Vitamin B12 is an essential nutrient that your body needs for processes like DNA synthesis, energy production, and central nervous system function. Although the vitamin is found in many foods, B12 insufficiency and deficiency are relatively common.

How prevalent is B12 deficiency?

Vitamin B12 deficiency is a relatively prevalent condition — research suggests it affects approximately 6 percent of the world’s population. However, this number may vary depending on the region, age group, gender, and medical conditions of the subjects. For example, adults over 60 are more prone to B12 deficiency, with a prevalence of between 10 percent and 19 percent.

Similarly, vitamin B12 deficiency is more prevalent in women than in men and is even more common during pregnancy. Region-wise, experts suggest that B12 deficiency is prevalent in developing countries, while wealthier regions show a lower incidence due to better diets.

Certain medical conditions can also influence the risk of B12 deficiency. Malabsorption-related conditions like celiac disease and autoimmune gastritis can represent a risk for B12 deficiency. Diet is another key factor for this condition. Strict vegetarians or vegans might not get enough B12 in their diet without supplementation.

What are the causes of B12 deficiency?

Vitamin B12 deficiency can mainly be caused by three factors: malabsorption, autoimmune conditions, or insufficient intake. The first one refers to the hindered capacity to incorporate B12 into the body, either due to age or medical conditions that affect the bioavailability of this vitamin. 

The second refers to pernicious anemia — an autoimmune disease that inhibits the protein responsible for absorbing B12. Pernicious anemia is the most common cause of vitamin B12, but its exact causes are still unknown. Yet, having a family history of the condition, being over 60, and being a woman can increase a patient’s risk of pernicious anemia.

Finally, insufficient intake of vitamin B12 stems from unbalanced diets. Vegetarians and vegans are at an elevated risk of B12 deficiency, as their diets don’t include natural B12 sources. While many solve this problem by taking B12 tablets, strict or orthodox vegetarians may not be willing to take supplements, further worsening the problem.

Why is B12 important?

Vitamin B12 is an essential nutrient for the human body, as it plays a crucial role in many biological functions. One of its primary functions is to promote and support brain development, especially among babies and children. Therefore, a lack of B12 at an early age could lead to brain damage.

Similarly, B12 is essential for forming red blood cells and synthesizing DNA. However, improper functioning of these processes doesn’t always show clear symptoms, making it hard to determine the exact consequences of B12 intake for a specific patient.

What are the symptoms of B12 deficiency?

B12 deficiency doesn’t have a clear set of symptoms — rather, this condition can manifest itself in many aspects of the patient’s life. The severity of these symptoms will also depend on the scope of the deficiency. These are some of the most common signs of a vitamin B12 deficiency:

  • lethargy and tiredness
  • general muscle weakness
  • mouth ulcers and unusually red tongue
  • paraesthesia (pins and needles on the skin)
  • depression
  • problems with memory and judgment

Severe cases of vitamin B12 deficiency can cause dementia, infertility, and heart palpitations. Leaving this condition untreated for long periods can result in irreversible neurological damage, so early detection is crucial for a healthy recovery.

How is B12 deficiency diagnosed and treated? 

If you suspect a patient has a B12 deficiency, they will require a thorough physical and history evaluation. Dietary history and medications should be reviewed carefully.

Look for gastrointestinal and neurologic disturbances that stem from anemia and B12 deficiency. A dermatologic exam is also recommended, along with taking note of other symptoms such as diarrhea and headaches.

If the evaluation suggests B12 deficiency, the patient must take a complete blood test to measure B12 and folate levels accurately. While other tests such as MMA and homocysteine levels can also be used, a blood test is often enough to determine B12 deficiency.

Treating vitamin B12 deficiency is relatively straightforward — in most cases, a high-dose sublingual oral supplement (≥ 1000 μg) will be enough to return the B12 levels to normal. However, if the patient can’t correctly absorb B12, a monthly intramuscular dose should be prescribed.

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