Vitamin B12 – what is its importance for the functioning of the body? Is it worth supplementing?

Vitamin B12 is an organic chemical compound that plays a significant role in the proper functioning of the body. Its main task is to regulate the production of erythrocytes. An adequate supply supports the metabolism of carbohydrates and amino acids, and even prevents pernicious anaemia. How does vitamin B12 affect overall health? What are the risks of deficiency and who should consider supplementation?

Vitamin B12 - what is its function?

Vitamin B12, also known as cobalamin, is one of the B vitamins that is soluble in water. An adequate supply significantly affects the functioning of the haematopoietic and nervous systems. Vitamin B12 participates in many important processes – one of its main functions is the production of vitamin B9 (folic acid) in its active form.

Vitamin B12, when supplied to the body in adequate amounts, has a visible effect on daily well-being. This is because its role is to protect the nerves by supporting the condition of the myelin sheaths. It has also been proven that supplying sufficient amounts of this vitamin can slow down the development of hepatitis C. Available forms include B12 methylcobalamin, aquacobalamin, deoxyadenosylcobalamin and B12 in the form of synthetic cyanocobalamin.

Causes of vitamin B12 deficiency

The main cause of vitamin B12 deficiency is an unbalanced diet. Its main source is meat. Nowadays, the worldview of a large part of society is influencing a reduction in the consumption of animal products.

The number of people following vegetarian and vegan diets is constantly increasing. The absence of meat in meals greatly contributes to B12 deficiency. Studies confirm that serum vitamin B12 concentrations are lower in vegetarians. Not only the type of food consumed plays a significant role, but also the length of time for which a meat-free diet is followed. Specialists suggest that all types of elimination diets, including those that exclude meat from the menu, should be followed under the supervision of a specialist dietitian.

Certain diseases are also risk factors, including type B gastritis with achlorhydria, Crohn's disease, Zollinger-Ellison syndrome and Addison-Biermer disease. Disorders can affect both the absorption and excretion of vitamin B12. The deficiency may also be caused by the interaction of vitamin B12 with chronic medications.

Vitamin B12 deficiency – what are the symptoms and effects?

Vitamin B12 deficiency is a serious condition. Diagnosis is difficult because clinical symptoms only appear several years after the deficiency in the diet has occurred. The symptoms are divided into psychiatric, neurological and haematological. It is estimated that they become apparent when 90% of reserves are lost. The most characteristic symptoms are fatigue, muscle weakness, irregular heartbeat, inflammation of the tongue and mucous membrane, low mood, irritability, as well as a set of symptoms characteristic of anxiety and depressive disorders.

What are the consequences of untreated vitamin B12 deficiency?

• pernicious anaemia - haematological changes caused by vitamin B12 deficiency
• changes in the bone marrow
• progressive atherosclerotic changes
• jaundice
• dementia and memory disorders
• psychosis and hallucinations
• depressive episodes
• paraesthesia
• dementia
• optic nerve neuropathy
• spinal cord degeneration

When is the demand for vitamin B12 increased?

Doctors often recommend supplementation to people who should pay special attention to consuming foods rich in vitamin B12. These are primarily pregnant women. Vitamin B12 plays a key role in the development of children. Older people should also regularly check their vitamin B12 levels, as they may have absorption problems caused by insufficient production of stomach acids.

People with diabetes are another risk group. Metformin, which is taken by patients with this disorder, significantly reduces the absorption of vitamin B12. Alcoholism is an often overlooked factor affecting B12 absorption disorders. Chronic alcohol abuse is often associated with malnutrition and reduces the absorption of nutrients from food.

Where to find vitamin B12? How is it absorbed?

Where is vitamin B12 found? Which foods have the highest content?

• veal, beef and chicken kidneys
• liver
• fish
• seafood
• blue cheese, natural yoghurt
• eggs

Trace amounts of vitamin B12 can also be found in pickled foods (due to the presence of lactic acid in their composition). Vitamin B12 is not found in vegetables and fruit. It is produced primarily in the digestive tract of animals. Vegetarians and vegans should definitely supplement this nutrient and monitor its levels to prevent deficiency. Currently, vitamin B12 lozenges are available on the market, and thanks to their convenient form, daily intake is not a burden.

The absorption of vitamin B12 can be divided into several stages. It begins in the mouth. It then passes into the stomach, where B12 is separated from protein compounds. The next stages take place in the duodenum and ileum. It is stored by the liver. Due to the fact that a certain percentage of this vitamin is passively absorbed in the intestine, it is possible to effectively use oral supplements and medicines.

Supplementation - B12 methylcobalamin

Vitamin B12 is available in various forms. It is widely recognised that methylcobalamin is the most easily absorbed. It is the active form found in nature. The body absorbs it automatically after ingestion. It is also indicated that it is stored in tissues for a relatively long time. This substance is considered to be the most effective and efficient way to supplement B12 deficiency. This is because it has the ability to cross the blood-brain barrier.

Cyanocobalamin is slightly more widely available on the market. This is because methylcobalamin requires more restrictive storage. Specialists often recommend sublingual methylcobalamin supplementation. This allows it to be absorbed into the plasma through the mucous membrane.

When should you take vitamin B12? Supplementation is recommended for all people who do not eat meat, as well as for patients who receive a recommendation from a specialist. People taking antidepressants, hormonal medications, aspirin or sleeping pills should also consider taking supplements. Most of the substances used in the production of these pharmacological agents reduce the absorption of B12 and can lead to deficiencies.

Bibliography

‘Interactions with drugs - an important indication for vitamin B12 supplementation’ - J. Biernat, M. Bronkowska, Department of Human Nutrition, Faculty of Food Sciences, Wrocław University of Environmental and Life Sciences, 2014

‘Vitamin B12 - structure, biosynthesis, functions and methods of determination’ A.Kośmider, K.Czaczyk, Faculty of Food Science, Warsaw, 2010

‘Vitamin B12 - effects of deficiency, justification for therapy and dietary supplementation in elderly people’ - M. Mziray, P. Domagała, R. Żuralska, M. Siepsiak, Medical University of Gdańsk 2016

‘Assessment of the needs and possibilities of increasing the vitamin B12 content in the diet’ E.Sicińska, M.Cholewa, Faculty of Human Nutrition and Consumption, Warsaw University of Life Sciences

‘Vitamin B12 deficiency in the elderly - causes, consequences, therapeutic approach’ J. Zabrocka, Z. B. Wojszel, Social Insurance Institution in Białystok, Municipal Office in Białystok, 2013

‘Type and duration of vegetarian diet and serum vitamin B12 concentration’ M.Chabasińska, J. Przysławski, A. Lisowska, M. Schlegel-Zawadzka, M. Grzymisławski, J. Walkowiak, K. Marcinkowski Medical University in Poznań, Jagiellonian University in Krakow