Foods with Vitamin B12

Vitamin B12 is an essential nutrient, also known as cobalamin and one of the water-soluble vitamins. In the human body, it plays a crucial role in nerve function and blood formation. Meeting the required intake level depends heavily on individual eating habits, so including vitamin B12-rich foods regularly is essential.

Vitamin B12 in foods at a glance

• Vitamin B12 is found in significant amounts primarily in animal foods such as meat, fish, and dairy products.
• Since plant-based foods contain virtually no vitamin B12, vegans rely on appropriately dosed supplements.
• Healthy individuals can easily meet their B12 needs through the regular consumption of animal products.
• If the body lacks vitamin B12, it can lead to long-term issues such as nerve damage and anaemia.
• To detect and correct a potential deficiency early, it is recommended to measure vitamin B12 levels in the blood.

Background: What is vitamin B12?

Exactly speaking, vitamin B12 is not a single vitamin but rather a collective term for several chemical compounds with similar effects. These substances are also referred to as cobalamins. Key forms of cobalamins include adenosylcobalamin, methylcobalamin, and cyanocobalamin. The first two are natural forms of the vitamin, while cyanocobalamin is a synthetically produced version of vitamin B12, commonly used in dietary supplements.

Why does the body need vitamin B12?

Vitamin B12 serves many essential functions in the human body. Among other roles, cobalamins are crucial to maintaining normal nerve function and the formation of red blood cells.

Additionally, vitamin B12 is important for:

• normal energy metabolism,
• normal homocysteine metabolism,
• normal immune system function,
• normal psychological function and cell division.

How high is the daily requirement for vitamin B12?

Certain gut bacteria can produce vitamin B12, though the body can only absorb very minimal amounts of it. Therefore, it’s essential to meet the body’s needs through diet.

• According to the reference values from the DGE (German Nutrition Society), the daily vitamin B12 requirement for those aged 13 and older is four micrograms.
• Pregnant and breastfeeding women have a higher need, requiring 4.5 and 5.5 micrograms of vitamin B12 daily, respectively.

Which foods contain vitamin B12?

Vitamin B12 is found in a variety of animal products. Rich sources of this water-soluble vitamin include meat and offal, fish and seafood, as well as dairy products and eggs. In contrast, plant-based foods contain either very small amounts of vitamin B12 or forms that the body cannot fully utilise. Shiitake mushrooms are one of the few exceptions, though their vitamin B12 content can vary significantly. Because of this variation, shiitake mushrooms are also a limited option as a vegan B12 source.

Can vegans meet their B12 requirements through nutrition?

Since plant-based foods contain minimal vitamin B12, vegans cannot meet their daily requirements through standard plant-based foods alone. To avoid deficiency and its related symptoms, the German Nutrition Society recommends the ongoing use of a vitamin B12 supplement for those following a vegan diet.

Can vegetarians meet their B12 requirements through nutrition?

Vegetarians can generally meet their daily needs without additional supplements, as eggs and dairy products provide suitable sources of vitamin B12. However, these foods do not contain as much vitamin B12 as meat and fish. Therefore, those following a vegetarian diet should pay extra attention to ensuring an adequate intake of this nutrient.

Table of selected foods rich in vitamin B12 (µg per 100 g)

Meat and offal (µg per 100 g)

Fish and seafood (µg per 100 g)

Dairy products and eggs (µg per 100 g)

How to get enough vitamin B12 through nutrition?

Healthy individuals can generally meet their daily B12 needs easily if they regularly consume animal products.

For example:

• 200 grams of pork fillet or beef is enough to fulfil the daily vitamin B12 requirement.
• 100 grams of herring or mussels can provide about double the daily requirement set by the German Nutrition Society (DGE).
• Vegetarians can meet their needs with combinations like 250 grams of low-fat quark and 150 ml of whole milk, or with four medium-sized eggs.

If a deficiency arises despite sufficient intake of B12-rich foods, this is usually due to health conditions, parasitic infections, or certain medications.

What are the effects of vitamin B12 deficiency?

The liver can store up to five milligrams of vitamin B12, which means it can take years before deficiency symptoms appear. However, once stores are depleted, initial symptoms like paleness and fatigue may emerge.

Long-term deficiency can lead to serious health issues, such as:

• anaemia,
• elevated homocysteine levels in the blood, and
• permanent nerve damage.

Additionally, there is some evidence to suggest that prolonged deficiency could increase the risk of developing dementia.

Is it possible to overdose on vitamin B12 through food?

When the intake is limited to nutrition alone, a vitamin B12 overdose is practically impossible. This is generally also the case for high-dose B12 supplements. However, study findings suggest that a daily dose of more than 55 micrograms could potentially increase the risk of lung cancer in the long term. Despite this, the European Food Safety Authority (EFSA) has not yet set a maximum daily dose for vitamin B12.

The German Federal Institute for Risk Assessment (BfR), on the other hand, recommends the following maximum amounts:

• For supplements: 25 µg per daily dose
• For fortified foods: 6 µg per 100 grams
• For fortified drinks: 1.6 µg per 100 millilitres.

Are algae a good vegan source of vitamin B12?

Vegan individuals are often advised to meet their vitamin B12 needs with seaweed. However, seaweeds typically have very low or highly variable amounts of B12. Additionally, they often contain so-called vitamin B12 analogues, which use the same transport mechanisms in the body. This can actually exacerbate a deficiency, rather than help prevent it. The freshwater algae Chlorella is currently the only type of algae for which this does not apply.

Is sauerkraut a good source of vitamin B12?

Fermented products like sauerkraut may contain trace amounts of vitamin B12. However, due to the small and highly variable quantities of the vitamin, they are not suitable for ensuring an adequate intake.

How effective are vitamin B12-fortified foods?

Those following a vegan diet can also turn to vitamin B12-fortified products to help meet their daily needs. However, the levels they contain are often not sufficient to ensure reliable and adequate intake. Whether these products make taking supplements unnecessary should be assessed on an individual basis.

Important to know

If you are not a medical professional and have complaints, specific health conditions, or suspect deficiencies, please make sure to consult a doctor to discuss this.