Vitamin B12 Deficiency in Indian Vegetarians: Signs, Tests and What Actually Helps

Ask around in any Indian office and you'll find someone who was told their B12 was low. Usually it came up by accident, in a routine health package, after months of feeling tired and putting it down to work.

That isn't a coincidence. Vitamin B12 deficiency is one of the most common nutrient gaps in India, and the reason is fairly simple: B12 comes almost entirely from animal foods, and a large part of the country eats little or none of them.

Here's what you need to know, without the scare stories.

What B12 actually does

Your body uses vitamin B12 to make healthy red blood cells, keep nerves working properly and build DNA. It also works with folate in a pathway that keeps a compound called homocysteine in check. High homocysteine is linked with heart and blood vessel problems, which is one reason doctors in India pay attention to B12 in people with heart risk.

You only need a small amount. ICMR-NIN's 2020 guidelines put the adult requirement at around 2.5 micrograms a day. The problem is getting even that much from a vegetarian Indian diet.

Why Indians run low

Diet. B12 is made by bacteria and ends up in meat, fish, eggs and, to a smaller extent, milk and curd. Plant foods don't reliably contain it. Lacto-vegetarians get some from dairy, but many people simply don't drink enough milk or eat enough curd and paneer to cover their needs. Strict vegans get almost none unless they use fortified foods or supplements.

Absorption. B12 needs stomach acid and a protein called intrinsic factor to be absorbed. Anything that interferes with that can cause a deficiency even if you eat enough. This is why non-vegetarians can be low too.

Medicines. Two very common ones are linked with lower B12 over time:

• Metformin, the first-line diabetes medicine. A large US study found people on long-term metformin were more likely to develop low B12.

• Acid reducers such as pantoprazole, omeprazole and similar tablets, which many people take daily for years for acidity.

If you take either, it's worth asking your doctor whether you should be tested periodically. Do not stop these medicines on your own.

Age and gut issues. Stomach acid drops with age, and conditions like gastritis or past stomach surgery can reduce absorption.

Several Indian studies, including work from Pune led by Dr CS Yajnik, have found low B12 in a large share of adults, with vegetarians most affected.

Signs that may point to low B12

Deficiency usually develops slowly, over months or years, because the liver stores B12. Symptoms are often vague:

• Tiredness and low energy that doesn't improve with rest

• Pale skin or breathlessness on exertion (from anaemia)

• Tingling, pins and needles or numbness in the hands and feet

• Poor balance or unsteady walking

• Sore, red or smooth tongue, mouth ulcers

• Low mood, irritability, forgetfulness or poor concentration

None of these is specific to B12. Thyroid problems, iron deficiency, poor sleep and diabetes can cause many of the same complaints. That's why testing matters more than guessing.

Nerve symptoms deserve attention. If left untreated for a long time, nerve damage from B12 deficiency may not fully reverse, so tingling or numbness should be checked by a doctor rather than ignored.

Which tests to ask about

• Serum vitamin B12. The usual first test and part of most health packages. Labs use slightly different ranges, but very low values are clear-cut.

• Complete blood count (CBC). B12 deficiency can cause large red blood cells (a high MCV) and anaemia.

• Homocysteine or methylmalonic acid (MMA). Useful when serum B12 is borderline. Raised levels suggest your cells aren't getting enough B12 even if the number looks okay.

One thing to know: taking a lot of folic acid can improve anaemia on a blood report while the nerve effects of low B12 carry on quietly. This is one reason folate and B12 are usually looked at together.

What may help

Food first, where possible. For vegetarians, regular dairy helps. Milk, curd, buttermilk and paneer all contribute some B12. If you eat eggs, they add a useful amount. Fish and meat are the richest sources for non-vegetarians. Some breakfast cereals and plant milks are fortified with B12, so check labels.

Be careful with claims online about plant sources. Spirulina, some seaweeds and mushrooms are often promoted as B12 sources, but much of what they contain may be inactive forms that the body can't use well. They aren't a reliable substitute.

Supplements or injections, if your doctor advises. When a deficiency is confirmed, treatment is usually simple. Depending on how low you are, your symptoms and the cause, your doctor may suggest oral tablets, sublingual forms or a course of injections. People with absorption problems often need injections at first. The right dose and duration is a decision for your doctor, so we won't suggest one here.

Re-test. Levels should be checked again after treatment, and people with ongoing risks (strict vegetarians, metformin users, older adults) may need periodic testing.

Who should consider getting tested

• Lifelong vegetarians and vegans, especially those who eat little dairy

• Anyone on metformin or long-term acid-reducing tablets

• People over 50

• Pregnant women and women planning pregnancy, since B12 matters for the baby's development

• Anyone with unexplained tiredness, anaemia, tingling or memory changes

The bottom line

B12 deficiency is common in India, easy to test for and usually straightforward to correct once it's found. If you're vegetarian, take metformin or acid tablets, or just feel run down for no clear reason, a simple blood test is a sensible first step. Combine that with enough dairy or eggs in your diet, and follow your doctor's advice on supplements.

If you're thinking about vegetarian nutrition more broadly, our guides on how much protein Indian vegetarians need and vitamin D deficiency in India are good next reads.

This article is for general information only and is not medical advice. Please speak to your doctor before starting any supplement or injection, and especially if you are pregnant, have diabetes, take metformin or acid-reducing medicines, or have numbness, tingling or memory changes.

References

1. Indian Council of Medical Research – National Institute of Nutrition. Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements, 2020.

2. Yajnik CS, et al. Vitamin B12 deficiency and hyperhomocysteinemia in rural and urban Indians. Journal of the Association of Physicians of India, 2006.

3. Aroda VR, et al. Long-term metformin use and vitamin B12 deficiency in the Diabetes Prevention Program Outcomes Study. Journal of Clinical Endocrinology & Metabolism, 2016.

4. Lam JR, et al. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA, 2013.

5. Stabler SP. Vitamin B12 deficiency. New England Journal of Medicine, 2013.

6. National Institutes of Health, Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals.