India’s most widespread
hidden deficiency is
vitamin B12.
Vitamin B12 deficiency affects about half of Indian adults, and around two in three vegetarians. Most people never find out, because the signs creep in slowly and look like stress or a busy life. Here is what vitamin B12 deficiency does, the symptoms to watch for, the vegetarian foods that really contain B12, methylcobalamin vs cyanocobalamin, which blood test to ask for, and how it is put right.
This guide is for education. If you have symptoms, see your doctor and get tested before you treat yourself.
Vitamin B12 deficiency in India: why it is so common
Is vitamin B12 deficiency common in India?
Yes. Vitamin B12 deficiency is one of the most common nutrient gaps in India. A 2025 analysis of 20 Indian studies found about 51% of people had low B12, rising to 65% among vegetarians. The main reason is diet: B12 comes almost only from animal foods.
When researchers pooled 20 Indian studies covering 18,750 people, they found that 51% had inadequate vitamin B12. Among vegetarians the figure was 65%, against 32% in non-vegetarians, and about two in three pregnant women were low.1 A North Indian study found 47% of adults deficient,2 and India’s national nutrition survey found B12 deficiency in 31% of adolescents.3
The reason is simple. Vitamin B12 is made by bacteria, and it reaches our plates almost only through animal foods — milk, curd, eggs, fish and meat. Plants don’t need B12, so vegetables, grains, dals and fruit don’t contain it.5 India has one of the largest vegetarian populations in the world, and many people who do eat meat or fish eat it only a few times a week. That is why B12 shortfall is common here, even in people who eat well.
Your liver stores 1–5 mg of B12, which is a thousand times or more what you need each day. So when intake runs low, it can take several years before symptoms appear.5 By then, people often blame stress, sleep or age.
What vitamin B12 does in your body
What does vitamin B12 do?
Vitamin B12 helps your body make healthy red blood cells, keeps your nerves working normally, and helps turn food into energy. It also helps cells divide and keeps homocysteine, an amino acid in the blood, in its normal range.
Vitamin B12 contributes to normal red blood cell formation, the normal functioning of the nervous system, normal energy-yielding metabolism, normal psychological function, normal immune function, normal homocysteine metabolism, the process of cell division and the reduction of tiredness and fatigue.7
Claims are ingredient-based and not specific to any product. Details of each study are in the “About the studies” box at the bottom of this page.
Blood and energy
- Works with folate to build DNA in new cells
- Without it, red blood cells come out large and weak (megaloblastic anaemia)
- Helps turn fats and some amino acids into energy
Nerves and brain
- Keeps the protective coating on nerves healthy
- Recycles homocysteine back into a useful amino acid
- Supports normal psychological function
B12 also works hand in hand with folate (vitamin B9). Our MTHFR and methylfolate guide explains how the two share the same pathway.
Vitamin B12 deficiency symptoms, from early to serious
What are the first signs of vitamin B12 deficiency?
The first signs of vitamin B12 deficiency are usually tiredness that rest does not fix, brain fog and poor memory, and low mood. Later come pins and needles in the hands and feet, a sore or smooth tongue, pale skin and breathlessness. Nerve signs can appear even when the blood count is normal.
Low B12 builds slowly, so its symptoms are easy to miss. UK health guidance lists these as the signs that should lead to a B12 test:6
Early signs
- Tiredness that doesn’t lift with rest
- Brain fog, poor concentration, short-term memory lapses
- Low mood or irritability
- A sore, red or smooth tongue; mouth ulcers
- Pale skin, breathlessness, a racing heart
Signs that need a doctor soon
- Pins and needles or numbness in hands or feet
- Poor balance, unsteady walking, falls
- Blurred vision or changes in eyesight
- Worsening memory or confusion
- Anaemia that doesn’t improve with iron in pregnancy
Two things matter most. First, nerve symptoms can appear before any anaemia, so a normal blood count does not rule B12 out.5,6 Second, nerve damage from long-standing deficiency can become lasting, which is why early testing pays off. Read more in our tingling hands and feet guide.
Who is most at risk of low B12
Who is most at risk of vitamin B12 deficiency?
Vegetarians and vegans are most at risk of vitamin B12 deficiency, followed by adults over 50, people taking metformin or long-term acid-reducing tablets, pregnant and breastfeeding women, and people with stomach or gut conditions or past gut surgery.
- Vegetarians and vegans — little or no B12 from food.1
- Adults over 50 — less stomach acid means less B12 is freed from food.5
- People on metformin or long-term acid-reducing tablets such as pantoprazole or omeprazole.5 See our metformin and B12 guide.
- Pregnant and breastfeeding women — needs rise, and a breastfed baby gets all its B12 from the mother.4,5
- People with gut conditions or surgery — coeliac disease, autoimmune gastritis (pernicious anaemia), weight-loss surgery or bowel surgery.6
- Recreational nitrous oxide (“laughing gas”) users — it inactivates B12.6
Vitamin B12 foods for vegetarians: what really counts
Which vegetarian foods have vitamin B12?
For vegetarians, milk, curd, cheese and eggs are the reliable vitamin B12 foods. One cup of milk gives about 1.3 mcg and one egg about 0.5 mcg, against an adult need of 2.2 mcg a day. Fruits, vegetables, grains and dals contain no usable B12, and spirulina contains a mostly inactive form.
India’s daily requirement is 2.2 mcg of B12 for adults, rising to 2.45 mcg in pregnancy and 3.2 mcg while breastfeeding.4 Here is how common foods compare:
| Food | Serving | Vitamin B12 | Share of 2.2 mcg |
|---|---|---|---|
| Milk | 1 cup (about 240 ml) | about 1.3 mcg | about 59% |
| Curd / plain yoghurt | 170 g bowl | about 1.0 mcg | about 45% |
| Cheese (cheddar) | 40 g | about 0.5 mcg | about 23% |
| Egg | 1 large | about 0.5 mcg | about 23% |
| Fish (salmon or tuna) | 85 g cooked | 2.5–2.6 mcg | over 100% |
| Fortified nutritional yeast | about ¼ cup | 8–24 mcg (varies by brand) | well over 100% |
| Vegetables, fruit, grains, dal | any | none usable | 0% |
So a vegetarian who drinks two cups of milk and eats a bowl of curd can come close to the daily 2.2 mcg. Many people don’t eat that much dairy every day, and vegans eat none, which is where fortified foods or a supplement help.5
Plant foods that are often oversold: spirulina and similar algae tablets contain mostly pseudo-B12, a form your body cannot use. Dried nori seaweed contains some active B12, and tempeh varies widely. Most fermented foods contain only traces.8 None of these is a dependable daily source.
Methylcobalamin vs cyanocobalamin: which B12 form?
What is the difference between methylcobalamin and cyanocobalamin?
Methylcobalamin is one of the two active forms of vitamin B12 that your cells use, and the main form found in blood. Cyanocobalamin is a stable form your body converts into the active forms. Both correct a dietary B12 shortfall, and UK guidelines accept either for B12 tablets.
Both forms do the job. Methylcobalamin is ready for use, while cyanocobalamin is the long-standing, low-cost form used in most older research. Here is how they compare:
| Feature | Cyanocobalamin | Methylcobalamin |
|---|---|---|
| Found in nature | No; made for supplements and fortified foods | Yes; the main form in blood |
| Active in the body | After the body removes the cyanide group and converts it | One of the two active forms cells use |
| Kept by the body | More lost in urine in some studies | Better retained in some studies |
| Research history | Most studied; stable and low-cost | Common in Indian B12 products; accepted in UK guidelines |
| Corrects dietary shortfall | Yes | Yes |
UK national guidance lists cyanocobalamin, methylcobalamin and adenosylcobalamin as suitable for B12 tablets.6 Once inside your cells, every form is turned into the same two active forms, methylcobalamin and adenosylcobalamin.9 What matters most is getting enough B12, every day, in a form your doctor is happy with.
How to test for vitamin B12 deficiency in India
Which test checks vitamin B12 deficiency?
A serum vitamin B12 blood test is the usual first test for B12 deficiency, and most labs in India offer it. A result under 180 pg/mL confirms deficiency, 180–350 pg/mL is a grey zone, and over 350 pg/mL makes deficiency unlikely. In the grey zone, a methylmalonic acid (MMA) test helps decide.
| Total (serum) B12 | Active B12 (holotranscobalamin) | What it means |
|---|---|---|
| Below 180 pg/mL | Below 25 pmol/L | Deficiency confirmed |
| 180–350 pg/mL | 25–70 pmol/L | Grey zone; MMA test if you have symptoms |
| Above 350 pg/mL | Above 70 pmol/L | Deficiency unlikely |
Labs set their own ranges, so read your report with your doctor.6 Other useful tests:
- Methylmalonic acid (MMA) — rises when cells are short of B12; the most sensitive marker.5
- Homocysteine — rises when B12 or folate is low.5
- Complete blood count (CBC) — a high MCV (large red cells) can point to low B12 or folate, but a normal CBC does not rule it out.6
If you already take a B12 supplement, tell your doctor before the test, because it can raise the reading.6
You have numbness, pins and needles, poor balance, eyesight changes or memory problems, you are pregnant or breastfeeding, or you take metformin or acid-reducing tablets long-term. Get tested before you treat yourself, and never stop a prescribed medicine on your own.
Food first, then fill the real gaps.
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Answer a few quick questions about your food, routine and symptoms to see which nutrients you may be running low on, and which tests to ask your doctor about.
Try the Nutrient Gap Finder →How vitamin B12 deficiency is put right
How long does it take to fix vitamin B12 deficiency?
With treatment, vitamin B12 deficiency symptoms often start to improve within 2 weeks, but they can take up to 3 months to settle, and nerve symptoms can take longer. Doctors usually recheck after about 3 months, or after 1 month in pregnancy.
- See your doctor and get testedA serum or active B12 test confirms the shortfall before any treatment starts.
- Find the causeDiet, medicines, gut problems or autoimmune gastritis each need a different plan.
- Follow the treatment your doctor givesDoctors usually use high-dose B12 tablets; injections are used when absorption is poor or symptoms are severe.
- Know that tablets work for most peopleIn trials, 1,000–2,000 mcg tablets a day raised blood B12 about as well as injections.
- Keep it topped upOnce levels are back, daily dairy, eggs, fortified foods or a daily multivitamin help keep B12 steady, especially for vegetarians.
- Recheck as advisedUsually after about 3 months, sooner if symptoms are severe or you are pregnant.
A daily multivitamin is built to maintain healthy B12 levels; it is not meant to correct a diagnosed deficiency, which needs the higher doses your doctor prescribes.6,10 One more thing to know: high doses of folic acid can correct the anaemia of B12 deficiency but not the nerve damage, so folic acid on its own can hide a B12 problem.11
“Low B12 is common, easy to test and easy to fix. The only real mistake is not checking.”
The simple version
- The 51% figure is a pooled estimate from 20 Indian studies (95% CI 44–57%); the studies used different cut-offs and groups, so the true figure varies by region and diet.1
- The North Indian figure (47%) comes from adults tested at one region’s centres.2 The adolescent figure (31%) comes from the Comprehensive National Nutrition Survey 2016–18 (preschool children 13.8%, school-age children 17.3%).3
- Food values are from US food data; Indian milk, curd and paneer vary with the animal’s feed and how the food is made, and B12 absorption from a single serving falls once the dose passes 1–2 mcg.5
- The methylcobalamin retention findings come from small older human studies and animal work; most people likely absorb all common forms similarly.5,9
- The tablets-versus-injections review included 3 trials and 153 people, followed for a few months; the evidence was rated low certainty.10
- The blood-test thresholds are from UK guidance; many Indian labs use 200 pg/mL as the lower limit.6
Vitamin B12 deficiency, answered simply.
What are the first symptoms of Vitamin B12 deficiency?
Why is Vitamin B12 deficiency so common in India?
Methylcobalamin vs cyanocobalamin — which is better?
What foods are rich in Vitamin B12 for vegetarians in India?
How do you test for B12 deficiency in India?
Does B12 deficiency cause hair loss?
Can B12 deficiency cause depression and anxiety?
What is the daily B12 dose in a multivitamin?
What is the multivitamin daily routine for correcting B12?
How much vitamin B12 do I need per day?
What B12 level is considered low?
Can vegetarians get enough B12 from milk and curd?
Does spirulina contain vitamin B12?
Which fruit is high in vitamin B12?
How long does it take to recover from B12 deficiency?
Are B12 tablets as good as injections?
Can low B12 cause tingling in hands and feet?
Can too much vitamin B12 be harmful?
Can folic acid hide B12 deficiency?
Which vitamin B12 supplement is best?
Is vitamin B12 deficiency serious?
Do non-vegetarians also get B12 deficiency?
Who should get a B12 test?
Can pregnant women take vitamin B12?
Studies behind this guide
- India’s unseen nutritional emergency: a meta-analysis of vitamin B12 deficiency. Eur J Cardiovasc Med. 2025;15(5):272–7 — 20 studies, 18,750 participants; 51% inadequate (95% CI 44–57%); vegetarians 65%, non-vegetarians 32%; pregnant women about 67%.
- Singla R, Garg A, Surana V, et al. Vitamin B12 deficiency is endemic in Indian population: a perspective from North India. Indian J Endocrinol Metab. 2019;23(2):211–4. PMID 31161105
- Shalini T, et al. Prevalence of vitamin B12 and folate deficiencies in Indian children and adolescents. Nutrients. 2023;15(13):3026. DOI 10.3390/nu15133026 — Comprehensive National Nutrition Survey 2016–18: B12 deficiency 13.8% preschool, 17.3% school-age, 31% adolescents.
- ICMR–National Institute of Nutrition. Nutrient Requirements for Indians, 2020 — vitamin B12 RDA 2.2 mcg/day for adults, 2.45 mcg in pregnancy, 3.2 mcg in lactation.
- NIH Office of Dietary Supplements. Vitamin B12 — Fact Sheet for Health Professionals (body stores, absorption, food values, groups at risk, MMA and homocysteine, interactions). ods.od.nih.gov
- National Institute for Health and Care Excellence (NICE). Vitamin B12 deficiency in over 16s: diagnosis and management. NG239, 2024 — symptoms, risk factors, test thresholds, oral forms, follow-up. nice.org.uk
- European Commission. Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (vitamin B12).
- Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians. Nutrients. 2014;6(5):1861–73. DOI 10.3390/nu6051861
- Paul C, Brady DM. Comparative bioavailability and utilization of particular forms of B12 supplements with potential to mitigate B12-related genetic polymorphisms. Integr Med (Encinitas). 2017;16(1):42–9.
- Wang H, Li L, Qin LL, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Cochrane Database Syst Rev. 2018;3:CD004655. PMID 29543316 — 3 trials, 153 people; 1,000–2,000 mcg tablets vs injections.
- NIH Office of Dietary Supplements. Folate — Fact Sheet for Health Professionals (folic acid and vitamin B12 deficiency). ods.od.nih.gov