What are the symptoms of vitamin B12 deficiency?

After thousands of years of searching for the sources of health and well-being, humanity has discovered many factors that can affect the length and quality of everyday life. Before the advent of modern medicine, even seemingly harmless ailments could be fatal. Biological and chemical discoveries that have taken place in more recent times have made it possible to optimise both physical and mental performance through nutrition, a prime example of which is the identification of the chemical structure and biological functions of vitamin B12.

1. Haematological symptoms of B12 deficiency
2. Neurological symptoms of B12 deficiency
3. Risk of B12 deficiency

Haematological symptoms of B12 deficiency

An important milestone in the history of discovering the properties of vitamin B12 was the observation of the effects of liver consumption by people with anaemia in the 1930s. Until then, pernicious anaemia was often fatal, especially among people living in poorer regions of the world.

Anaemia is a disorder of blood cell production, manifested by decreased haemoglobin and haematocrit levels and pathological enlargement of red blood cells. In the course of this disease, blood cells do not mature, which means they cannot perform their functions, including transporting oxygen from the lungs to peripheral tissues. This is associated with a spectrum of neurological symptoms. Additional ‘external’ symptoms may include pale skin and inflammation of the tongue.

Neurological symptoms of B12 deficiency

An insufficient supply of vitamin B12 affects the functioning of the nervous system not only by limiting oxygen transport. It is a cofactor and coenzyme in many processes in the body, including the biosynthesis of proteins and DNA in nerve structures. These functions have a direct impact on the development of the nervous system and its regeneration after injuries.

What is more, vitamin B12 participates in energy metabolism, so its deficiency can result in reduced performance of both muscles and the brain. Deficiency symptoms include constant fatigue, which may be accompanied by skeletal muscle control disorders, tremors and tingling in the limbs, symptoms of dementia, and low mood. 

Risk of B12 deficiency

In addition to calculating the average daily intake, laboratory tests are also used to assess vitamin B12 levels in the body. A complete blood count with a smear test is performed, and vitamin B12, methylmalonic acid and homocysteine levels are checked. If, despite a long-term and high intake of this compound in the diet, the laboratory test results are cause for concern, it is worth consulting a doctor for the diagnosis of autoimmune diseases or gastrointestinal disorders.

Anaemia can occur not only as a result of iron deficiency, but also due to insufficient production of a compound that enables the absorption of cobalamin, i.e. intrinsic factor. This is pernicious anaemia and has an autoimmune basis. People suffering from coeliac disease (also an autoimmune disease) and inflammatory bowel disease, as well as those who chronically use medicines that reduce stomach acidity, may also have problems with the production and activity of the intrinsic factor.