Vitamin B12, or Cobalamin, is one of the eight B vitamins. It is needed to ensure the proper functioning and health of nerve tissue, brain function, and red blood cells.
Like all B vitamins, vitamin B12 is a water-soluble vitamin. This means it dissolves in water and travels through the bloodstream. The human body does not store cobalamin. Any excess or unwanted amounts are excreted through urine.
Structurally, vitamin B12 is the most complicated vitamin. It is also the largest. Cobalamin can only be industrially produced through bacterial fermentation synthesis.
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What does vitamin B12 do?
Vitamin B12 plays a vital role in the normal functioning of the brain and the nervous system and in the formation of red blood cells. It also helps to regulate and synthesize DNA.
It is needed in the metabolism of every cell in the body, and it plays a part in the synthesis of fatty acids and energy production. By helping the human body to absorb folic acid, it facilitates the release of energy.
The human body produces millions of red blood cells every minute, but without vitamin B12, cells cannot multiply properly. The production of red blood cells goes down if a person's vitamin B12 levels are too low. As the red blood cell count drops, anemia results.
The most common symptoms of anemia are fatigue, shortness of breath and palpitations, or irregular heartbeat. People with anemia might also have:
- A sore mouth or tongue
- Weight loss
- Pale or yellowish skin
- Menstrual problems
Vitamin B12 deficiency also leaves people more susceptible to infections.
Where do we get vitamin B12 from?
Vitamin B12 can be found naturally in animal products, such as fish, meat, eggs, and dairy products. It does not typically occur in plant foods.
Foods that are good sources of vitamin B12 include:
- Beef, pork, ham, poultry, and lamb
- Fish, especially haddock, and tuna
- Milk, cheese, and yogurt
- Some nutritional yeast products
Vegans consume no animal products., but they can take vitamin B12 dietary supplements to avoid deficiency. This is particularly important during pregnancy and while breastfeeding.
Some types of soya milk and breakfast cereals are fortified with vitamin B12.
Some nutritional yeast products may contain vitamin B12.
What happens in vitamin B12 deficiency?
Vitamin B12 deficiency can result in irreversible and potentially severe damage, especially to the human nervous system and brain. It can also cause anemia. Even at slightly lower-than-normal B12 levels, a person can experience depression, confusion memory problems and tiredness. However, these symptoms are not specific enough to diagnose vitamin B12 deficiency.
Constipation, loss of appetite, and weight loss can result.
More serious symptoms include neurological changes, such as numbness and tingling in the hands and feet. Some people may have difficulty maintaining balance.
Infants who lack vitamin B12 may have unusual movements, such as face tremors, reflex problems, feeding difficulties, irritation, and eventual growth problems if left untreated.
Who is at risk of vitamin B deficiency?
Vegans consume no animal sourced food products at all. They have a considerably higher risk of developing vitamin B12 deficiency, especially during pregnancy and lactation. Plant-sourced foods do not have enough cobalamin to guarantee long-term human health.
Low levels of vitamin B12 can contribute to dementia and confusion.
People with pernicious anemia may lack vitamin B12. Pernicious anemia is an autoimmune disease that affects the blood. Patients with this disorder do not have enough intrinsic factor (IF), a protein substance in the stomach that allows the body to absorb vitamin B12.
Other groups who are at risk include those with problems that affect the small intestine, for example, those whose small intestine has been shortened. They may not be able to absorb cobalamin properly. People with Crohn's disease may be at risk, but researchers say there is a lack of evidence to confirm this.
People with chronic alcoholism may lack vitamin B12, as they are not able to absorb nutrients efficiently.
People with diabetes who are using metformin are advised to monitor their levels of vitamin B12. Metformin might reduce the absorption of vitamin B12.
Treatment includes vitamin B12 injections. Vitamin B12 must be injected in patients who have problems absorbing nutrients, because they are not able to absorb sufficiently vitamin B orally.
How common is B12 deficiency?
Most children and adults in North America and Europe consume enough vitamin B12, but the prevalence of vitamin B deficiency in the United States is estimated to be between 1.5 percent and 15 percent of the population.
This is because some people, such as older people, patients with pernicious anemia, and those with achlorhydria or intestinal disorders may have problems absorbing vitamin B12 from food properly, and even oral supplements do not help.
How much vitamin B12 should people consume?
In the U.S., the National Institute of Health, recommends that teens and adults over the age of 14 years should consume 2.4 micrograms (mcg) of vitamin B12 a day, pregnant women 2.6 mcg and lactating women 2.8 mcg.
Excessive intake of vitamin B12 has not proven to be toxic, but people are always advised to speak to their physician before starting to take supplements.
Some medications may interact with vitamin B12. These include metformin, proton pump inhibitors and h2 receptor agonists, used for peptic ulcer disease, all of which may interfere with absorption. There is also evidence that the bacteriostatic antibiotic, Chloramphenicol, or Chloromycetin, may interfere with production of red blood cells in some patients who are taking vitamin B12 supplements.