My Cart

You have no items in your shopping cart.

You're currently on:


What are the sources of Vitamin B12? Learn how to avoid shortages

How to combat stress and fatigue

Important for everybody, essential to vegetarians and vegans

We have become so accustomed to being told that vitamins are essential for the health of our body, that we do not always pay due attention to this wise, though perhaps abused, advice. However, when talking about vitamin B12, we are forced to repeat: it is a vital vitamin for the human body health. A deficiency of this vitamin, as explained in an article published on the website of the Veronesi Foundation, is mainly due to a poor diet. What are the specific risks associated with a B12 deficiency, and who is the most at risk? Most importantly, where is vitamin B12 found and what foods should we eat to prevent deficiencies?

How to detect a deficiency of vitamin B12?

In addition to an overly restrictive diet, there are other factors that can cause a B12 deficiency. It must be remembered that Vitamin B12 deficiency also increases with advancing age since its absorption decreases progressively with age: the stomach is less efficient in producing the enzyme that helps its absorption or there is intestinal malabsorption. Not only that, but also taking certain medications may hinder the absorption of vitamin B12.

To know with certainty whether a shortage is taking place, simply run blood tests to assess the levels of vitamin B12, folic acid and homocysteine, parameters that must always be considered together; after detecting these values, you can decide with your doctor whether and how to proceed to a supplementation.

The daily requirement of B12 for a healthy adult is between 2 and 4 micrograms. Such dose can be easily reached with food. However, there are medical conditions that limit the absorption of this vitamin (Crohn's disease, malabsorption syndromes, medicine consumption). Under these conditions, or with an unbalanced diet, it might be useful to resort to a vitamin B12 supplement.

What are the "risks" associated with a B12 deficiency?

A deficiency of vitamin B12, especially if protracted in time, may promote the onset of various disorders, which should not be neglected:

  • chronic fatigue and / or paleness;
  • nervousness and headache;
  • onset of increasing anaemia;
  • memory and concentration problems;
  • depression.

Some research has also shown that a B12 deficiency in pregnancy may encourage the birth of children with growth delay, or underweight.
Instead, the role played by this vitamin to ensure the proper functioning of the immune system is now confirmed. In people deficient in this vitamin, then, you can see a reduction in lymphocytes or Natural killer cells, resulting in a general weakening of the body's defences.

Vitamin B12 and its interactions

Vitamin B12 and folic acid are closely related in chemical reactions: the first is used to regenerate the second in the active form. It is interesting to note that "vitamin B12 also affects the secretion of melatonin. The low levels of melatonin in the elderly may be the result of a vitamin B12 deficiency. Vitamin B12 (1.5 mg methylcobalamine per day) gives good results in the treatment of sleep-wake cycle disorders, probably due to an increase in melatonin secretion" (MT Murray, Guida medica agli integratori alimentari, Milano 2005).

Where is Vitamin B12 found? Animal and vegetable sources

As mentioned previously, the best sources of vitamin B12 are mainly of animal origin. Before explaining in detail where vitamin B12 is found, however, we should make an important clarification.

In addition to the amount of B12 made available by individual foods, you should also understand the bioavailability thereof. Bioavailability refers to the amount of a nutrient that the body is able to assimilate. Too high a dose of B12 but with a low bioavailability is, in fact, unnecessary for our body.

Listed below are the foods that contain higher amounts of vitamin B12 in bioavailable form.

1) All the entrails, especially the liver

As mentioned previously, the best sources of vitamin B12 are mainly of animal origin. This vitamin is present in good quantities and in bioavailable form especially in the sheep and beef liver (respectively 90.05 and 59.85 micrograms about every 100 g). It is generally contained in all the entrails although in a smaller amount.

2) Caviar

Caviar is a good source of vitamin B12, although it can hardly become part of the daily diet in large quantities. In fact, it contains about 20 micrograms per 100 g of product.

3) Clams and octopus

Fish is also a good source of B12 whose bioavailability has been estimated, according to some studies, around 42%. The richest sources include clams (49 micrograms) and octopus (20 micrograms). However, herrings and tuna also rank high enough in the standings.

4) Cereals, only if fortified

Non-animal alternative sources, for those who follow vegetarian or vegan diets, are cereals or granola, but only if fortified. Remember that we define fortified those foods enriched with nutrients (vitamins in this case) by means of a special technological process. Generally, it is recommended especially to those who follow a vegan diet, to add fortified foods to their diet.

5) Some algae

Several studies have shown that some seaweeds contain good amounts of vitamin B12. Nori seaweed is the richest plant source as it can provide variable amounts of vitamin B12 (from 63.6 to 31.8 micrograms). Fairly rich in vitamin B12 are also Spirulina and Chlorella. But there are still doubts about the bioavailability of vitamin B12 present in seaweeds and there is no unanimity of opinion among experts: some studies have questioned the ability to be absorbed by the human body, while others have suggested that these seaweeds (Nori in particular) can prevent deficiencies in a vegan diet.

 Why so much vitamin B12 in the liver?

Ruminant animals, unlike humans, have abundant bacterial flora also in the high sections of the digestive system; this means that the vitamin B12 is more easily absorbed and accumulated in the liver, and explains why in the cattle can be found in significant amounts.


Conclusion: what are the sources of Vitamin B12 and when is it useful to supplement it?

As we have seen, the main sources of vitamin B12 are mostly of animal origin. However, this vitamin is present in good quantities in some algae, although some scholars have expressed doubts about its bioavailability. According to some, indeed, the vitamin B12 present in the algae would be a viable alternative to animal proteins, while for others it would not be absorbed by the human body.

What is however certain is that this vitamin plays a vital role in our bodies. A deficiency, if substantial and protracted, can favour the development of severe forms of anaemia.

A B12 deficiency can be promoted by various factors, which may require its supplementation with specific products. In particular, you may need to resort to vitamin B12 supplements in the following cases:

  • wrong diet;
  • alcohol abuse;
  • some illnesses (stomach ulcers, gastritis, Crohn's disease)
  • use of specific medicines (for example those aimed at reducing gastric acidity).

Vitamin B12 for vegetarians and vegans

Right because the main sources of this substance are mainly of animal origin, vegans and, to a lesser degree, vegetarians, are the most exposed to potential deficiencies of vitamin B12, and may need to supplement it with "fortified" foods (e.g. fortified with this vitamin), sold in specialty stores.

In these cases, in the face of overt deficiency, more help may also arrive from the consumption of specific supplements. Among the products on the market, you can choose from vitamin B12 supplements, or those enriched with other B vitamins, particularly folic acid (which plays a complementary role to vitamin B12). Although consuming vitamin B12 is absolutely safe, when in doubt, for extreme safety you should always consult the doctor.

Remember that the Italian Ministry of Health set to 25 milligrams, the maximum daily intake of vitamin B12 that can be provided by a supplement. We also emphasize that, to date, we do not know specific side effects associated with an overdose of this vitamin so its intake in general should be considered absolutely safe.




© Developed by CommerceLab








  • 100% MADE IN ITALY
Sign Up for Our Newsletter: