Vitamin B12 deficiency is common in India, mainly because many people follow a vegetarian diet. It often develops slowly, and early signs are easy to ignore. This guide explains the symptoms, who is at risk and how the test works.
What does vitamin B12 do?
Vitamin B12 (cobalamin) helps your body:
- Make healthy red blood cells
- Keep nerves working properly
- Make DNA, the genetic material in every cell
The body cannot make B12 on its own. It comes mainly from animal foods such as milk, curd, paneer, eggs, fish, chicken and meat. Plant foods have little or no natural B12, unless they are fortified.
Common symptoms
Symptoms often start slowly and get worse over months or years:
- Tiredness and weakness
- Pale or yellowish skin
- Breathlessness on mild effort
- Tingling or numbness in hands and feet (jhunjhuni)
- Problems with balance or walking
- Memory problems or poor concentration
- Low mood or irritability
- Sore, red tongue or mouth ulcers
Low B12 can cause a type of anemia where red blood cells are large and fewer in number. Nerve damage from long-term deficiency may not fully recover, so early testing matters.
Who is at higher risk?
Vegetarians and vegans
People who eat little or no animal food are at higher risk. Vegans, who avoid milk products as well, are at the highest risk. Even lacto-vegetarians can be low if they do not take enough milk and curd.
People taking metformin
Metformin is a common diabetes medicine. Long-term use can reduce B12 absorption in some people. If you have been taking metformin for a long time, ask your doctor whether you should check your B12 level. Do not stop your medicine on your own.
Other risk groups
- Older adults, as the stomach absorbs B12 less well with age
- People who take acidity medicines for a long time
- People with stomach or gut conditions, or who had stomach or bowel surgery
- Heavy alcohol users
- Pregnant and breastfeeding women on a vegetarian diet
The vitamin B12 test
The B12 test is a simple blood test from a vein. It measures the amount of B12 in your blood.
A common adult reference range is about 200 to 900 pg/mL (some labs use slightly different limits). Results below about 200 pg/mL usually suggest deficiency. Results between about 200 and 300 pg/mL may be borderline. Ranges differ between labs, so always use the reference range printed on your report.
Fasting is usually not needed for B12 alone, but some labs prefer a morning sample. If your doctor advises fasting, follow that.
If you take B12 tablets or injections, tell your doctor, as they can raise your blood level.
Other tests your doctor may suggest
- CBC: to check hemoglobin and the size of red blood cells
- Folate (folic acid): often low along with B12
- Homocysteine or methylmalonic acid: can help when B12 is borderline
What happens if B12 is low?
Your doctor will look for the cause and decide on treatment. This may include diet changes, tablets or injections. Do not self-medicate with high doses. Your doctor may repeat the test after a few months to check progress.
Food sources of vitamin B12
- Milk, curd, buttermilk and paneer
- Eggs
- Fish, chicken and meat
- Fortified foods, such as some breakfast cereals and plant milks
Vegetarians who cannot get enough from food should talk to a doctor about supplements.
Frequently asked questions
Can low B12 cause tingling in feet?
Yes. Low B12 can affect nerves and cause tingling or numbness in the hands and feet. Many other conditions, including diabetes, can also cause this, so talk to your doctor.
Should all vegetarians test B12?
Vegetarians, and especially vegans, are at higher risk. Testing once, and then as your doctor advises, is a sensible step, especially if you have any symptoms.
Is high B12 a problem?
A high level is often due to supplements or injections. Sometimes it can point to other health issues. If your result is high and you are not taking B12, show it to your doctor.
Book this test
You can book a vitamin B12 test, alone or with vitamin D and CBC, with home sample collection. Book a test, see all tests, or check your report values.
This article is for general information only and is not medical advice. Please talk to your doctor about your symptoms and report.
