Pernicious Anaemia: When Your Body Can’t Absorb Vitamin B12 Properly

December 1, 2025

Pernicious Anaemia: When Your Body Can’t Absorb Vitamin B12 Properly

Verified By
KIMS-SUNSHINE
Specialist,
01 December, 2025

Pernicious Anaemia: When Your Body Can’t Absorb Vitamin B12 Properly

Pernicious anaemia is a condition that renders the body incapable of absorbing enough amounts of Vitamin B12 from diet alone. This condition has not been studied extensively in the Indian context, as it is thought to be more prevalent in Northern European populations, when compared to those in Asia. Indians have another issue that is unrelated- systemic Vitamin B12 deficiency. Pernicious anaemia occurs when the immune system attacks the healthy, specialised cells of the stomach that produce the intrinsic factor. It is this intrinsic factor that binds to Vitamin B12 and helps it enter the bloodstream after absorption. When there is no intrinsic factor to bind to Vitamin B12, there is lesser absorption of the vitamin. Vitamin B12 is a major B vitamin that is involved in a host of molecular reactions in the body.

Symptoms Of Pernicious Anaemia

Most individuals never know they have pernicious anaemia until it has progressed greatly. Many people face minor issues, while some may deal with more pronounced symptoms. Some of the early signs that point to this condition include-

Feeling lightheaded when you exert yourself
Not having much of an appetite
You may notice that your skin and eyes are jaundiced or yellow in colour.
Not being able to breathe normally while exercising
Bleeding gums
Swollen, red looking tongue
Gut related issues like constipation or diarrhoea

If there is long term Vitamin B12 deficiency, then the signs are

Memory loss and confusion
Not being able to balance
Numbness or tingling
Feeling depressed
Irritability or hallucinations in some cases.
Not being able to focus on tasks at hand- all of which point to neurological problems.
Loss of vision- as the optic nerve is not able to function normally. This is in very severe cases.
Issues related to blood cells- anaemia for example, as bone marrow where new blood cells are made does not get enough Vitamin B12 to work with.

Diagnosing Pernicious Anaemia

Simple blood tests normally help diagnose pernicious anaemia. So, the tests you will be asked to get done are- a complete blood count to check if you have any type of anaemia, reticulocyte count to see how many new blood cells are being made in the body, serum bilirubin levels which tell how many cells are being lost as bilirubin is a byproduct of blood cell breakdown and checking amounts of homocysteine and methylmalonic acid – higher values of which confirm B12 deficiency. Endoscopy may also be done to check how your stomach is doing.

Treatment of Pernicious Anaemia

Consuming B12-rich foods and supplements is very helpful in increasing Vitamin B12 reserves in the body. Regular B12 injection treatments are a sure way to help you get better soon. But, it is important to remember that pernicious anaemia has no permanent cure and hence it is a chronic condition that will need to be managed effectively in the long run. B12 rich foods include animal organ meats, eggs and dairy products. Vegans and vegetarians should consider including nutritional yeast in their diet on a regular basis, while other sources include fortified cereals and plant based milks. Adults need about 2.5 mg of this vitamin daily, for blood cell health and overall vitality.

Conclusion

There is no way you can prevent pernicious anaemia from ever affecting you, but you can learn how to lessen its devastating impacts on your system in the long run by being a little smart about how you eat and checking Vitamin B12 levels in blood regularly. Regular B12 injections are the only treatments that seem to work, as excess amounts of Vitamin B12 are not stored in the body but rather excreted (it is a water soluble vitamin). Traditionally, the B group of vitamins have been derived from foods of animal origin, so it may be hard for pure vegetarians or vegans to get enough from diet alone. In such cases, supplementation is very useful, but you should talk to your doctor about how it will work for your case.

Frequently Asked Questions

What is pernicious anaemia?

Pernicious anaemia is an autoimmune condition in which the body cannot absorb vitamin B12 because it attacks the stomach cells that produce intrinsic factor, a protein required for B12 absorption. Without intrinsic factor, B12 levels fall, leading to reduced red blood cell production and damage to the nervous system.

Can pernicious anaemia cause neurological problems?

Pernicious anaemia can cause neurological problems. Low B12 affects the myelin sheath that protects nerves. This can lead to numbness, tingling, balance problems, memory issues, mood changes, vision disturbances and, in severe cases, nerve damage.

How is pernicious anaemia treated?

Treatment for pernicious anaemia involves restoring and maintaining adequate B12 levels. The standard treatment is intramuscular vitamin B12 injections, usually given at frequent intervals at first and then at longer intervals once levels stabilise. Some patients use high-dose oral B12 if absorption is sufficient, though injections remain the most reliable method. Treatment corrects the anaemia and prevents further nerve damage.

What happens if pernicious anaemia is left untreated?

If pernicious anaemia is left untreated, the consequences can be serious. Anaemia may worsen, causing fatigue, breathlessness, palpitations and pale skin. Neurological damage can progress and may become permanent, affecting movement, sensation and cognitive function. Untreated disease can also increase the risk of stomach cancer due to chronic inflammation of the stomach lining.

Do patients need lifelong B12 injections?

Most patients need lifelong B12 injections. Pernicious anaemia does not resolve because the autoimmune destruction of intrinsic factor continues. Long-term replacement keeps B12 levels stable and prevents relapse of symptoms. Regular monitoring ensures that treatment remains effective and that complications do not develop.