What is Vitamin B12 Deficiency?
Vitamin B12, also known as cobalamin, is a type of nutrient that dissolves in water. You can get it from animal foods like red meat, dairy products, and eggs. Our stomachs produce a special protein called intrinsic factor that helps our bodies absorb this vitamin in a part of our intestines called the terminal ileum.
After absorption, Vitamin B12 aids in various important body processes. It helps certain enzymes create DNA, fatty acids, and a substance called myelin which covers and protects nerve cells. If someone doesn’t have enough B12, they may experience blood-related or nervous system symptoms.
Our body can store a lot of B12 in the liver. But if for some reason the body can’t absorb enough B12 for a long time — maybe because a person’s diet doesn’t include enough B12, they have a condition that prevents proper absorption, or they don’t produce enough intrinsic factor — then the stored B12 in the liver may run out, causing a deficiency.
What Causes Vitamin B12 Deficiency?
Vitamin B12 deficiency can happen due to four main reasons:
First is an autoimmune issue. People suffering from a condition called Pernicious anemia produce antibodies that affect intrinsic factors – these are substances needed to absorb B12 properly. When these factors are targeted and neutralized by antibodies, B12 can’t be taken in appropriately by part of the small intestine known as the terminal ileum.
Second, is malabsorption. The problem occurs when B12 can’t be absorbed well by your body. For instance, if you’ve had gastric bypass surgery, you might be prone to a B12 deficiency because the part of your stomach that creates intrinsic factor is bypassed. In people with normal intrinsic factor production, any damage to the terminal ileum such as in surgeries due to Crohn’s disease, can interfere with B12 absorption, leading to a deficiency. Other conditions damaging the small intestine, like celiac disease or tapeworm infection can also cause B12 deficiency.
Third, you might not be getting enough B12 in your diet. While it’s true that our liver stores extra vitamin B12, people following a strict vegan diet for around three years might lack this essential nutrient due to dietary restrictions.
Lastly, exposure to certain toxins can lead to a deficit. Specifically, exposure to nitrous oxide can lead to a vitamin B12 deficiency and cause neurological symptoms.
Risk Factors and Frequency for Vitamin B12 Deficiency
Vitamin B12 deficiency among different groups of people varies, depending on the cause. Among those with anemia, studies have found that 1% to 2% of these cases are because of a lack of vitamin B12. Additionally, around 18% to 20% of people with larger than average red blood cells, a condition also known as macrocytosis, are found to have a B12 deficiency. This deficiency is more common in the elderly population and among individuals of Northern European origin, especially due to a condition known as pernicious anemia. However, African people and individuals from other parts of Europe show a lower incident rate of pernicious anemia.
- Vitamin B12 deficiency varies depending on the cause.
- Among patients with anemia, 1% to 2% are found to have a B12 deficiency.
- Among those with larger red blood cells, or macrocytosis, 18% to 20% are due to Vitamin B12 deficiency.
- This deficiency is more common in older people.
- Pernicious anemia, a common cause of B12 deficiency, is more common in people of Northern European ancestry.
- People of African descent or from other parts of Europe have a lower incidence of pernicious anemia.
Signs and Symptoms of Vitamin B12 Deficiency
Vitamin B12 deficiency is a condition that should be carefully evaluated. It’s important to pay special attention to signs related to the digestive and nervous systems. The deficiency often leads to a type of anemia known as macrocytic anemia, presenting symptoms like tiredness and pale skin. Due to inaccuracies in red blood cell formation, you might also notice skin yellowing, known as jaundice. Other potential symptoms include nerve problems in the hands and feet, swollen or inflamed tongue, diarrhea, headaches, and psychological issues.
When discussing your medical history with your doctor, make sure to mention any digestive disorders, such as celiac disease or Crohn’s disease. If you had any surgeries involving the removal of part or all of your stomach or small intestine, particularly the lower end of it (ileum), this is also vital information. Recent changes to an entirely plant-based diet can potentially lead to B12 deficiency as well.
In more severe instances, vitamin B12 deficiency can affect the nervous system. It can cause SCDSC, a condition that harms different parts of the spinal cord. Symptoms indicating nervous system involvement include memory loss, nerve problems in the hands and feet, lack of coordination, and impaired sense of physical position or movement. Changes in mental state may also occur, adding another reason to perform a mental health assessment.
- Tiredness
- Pale skin
- Jaundice (yellowing of the skin)
- Nerve problems in the hands and feet
- Inflamed or swollen tongue
- Diarrhea
- Headaches
- Psychological issues
Testing for Vitamin B12 Deficiency
If your doctor believes you might have a B12 deficiency, they will likely start by ordering a set of blood tests. This includes a complete blood count (CBC), a check of your B12 and folate levels, and a peripheral smear, which is a procedure to examine your blood cells under a microscope.
If the results from these tests are not clear, more tests can be done. For example, your doctor may check your levels of MMA and homocysteine, two substances that can build up in your blood if you’re low on B12.
Typically, when someone has a B12 deficiency, their blood count test reveals they have anemia, meaning they have a low level of red blood cells. In B12 deficiency cases, these red blood cells are often larger than usual, a condition known as “macrocytic anemia.” The peripheral smear might show that a type of white blood cell called the neutrophil is “hypersegmented” – meaning it has too many sections or “lobes.”
Your doctor will also look at the levels of B12 and another nutrient called folate in your blood. This is because a lack of either of these can lead to macrocytic anemia, so it’s necessary to know which one is causing the problem. If your B12 level is above 300 pg/mL, it’s considered normal. If it is between 200 and 300 pg/mL, it’s considered borderline, and further testing might be needed. A B12 level below 200 pg/mL is noted as deficiency.
After confirming B12 deficiency, your doctor will then try to find out what is causing it. This might include asking about any recent surgeries such as stomach or bowel operations, since these can affect the body’s ability to absorb B12. They might also run tests for conditions that impair your ability to digest nutrients, such as Crohn’s or celiac disease. If you’re following a strict vegan diet, this might be the cause, as B12 is mainly found in animal products. If none of these seem to be the cause, your doctor might then check for an autoimmune condition called pernicious anemia, which prevents the body from absorbing B12 properly. This would involve testing your blood for certain antibodies.
Treatment Options for Vitamin B12 Deficiency
Treating a vitamin B12 deficiency requires replenishing the body’s B12 levels. However, how this is done can change based on the reason for the deficiency. If someone is deficient because they’re following a very strict vegan diet, taking an oral B12 supplement will likely suffice. However, if a person can’t properly absorb B12, as in the case of pernicious anemia or after gastric bypass surgery, B12 needs to be administered in a different way. In these cases, a monthly 1000 mcg dose of B12 is typically recommended to be given via an injection. In patients who are newly diagnosed with a deficiency, they come in once a week for their B12 injection for the first month. After four weeks, they switch to a monthly schedule. Research suggests that if the oral B12 supplement is given in high enough doses, it can be effective even in patients who can’t absorb B12 efficiently. It’s important for individuals at risk of a B12 deficiency, such as those with Crohn’s disease or celiac disease, to have their B12 levels checked regularly. If the severity of their disease increases and their B12 levels start to drop, treatment can then be started. However, it’s not recommended to start treatment before B12 levels begin to fall.
What else can Vitamin B12 Deficiency be?
When doctors try to identify why a patient might be experiencing certain health problems, they may consider several potential causes. Some of the possible conditions they might explore include:
- Lead poisoning
- Syphilis, which is a sexually transmitted infection
- HIV-related myelopathy, which is damage to the spinal cord caused by HIV
- Multiple sclerosis, which is a disease that affects the brain and spinal cord
All of these conditions have unique symptoms and health impacts, so it’s crucial to accurately diagnose which one (if any) is affecting the patient.
What to expect with Vitamin B12 Deficiency
People who get quick treatment with vitamin B12 usually have a good outcome. Younger patients typically fare better than older individuals. The best results are seen in people who don’t have severe neurological deficits.
Possible Complications When Diagnosed with Vitamin B12 Deficiency
There are several risks and complications associated with certain medical conditions. These can include:
- Heart failure as a result of anemia
- Severe neurological deficits that can cause disability
- Increased risk of developing gastric (stomach) cancer
- Increase in the risk of developing an autoimmune disorder, such as:
- Type 1 diabetes
- Myasthenia gravis
- Hashimoto’s disease
- Rheumatoid arthritis
Preventing Vitamin B12 Deficiency
It’s important to teach patients about the benefits of consistently taking B12 supplements and regularly checking in with their primary doctor. People who follow a strict vegan diet need to understand the need for these supplements to prevent a B12 deficiency. Any patients who have a higher risk of B12 deficiency due to certain factors should be regularly tested in a lab to monitor their levels.
