What is Vitamin B12? What Are the Symptoms of B12 Deficiency?

Vitamin B12, also known as cobalamin, is a bright red, crystalline substance due to its cobalt (Co) element content. It works alongside folic acid in the production of vital body structures such as DNA synthesis, red blood cell (RBC) production, and myelin (nerve sheath) synthesis.

Vitamin B12 is found exclusively in animal-based foods, and for it to be absorbed, the stomach secretes intrinsic factor. This secretion helps facilitate the absorption of B12 in the small intestine. Although vitamin B12 is water-soluble and can be stored in the liver, kidneys, and other tissues, unlike other vitamins of the same type, it cannot be synthesized by the body.

In other words, vitamin B12, which is crucial for the body, can only be naturally obtained through food. When there is a deficiency of vitamin B12 due to poor and unhealthy nutrition, the functions of nerve cells are impaired. This leads to neurological symptoms such as loss of sensation, pain, burning, and tingling. B12 deficiency is also characterized by a slowdown in cognitive functions and is more commonly seen among the elderly. In this age group, B12 deficiency is one of the main causes of depression and can lead to various other symptoms. Be

What is Vitamin B12?

Also known as cobalamin, vitamin B12 is a water-soluble vitamin that the body cannot produce but is essential for the body. Being water-soluble, it can easily travel through the bloodstream. Vitamin B12 can only be obtained naturally through animal-based foods and plays an active role in the production of red blood cells, DNA, and the proper functioning of the nervous system. Unlike other B vitamins, B12 is unique because it contains the cobalt element. Vitamin B12 also facilitates the absorption of another important vitamin, folic acid (B9), and helps in the synthesis and release of energy. Red blood cells, which are continuously produced every second, cannot multiply healthily without vitamin B12, and production can decrease. As a result, various health problems, such as anemia, can arise. Although vitamin B12 cannot be synthesized by the body, it can be stored in the liver and kidneys for up to four years. After storage, any excess vitamin B12 taken is excreted through urine.

What Does Vitamin B12 Do and What Are Its Benefits?

Vitamin B12 plays an important role, together with folic acid, in the production of red blood cells (erythrocytes) in the bone marrow. In other words, it helps maintain cell production, delays aging, and prevents anemia. It converts carbohydrates into glucose, reduces fat, facilitates protein synthesis, and supports energy production. It is thought to help balance blood pressure, prevent osteoporosis (bone loss), reduce the risk of macular degeneration, and lower cholesterol. Vitamin B12 is also beneficial for strengthening the immune system.

It plays a crucial role in the production of myelin, which is essential for the nervous system, preventing nerve damage, and strengthening the central nervous system. Thus, it is important for the healthy functioning of the nervous system. Vitamin B12 is highly effective on cognitive functions, especially memory. It facilitates learning, prevents forgetfulness, and may delay the onset of Alzheimer's disease and dementia. It is also effective in preventing depression. Additionally, vitamin B12 is known to have a positive role in fertility. Among its benefits, vitamin B12 also contributes to the synthesis of DNA, the building block of cells. It may help prevent serious health issues such as heart disease, stroke, and cancers like breast, prostate, colon, and lung cancer.

Which Foods Contain Vitamin B12?

Vitamin B12, which cannot be synthesized by the body, can only be obtained through food. Foods that contain vitamin B12 include:

• Red Meat: Organ meats such as liver (104 mcg*/100 g), spleen, and kidneys (63 mcg/100 g), as well as other types of red meat, are rich in vitamin B12.
• Fish: Fish like trout (5 mcg/100 g), bass (1 mcg/100 g), and salmon (14 mcg/100 g) contain vitamin B12.
• Eggs: One hundred grams of chicken eggs contain 2 mcg of vitamin B12.
• Cheese: Some types of cheese contain up to 1.8 mcg/100 g of vitamin B12.

In addition, poultry, milk, and yogurt are sources of vitamin B12. Fermented soy products also contain vitamin B12. However, long cooking times or excessive heat can reduce the vitamin B12 content in these foods.

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What Are the Symptoms of Vitamin B12 Deficiency?

Vitamin B12 deficiency is common in people who consume a diet low in B12, particularly among those following a vegan diet. Unlike other water-soluble vitamins, B12 can be stored in the liver, kidneys, and other tissues. Therefore, after a disruption in a balanced diet, a person may not experience B12 deficiency symptoms for up to four years. In other words, symptoms related to B12 deficiency may not appear for 5 to 6 years. The most common symptom of B12 deficiency is pernicious anemia, but nerve tissue and brain function can also be affected. The common symptoms of B12 deficiency include:

• Anemia
• Tingling, numbness, and burning sensations in the hands, feet, and legs
• Muscle cramps in the legs
• Weakness in mental functions
• Physical and mental fatigue
• Depression
• Swelling, redness, and burning sensation on the tongue
• Diarrhea
• Pain and sensitivity
• Skin yellowing
• Tinnitus (ringing in the ears)
• Palpitations
• Slowed metabolism

What Does Vitamin B12 Deficiency Lead To?

When the body lacks sufficient amounts of vitamin B12, red blood cell production is disrupted, and the body cannot produce erythrocytes. This can lead to pernicious anemia (a condition in which there are fewer red blood cells than normal in the bloodstream). The red blood cells produced in the bone marrow cannot divide normally and become larger than usual. This prevents the blood cells from passing from the bone marrow into the bloodstream, causing the person to feel weak and fatigued. In severe cases, memory loss and nerve damage may occur. The brain, heart, and other organs may also be damaged. Anemia caused by B12 deficiency is a significant risk for pregnancy, as it may lead to miscarriage, preterm birth, and stillbirth. Additionally, in newborns, frequent illnesses, attention deficits, and a decrease in perception and learning functions may occur.

Nerve cell functions are also impaired due to B12 deficiency. In this case, the person may experience numbness, tingling, and pain. Mental functions may decline, leading to difficulty in learning, concentration problems, and forgetfulness. It may be the cause and/or result of neurological diseases such as Alzheimer’s and dementia. Vitamin B12 deficiency is also one of the primary causes of depression. It is commonly observed in people aged 65 and older. When diagnosed early, this condition, which leads to neurological and mental problems, can be easily treated.

How Much Vitamin B12 Is Needed?

A B12 level above 800 pg/ml is considered to indicate vitamin B12 excess. However, having fully stocked B12 stores does not lead to a health problem. In other words, excess B12 taken beyond the body's capacity can be excreted through urine. The recommended daily intake of vitamin B12, based on age groups, is as follows:

• 0-6 Months: 0.3 mcg
• 6-12 Months: 0.5 mcg
• 1-3 Years: 0.7 mcg
• 4-6 Years: 1 mcg
• 7-10 Years: 1.4 mcg
• 11 Years and Older: 2 mcg
• Pregnant Women: 2.2 mcg
• Breastfeeding Mothers: 2.1 mcg

Vitamin B12 has a wide range of benefits. It plays an essential role in regulating homocysteine and energy metabolism, immune function, and the healthy functioning of the nervous system. If B12 levels are found to be below the reference value through a laboratory test, a doctor may suggest adjustments to the diet and may prescribe vitamin B12.