Vitamin B12 Benefits, Potential Risks and If You're Getting Enough

CNET

22-06-2025

When it comes to vitamins, most people focus on the most common ones, like vitamin A, C or D. Vitamin B12 is overlooked, though it shouldn't be because it helps produce vital red blood cells and boost energy levels. Unlike other nutrients, our bodies can't make vitamin B12 on their own.
A balanced diet including meat, eggs and fish can usually fulfill all of your B12 needs. However, your diet or conditions like Crohn's disease might mean that your body needs a little extra help getting enough B12.
This is the ultimate guide on the importance of vitamin B12, what happens if you don't get enough and key information on supplementation.
What is vitamin B12?
Vitamin B12 contains cobalt, hence its name, cobalamin. It's a water soluble vitamin your body uses to create red blood cells and DNA. It also helps develop your central nervous system. Your central nervous system is like your body's mail delivery system, carrying messages from your nerves to your brain, where your brain responds. Moreover, the vitamin helps your hair, nails and skin remain healthy.
You can find B12 in four chemical compounds: methylcobalamin, hydroxocobalamin, adenosylcobalamin and cyanocobalamin. Methylcobalamin and adenosylcobalamin are in meat and dairy products. You might have to take a vitamin B12 supplement to avoid a B12 deficiency if you're a vegan or vegetarian. Cyanocobalamin is the synthetic form of vitamin B12, broken down into methylcobalamin and adenosylcobalamin in supplements.
Meanwhile, if you have a vitamin B12 deficiency, you might require a shot or IV drip. This is where hydroxocobalamin comes into play. It is a manufactured version of the vitamin used to treat deficiencies.
Vitamin B12 benefits
Taking healthy doses of vitamin B12 can benefit your body in the following ways:
1. Supports red blood cell formation
Your body needs red blood cells to make DNA. Your body loses 1% of your oldest red blood cells daily. Vitamin B12 with vitamin B9 (folate) helps your body replenish the red blood cells you lost. Without a healthy dose of regular vitamin B12, you can become anemic.
2. Boosts energy levels
Some energy drinks use vitamin B12 to give you a pep in your step. However, they only work well if you have a vitamin B-12 deficiency. When this happens, you might experience fatigue, tiredness and become cranky. Proper vitamin B12 levels from food or supplements can give your body the perk to tackle your tasks.
3. Supports nerve health
Taking regular doses can help your nervous system. Vitamin B12 has a rep for being a neurotropic vitamin for its ability to heal damaged nerve cells. When you take the vitamin, it contains myelin. Myelin is a sheath surrounding nerve fibers, allowing for better communication between them and the brain. It is why some of the problems with vitamin B12 deficiencies include numb toes or fingers, muscle weakness and problems with coordination.
Juan Gaertner/Science4. Improves mood and cognitive function
Vitamin B12 helps play a role in the brain, producing chemicals that impact your mood. While studies show low vitamin levels can lead to depression, they can't determine if regulated vitamin levels boost mood or improve cognitive function.
Potential risks of vitamin B12 deficiency
When your body doesn't receive enough vitamin B12, you could be susceptible to the following medical conditions:
1. Anemia and related symptoms
When your body doesn't receive enough vitamin B12, it slows the growth of red blood cells. A cumulative loss of red blood cells can result in vitamin B12 deficiency anemia. With it, you can experience muscle weakness and fatigue.
2. Neurological issues
A lack of vitamin B12 in your body could result in neurological issues. Some of the symptoms include:
Memory loss
Vision problems
Ataxia, a condition where you lose physical coordination
Damage to the central nervous system, especially in your legs
Your body needs vitamin B12 to help support your central nervous system. Without it, your nerves might have trouble sending signals to your brain, particularly in your fingers or toes. Over time, it could lead to nerve damage if left untreated.
3. Long-term health risks
Many symptoms of vitamin B12 deficiencies could mimic other illnesses, making it hard to identify. If left untreated it could lead to more serious health issues, which can increase in severity quickly.
Some of the top risks include a decline in cognitive function. More specifically, memory loss or trouble reasoning can occur. It could also result in strange sensations like tingling in your arms or feet or a swollen tongue. If you notice these symptoms, consult your doctor on root causes.
Who should consider vitamin B12 supplements?
Here are a few groups who should consider vitamin B12 supplements:
Vegans and vegetarians : You'll find vitamin B12 in fish, poultry and other meats. The only issue is if your diet restricts you from consuming these items, you need another source of vitamin B12. You can find these in fortified foods such as breakfast cereals or dairy products.
: You'll find vitamin B12 in fish, poultry and other meats. The only issue is if your diet restricts you from consuming these items, you need another source of vitamin B12. You can find these in fortified foods such as breakfast cereals or dairy products. Older adults : As you age, your stomach acid declines, making it more difficult for your body to absorb vitamin B12 from foods. It is wise to consider a supplement if your levels are low.
: As you age, your stomach acid declines, making it more difficult for your body to absorb vitamin B12 from foods. It is wise to consider a supplement if your levels are low. Individuals with certain medical conditions: Some medical conditions, such as celiac disease, pernicious anemia and Crohn's disease, make it difficult for your body to absorb vitamin B12. In each of these instances, your doctor might recommend a shot or IV drip.
Best vitamin B12 food sources
You can find vitamin B12 in the following sources:
Animal-based sources: Meat, chicken, fish, clams, salmon, sardines, tuna, trout and dairy products all contain vitamin B12. Some organ meats, such as kidney and liver, are also high in vitamin B12.
Plant-based sources: Vegans and vegetarians who can't source their vitamins from meat can consume seaweed or nutritional yeast. Nutritional yeast is good as a popcorn topping or sprinkle it onto tofu or other plant-based foods.
Fortified foods: Manufacturers add vitamins to some foods to make it more nutritious. Fortified breakfast cereals, such as one cup of Malt-O-Meal Raisin Bran, contain more than 60% of your daily allotment of vitamin B12.
ScienceB12 injections vs. B12 supplements
There are many factors at play when considering injections and dietary supplements. On the supplement front, it's imperative to consider any medical conditions that might impede your body's ability to absorb it. If you have Crohn's disease, you want a shot instead because it absorbs into your bloodstream, making it a more effective absorption method.
However, when considering shots, you'll want to consider a few things. One, they'll be more expensive than vitamin B12 supplements. They can also cause side effects, such as skin rashes, headaches, itching, diarrhea and nausea.
Meanwhile, vitamin supplements are more cost-effective if you don't have a medical condition where you'll need help with absorption. However, refrain from taking them before speaking with your doctor if you're on folic acid supplements or if you have sensitivities to cobalt.
Ultimately, your doctor can help you determine the best course of action. Expect to take a blood test to check your vitamin B12 levels before adding a supplement or shot.
Vitamin B12 dosing and absorption tips
One of the best ways to maximize absorption is through proper gut health. Before trying vitamin supplements, it's important that you don't experience regular diarrhea, constipation or other issues, which can prevent your body from absorbing the vitamin well.
If your doctor is OK with you taking a supplement, follow the instructions on the label. The daily recommended dose of vitamin B12 is 2.4 micrograms. If you eat a well-balanced diet full of chicken, seafood or eggs, you'll receive this amount through your diet.
If you need a vitamin B12 supplement, be aware of other nutrients that can lessen its effectiveness. Vitamin C supplements have the opposite effect, lowering the vitamin B12 in your body. Having a medical professional weigh in before taking a supplement or shot helps you cover all your bases and avoid any drug or nutrient interactions.
B12 Vitamin FAQ
What are the symptoms of a B12 deficiency?
The symptoms of a vitamin B12 deficiency vary, though one of the most common is feeling very tired or weak, nausea, loss of appetite and weight loss. Some people may also experience cognitive problems, a yellowish tint to their skin or develop sores on their mouth or tongue. If you're experiencing any of these symptoms, it's important to see your doctor.
What are some good sources of vitamin B12?
You can make sure you're getting enough vitamin B12 by packing your diet with nutrient-rich foods. The foods that include vitamin B12 include, but are not limited to: Beef
Eggs
Fortified cereal
Fish like tuna, trout or salmon
Milk and other dairy products like yogurt and cheese
Fortified nondairy milk
Clams
If you have dietary restrictions, your doctor may recommend that you take vitamin B12 supplements to ensure you're getting enough.