Sandeep Dhand
Nutritionist And Health Educator
Introduction
Vitamin B12, also known as cobalamin, is one of the most important vitamins for the human body. It plays a vital role in keeping our nerves, blood cells, and brain healthy. Unlike other vitamins, Vitamin B12 is unique because it is only found naturally in animal-based foods. This makes it an essential nutrient to monitor, especially for vegetarians and vegans.
Many people are unaware of how important Vitamin B12 is until they start facing symptoms of its deficiency. Feeling tired, weak, or forgetful may seem normal due to a busy lifestyle, but in many cases, these signs point toward low B12 levels. Let’s understand this crucial vitamin in full detail, from its role in the body to where we can get it and why it matters so much.
What is Vitamin B12?
Vitamin B12 is a water-soluble vitamin, meaning it dissolves in water and travels through your bloodstream. The body does not store it for long periods (except in the liver), so we need to consume it regularly through diet or supplements. It is involved in many body processes, including:
DNA synthesis
Red blood cell formation
Brain function and nerve health
Energy production
Unlike vitamins like Vitamin C, which you can get from fruits and vegetables, Vitamin B12 is mainly found in animal-based foods. That’s why people on plant-based diets are more likely to be deficient.
Why is Vitamin B12 Important for the Body?
Vitamin B12 is essential for several reasons:
- Supports Red Blood Cell Formation and Prevents Anemia
One of the main jobs of Vitamin B12 is to help produce healthy red blood cells. Without enough B12, your body creates larger and abnormal red blood cells that can’t move easily through the bloodstream. This leads to a condition called megaloblastic anemia, which makes you feel tired and weak.
- Boosts Brain and Nerve Health
Vitamin B12 helps maintain the protective covering (myelin sheath) of nerve cells. Without enough B12, nerve cells can get damaged, leading to numbness, tingling, balance problems, and even memory loss. Long-term deficiency may cause permanent nerve damage.
- Supports Mental Health and Mood
Vitamin B12 helps in the production of chemicals like serotonin, which affect mood. Low levels are linked to symptoms of depression, mood swings, and mental fog. B12 plays a role in keeping your mind sharp and focused.
- Improves Energy Levels
Although B12 doesn’t provide energy directly, it is required to convert the food we eat into usable energy. Without it, the body struggles to perform daily tasks, making you feel constantly tired or lazy.
- Helps in DNA Production
Vitamin B12 is essential for making and repairing DNA, which is the genetic material in all cells. This process is important for cell division and growth, especially in children and pregnant women.
Symptoms of Vitamin B12 Deficiency
Vitamin B12 deficiency can develop slowly over time or come on quickly. Common symptoms include:
Fatigue or weakness
Pale or yellowish skin
Shortness of breath
Tingling or numbness in hands and feet
Difficulty walking or balance issues
Memory loss or confusion
Mood changes or depression
Glossitis (inflamed tongue)
Mouth ulcers
Vision problems
Irregular heartbeat
If untreated, the deficiency can lead to permanent nerve damage or serious neurological disorders.
Causes of Vitamin B12 Deficiency
There are several reasons why someone may become deficient in Vitamin B12:
- Poor Dietary Intake
People who follow a vegetarian or vegan diet may not get enough B12 from their food. Since B12 is found mainly in animal products, plant-based diets need fortified foods or supplements.
- Poor Absorption
Sometimes the body can’t absorb B12 properly due to conditions like:
Pernicious anemia – an autoimmune condition where the body doesn’t produce enough “intrinsic factor,” a protein needed to absorb B12.
Gastrointestinal issues – like Crohn’s disease, celiac disease, or gastritis.
Bariatric surgery – reduces the stomach’s ability to absorb nutrients.
Old age – older adults may produce less stomach acid, which is needed to absorb B12.
- Alcoholism and Smoking
Alcohol and tobacco use can interfere with B12 absorption and increase the risk of deficiency.
- Certain Medications
Long-term use of medications like metformin (for diabetes) or proton pump inhibitors (PPIs) for acidity can reduce B12 absorption.
Who is at Risk of Vitamin B12 Deficiency?
The following groups are more likely to have low Vitamin B12 levels:
Vegetarians and vegans
Adults over the age of 60
People with gastrointestinal disorders
People who have had weight-loss surgery
Chronic alcoholics
Diabetics on long-term metformin
Pregnant and breastfeeding women (especially vegans)
Daily Requirement of Vitamin B12
The recommended dietary allowance (RDA) for Vitamin B12 depends on age, gender, and other factors like pregnancy.
Adults: 2.4 micrograms/day
Pregnant women: 2.6 micrograms/day
Breastfeeding women: 2.8 micrograms/day
The good news is that the body doesn’t need a huge amount of B12 daily. However, regular intake is necessary because the body can’t produce it on its own.
Sources of Vitamin B12
Non-Vegetarian Sources (Natural)
- Liver (especially beef liver) – extremely rich in B12
- Fish – like tuna, salmon, sardines, mackerel
- Shellfish – clams and oysters are excellent sources
- Chicken
- Red meat (beef, lamb)
- Eggs – especially the yolk
- Dairy products – milk, cheese, curd, paneer
These are the most bioavailable sources, meaning the body absorbs B12 from them very efficiently.
Vegetarian and Vegan Sources
Unfortunately, there are no reliable plant-based natural sources of B12. But don’t worry! Many foods are now fortified with B12, and supplements are widely available.
Fortified Foods:
Fortified breakfast cereals
Fortified soy milk, almond milk, and other plant-based milks
Fortified nutritional yeast (a favorite among vegans)
Fortified tofu and plant-based meat substitutes
Supplements:
Vitamin B12 supplements are available in different forms:
Tablets and capsules (cyanocobalamin or methylcobalamin)
Sublingual tablets (dissolve under the tongue for better absorption)
Injections (used in severe deficiency or poor absorption cases)
Oral sprays and drops
These supplements are often vegan-friendly and safe when taken as per guidance.
Types of Vitamin B12
There are four forms of Vitamin B12:
- Cyanocobalamin – Synthetic form, commonly used in supplements.
- Methylcobalamin – Active form, better absorbed by the body.
- Hydroxocobalamin – Used in injections, lasts longer in the body.
- Adenosylcobalamin – Active form used by mitochondria in cells.
Most over-the-counter B12 supplements use cyanocobalamin or methylcobalamin.
How to Improve Vitamin B12 Levels?
Here are ways to maintain or improve B12 levels:
Include animal-based foods regularly (for non-vegetarians).
Choose fortified foods (for vegetarians and vegans).
Take regular B12 supplements, especially if you’re at risk of deficiency.
Get tested yearly if you have risk factors.
Consider B12 injections if your doctor recommends them (especially for older adults or people with poor absorption).
B12 and Pregnancy
Vitamin B12 is extremely important during pregnancy for the baby’s brain and spinal cord development. Deficiency during this period can cause neural tube defects, premature birth, or low birth weight. Pregnant women, especially vegans, should be very careful and consult their doctor for supplements.
Complications of Untreated B12 Deficiency
If left untreated, low Vitamin B12 levels can lead to:
Permanent nerve damage
Memory loss and confusion
Heart palpitations
Infertility
Depression and other mental health issues
Birth defects in newborns (if the mother is deficient during pregnancy)
Early diagnosis and treatment can prevent all of these complications.
Can You Take Too Much Vitamin B12?
Vitamin B12 is a water-soluble vitamin, so any excess usually passes out of the body through urine. There is no established upper limit for B12, and toxicity is rare. However, always follow the prescribed dosage and consult your healthcare provider, especially if taking high doses for a long time.
Testing for Vitamin B12 Deficiency
Doctors usually recommend a blood test to measure B12 levels. In some cases, additional tests like methylmalonic acid (MMA) or homocysteine may be used for accurate diagnosis.
Normal serum B12 levels are generally between 200 to 900 pg/mL. A level below 200 is considered deficient.
Conclusion
Vitamin B12 is a life-essential nutrient that supports energy, memory, mood, and overall well-being. It is especially important for red blood cell production and nervous system health. Since it is mainly found in animal-based products, vegetarians and vegans need to be extra careful and look for fortified foods or supplements.
Symptoms of B12 deficiency can be mild at first but may become serious over time if left untreated. The good news is that it’s easily preventable with the right diet, awareness, and supplementation.
Whether you’re a health-conscious person or someone already facing