Vitamin B12 deficiency affects many people. 5 to 7 percent of the younger people and up to 30 percent of the older people are demonstrably undersupplied with vitamin B12. The number of unreported cases is likely to be much higher, since vitamin deficiencies are not routinely checked during the usual medical check-up.
A vitamin B12 deficiency can remain without symptoms for many years, which is due to the fact that the body’s reserves last for a very long time. Around 4000 micrograms of vitamin B12 are stored in the liver and muscles of an adult. These reserves are slowly used up if the vitamin is not supplied, so that a deficiency can only become symptomatic after three or even more years.
When vitamin B12 levels are low but there are no symptoms yet, this is called an asymptomatic vitamin B12 deficiency.
Officially, symptomatic vitamin B12 deficiency includes pernicious anemia and also the so-called Hunter glossitis. On the other hand, unspecific symptoms are not always associated with a vitamin B12 deficiency by doctors.
The first non-specific symptoms of vitamin B12 deficiency include the following. If you notice these, have your vitamin B12 levels checked:
Later, there are serious illnesses, e.g.:
In pernicious anemia, the red blood cells are enlarged. They also contain more hemoglobin (red blood pigment) than normal blood cells. These enlarged blood cells are also called megaloblasts, normal blood cells are called normoblasts. Pernicious anemia is therefore one of the megaloblastic anemias, which also includes folic acid deficiency anemia.
The symptoms of megaloblastic anemia are similar to those of other anemias and consist of tiredness, rapid exhaustion, reduced performance, tachycardia, paleness and possibly Hunter glossitis. Hunter glossitis is a pathological change in the tongue with burning tongue, smooth tongue surface, initially pale tongue, later tongue colored fiery red. In extreme cases, pernicious anemia can develop into funicular myelosis.
Funicular myelosis is a disease that is similar to multiple sclerosis but, unlike it, can be treated with the administration of vitamin B12. Funicular myelosis also causes degeneration of the myelin sheaths of the nerves in the brain and spinal cord. (Myelin sheaths are a kind of protective layer that surrounds nerve fibers). In most cases, abnormal sensations such as tingling or pain occur first, followed later by unsteady gait, muscle weakness and (spastic) paralysis. If the brain is affected, cognitive disorders, fatigue and psychoses appear.
It is often asked how quickly the vitamin B12 deficiency symptoms improve when you start taking vitamin B12 as a dietary supplement. If you take vitamin B12 in the case of vitamin B12 deficiency symptoms, the haematological symptoms usually improve within a week, the neurological symptoms within three months – depending on the severity, of course.
While you usually take high doses of vitamin B12 in the event of a deficiency in order to remedy the deficiency quickly, the body only needs a small amount of vitamin B12 every day once it has filled its stores. The daily requirement of vitamin B12 is as follows (each in µg (micrograms) per day):
Teenagers and adults
A vitamin B12 deficiency can easily be diagnosed by a doctor, an alternative practitioner or a home test. If you have a vitamin B12 deficiency, you can generally correct it very easily.
Since vitamin B12, in contrast to all the other vitamins of the B complex, is found almost exclusively in animal foods, vegans are considered predestined for a vitamin B12 deficiency. But non-vegans can also suffer from a vitamin B12 deficiency.
Because some medications, an unhealthy diet or infections can damage the stomach and intestines, it can make a vitamin B12 deficiency very likely. Alcohol abuse, anorexia and general forms of malnutrition (e.g. in old age, when eating too little or one-sided) are also considered causes of vitamin B12 deficiency.
Both vegans and non-vegans can be affected by a vitamin B12 deficiency – only the cause is usually different.
Omnivores with B12 deficiency usually have a gastrointestinal disease, while vegans simply lack the raw material because a purely plant-based diet contains little vitamin B12, if any.
Vitamin B12 requires a healthy gastrointestinal tract to be fully absorbed for the following reason:
The so-called intrinsic factor is produced in the parietal cells of the gastric mucosa – a transporter protein to which vitamin B12 from food can attach itself so that it can then be absorbed in the small intestine (ileum).
However, when the mucous membrane of the stomach is damaged, there is first an intrinsic factor deficiency and consequently also a B12 deficiency. But a lot of people have a bad stomach, more omnivores than vegans.
The same is true for intestinal diseases. These, too, often lead to a vitamin B12 deficiency if the vitamin can no longer be fully absorbed, e.g. in an irritable bowel with frequent diarrhea or in chronic inflammatory bowel diseases or of course if parts of the intestine have already been surgically removed.
In the case of stomach problems, it does not even have to be a serious stomach disease, such as e.g. gastritis type A (inflammation of the gastric mucosa), which can also lead to a vitamin B12 deficiency. Heartburn is enough. Because many people take acid blockers (proton pump inhibitors, such as omeprazole) because of heartburn – and it is precisely these drugs that promote the development of B12 deficiency.
Omeprazole and similar acid blockers not only inhibit the formation of gastric acid, but also the formation of the intrinsic factor so that no more (or too little) vitamin B12 can be absorbed (malabsorption).
In addition to antacids, metformin can also lead to vitamin B12 deficiency, as you will see in a moment:
Infection with a fish tapeworm can also lead to a vitamin B12 deficiency. Fish tapeworm is most commonly aquired by eating raw fish. The parasite sheds thousands of eggs daily, which are easily detected in stool, making diagnosis easy.
A vitamin B12 deficiency is therefore by no means a problem that would only affect vegan people. It’s a vitamin deficiency that can basically affect anyone, just like vitamin D deficiency, magnesium deficiency or any other deficiency.
There are several ways to diagnose a vitamin B12 deficiency:
Many doctors still determine the total vitamin B12 level in the blood serum, but this does not make sense, since the inactive B12 is then also measured, which the body cannot use anyway.
It is therefore possible that this B12 total value is still perfectly fine, but in reality there is already a vitamin B12 deficiency. Only when the B12 level has already fallen very dramatically would one be able to determine it from the total B12 value in the blood.
The simplest method is the vitamin B12 urine test, which you can order online and carry out yourself at home. This test measures the level of methylmalonic acid in the urine, which is increased in vitamin B12 deficiency (both in the urine and in the blood).
However, since there are also people (especially those over 70 years of age) who have elevated methylmalonic acid levels without having a B12 deficiency and also (at any age) an intestinal flora disorder can falsify the methylmalonic acid levels, another test should be carried out to be on the safe side (if the methylmalonic acid test was elevated). This test measures the so-called holo-transcobalamin value (holo-TC) in the blood.
Transcobalamin is the transporter protein for vitamin B12 (cobalamin). When the active vitamin B12 binds to transcobalamin, this compound is called holo-transcobalamin
With the Holo-TC test, only the active vitamin B12 is measured, so that a B12 deficiency can be detected at the very beginning and not only when the body’s vitamin B12 stores have already been more or less emptied. Of course, you can also just have the holo-TC value determined.
The methylmalonic acid test is then not necessary. It is particularly useful for those who do not like having blood taken and is also available as a home test.
In addition, the homocysteine level in the blood can be determined to be on the safe side. If it is elevated, a vitamin B12 deficiency – but also a folic acid deficiency and/or vitamin B6 deficiency – could be at play (or all three deficiencies together).
Below are the reference values for vitamin B12 (for adults) so that you can correctly classify your readings.
If your doctor measures the vitamin B12 in the serum and it is too low, there is clearly a vitamin B12 deficiency. However, if it is normal but on the lower end of the normal scale (low-normal), you should have other tests done, such as a holo-TC or MMA test. Because the serum vitamin B12 level can still be normal when there is actually already a vitamin B12 deficiency, so that the serum measurement is not suitable for diagnosing an incipient deficiency:
The reference values for the determination of methylmalonic acid in urine are as follows:
The reference values for the determination of methylmalonic acid in blood serum are as follows:
If there is a low holotranscobalamin level at the same time, a manifest vitamin B12 deficiency can be assumed with certainty.
The reference values for the determination of holotranscobalamin in serum are as follows:
Since low holo-TC levels are also present in the case of renal insufficiency, the kidney values should always be checked, especially in older people.
If your serum vitamin B12 level was determined but your result was given in a different unit, you can convert it as follows and then compare it back to the reference values above:
Please note, however, that reference values can often differ depending on the type of analysis and laboratory, so that you should use the reference values of the respective laboratory as a precaution.
Vitamin B12 can be absorbed by the body via two mechanisms:
If it is clear that there is a vitamin B12 deficiency, then the question naturally arises as to how this can be rectified. The necessary measures depend on the cause of the defect.
If you suffer from chronic gastrointestinal complaints, optimizing your gastrointestinal health should be the focus of further action. At the same time, a high-dose vitamin B12 preparation (daily dose from 1000 micrograms) makes sense, since this can be absorbed by passive diffusion, so it can often remedy the previous undersupply even with an ailing gastrointestinal tract.
In some cases, vitamin B12 injections are an even better solution, especially when there is already a pronounced vitamin B12 deficiency. They are given intramuscularly, i.e. into the muscle, and can usually remedy a vitamin B12 deficiency within a few weeks.
If you’re taking medications that may contribute to vitamin B12 deficiency, talk to your doctor about whether they’re still needed or whether you can stop taking them. If you have to continue taking your medication, ask your doctor whether it is sufficient if you regularly take a vitamin B12 supplement or – if the deficiency is severe – weather you should not have a B12 injection regimen first otherwise your vitamin B12 deficiency may not be corrected or may only be corrected slowly.
If the vitamin B12 deficiency has developed as a result of a vegan diet or other unknown causes, you can remedy the deficiency by regularly taking a vitamin B12 supplement. A wide variety of preparations are available for this purpose.
If you want to remedy a pronounced vitamin B12 deficiency, high-dose vitamin B12 preparations with a daily dose of 1000 micrograms of vitamin B12 are recommended.
Capsule preparations that contain a mixture of the best forms of vitamin B12, i.e. the storage vitamin B12 (hydroxocobalamin) and the active B12 forms (methylcobalamin and adenosylcobalamin), are ideal.
Vitamin B12 nasal drops are now also commercially available. With the drops you can take 1000 micrograms of vitamin B12 per daily dose (2 drops). The vitamin can be absorbed through the nasal mucosa, bypassing the gastrointestinal tract.
Toothpastes with vitamin B12 can also help to cover the daily requirement of vitamin B12. They must be used at least twice a day to affect vitamin B12 levels.
In a 2017 study, vegans who used an appropriate toothpaste for 12 weeks had significant increases in both holo-TC and serum B12, the latter increasing by an average of 81 pg/mL, which is quite a lot. If the values are below 150 to 200 pg/ml, there is a deficiency. Levels of 300 pg/ml and above are considered normal, so regular use of enriched toothpaste can continuously improve or maintain healthy levels of B12.
Intramuscular vitamin B12 injections can also be used in the case of a diet-related vitamin B12 deficiency – if the value is already very low. These are usually given once or twice a week for a few weeks.