Vitamin B12 is a tough call. Do only vegans develop deficiencies because it’s not found in plant products? Is there another source of this vital nutrient for vegetarians? Maybe you have been eating plant-based for years and don’t feel a difference.
Just like that, many underestimate the role of the water-soluble vitamin from animal foods. Even though, without the vitamin, anemia and nerve damage can occur. Very few people know that they could also be in a risk group for serious B12 deficiency.
Some important facts about vitamin B12
- B12 is part of the vitamin B complex, a vitamin group consisting of 8 nutrients (B1, B2, B3, B5, B6, biotin, folic acid, and B12).
- Its chemical name is cobalamin because it is the only organic molecule that contains cobalt.
- There are several forms of B12:
- Methylcobalamin and 5-deoxyadenosylcobalamin are metabolically active in the human body
The daily requirement can be covered by animal products or fortified food. In case of a deficiency, vitamin storages in the liver can only be replenished through high-dose food supplements or injections.
Older people and vegetarians are in the risk group
In general, vitamin B12 deficiency can have two causes:
- Low intake through food: due to a strictly plant-based or one-sided diet
- Problems with the intake of dietary B12: older adults, anemic people, patients with digestive system disorders (Crohn's disease, celiac disease), patients after digestive system surgery
10-30% of the elderly produce less gastric acid. As a result, it is no longer possible for them to separate B12 from proteins in their food. However, the uptake of the free B12 form from supplements or fortified foods is still possible.
Ovo-Lacto vegetarians and vegans cannot meet their daily B12 needs through food. In the long run, this depletes their liver storage. To prevent a shortage, they should take supplements regularly to replenish them. Regular blood checks by a doctor are also important.
Since B12 reaches the baby via the placenta during pregnancy. This is why mothers with a vegetarian or vegan diet should supplement B12 in order for their child to develop normally.
What does a deficiency mean for me?
A B12 deficiency can have different effects depending on its severity - from mild fatigue to severe neurological impairment and nerve damage. Other deficiency symptoms include Pernicious anemia and psychiatric disorders such as memory disorders, depression, irritability or dementia,.
B12 deficiency is difficult to assess because our liver has a huge b12 storage. We only need about 2.4 µg of cobalamin per day, but our stocks in the liver are between 2,000-4,000 µg.
This was vital for the survival of our ancestors, as it allowed us to live without meat (no hunting, etc.) for longer periods of time.
Starting on the day you stop consuming animal products the 4 phases of B12 deficiency begin - until your storages are fully depleted. Generally, you wouldn’t feel any symptoms in the early phases of deficiency. But as soon as your status reaches clinical deficiency, your condition might already be considered critical.
4 Phases of B12-deficiency
- Decrease of holotranscobalamin in the blood
- Decrease of cobalamin in cells
- Biochemical deficiency: DNA synthesis slower, more homocysteine and methylmalonate in blood
- Clinical deficiency: anemia
Therefore, the rule of thumb is: If you belong to a B12 risk group, you should regularly have your status checked by blood tests. This is the only way to detect the deficiency as early as possible and simply compensate for it.
Beware of too much folic acid!
A high folic acid intake can mask a vitamin B12 deficiency until it has serious consequences. Therefore, folic acid intake from fortified foods or supplements should be limited to 1,000 µg per day.
Compensating for a B12 deficiency
If there is an acute deficiency, B12 injections are usually prescribed.
However, oral B12 injections can also compensate for a deficiency. In the course of a cure to compensate for a deficiency, first 2,000 µg daily, then 1,000 µg daily, then weekly and finally, 1,000 µg monthly should be taken.
Liver storage filled in this way can then supply the body over several months with small daily doses of B12. This should be repeated several times a year, especially for vegans and elderly people.
In order to maintain your level you can also take:
- a dose of 2000 µg (food supplementation) weekly
- OR a dose of 3 µg (fortified food) two to three times a week
- OR 10 µg via dietary supplements daily .
In general, you don’t have to be afraid of overdosing b12. So far, no maximum daily dose has been set, as no side effects of a very high dose have been observed.
Don’t neglect B12, vegetarians!
Many people who opt for a predominantly vegetable or even vegan diet do not make sure they will be sufficiently supplied with B12 during the months and years that follow.
This is a big problem because a B12 deficiency starts showing symptoms after years of B12 intake stop. Sometimes the delay of symptoms can take up to 10 years. Once they occur, it‘s already too late, since a deficiency can lead to nerve damage and other severe implications.
What is also dangerous: Especially in the vegan community, B12 is known. However, its role is sometimes played down massively or miraculous plant sources, such as tempeh or algae, are praised without really containing B12.
Remember: bioactive, sufficient B12 is found exclusively in meat, fish and animal products such as milk and eggs or in food supplements.
B12 is originally produced by microorganisms in the soil and digestive system of animals. It can therefore also be produced in a vegan way by these microorganisms.
If you’re a vegetarian or vegan
Start reading labels! Some Cereal or nutritional yeast products, you use, might already be fortified with B12. Enriched foods are great options to cover your daily needs.
If you didn’t pay much attention to your B12 intake in the past, you can still restore your liver storage with high-dose dietary supplements.
Does liposomal formulation of B12 make sense?
The absorption mechanism of B12 from food is complicated.
B12 from food is usually bound to proteins and must first be cleaved from them. This happens in the stomach through acid and enzymes.
The free B12 now binds to Haptocorrine for further transport. In the small intestine, this compound is dissolved again and B12 binds to the intrinsic factor, which also mediates uptake.
About 56% of a 1 µg dose of B12 is absorbed in the intestine. If the amount of B12 to be absorbed increases, the uptake percentage continues to decrease because the intrinsic factor is not sufficient for this amount.
If a dose of a dietary supplement contains 500 µg, only 10 µg of it effectively crosses the intestinal barrier – provided that the intestine is healthy. If the intestine is not healthy, B12 is usually injected intramuscularly to make it easier to compensate for an acute deficiency.
However, liposomal B12 can also bring free cobalamin into the bloodstream efficiently. Here, the passive uptake of phospholipids can bypass the controlled transport by the intrinsic factor.
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 Stephen Walsh and other members from the International Vegetarian Union science group (IVU-SCI) (2001): What Every Vegan Should Know about Vitamin B12: An Open Letter from Health Professionals and Vegan Organizations; https://veganhealth.org/explanation-of-vitamin-b12-recommendations/
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 Carmel R. How I treat cobalamin (vitamin B12) deficiency. Blood.2008;112:2214-21.