Imagine taking vitamin B12 supplements every day – but your levels never improve. You feel tired, weak and forgetful. You wonder – “What’s going wrong?” The answer might surprise you. There is a hidden condition that can block B12 absorption completely. Even with a healthy diet and regular supplements, your body may not be able to use this essential vitamin. This mystery lies behind a serious disorder called Pernicious Anemia, which can cause recurring vitamin B12 deficiency.
Autoimmune Deficiency Causing Vitamin B12 Deficiency
AIIMS Dr Priyanka Sehrawat explains that pernicious anaemia is the reason B12 deficiency keeps coming back, even with supplements. The problem isn’t your diet, but your body. In this condition, the immune system attacks a vital protein called Intrinsic Factor (IF). IF is essential for absorbing B12 from the gut into the bloodstream. Without it, no amount of supplements can fix the deficiency.
The term “autoimmune” explains what happens: the body’s defence system turns against itself. Antibodies target either the intrinsic factor or the stomach cells that produce it. As a result, B12 remains in the gut and never reaches your blood. This is why people with pernicious anemia continue to show low B12 levels despite taking vitamins.
What Happens When You Have Vitamin B12 Deficiency
Vitamin B12 is critical for making healthy red blood cells. Without it, your blood cannot carry oxygen efficiently. Over time, this causes anemia, leading to fatigue, weakness, pale skin and shortness of breath. In serious cases, neurological symptoms may appear, such as tingling in hands and feet, memory problems, mood changes and difficulty walking.
Because pernicious anemia gradually damages intrinsic factor or stomach cells, deficiency builds up over years. Early symptoms are often mild or vague, sometimes dismissed as normal tiredness or stress. This is why many people remain undiagnosed for a long time.
Who Is At Risk – And When To Suspect It
Anyone can develop pernicious anemia, but certain factors increase the risk. People with other autoimmune disorders, like thyroid problems or type 1 diabetes, are more susceptible. Older adults are also at higher risk.
If you notice persistent low B12 levels despite a proper diet and supplements, or if you experience fatigue, tingling limbs, or memory issues, it’s time to consult a doctor. Tests for B12 levels, red blood cell counts, and antibodies against intrinsic factor or stomach cells can help detect the problem.
Why Supplements Alone May Not Help And How Doctors Treat It
Even high-dose B12 supplements often fail in pernicious anemia because the vitamin cannot enter the bloodstream without intrinsic factor. That’s why doctors usually recommend B12 injections or high-dose supplements administered in ways your body can absorb without relying on IF.
With treatment, many symptoms improve, but this condition is lifelong. Regular monitoring and ongoing B12 support are essential to stay healthy.
If your B12 levels remain low despite a healthy diet and supplements, don’t ignore it. Pernicious anemia is a hidden and serious condition that requires proper diagnosis and lifelong care. With correct treatment, you can manage it. But first, you need to understand what’s really happening. Remember, low B12 isn’t always about diet. Sometimes, it’s about absorption and the body’s own defence system.
Disclaimer: This content is for general information only and not a substitute for professional medical advice. DNP India neither confirms nor denies the claims. Always consult a doctor before following any suggestions, treatments or diets.
