Introduction

Vitamin B12 deficiency is common and often goes undiagnosed. In India, more than 47% of people may be affected, and the rate is even higher—over 70%—among vegetarians and vegans.The problem is that symptoms develop slowly. Many people have had low B12 for years, thinking it is just tiredness, aging, or stress. If left untreated, B12 deficiency can cause permanent nerve damage, serious anemia, and problems with memory and thinking.

This guide explains the main signs of vitamin B12 deficiency, who is most at risk, and when you should get tested.

What Is Vitamin B12, and Why Does Your Body Need It?

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that your body cannot produce by itself. You need to get it from food or supplements.

B12 is important for three main reasons:

Early Signs and Symptoms of Vitamin B12 Deficiency

Early signs of vitamin B12 deficiency are easy to overlook. They can show up before blood tests detect a problem. Spotting them early can help you get better results from treatment results.

• Persistent Fatigue and Weakness

This may be due to a lack of vitamin B12. Without enough B12, the body cannot produce enough healthy red blood cells, so less oxygen reaches the muscles and organs. This can cause deep, constant tiredness that does not improve with sleep. When fatigue is ongoing and unexplained, B12 deficiency should be considered as a possible cause.

• Tingling and Numbness in Hands and Feet

Feels like pins and needles, burning, or even a loss of feeling. Low B12 levels can damage the protective layer around your nerves, leading to these symptoms. Problems with your hands and feet are often some of the first and most important signs of B12 deficiency.

• Pale or Slightly Yellow Skin

This may be caused by anemia, and the yellow color comes from red blood cells breaking down too quickly. If you notice these skin changes along with tiredness, it could be a sign of B12 deficiency.

• Sore, Swollen Tongue and Mouth Ulcers

These problems occur because the cells in your mouth are affected early when B12 levels are low. Glossitis, or an inflamed tongue, is a common sign of deficiency but is often confused with dental problems.

• Breathlessness and Heart Palpitations

This can feel like shortness of breath during light activity or a fast, pounding heartbeat. These happen because your heart works harder when your blood cannot carry enough oxygen due to B12-related anemia. If you feel breathless for no clear reason, it is a good idea to check your B12 levels.

• Dizziness and Balance Problems

You are feeling lightheaded or unsteady when walking  and feeling dizzy often. These issues occur because B12 deficiency affects the nerves in your spine and throughout your body. Trouble with balance from low B12 can raise the risk of falls, especially for older people.

• Blurred or Disturbed Vision

This mean your vision is slowly getting worse, you're seeing odd things, or you're losing part of your vision. Long-term B12 deficiency can damage the nerve connecting your eye to your brain. If your vision changes for no clear reason, especially if you have other symptoms, see a doctor right away.

What Happens When B12 Deficiency Goes Untreated

If low B12 is not treated for a long time, symptoms can get worse, and some may not go away even after treatment.

• Memory Loss and Cognitive Decline

Low B12 can cause brain fog, trouble concentrating, confusion, and memory problems. In serious cases, it can look like early dementia. B12 deficiency is also linked to high homocysteine, which can speed up brain aging and increase the risk of dementia.

• Difficulty Walking and Loss of Coordination

Severe B12 deficiency can cause unsteady walking, weak limbs, and trouble with coordination if it damages the spinal cord. If left untreated, these problems can become permanent.

• Megaloblastic Anaemia

B12 deficiency can lead to extreme tiredness, pale skin, a fast heartbeat, and shortness of breath because your blood cannot carry enough oxygen. Doctors diagnose it with blood tests, and it needs quick treatment.

Critical fact: Neurological damage from prolonged B12 deficiency may only partially recover even with treatment. Anemia fully reverses, but nerve damage may not. Early detection is the only reliable protection.

Most at Risk of Vitamin B12 Deficiency?

Anyone can have low B12 levels, but some people are at much higher risk and should be tested regularly.

• Adults over 50: As you get older, your body absorbs less B12 from food because stomach acid decreases. Older adults are at higher risk and should be checked regularly.
• People with pernicious anaemia: This autoimmune condition destroys cells that produce intrinsic factor, making dietary B12 absorption impossible. These patients require lifelong B12 injections.
• Digestive problems such as Crohn's disease, celiac disease, inflammatory bowel disease, and atrophic gastritis make it harder for your body to absorb B12.
• Post-bariatric surgery patients: Weight-loss surgeries that alter the stomach or small intestine can reduce B12 absorption and often require lifelong supplementation.
• Long-term metformin users: Metformin, a common type 2 diabetes medication, can reduce B12 absorption over time. People who take it long-term should have their B12 levels checked every year.
• Heavy alcohol drinkers: Drinking a lot of alcohol for a long time can use up B12 stored in your liver and make it harder to absorb B12 from food.
• Pregnant and breastfeeding women: You need more B12 during pregnancy and breastfeeding. Not getting enough B12 at this time can affect your baby's development.

When Should You Get Tested for Vitamin B12 Deficiency?

You do not have to wait until symptoms get bad. B12 levels can fall slowly over the years before you notice any problems. Getting tested early can stop the deficiency from becoming serious.

• You follow a vegetarian or vegan diet without consistent B12 supplementation
• aged 50 or above, especially with any digestive symptoms
• Crohn's disease, celiac disease, or atrophic gastritis
• Taking metformin for more than 12 months
• If pregnant, planning pregnancy, or breastfeeding
• have had bariatric or gastrointestinal surgery
• have a family history of pernicious anaemia or autoimmune conditions

Vitamin B12 Blood Tests: What Your Doctor Will Order

To correctly diagnose B12 deficiency, doctors often use multiple tests. Your doctor will choose the right tests based on your symptoms and risk factors.

• Serum Vitamin B12 Test:

Measures B12 in blood It may appear normal even if the body lacks usable B12.(Book now)

• MMA Urine Test

Detects cellular B12 deficiency. One of the most accurate tests, especially when B12 levels are borderline. (book now)

• Homocysteine Test:

High levels suggest B12 deficiency and indicate a higher risk of heart and brain health. (book now)

• CBC Test

Checks blood cells. Large abnormal red cells can signal B12-related anemia.(book now)

• Intrinsic Factor Antibody Test:

Identifies pernicious anemia. A positive result means the body cannot absorb B12 properly and requires a near-term treatment. (book now)

Vitamin B12 Deficiency Treatment Options

Treatment depends on the cause of the deficiency and its severity. Options include changing your diet or getting B12 injections.

• Dietary improvements:

Increasing intake of B12-rich foods alongside supplementation. Key sources include meat, fish, eggs, dairy products, B12-fortified plant milks, cereals, and nutritional yeast.

• Vitamin B12 injections:

These are used when your body cannot absorb B12 well, such as with pernicious anemia, after certain surgeries, or in severe cases. Injections go straight into your body and work quickly. Usually, you get them every other day for two weeks, then once a month to maintain your levels.

• High-dose oral B12 supplements:

These work well if your deficiency is due to not getting enough B12 in your diet, not from absorption problems. Doctors often recommend 1000 to 2000 mcg of cyanocobalamin or methylcobalamin daily.

Best Food Sources of Vitamin B12

• Clams and oysters: Among the richest natural sources available
• mackerel: Excellent marine sources of B12
• Beef, lamb, and chicken: These are good everyday sources of B12 for people who eat meat.
• Eggs and dairy products like milk, yogurt, and cheese: These are moderate sources of B12 and are suitable for vegetarians who eat eggs and dairy.
• B12-fortified plant milks, breakfast cereals, and nutritional yeast: These are the main ways for vegans to get B12 from their diet.

Ready to Check Your Vitamin B12 Levels?

Maxathome offers health monitoring, blood test coordination, and expert care right at your home. Our trained teams handle everything, so you get the answers you need without leaving home.

Book a vitamin panel today and take charge of your health without leaving your home.

Conclusion

Vitamin B12 deficiency is common, often goes unnoticed, and can be serious. Symptoms develop slowly, and by the time you notice them, some damage may already be done. But B12 deficiency is also easy to test for, treat, and prevent. One simple blood test can show if you have a problem. If you notice any of the signs listed here, are in a high-risk group, or have never been tested, now is the time to take action. Finding B12 deficiency early means you can fully recover. Waiting too long can lead to lasting problems.