Vitamin B12 is an essential nutrient that keeps your body working properly. It plays a big role in how your body makes blood, supports your nervous system, and helps produce DNA. Even though your body doesn’t need a huge amount of it, getting enough B12 is important for your energy, focus, and overall health.
In this article, you’ll learn everything you need to know about vitamin B12—what it does, where to find it, signs of low B12, and how to keep your levels healthy.
Table of Contents
What Is Vitamin B12?
A Vital B Vitamin
Vitamin B12 is one of the eight B vitamins. It’s also called cobalamin, and it helps your body convert food into energy. It’s water-soluble, which means your body doesn’t store it for long—so you need to get it regularly through your diet or supplements.
Vitamin B12 is mostly found in animal products, which is why vegetarians and vegans need to pay special attention to their intake.
Why Is Vitamin B12 Important?
Helps Make Red Blood Cells
One of B12’s most important jobs is to help your body make red blood cells. These cells carry oxygen from your lungs to the rest of your body. If you don’t have enough B12, you might develop anemia, which can make you feel tired, weak, and dizzy.
Supports Brain and Nerve Health
Vitamin B12 plays a role in your nervous system. It helps protect your nerves and keep your brain working well. Low B12 levels can lead to memory problems, confusion, or even depression.
Keeps DNA Healthy
Your body needs B12 to create DNA, the genetic material in every cell. Without enough B12, your body can’t make new cells properly.
Sources of Vitamin B12
Animal-Based Foods
The best sources of vitamin B12 come from animal products. These include:
- Meat (beef, pork, lamb)
- Poultry (chicken, turkey)
- Fish and shellfish (salmon, tuna, clams)
- Eggs
- Milk and dairy products
Even a small amount of these foods can give you a good dose of vitamin B12.
Fortified Foods
Some foods don’t naturally have B12 but are fortified—which means the vitamin has been added. These include:
- Breakfast cereals
- Plant-based milks (soy, almond, oat)
- Meat substitutes
Supplements
If you can’t get enough B12 through food—especially if you’re vegan or have absorption issues—vitamin B12 supplements are a good option. They come in pills, sprays, or injections, depending on what your doctor recommends.
How Much Vitamin B12 Do You Need?
The amount of vitamin B12 you need depends on your age and health. Here are the general recommendations:
- Adults: 2.4 micrograms (mcg) per day
- Pregnant women: 2.6 mcg per day
- Breastfeeding women: 2.8 mcg per day
Children and teens need less, and older adults may need more due to absorption problems.
Signs of Vitamin B12 Deficiency
A lack of vitamin B12 can cause many health problems. These are some common signs to watch for:
Fatigue and Weakness
Feeling very tired or weak is one of the most common symptoms. Without enough red blood cells, your body doesn’t get the oxygen it needs.
Pale or Yellow Skin
If your skin looks pale or slightly yellow, it could be a sign of low B12, especially if paired with tiredness.
Numbness or Tingling
Low B12 can damage your nerves. You might feel pins and needles in your hands, feet, or legs.
Memory or Mood Problems
B12 is important for brain health. A deficiency can cause memory loss, depression, or confusion.
Swollen Tongue and Mouth Issues
Some people notice a smooth, red tongue, mouth sores, or a burning feeling in the mouth or tongue.
Who Is at Risk of Low Vitamin B12?
Vegetarians and Vegans
Because B12 is mostly found in animal foods, people who eat little or no meat or dairy are at higher risk. They should rely on fortified foods or take a supplement.
Older Adults
As we age, the stomach produces less acid, making it harder to absorb B12 from food.
People With Digestive Problems
Conditions like Crohn’s disease, celiac disease, or surgeries that affect the stomach or small intestine can reduce B12 absorption.
People Taking Certain Medications
Some medicines—like metformin (for diabetes) or acid-reducing drugs—can lower your ability to absorb B12.
How to Prevent Vitamin B12 Deficiency
Eat a Balanced Diet
Include plenty of B12-rich foods like meat, dairy, eggs, or fortified products if you’re plant-based.
Take a Supplement if Needed
If you’re at risk or already have low levels, talk to a doctor about taking a B12 supplement. These are usually safe and easy to take.
Get Regular Checkups
Blood tests can check your B12 levels, especially if you have symptoms or are in a high-risk group.
Vitamin B12 and Pregnancy
Vitamin B12 is very important for pregnant women. It supports the baby’s brain and nervous system as it grows. Low B12 during pregnancy can cause birth defects or developmental problems.
If you’re pregnant or planning to be, make sure you’re getting enough through diet or a prenatal vitamin.
Can You Get Too Much Vitamin B12?
Vitamin B12 is generally safe, even at higher doses. Since it’s water-soluble, your body gets rid of what it doesn’t use through urine.
Still, there’s no need to take more than your body needs unless recommended by a doctor. Extremely high doses from supplements may sometimes cause mild side effects like acne or rash in sensitive people.
B12 Injections: What to Know
For people with very low B12 or trouble absorbing it, injections may be necessary. These shots go directly into your muscle, helping your body get the vitamin without relying on digestion.
Injections are usually given by a doctor or nurse, either once a week at first, and then less often as your levels improve.
Best Practices to Keep B12 Levels Healthy
Eat a Variety of Foods
Don’t rely on just one source. Mix things up with meat, eggs, fish, and dairy—or fortified products if you’re plant-based.
Watch for Symptoms
Stay aware of warning signs like tiredness, memory issues, or tingling. Early treatment can prevent serious problems.
Get Blood Tests if Needed
If you feel “off” and don’t know why, a blood test can show if low B12 is part of the problem.
Talk to Your Doctor
If you have health issues or take medications that affect B12, ask your doctor what’s best for you. They may recommend routine supplements or injections.
Final Thoughts
Vitamin B12 is small, but it has a huge impact on your body and mind. It helps your blood, brain, and nerves stay healthy and strong. While most people get enough from food, others—especially vegans, older adults, and people with digestive problems—need to be extra careful.
The good news? It’s easy to prevent or fix a B12 deficiency with diet, supplements, or medical support. By learning the signs and knowing what your body needs, you can stay energized, clear-headed, and healthy.
