Vitamin B12: Our bodies need a lot of vitamins. If we feel a deficiency of any vitamin, its effects begin to show in the body. Let us tell you what happens when you have a B12 deficiency.

Hien Vitamin B12 Deficiency: Many people assume that if their vitamin B12 test results are normal, they're in good health. However, Apollo Delhi surgeon Dr. Anshuman Kaushal, known as The Angry Doc on social media, warns that normal tests don't always tell the truth. Many people struggle with problems like fatigue, tingling in their legs, forgetfulness, and irritability, even though their tests appear completely normal.

Functional B12 Deficiency: When the report is fine, the body remains deficient

Dr. Kaushal said in a video, "Have you seen people who are always tired, forgetful, and depressed, yet their B12 levels are normal? This is functional B12 deficiency." He explained that in this condition, B12 is present in the blood, but the body's cells are unable to use it. Giving an example, he said, "On paper, the B12 level looks perfect, but in reality, the cells have nothing. It's like having money in the bank account but no ATM card; looking rich, feeling poor."

Why are normal tests not reliable?

According to Dr. Kaushal, most labs simply measure serum B12 and report, while the actual deficiency occurs at the cellular level. He said, “B12 and folate work like Batman and Robin. From DNA repair to RBC formation and neuron protection, both work together. If even one of these is deficient, the brain goes into 'Gotham mode.' Stress, numbness in the hands and feet, and tingling all come for free.”

Which people are more at risk?

Dr. Kaushal explains that certain groups are already at risk. These include those taking metformin or acidity medications, those on a vegan diet, and those who have undergone bariatric surgery. He says that if symptoms persist but the results are normal, testing for MMA, homocysteine, or active B12 is essential. He adds, "Sometimes tablets don't work, and injections are needed. The problem isn't the vitamin itself, but observation." A functional deficiency means your cells aren't using B12 properly. Don't go by the numbers; it's the function that matters. Save your neurons and don't rely on B12 gummies for energy. This is biochemistry, not Bollywood.

Other doctors have also issued warnings.

Apollo neurologist Dr. Sudhir Kumar also told X that fatigue, forgetfulness, and lethargy are common in people with B12 deficiency, and a normal blood test doesn't always tell the whole story. He explained that a large portion of B12 in the blood is bound to a protein that doesn't transport the vitamin to cells. This makes B12 appear normal on the test, but the body doesn't benefit from it. This is why fatigue and brain function problems can persist despite a positive test result.

What is Vitamin B12?

According to the Cleveland Clinic, B12 is an essential nutrient that keeps nerves and red blood cells healthy and helps make DNA. The body doesn't make it on its own, so it must be obtained from foods like meat, fish, eggs, dairy, and fortified foods. Adults typically need about 2.4 micrograms of B12 daily, while pregnant and breastfeeding women need more.