Vitamin B12 is one of the vitamins the body needs to function properly. It is water-soluble and contains cobalt, which is where its name — cobalamin — comes from. Unlike the other water-soluble vitamins, B12 alone accumulates in a healthy liver. It is irreplaceable and enters the body with food. Although daily requirements are low, it is good for the diet to be rich in foods that contain it. Even a mild deficiency can cause anaemia, depression and chronic fatigue. B12 is produced by certain fungi and bacteria, which is why it is found mainly in products of animal origin. Even so, it can also be found in some vegan foods: tempeh, brewer's yeast, tofu and breakfast cereals (muesli). If our diet is poor in such foods, it is worth getting B12 from a supplement.
A raised risk of vitamin B12 deficiency can be seen in the following conditions:
- pernicious anaemia — an inherited autoimmune condition;
- atrophic gastritis — inflammation and deterioration of the stomach lining;
- stomach surgery such as gastric bypass, or partial or full gastric resection (removal of the ileum), which also leads to B12 deficiency, because that is where the receptors needed for its absorption are;
- Crohn's disease (inflammatory bowel disease);
- enteritis and coeliac disease, which can also disturb absorption of this important vitamin;
- exposure to nitrous oxide during surgery;
- poisoning with heavy metals such as mercury, which interferes with B12's ability to cross the blood–brain barrier and reach the neurons that need it.
Why vitamin B12 is one of the most important vitamins
Vitamin B12 plays a very important role in stimulating metabolism, producing energy and the normal functioning of the nervous system. Normal levels help reduce feelings of weakness and fatigue. B12 stimulates energy production and takes part in the metabolism of carbohydrates, proteins and fats. It supports proper DNA synthesis in the formation of red blood cells and looks after the transport of oxygen to all the organs. It is necessary for a trouble-free pregnancy.
Signs that may suggest a lack of vitamin B12:
- difficulty with memory
- numbness in the limbs
- depressive states
- slowed reactions
- arrhythmia
- fatigue
B12 deficiency is a metabolic disorder that can lead to serious health problems.
Causes that can lead to a B12 deficiency:
- stress — cortisol is released, builds up in the stomach and intestines and slows digestion; stress interferes with the absorption of food and of vitamin B12;
- inflammation and infection;
- disturbed secretion of hydrochloric acid and destruction of intrinsic factor;
- use of contraceptives, antibiotics and anticonvulsant medicines;
- an unhealthy lifestyle and poor diet;
- Helicobacter pylori;
- atrophic gastritis;
- medicines against stomach acid;
- overgrowth of particular strains of gut bacteria.
Where to get vitamin B12
There are two kinds of source:
- Food — products of animal origin such as liver, heart, kidneys, chicken and beef; fish and seafood; dairy products and eggs. Some vegan foods too: tempeh, tofu, miso, muesli and brewer's yeast.
- Supplements — there are various supplements on the market in the form of lozenges, liquid vitamins, nasal sprays and injections, which help restore this vitamin quickly. When there is a large deficiency it is worth consulting a doctor and starting with injections, then moving to lozenges or nasal sprays.
The different forms of vitamin B12
Cyanocobalamin
A form of B12 that has to go through metabolic steps before it is converted into methylcobalamin or adenosylcobalamin. It does not occur in foods of animal origin; it is made synthetically, with cyanide binding compounds attached after B12 is produced by particular strains of bacteria. Smoking already burdens the body with cyanide, so large amounts of B12 in the cyanocobalamin form are not suitable for smokers.
Methylcobalamin
One of the two biologically active forms of vitamin B12 the human body needs; it takes part in regulating the amino acid homocysteine. Methylcobalamin is needed for the methylation of homocysteine into methionine, which takes part in a number of biochemical processes, such as the metabolism of neurotransmitters. Besides damage to the myelin sheath, a B12 deficiency can lead to depressive states (read more about depression here), sleep problems, panic attacks, schizophrenia and more. Raised homocysteine is a known risk factor for cardiovascular disease, and as vitamin B12 levels fall, homocysteine levels rise. A lack of B12 in the methylcobalamin form leads to DNA damage.
According to reports from shared experience, methylcobalamin, like other methyl donors, can have a negative effect in some people. There are experiments providing evidence that methylcobalamin can methylate mercury, forming the still more toxic methylmercury. People exposed to mercury (from amalgam, for instance) should therefore use other forms of B12. Methylcobalamin achieves three times higher B12 stores in the liver than cyanocobalamin.
Adenosylcobalamin
The second biologically active form of B12. According to b12-vitamin.com, adenosylcobalamin takes part in energy production in the mitochondria of cells, in all organs and tissues, and makes up around 20% of the vitamin B12 in the blood. A lack of B12 in this form disturbs ATP production at cell level, with symptoms such as:
- chronic fatigue
- severe exhaustion
- muscle weakness
- weight loss
- developmental disturbances
Hydroxocobalamin
Not itself a coenzyme form of B12, but the body can convert it into both methyl- and adenosylcobalamin, and it is a common transitional form in B12 metabolism. It also binds particularly well to the body's transport molecules and so circulates in the blood for a long time — which makes it the best form for storing the vitamin.
Tests that confirm or rule out a B12 deficiency
- full blood count with MCV, RDW and MCH
- serum vitamin B12
- reticulocytes
- serum iron
- total iron-binding capacity (TIBC)
- folic acid (vitamin B9)
- homocysteine
A vitamin B12 deficiency can lead to digestive disturbances, a raised risk of heart disease and disturbances in all cognitive functions. High levels, however, can harm the liver, because that is where it is stored. It is easy to establish whether you are deficient through a blood test. This vitamin matters both for children and for adults. To protect ourselves from a shortage, it is good to live healthily and eat properly.
This article is informational and does not replace consultation with a doctor.
Sources: histameany.de · b12-vitamin.com
