Vitamin B12 deficiency: symptoms, causes and treatment

What is vitamin B12 deficiency and how much vitamin B12 do you need every day?

A vitamin B12 deficiency is when your body does not have a sufficient supply of the vital vitamin B12 (cobalamin). Vitamin B12 plays a central role in haematopoiesis, the function of the nervous system and many metabolic processes. It is essential for the formation of the sheath of nerve fibres (myelin sheath), cell division and DNA synthesis.

The recommended daily dose of vitamin B12 for adults is 4 micrograms. As vitamin B12 is found almost exclusively in animal foods, vegans have an increased risk of a deficiency and should supplement regularly. Older people over the age of 50, people with chronic gastrointestinal diseases and after stomach surgery can also be more frequently affected by a vitamin B12 deficiency.

Vitamin B12 deficiency symptoms

The symptoms of a vitamin B12 deficiency can occur gradually and can be easily overlooked at first. The most common signs include

• Fatigue and exhaustion
• Pallor
• Shortness of breath
• Heart palpitations
• Sweating
• Headaches
• Dizziness
• Concentration and memory problems
• Joint pain
• Pain in the legs
• Balance problems
• Changes in the sense of taste and sense of smell
• Loss of appetite and weight loss

Vitamin B12 deficiency symptoms in women

Women are particularly frequently affected by a vitamin B12 deficiency, as the requirement is increased during pregnancy and breastfeeding. In addition to the general symptoms, women with a vitamin B12 deficiency may notice the following specific signs:

• Irregular or absent menstruation
• Infertility
• Pregnancy complications such as premature birth or miscarriage
• Puerperal depression

Vitamin B12 deficiency weight gain

Although vitamin B12 deficiency is often associated with weight loss, in rare cases it can also lead to weight gain. This is because a lack of vitamin B12 can slow down the metabolism and lead to water retention in the body. A balanced diet and treatment of vitamin B12 deficiency can help to regulate weight.

Vitamin B12 deficiency symptoms eyes

Vitamin B12 deficiency can also affect the eyes. Possible symptoms are:

• Blurred vision or visual disturbances
• Sensitivity to light
• Burning or itching of the eyes
• Yellowing of the eyes (jaundice)

In severe cases, an untreated vitamin B12 deficiency can even lead to optic nerve damage and blindness.

Vitamin B12 deficiency Neurological symptoms

Vitamin B12 deficiency can also lead to various neurological symptoms. These include:

• Tingling or numbness in the hands, feet or other parts of the body (paraesthesias)
• Burning or painful sensations (neuropathies), which are particularly common in the legs
• Muscle weakness and loss of strength, especially in the legs
• Coordination and balance disorders, unsteady gait
• confusion, forgetfulness and memory problems and even dementia
• visual disturbances such as blurred vision or visual field defects
• depressive moods, irritability and personality changes

Vitamin B12 deficiency causes

The most common cause of a vitamin B12 deficiency is insufficient intake through food. People are particularly at risk:

• Vegans and vegetarians, as vitamin B12 is found almost exclusively in animal foods
• People with an unbalanced or unbalanced diet
• Older people, as the absorption of vitamin B12 is often impaired in old age
• People with chronic gastrointestinal diseases such as Crohn's disease, ulcerative colitis or coeliac disease
• People who have undergone stomach surgery in which parts of the stomach were removed
• People with autoimmune diseases such as pernicious anaemia, which interfere with the absorption of vitamin B12
  
  Certain medications can also promote vitamin B12 deficiency by impairing the absorption or utilisation of vitamin B12. These include, for example, medications for the treatment of heartburn (proton pump inhibitors), metformin for diabetes, antibiotics or anticonvulsants.

Vitamin B12 overdose

Although vitamin B12 deficiency is far more common, it is also possible to consume too much vitamin B12. As vitamin B12 is water-soluble, the body usually excretes excess amounts via the urine. Nevertheless, extremely high doses, usually due to improper use of food supplements or injections, can lead to side effects. Possible symptoms of a vitamin B12 overdose include skin rashes, acne, hives, swelling, diarrhoea, constipation, tiredness and headaches. In very rare cases, an overdose can lead to life-threatening allergic reactions or cardiac arrhythmia. It is important to note that most people do not suffer an overdose even with a high dietary intake, as the body regulates the absorption of vitamin B12 in the intestine. Nevertheless, supplements should always be taken as directed by a doctor or pharmacist to avoid overdosing.

Vitamin B12 in food

There are many good sources of vitamin B12, both plant and animal-based. Here is an overview of the 10 foods richest in vitamin D (plant-based and animal-based) with their average vitamin D content per 100 g:

Vegan sources of vitamin B12

Plant-based foods do not naturally contain vitamin B12. Vegans and vegetarians should therefore opt for foods fortified with vitamin B12, such as special margarine, soya milk, breakfast cereals or yeast products, or take vitamin B12 supplements.