so, cyanocobalamin can cause mild headaches and some people just don’t benefit from it. For these reasons Dr. Chandy didn’t recommend taking B12 in this form but as either of the active forms or as hydroxocobalamin which converts more easily into the active forms.

Methylcobalamin

Picture methylcobalamin as the VIP guest at your body's nutrient party. This form of B12 doesn't need a special invitation or to change outfits - it's ready to mingle with your cells right away. Unlike its synthetic cousin cyanocobalamin, which needs a makeover before it can join the festivities, methylcobalamin arrives dressed for success and ready to work its magic.

This instant access is a game-changer, especially for folks with a unique genetic twist. Imagine some people have a bouncer at their cellular doors - that's the MTHFR gene mutation. This bouncer has a hard time recognizing and letting in the synthetic B12 forms. But methylcobalamin? It's on the VIP list and breezes right past, no questions asked.

Once inside, methylcobalamin becomes your body's multitasking superhero. It's like having a personal trainer, brain booster, and wellness guru all rolled into one vitamin. Here's what this wonder nutrient does for you:

When methylcobalamin enters your body, it's like having a Swiss Army knife of health benefits at your disposal. This powerhouse form of B12 gets to work right away, supporting a variety of crucial bodily functions:

1. Nerve Whisperer: It helps maintain the protective coating around your nerves, ensuring messages zip through your body smoothly and efficiently.
2. Brain Booster: Think of it as brain food, supporting memory and mental clarity. It's like giving your mind a daily tune-up to keep it running at its best.
3. Heart Helper: By aiding in the breakdown of homocysteine (a potentially troublesome amino acid), methylcobalamin lends a hand in keeping your cardiovascular system happy.
4. Detox Dynamo: It plays a key role in your body's natural cleansing processes, helping to clear out unwanted substances.
5. Energy Enhancer: Feeling sluggish? Methylcobalamin is essential for turning the food you eat into the energy you need to tackle your day.
6. Mood Maestro: By supporting the production of feel-good brain chemicals, it helps orchestrate a balanced mood.

In essence, methylcobalamin is like a health-conscious multitasker, working behind the scenes to keep various aspects of your wellbeing in harmony. This is why our Green Valley Naturals formulas contain methylated forms of B vitamins, including methylated B12 in the form of methylcobalamin.

Vitamin B12 and Folate

B12 may be supplied as a standalone supplement or combined with other B vitamins and/or other nutrients depending on which organ system the supplement is designed to support.

Since B12 contributes to DNA synthesis from its interaction with folate, this is often included in supplements. Folate availability to the body depends on B12 status which means that serum folate deficiency can sometimes be resolved with B12 alone; folate or folic acid supplementation isn't always needed.

Supplements come in the form of tablets, capsules, under the tongue drops or skin patches.

The recommended daily amount (RDA) is 2.4 micrograms per day for adults. B12 is especially important in fetal and baby development, so the RDA increases to 2.6 in pregnancy and 2.8 for nursing mothers.

Best of all, the research shows that the body only needs small amounts of vitamin B12 yet no harm comes from even very high doses because it's possibly the safest nutrient there is.

Nutritional toxicologist John Hathcock claims it’s “virtually nontoxic”. The European Scientific Committee on Food concluded that “it is not possible to derive an Upper Intake Level, mainly because no clearly defined adverse effect could be identified.” Similarly, the US Institute of Medicine hasn’t established any upper limit “because of its low potential for toxicity.” It's no wonder that most natural, alternative and functional doctors recommend vitamin B12 supplements.

Deficiency is Widespread

Prevalence and Risk Factors

A century ago, deficiency was a serious problem with 10,000 deaths per year in the U.S. alone until the link to diet was made with the accidental discovery that eating liver cured pernicious anemia. It took another 20 years for the missing factor in liver – B12, to be isolated. Even though the fatality rate has shrunk, B12 deficiency remains a problem today.

The U.S. National Health and Nutrition Examination Surveys from 1999 to 2002 found deficiency - defined as blood serum containing less than 148 picomoles per liter (pmol/L) or its equivalent - 200 picograms per milliliter (pg/mL) – in less than 3% of those aged 20–39, about 4% of those aged 40–59, and about 6% of the over 70s. Marginal deficiencies, however, (148-221 pmol/L) were much more common, occurring in 15% of those aged 20 to 59 and more than 20% of those aged over 60. [11]

In a major research project for the U.S. Department of Agriculture (USDA) involving 3,000 men and women aged 26 to 83, nearly 8% fell below the current deficiency threshold of 148 pmol/L, more than 16% were below 185 pmol/L, while almost 40% were in the “low normal” range - below 258 pmol/L.

Katherine Tucker, who led the research said, “I think there is a lot of undetected vitamin B12 deficiency out there.” [12]

Among Dr. Chandy's medical practice population of 5,760 patients, the prevalence of deficiency was 18%. Dr. Chandy confirmed deficiency by whether his patients' symptoms were relieved by taking supplements of B12 by injection, regardless of the result of the usual blood test.

While long-held scientific dogma insists that deficiency is solely limited to strict vegetarians, as USDA Hall of Fame scientist Lindsay H. Allen demonstrated, it’s also widespread in men, women and children who consume inadequate amounts of animal-source foods. [13]

Another key reason is because pernicious anemia was originally considered a blood disorder so that even today, unless a blood test shows that anemia is present as well as antibodies to intrinsic factor, as far as the physician is concerned, B12 can’t be the cause of the patient’s condition even though a large percentage of patients with B12 deficiency do not display any red blood cell or intrinsic factor anomalies.

As Dr. Chandy wrote, “patients fail the test for B12 deficiency in spite of presenting with obvious symptoms; physicians set criteria for diagnosis that guarantee that only the most extreme cases will be diagnosed; and they promote expensive solutions and restrict access to a simple, cheap, and effective supplement. This means misery for a great many people.”

Another reason B12 deficiency goes undetected is because the blood test and cut off value for deficiency of below 148 pmol/L has serious limitations. Patients can have a “normal” reading and still be deficient. We’ll cover this in more detail shortly.

How To Know if You Suffer Vitamin B12 Deficiency

Causes and Risk Factors

Perhaps the most challenging part of trying to increase your vitamin B12 levels is to understand that even if you consume adequate amounts, vitamin B12 absorption by your body's 100 trillion cells can still fail. That's because vitamin B12 absorption can be disrupted by:

• Abnormal bacterial growth in the small intestines
• Atrophic gastritis – inflammation of the stomach
• Intestinal infections/disease such as celiac disease and Crohn’s disease
• Lack of intrinsic factor
• Pancreatic insufficiency – the pancreas doesn't make enough enzymes to break down food and absorb nutrients
• Insufficient stomach acid
• Faulty enterohepatic circulation causing excessive losses of B12 through the gut
• Gastrointestinal surgery
• Genetic conditions (such as the MTHFR gene mutation)
• Medications such as antacids, proton pump inhibitors and the diabetes drug metformin that inhibit absorption
• Aging

What's more, you can be deficient and not know it for quite some time. That's because the liver acts as a storage facility for B12 – it can hold it for up to 5 years - and will slowly release it to the cells if not enough is available to the body.

Since so many body systems are affected by B12 deficiency, the number of symptoms possible are extensive.

Symptoms

The most likely symptoms are:

• Fatigue
• Depression
• Hair loss
• Pins and needles
• Numbness in hands or feet
• Tremors and palsies
• Palpitations
• Recurrent headaches
• Dizziness

Conditions

As just about every area of the body can be affected, vitamin B12 deficiency can cause a vast number of seemingly unrelated conditions such as:

• Dermatitis
• Osteoporosis
• Loss of libido
• Dementia
• Poor wound healing
• Tinnitus
• Heart failure
• Mouth ulcers
• Anxiety
• Bruising

How can you know your vitamin B12 status? If you or your doctor suspects you may suffer with a vitamin B12 deficiency, a sample of your blood will be sent to the lab. And that's when you've got to pay very close attention to the results

How to Diagnosis Vitamin B12 Deficiency

Blood Tests

A recognized authority on B12 is Dr. David Smith, Emeritus Professor of Pharmacology at the University of Oxford. From his own research and quoting other experts he notes that commonly used blood tests can give false normal readings. In fact, tailure rates range from 22 to 35%.

Fortunately, researchers developed more specific blood tests that appear to be superior. One is called Active B12. If it proves its worth it could become the method of choice for determining a patient’s B12 status. Another is called Methylmalonic acid (MMA). Some doctors will choose to look at your homocysteine levels, but this is not widely used because it isn’t specific to B12.

Now, even if your test is accurate, the normal range of vitamin B12 which, you may recall, begins at 148 pmol/L is too low, Dr. Smith writes. People can be deficient even with levels 2½ times this amount because patients can have pernicious anemia without abnormal blood cells but will still have neurological or psychiatric symptoms or both.

Unfortunately, until these issues are better explained by doctors, many people who are suffering due to lack of vitamin B12 will continue to fall under the radar and suffer greatly.

Summary

Vitamin B12 is used by every cell in the body, has multiple functions and is needed for the health of almost all systems in the body. It’s only found naturally in animal foods, but meat eaters can be at risk of deficiency as well as vegans because B12 must travel through a lot of physical hoops to reach cells and doesn’t always make it, especially with aging.

By increasing your vitamin B12 levels you can experience improved energy, sharper thinking and better heart health. Blood tests aren’t reliable as a means of diagnosing B12 deficiency leaving many people at risk. Taking supplements of B12 is a safe and easy way to make sure you don’t fall short of this essential nutrient.

Frequently Asked Questions

How can I increase my vitamin B12 naturally?

Animal foods are the most reliable source. There are few plant sources so those on a vegan diet can obtain B12 from foods that have been fortified with B12. The best way to improve vitamin B12 levels is to supplement.

What does vitamin B12 do for you?

It’s easier to ask what vitamin B12 doesn’t do for you! This essential vitamin is needed by every cell in the body and has key functions in nine body systems; everything from skin, hair and nails to bone health, energy production, mood, brain and heart health.

How do you know if you're low in vitamin B12?

You won’t know for sure until a diagnosis is made when a blood test shows macrocytosis (large, immature red cells) and intrinsic factor antibodies. However, deficiencies can exist without these showing up on blood tests. Experts in B12 deficiency suggest using a wider range of tests and to prescribe B12 based on the patient’s symptoms, which most commonly are neurological or psychiatric or both.

Is taking vitamin B12 everyday good for you?

It's important to get adequate amounts every day from your diet to meet the recommended dietary allowance. Vitamin supplementation will guarantee getting this. Folic acid supplements are also useful as B12 and folate work together in some body functions.