What Is Vitamin B12?
Vitamin B12 is a water-soluble vitamin that helps the body make red blood cells, maintain normal nerve function, and produce DNA.
It is naturally found mainly in animal-derived foods, although some plant-based foods are fortified with vitamin B12.
Vitamin B12 is therefore an especially useful nutrient to understand when comparing different dietary patterns.
Why Does the Body Need Vitamin B12?
Vitamin B12 contributes to several important functions in the body.
It helps with:
- Normal red blood cell formation
- Normal nervous system function
- DNA production
- Normal energy metabolism
- Normal psychological function
Vitamin B12 also works with other nutrients involved in blood formation and normal cell function.
Which Foods Contain Vitamin B12?
Vitamin B12 is naturally found in foods such as:
- Fish
- Shellfish
- Meat
- Poultry
- Eggs
- Milk and other dairy products
Some foods that do not naturally contain much vitamin B12 can also be fortified with it.
Examples include certain:
- Plant-based drinks
- Breakfast cereals
- Meat alternatives
- Nutritional yeast products
The amount can vary considerably between products.
Vitamin B12 in Fish and Seafood
Fish and seafood can provide useful amounts of vitamin B12.
Examples include:
- Salmon
- Tuna
- Sardines
- Trout
- Clams
- Crab
Seafood can also provide other nutrients, including protein and, depending on the food, different types of fats and minerals.
This is another example of why foods are usually better considered as packages of nutrients rather than isolated sources of one vitamin.
Vitamin B12 in Meat
Meat can provide vitamin B12 along with other nutrients.
Examples include:
- Beef
- Lamb
- Pork
Different cuts and types of meat have different nutritional profiles.
When comparing meat products, factors such as fat content, portion size, preparation method, and sodium can also be relevant.
Vitamin B12 in Eggs
Eggs contain vitamin B12, particularly in the yolk.
Eggs also provide:
- Protein
- Fat
- Choline
- Selenium
- Other nutrients
Including eggs in a varied diet can therefore contribute several nutrients at the same time.
Vitamin B12 in Dairy Foods
Milk, yogurt, and cheese can provide vitamin B12.
The amount varies between products.
Dairy foods can also contribute:
- Calcium
- Protein
- Other vitamins and minerals
This is one reason dairy products can appear in discussions about both vitamin B12 and calcium.
Can Plant Foods Provide Vitamin B12?
Most unfortified plant foods are not reliable natural sources of vitamin B12.
This is an important distinction.
Foods such as:
- Fruits
- Vegetables
- Beans
- Lentils
- Nuts
- Seeds
- Whole grains
can provide many valuable nutrients, but they generally should not be assumed to provide enough vitamin B12.
Some plant-based products are fortified with vitamin B12.
What Are Fortified Foods?
Fortified foods have nutrients added during processing.
Some foods are fortified with vitamin B12 to help provide a source of the vitamin.
Examples can include:
- Plant-based milk alternatives
- Breakfast cereals
- Meat alternatives
- Certain nutritional yeast products
Fortification is not standardized across every product.
Always check the nutrition label rather than assuming that a product contains vitamin B12.
Vitamin B12 and Vegetarian Diets
Vegetarian diets can contain vitamin B12 through foods such as:
- Eggs
- Milk
- Yogurt
- Cheese
- Fortified foods
However, the amount available depends on the individual’s dietary pattern.
Someone who eats very little or no animal-derived food may need to pay closer attention to reliable vitamin B12 sources.
Vitamin B12 and Vegan Diets
Vitamin B12 deserves particular attention in vegan diets because naturally occurring B12 is found mainly in animal-derived foods.
Reliable options can include appropriately fortified foods and vitamin B12 supplements when suitable.
Simply eating a wide variety of fruits, vegetables, beans, grains, nuts, and seeds does not automatically provide sufficient vitamin B12.
This is an important example of why “plant-based” and “nutritionally complete” are not necessarily the same thing.
How Much Vitamin B12 Do People Need?
Vitamin B12 requirements vary according to factors such as:
- Age
- Life stage
- Pregnancy
- Breastfeeding
- Individual health circumstances
Different health authorities may use different reference values.
Rather than treating one number as a universal target, it is more useful to understand the major food sources and whether a particular dietary pattern provides reliable B12.
What Happens If You Don’t Get Enough Vitamin B12?
A prolonged lack of sufficient vitamin B12 can affect normal red blood cell formation and nervous system function.
Vitamin B12 deficiency can lead to medical problems, including certain forms of anemia and neurological problems.
Symptoms can vary and may overlap with other conditions.
This means symptoms alone are not a reliable way to determine whether someone has a vitamin B12 deficiency.
Anyone concerned about deficiency should discuss their situation with a qualified healthcare professional.
Who May Need to Pay More Attention to Vitamin B12?
Some groups may have a greater risk of inadequate vitamin B12 intake or absorption.
These can include:
- People following vegan diets
- Some vegetarians
- Older adults
- People with certain digestive or absorption problems
- People taking certain medications that affect vitamin B12 absorption
Individual circumstances differ, so nutritional advice should be personalized when a deficiency risk is suspected.
Vitamin B12 and Energy
Vitamin B12 is often marketed as an “energy vitamin.”
There is an important distinction here.
Vitamin B12 is involved in normal energy metabolism.
However, taking extra vitamin B12 does not automatically provide extra energy if someone already has adequate B12 status.
If someone feels tired, there can be many possible reasons.
Fatigue should not automatically be attributed to vitamin B12 deficiency.
Vitamin B12 and Red Blood Cells
Vitamin B12 is involved in normal red blood cell formation.
Red blood cells carry oxygen throughout the body.
When vitamin B12 deficiency affects red blood cell production, it can contribute to a type of anemia.
However, anemia can have many different causes.
For example, iron deficiency is another nutritional cause of anemia.
This is why it is important not to assume that every case of anemia is caused by the same nutrient.
Vitamin B12 and the Nervous System
Vitamin B12 contributes to normal nervous system function.
A prolonged deficiency can affect the nervous system and may cause neurological problems.
Because some neurological effects can become serious, suspected deficiency should be evaluated appropriately rather than managed through self-diagnosis.
Can You Get Vitamin B12 From a Nutrition Label?
Yes.
Vitamin B12 may appear in the nutrition information of fortified foods and some other packaged foods.
Depending on the country and labeling system, it may be shown using:
- Micrograms (mcg)
- A percentage of a daily value or reference value
When comparing products, check both the serving size and the amount of vitamin B12.
Why Do Similar Products Have Different Amounts of Vitamin B12?
Two products from the same category may contain very different amounts of vitamin B12.
For example:
Plant-based drink A
Vitamin B12: fortified
Plant-based drink B
Vitamin B12: not fortified
Both may look similar on the supermarket shelf.
This is why checking the nutrition label is more reliable than assuming products within the same category have identical nutritional content.
Vitamin B12 and Other Nutrients
Vitamin B12 is only one part of a balanced diet.
For example:
Eggs
can provide B12, protein, choline, and other nutrients.
Fish
can provide B12, protein, and other nutrients.
Milk
can provide B12, calcium, and protein.
This illustrates an important nutrition principle:
One food can contribute several nutrients at the same time.
Is Vitamin B12 the Same as Iron?
No.
Vitamin B12 and iron are different nutrients.
However, both are involved in normal blood-related functions.
Iron is a mineral, while vitamin B12 is a vitamin.
A person with anemia should therefore not automatically assume that they need more iron or more vitamin B12 without understanding the underlying cause.
For more information, see:
What Is Iron? A Simple Guide to Iron in Food
Is Vitamin B12 Found in Fruit?
Most fruits are not meaningful natural sources of vitamin B12.
Fruits can still be an important part of a balanced diet because they provide other nutrients and beneficial plant compounds.
For example:
Oranges → Vitamin C
while:
Salmon → Vitamin B12
Different foods contribute different nutrients.
Should Everyone Take a Vitamin B12 Supplement?
Not necessarily.
People who regularly consume reliable sources of vitamin B12 may not need a supplement.
However, supplementation may be useful for some people depending on their dietary pattern or individual circumstances.
Anyone considering supplementation should consider the amount already obtained from food and fortified products.
For people with specific medical or nutritional concerns, professional guidance is preferable.
How Can You Include More Vitamin B12 in Your Diet?
Depending on your dietary pattern, practical options include:
- Eating fish or seafood
- Including eggs
- Including dairy foods
- Choosing vitamin B12-fortified plant-based drinks
- Choosing appropriately fortified breakfast cereals
- Using suitable fortified foods
- Considering supplements when appropriate
The best approach depends on the foods you normally eat.
A Simple Vitamin B12 Meal Example
Consider a meal containing:
- Grilled salmon
- Brown rice
- Broccoli
- Yogurt
This meal can provide a combination of:
- Vitamin B12
- Protein
- Calcium
- Fiber
- Various vitamins and minerals
No single food needs to provide every nutrient.
A varied eating pattern makes it easier to obtain a broader range of nutrients.
The Simple Takeaway
Vitamin B12 is a water-soluble vitamin involved in red blood cell formation, nervous system function, DNA production, and normal energy metabolism.
The most important things to remember are:
- Vitamin B12 is naturally found mainly in animal-derived foods.
- Fish, seafood, meat, eggs, and dairy can provide vitamin B12.
- Some plant-based foods are fortified with vitamin B12.
- Most unfortified plant foods are not reliable sources of B12.
- People following vegan diets need a reliable source of vitamin B12.
- Vitamin B12 is involved in normal energy metabolism, but extra B12 does not automatically increase energy.
- Long-term inadequate intake can cause health problems.
- Vitamin B12 and iron are different nutrients even though both are relevant to blood health.
- Nutrition labels can help identify fortified foods.
- A varied diet should be considered as a whole rather than focusing on one nutrient alone.
Vitamin B12 is therefore a particularly useful nutrient to understand when comparing different food choices and dietary patterns.
Sources & Further Reading
National Institutes of Health — Office of Dietary Supplements: Vitamin B12
General information about vitamin B12, food sources, recommended amounts, deficiency, and supplementation.
U.S. Department of Agriculture — FoodData Central
A database for exploring vitamin B12 and other nutrient information in individual foods.
NHS — Vitamin B12 or Folate Deficiency Anaemia
Consumer information about vitamin B12 deficiency and related health issues.