Vitamin B12, also called cobalamin, is a water soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the human body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production. As the largest and most structurally complicated vitamin, it can be produced industrially only through bacterial fermentation-synthesis.
Vitamin B12 is vital for the formation of red blood cells, as well as for the proper functioning and health of nerve tissue. If left untreated, vitamin B12 deficiency, also known as B12 deficiency, can lead to anemia, as well as nerve and brain damage, which may eventually become irreversible.
People with B12 deficiency may eventually develop pernicious anemia, a type of blood disorder. Patients with pernicious anemia cannot produce enough IF (intrinsic factor) in their stomach. IF is needed so that the body can absorb vitamin B12. People with this blood disorder need to have vitamin B12 injections which go straight into their bloodstream, bypassing the stomach.
VITAL Vitamin B12 Health Benefit
Signs of B12 Deficiency
Poor growth/failure to thrive in infants
Premature grey hair
Disturbed carbohydrate metabolism
Loss of hearing and tinnitus
Numbness and tingling in the hands and feet
Hyperpigmentation and hypopigmentation (dark and light patches in the skin)
Neuralgia, neuritis and bursitis
Anemia, including pernicious anemia
Spinal cord degeneration
Psoriasis and other skin problems
Irrational or chronic anger
Lack of balance/abnormal gait
Any emotional disorder up to and including insanity
Sources of Vitamin B12
Mollusks (clams, oysters, mussels, etc) 3 ounces 84.1 micrograms
Liver, beef, 1 slice 47.9 micrograms
Trout, wild, 3 ounces 5.4 micrograms
Salmon, 3 ounces 4.9 micrograms
Trout, farmraised, 3 ounces 4.2 micrograms
Beef sirloin, 3 ounces 2.4 micrograms
Yoghurt 1.4 micrograms
Milk, 1 cup 0.9 micrograms
Pork, cured ham, canned, 3 ounces 0.6 micrograms
Egg, hardboiled 0.6 micrograms
Chicken breast, 1/2 breast 0.3 micrograms
Vitamin B12 Recommended Daily Allowance
0-6 months no RDA
7-12 months no RDA
1-3 years 0.9 micrograms
4-8 years 1.2 micrograms
9-13 years 1.8 micrograms
14 and older 2.4 micrograms
Pregnancy 2.6 micrograms
Lactation 2.8 micrograms
Model of the brain
Elderly people with low-vitamin B12 are more likely to suffer from brain shrinkage and cognitive decline.
The team performed a study on 121 seniors, all aged 65 years or more. They took blood samples to check levels of vitamin B12 and B12-related metabolites, which can also help detect a deficiency. Their memories and other cognitive skills were also assessed.
Fifty-two months later MRI scans were done of their brains to check their size, as well as to determine whether there were any signs of brain damage.
The team found that those with four of five vitamin B12 deficiency markers were much more likely to have lower cognitive test scores and smaller total brain volumes.
What are the causes?
Pernicious anemia is caused by an autoimmune disease; a person's own immune system attacks good parts of the body, as if they were bacteria or viruses.
The immune system of patients with pernicious anemia creates antibodies which attack the lining of the stomach, damaging cells that produce intrinsic factor. Intrinsic factor is a substance that is secreted by the gastric mucous membrane (lining of the stomach) and is vital for the absorption of vitamin B12 in the intestines. If the production of intrinsic factor is undermined, vitamin B12 cannot be absorbed into the body properly.
Patients with Crohn's disease, as well as people who have had their bowels surgically shortened, may have problems absorbing vitamin B12 into their bloodstream. Short bowel syndrome is a term used for people who have had their bowel shortened (half or more of their small intestine removed). Patients with short bowel syndrome typically experience diarrhea, cramping and heartburn. It is not uncommon for individuals to become malnourished because what is left of the small intestine cannot absorb adequate quantities of vitamins, water and other nutrients.
Some people who follow a vegan diet may suffer from B12 deficiency if they do not eat fortified foods, or some types of yeast. Japanese and Italian scientists wrote in the Journal of Agricultural Food Chemistry that vegetarians and vegans are much more likely to develop vitamin B12 deficiency. The human body cannot use the plant-based form of the vitamin, they explained.
Chronic alcoholism may also be a cause of B12 deficiency, according to the National Library of Medicine.
How is it diagnosed?
The primary care physician will interview the patient and carry out a physical examination, looking out for such signs as an accelerated pulse and pale or yellowish skin.
Blood test - to determine whether the red blood cell count is low. The appearance of the red blood cells is also checked because they may have an unusual shape. A blood test can also determine what the level of B12 is. The doctor may also want to check the patient's blood intrinsic factor antibody levels, in order to determine whether a person has pernicious anemia.
Bone marrow biopsy - the aim here is to rule out other possible causes of red cell abnormalities or anemia.
Scientists from the University of Florida at Gainesville developed a non-invasive breath test to diagnose vitamin B12 deficiency.
What are the treatment options?
Hydroxocobalamin injections - this is a form of B12. It is injected into a muscle every two to four days. After about six injections, the patient should have a good store of B12.
In the majority of cases, the patient will notice significant improvements in symptoms soon after receiving injections.
Vegetarians who do not eat eggs, as well as vegans, should make sure their B12 intake is adequate.
Annual blood tests are common, to monitor the success of treatment.
Most patients require booster injections of B12 every three months for the rest of their lives.
Preventing the deficiency
Vegans and some vegetarians - vegetarians who do not eat eggs, as well as vegans, should make sure their B12 intake is adequate. There are various breakfast cereals which are fortified with vitamin B12. Some brands of nutritional yeast are also good sources of B12. Some types of soy milk are fortified with B12. According to Patrick J. Skerrett, Executive Editor, Harvard Health4, a standard multivitamin contains 6 micrograms of vitamin B12, which is more than enough to cover an average person's daily requirement.
Testing for B12 Deficiency
The first step in determining B12 deficiency is a test of B12 levels in the blood. However, many doctors believe that blood levels are an unreliable indicator of deficiency and that tissue levels of B12 may be quite low even though blood levels are normal. They recommend also testing for elevated levels of homocysteine and methylmalonic acid , two precursors to the metabolic reactions controlled by B12. Since homocysteine levels can be elevated by a number of conditions (folic acid deficiency, B6 deficiencies, renal failure, hypothyroidism and certain genetic defects), doctors consider elevated levels to be the more reliable indication of B12 deficiency.
Other tests include the Schilling test, in which a tiny dose of radioactive B12 is given by mouth and the amount absorbed measured. If vitamin B12 is absorbed only when given with intrinsic factor, the diagnosis of pernicious anemia is confirmed.
Because testing is so complicated, the levels considered normal in dispute, and disruption possible at numerous levels, many physicians have come to the conclusion that the only reliable way to assess the effects of subtle B12 deficiency on the blood, especially in older patients, is to observe changes (especially psychological changes) after treatment and determine empirically the best amount of supplementation for the individual patient. Since B12 is not toxic, except perhaps at extremely high levels, the empirical use of large doses to treat patients poses no danger.
Vitamin B12 also helps our bodies absorb folic acid, which facilitates the release of energy.
According to the American Journal of Clinical Nutrition, approximately 6% of people aged 60+ years are vitamin B12 deficient in the United Kingdom and the United States. Deficiency is much more common in developing countries, "starting in early life and persisting across life span."
A symptom is felt by the patient and reported to the doctor or people around them, while a sign can be detected by others. An example of a symptom is headache, while a skin rash or swelling are examples of signs.
Red blood cells
For our cells to multiply properly, an adequate level of vitamin B12 is required. If this production goes down, your vitamin B12 levels are deficient, resulting in anemia.
Vitamin deficiencies are slowly progressing; they may take several years to start affecting people. Initial signs and symptoms may be subtle, but in time, they become more noticeable.
For our cells to multiply properly, an adequate level of vitamin B12 is required. The human body produces millions of red blood cells every minute. This production goes down if your vitamin B12 levels are deficient, resulting in anemia as the red blood cell count drops.
The most common symptoms of anemia are:
Panting (shortness of breath)
Palpitations (disagreeable sensations of irregular or heavy beating of the heart).
B12 deficiency anemia may also be caused by a lack of intrinsic factor - pernicious anemia. The patient's digestive system cannot absorb B12 properly.
Signs and symptoms of pernicious anemia may include:
Shortness of breath
Anemia may also have the following signs and symptoms:
A sore mouth or tongue
Pale or yellowish skin
Higher susceptibility to infections.
If the deficiency continues untreated the patient may have the following neurological signs and symptoms:
Tingling or numbness of the fingers
Tingling or numbness of the toes
General muscle weakness
Difficulty walking properly (staggering)
How much is needed?
According to the National Institutes of Health1, how much vitamin B12 you need per day depends on your age. Below are the average daily recommended amounts for different ages (in micrograms, mcg):
Life Stage Recommended Amount
Birth to 6 months 0.4 mcg
Infants 7 to 12 months 0.5 mcg
Children 1 to 3 years 0.9 mcg
Children 4 to 8 years 1.2 mcg
Children 9 to 13 years 1.8 mcg
Teens 14 to 18 years 2.4 mcg
Adults 2.4 mcg
Pregnant teenagers and women 2.6 mcg
Breastfeeding teenagers and women 2.8 mcg
Risk of brain shrinkage
Elderly people with low-vitamin B12 are more likely to suffer from brain shrinkage and cognitive decline, scientists from Rush University Medical Center reported in Neurology.
Could your declining brain function be a B12 deficiency?
Because B12 is so vital for brain function, a B12 deficiency can manifest as numbness and tingling in the hands and feet, shakiness, depression, and loss of memory and cognition that can mimic the beginnings of dementia. It’s especially important to pay attention to a possible B12 deficiency in older people as the ability to absorb the vitamin declines with age. Studies show older people with higher B12 levels show less brain shrinkage and cognitive decline than their B12 deficient counterparts.
As a clinical nutritionist and chiropractic neurologist, I support patients in my Clifton Park, NY office with various chronic health issues. A B12 deficiency is not uncommon in those with chronic health issues or brain function issues. I see patients from Guilderland, Loudonville, Delmar, Colonie, and other areas of the Capital District. When patients come in with complaints from a chronic health condition, we use clinical nutrition, dietary strategies, and other tools to manage the condition. Addressing a B12 deficiency is an important part of the overall approach.
Is your anemia a B12 deficiency?
Other common manifestations of B12 deficiency are symptoms of anemia, which include fatigue, lethargy and weakness. Many people with B12 anemia discover they have an autoimmune disease called pernicious anemia, which inhibits the absorption of B12. In this case managing the autoimmune disease is important as well as supplementing with B12 sublingually or through injection.
A deficiency in B12 is also linked to an increased risk of cardiovascular disease, autism, autoimmune disease, infertility, and more.
B12 deficiency often due to poor absorption
So what causes B12 deficiency? For many people it’s due not to diet but rather to poor absorption of nutrients.
Many people today have damaged guts due to diets high in inflammatory foods, chronic stress, and food intolerances, such as to gluten. It’s difficult for nutrients such as B12 to pass through an inflamed and damaged gut lining into the bloodstream.
Other factors that can lead to a B12 deficiency include a decline in stomach acid (common in elderly), the use of antacids and acid-blocking drugs, the use of metformin and other prescription drugs, alcoholism, and weight-loss surgery.
Repairing and restoring gut health should always be addressed in the event of a B12 deficiency.
At Capital District Vitality Center we can help patients rom Guilderland, Loudonville, Delmar, Colonie, and other areas of the Capital District address a B12 deficiency to better support their condition.
Vegans and vegetarians at risk for B12 deficiency
One group at risk for dietary deficiency of B12 are vegans and vegetarians B12 is only found in animal foods. Natural plant sources of B12 such as spirulina, algae, seaweed, or grasses are poorly absorbed and may give a false reading of normal B12 on a lab result. This population especially should supplement with B12.
Also, although gut bacteria can synthesize B12, this requires healthy gut function and flora, and most of it is synthesized downstream of the small intestine where B12 is absorbed.
A Vital Nutrient
B12 is an essential vitamin with roles throughout the body. It is needed for the development and maintenance of a healthy nervous system, the production of DNA and formation of red blood cells.
A severe B12 deficiency results in anemia, which can be picked up by an ordinary blood test. But the less dramatic symptoms of a B12 deficiency may include muscle weakness, fatigue, shakiness, unsteady gait, incontinence, low blood pressure, depression and other mood disorders, and cognitive problems like poor memory.
Labs differ in what they consider normal, but most authorities say a deficiency occurs when B12 levels in adults fall below 250 picograms per milliliter of blood serum. Like all B vitamins, B12 is water-soluble, but the body stores extra B12 in the liver and other tissues. Even if dietary sources are inadequate for some time, a serum deficiency may not show up for years.
If the amount of B12 in storage is low to begin with, a deficiency can develop within a year, even more quickly in infants.
Recommended dietary amounts of B12 vary: 2.4 micrograms daily for those age 14 and older, 2.6 micrograms for pregnant women and 2.8 micrograms for nursing women. Barring circumstances that impair B12 absorption, these are levels easily obtained from a well-balanced diet containing animal protein.
In its natural form, B12 is present in significant amounts only in animal foods, most prominently in liver (83 micrograms in a 3.5-ounce serving). Good food sources include other red meats, turkey, fish and shellfish. Lesser amounts of the vitamin are present in dairy products, eggs and chicken.
Those at Risk
Natural plant sources are meager at best in B12, and the vitamin is poorly absorbed from them. Many strict vegetarians and all vegans, as well as infants they breast-feed, must consume supplements or fortified breakfast cereals to get adequate amounts.
Certain organisms, like the bacterium Spirulina and some algae, contain a pseudo-B12 that the body cannot use but may result in a false reading of a normal B12 level on a blood test. Despite claims to the contrary, laver, a seaweed, and barley grass are not reliable sources of B12.
In animal foods, B12 is combined with protein and must be released by stomach acid and an enzyme to be absorbed. Thus, chronic users of acid-suppressing drugs like Prilosec, Prevacid and Nexium, as well as ulcer medications like Pepcid and Tagamet, are at risk of developing a B12 deficiency and often require a daily B12 supplement.
Stomach acid levels decline with age. As many as 30 percent of older people may lack sufficient stomach acid to absorb adequate amounts of B12 from natural sources. Therefore, regular consumption of fortified foods or supplementation with 25 to 100 micrograms of B12 daily is recommended for people over 50.
Synthetic B12, found in supplements and fortified foods, does not depend on stomach acid to be absorbed. But whether natural or synthetic, only some of the B12 consumed gets into the body. Treatment to correct a B12 deficiency typically involves much larger doses than the body actually requires.
Free B12 from both natural and synthetic sources must be combined with a substance in the stomach called intrinsic factor to be absorbed through the gut. This factor is lacking in people with an autoimmune disorder called pernicious anemia; the resulting vitamin deficiency is commonly treated with injections of B12.
Although most doctors are quick to recommend injections to correct a B12 deficiency, considerable evidence indicates that, in large enough doses, sublingual (under-the-tongue) tablets or skin patches of B12 may work as well as injections for people with absorption problems, even for those with pernicious anemia.
Most often, a daily supplement of 2,000 micrograms is recommended for about a month, then lowered to 1,000 micrograms daily for another month, then lowered again to 1,000 micrograms weekly. Sublingual B12 or B12 patches, or even B12 lollipops, can be helpful for people who require a supplement but cannot swallow pills.
Others at risk of developing a B12 deficiency include heavy drinkers (alcohol diminishes B12 absorption), those who have had stomach surgery for weight loss or ulcers, and people who take aminosalicylic acid (for inflammatory bowel disease or tuberculosis) or the diabetes drug metformin (sold as Glucophage and other brands). Patients who take the anticonvulsants phenytoin, phenobarbital or primidone are also at risk.
Large doses of folic acid can mask a B12 deficiency and cause permanent neurological damage if normal levels of B12 are not maintained. Supplements of potassium impair B12 absorption in some people.
Although a B12 deficiency can raise blood levels of the amino acid homocysteine, a risk factor for heart disease and stroke, supplements of B12 have not reduced cardiovascular risk.