The deficiency of vitamin B12 is one of the most common micronutrient deficiencies worldwide.
It is most confirmed in elderly people and strict vegetarians who do not consume animal products.
The important role it plays in the body determines the nature and severity of the consequences of its deficiency, among which, by the way, is a decrease in sports performance.
In this article, we will discuss the symptoms of vitamin B12 deficiency.
Main thoughts:
Chronic vitamin B12 deficiency can lead to coordination problems and falls.
With chronic vitamin B12 deficiency, vision may deteriorate due to damage to the optic nerve.
The Important Role of Vitamin B12
Vitamin B12 or cobalamin is a water-soluble vitamin that plays an important role in the formation of red blood cells and DNA, as well as in the proper functioning of the nervous system.
Neither humans nor animals can synthesize it on their own. Food is its only source 1.
In its natural form, vitamin B12 is found in animal products, including meat, fish, poultry, eggs, and dairy products. It is also added to a considerable number of processed foods, including sports nutrition, breakfast cereals, bread, and non-animal types of milk (soy, rice, almond).
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Risk groups for vitamin B12 deficiency
Vitamin B12 deficiency is one of the most common deficiencies of vitamins and minerals worldwide 1.
The causes may be insufficient intake from food or the body’s inability to absorb it.
The following groups are at risk for vitamin B12 deficiency:
- elderly people;
- vegetarians (those who completely exclude animal products from their diet, particularly vegans and raw foodists);
- those who have undergone surgery that removed part of the intestine responsible for B12 absorption;
- those taking certain medications (metformin for diabetes, antacid medications for heartburn).
The only source of vitamin B12 for humans is food, specifically animal products. At risk for deficiency are vegetarians and elderly people.
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Challenges in diagnosing vitamin B12 deficiency
The main challenge is that the signs of vitamin B12 deficiency may appear years after its development.
Also, there is no single symptom that can definitively diagnose it 1. It cannot be done solely through a blood test: the level of this vitamin in the blood is not a definitive indicator 1, as it depends on the type of deficiency.
In terms of symptoms, vitamin B12 deficiency is very similar to vitamin B9 (folate) deficiency.
The concentrations of B9 and B12 are interrelated: if the body lacks vitamin B12, the level of B9 also drops. If vitamin B9 is then taken, it may “mask” the deficiency of vitamin B12 2.
Below are 9 signs of vitamin B12 deficiency. Any of them (especially if there are several) is a reason to consult a doctor.
Signs of vitamin B12 deficiency may appear years later, and there is no single symptom that could be used to diagnose it.
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Symptoms of vitamin B12 deficiency
1 Pale yellowish skin
People with vitamin B12 deficiency often have pale skin with a slight yellowish tint; the yellow color also appears on the cornea of the eyes (the visible white part).
The reason for this is the decrease in the production of red blood cells (erythrocytes), which are indeed red and “responsible” for the pink healthy color of the skin 3. In medical terms, this condition is called anemia.
Vitamin B12 plays a very important role in the creation of DNA molecules, in which the mechanism for synthesizing erythrocytes is “recorded” 3.
Its deficiency leads to a type of anemia, where non-functional red blood cells of very large size are formed in the bone marrow: they simply cannot exit the bone marrow and enter the bloodstream. As a result, the blood becomes less red, and the skin loses its pink hue.
Such non-functional blood cells are easily destroyed, leading to an increase in bilirubin levels – a reddish-brown substance produced by the liver during the disposal of erythrocytes.
It is bilirubin that colors the normally white cornea of the eye yellow 4. (The same happens, by the way, in jaundice.)
With a deficiency of vitamin B12, the skin becomes pale, and the cornea of the eye (the visible white part) acquires a yellowish tint due to anemia.
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2 Weakness and fatigue
This is another characteristic symptom of vitamin B12 deficiency.
The reason is the same: anemia, due to the disruption in the production of red blood cells, which are responsible for transporting oxygen to the cells in the body, without which their functioning and life are impossible.
(To illustrate the importance of oxygen: complete deprivation of brain cells of oxygen leads to their death within a few minutes.)
Oxygen is necessary for obtaining energy from food. Its deficiency logically leads to feelings of lethargy and weakness.
In sports, a deficiency of vitamin B12 means a decrease in performance: supplying muscles with oxygen is a determining factor in physical performance; that is why the action of many types of doping is aimed at improving the blood’s transport function in carrying oxygen; in the case of B12 deficiency, the opposite effect occurs.
The cause of weakness and lethargy in vitamin B12 deficiency is the disruption of oxygen supply to the muscles and other organs due to the disruption in the production of red blood cells (anemia). In sports, this leads to a decrease in performance.
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3 Tingling sensation in hands and feet
One of the serious side effects of vitamin B12 deficiency is nerve cell damage.
This occurs over time and is related to the fact that vitamin B12 is necessary for the creation of a protective sheath for nerve cells, called myelin 5.
A sign that damage has occurred is paresthesia or a tingling sensation in the limbs (arms and legs).
This type of nerve function disorder due to vitamin B12 deficiency often occurs against the backdrop of the anemia described above. But not always.
Results from one study show that 28% of patients with B12 deficiency exhibited neurological symptoms, while anemia was absent 6.
This indicates that the presence of one sign (anemia or tingling in the fingers) is an insufficient basis for diagnosing vitamin B12 deficiency.
Vitamin B12 plays an important role in creating the protective sheath of nerve cells – myelin; a deficiency of this vitamin leads to nerve damage, which is accompanied by a tingling sensation in the limbs.
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4 Coordination Disorders
If vitamin B12 deficiency is not recognized in time and treatment is not started, ongoing damage to the nervous system can lead to impaired motor function.
In particular, this can affect coordination, increasing the risk of falls. This symptom is especially common in the elderly 7 and not infrequently in young people 8 and vegetarians with a severe degree of vitamin B12 deficiency.
Diagnosis and treatment improve mobility.
Chronic vitamin B12 deficiency can lead to coordination disorders and falls.
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5 Inflammation of the Tongue and Oral Cancer
Inflammation of the tongue or glossitis manifests as changes in its color, shape, and the appearance of tenderness. It becomes redder than usual and swells, while the surface becomes smooth as the small bumps containing taste receptors disappear.
Such changes can significantly affect the ability to speak and eat.
Scientists state that an inflamed and swollen tongue with elongated lesions on its surface is one of the early signs of vitamin B12 deficiency 9,10.
Sometimes, vitamin B12 deficiency can lead to the development of tongue cancer, along with sensations of tingling, burning, and itching in it 9.
One of the early symptoms of vitamin B12 deficiency is a red swollen tongue with elongated lesions on the surface.
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6 Shortness of breath and dizziness
Anemia due to vitamin B12 deficiency leads to shallow rapid breathing and dizziness, especially during physical exertion.
This is a consequence of poor oxygen supply to the organs: when the blood’s transport function is impaired, the body tries to meet its constant demand for oxygen by pushing a larger volume of air through the lungs, increasing the breathing rate.
However, shortness of breath and dizziness do not always indicate a lack of vitamin B12: this symptom can have a vast number of other causes.
Anemia that develops from vitamin B12 deficiency often leads to shortness of breath and dizziness, as the cells receive insufficient oxygen.
7 Deterioration of vision
Another symptom of vitamin B12 deficiency is the deterioration of vision.
This occurs because the optic nerve is damaged, through which signals are transmitted from the retina to the brain 11,12. In medical terms, this condition is called optic neuropathy.
Despite its seriousness, this symptom is reversible if vitamin B12 is taken.
With chronic vitamin B12 deficiency, vision may deteriorate due to damage to the optic nerve.
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8 Poor mood
People with vitamin B12 deficiency often complain of a worsening mood.
Low levels of this vitamin are associated with psychological and cognitive disorders such as depression and dementia 13,14.
This is a result of increased levels of the amino acid homocysteine, which occurs with decreased concentrations of vitamin B12, which scientists believe can lead to brain damage and disrupt the transmission of nerve impulses to and from the brain 15.
Supplementing with vitamin B12 may alleviate this symptom 16.
However, it is also important to understand that mood changes, depression, and dementia can occur for many other reasons. Therefore, taking vitamin B12 for their treatment may not yield any results.
Sometimes a deficiency of vitamin B12 is accompanied by mood deterioration, depression, and decreased cognitive function, particularly dementia.
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9 Increased temperature
In rare cases, a lack of vitamin B12 may be accompanied by an increase in temperature.
It is not entirely clear why this occurs; however, doctors have recorded several cases where patients with B12 deficiency had their body temperature return to normal after additional intake of the vitamin 17.
Sometimes one of the symptoms of vitamin B12 deficiency can be an increase in body temperature.
Treatment of vitamin B12 deficiency
Injections
To treat vitamin B12 deficiency, doctors often prescribe intramuscular injections (shots) of hydroxocobalamin or cyanocobalamin.
This is the most effective method of treatment.
In terms of safety, injections do not have serious side effects. In rare cases, an allergic reaction is noted 18,19.
Food products
Vitamin B12 is found in animal products and fortified foods. To replenish its deficiency or to avoid it, it is enough to regularly include these foods in the diet.
Most often, breakfast cereals and plant-based milk (soy, rice, almond) are fortified with it. Check the labels for descriptions.
A list of foods that contain a large amount of vitamin B12 22:
- Liver: 1/3 cup (~75 g) provides about 881% of the daily requirement;
- Beef kidneys: 1/3 cup (~75 g) provides about 331% of the daily requirement;
- Trout: 1/3 cup (~75 g) provides about 61% of the daily requirement;
- Canned salmon: 1/3 cup (~75 g) provides about 61% of the daily requirement;
- Ground beef: 1/3 cup (~75 g) provides about 40% of the daily requirement;
- Eggs: 2 large eggs provide about 25% of the daily requirement;
- Milk: 1 cup (250 ml) provides 20% of the daily requirement;
- Chicken: 1/3 cup (75 g) provides 3% of the daily requirement.
For an extended list of products indicating the content of vitamin B12, see the article Which products contain the most vitamin B12 (Table).
As can be seen, the list includes only animal products. This means that it is quite challenging to provide the necessary amount of vitamin B12 for individuals following a strict vegetarian diet (vegans and raw foodists).
Therefore, to avoid vitamin B12 deficiency and its treatment, it is recommended that all individuals in the risk group take it as a dietary supplement.
Tablets
Scientific studies confirm that oral vitamin B12 preparations (tablets) are at least as effective in treating its deficiency as injections 20,21.
Vegetarians and vegans are advised to take at least 10 mcg of vitamin B12 per day or 2000 mcg once a week 22.
However, many doctors prefer injections, considering them more effective.
For the prevention and treatment of vitamin B12 deficiency, injections, oral preparations (tablets), and foods high in it are recommended. Scientists speak of the equal effectiveness of injections and oral preparations.
Conclusion
Vitamin B12 deficiency is very common worldwide and can manifest with multiple symptoms, making accurate diagnosis challenging. Among them are pallor and yellowing of the skin, vision and coordination disturbances, tingling in the limbs, worsening vision, and others.
Individuals at particular risk of deficiency include the elderly and strict vegetarians who do not consume animal products.
In most cases, simple intake of vitamin B12 as a supplement by individuals in the risk group can be an effective preventive measure to avoid serious consequences.
