Vitamin B12: What are the benefits and what to do if you have a deficiency?

Vitamin B12 is a well-known vitamin, and many people are deficient in it. But what exactly is vitamin B12? What should you do if you have a deficiency, and which foods can you get it from?

In this article you will learn all about it

Vitamin B12, also known as cobalamin, is an essential, water-soluble vitamin. It plays a key role in the nervous system, metabolism, red blood cell production, and cell division.

This vitamin is found exclusively in animal products such as meat, fish, dairy, and eggs. Therefore, it's especially important for vegans to supplement their diet with supplements.

Active forms of vitamin B12, such as methylcobalamin and adenosylcobalamin, are recommended for supplement use.

Vitamin B12 plays a crucial role in various bodily functions.

Thus it contributes to:

1. The formation of red blood cells
2. A normal cell division
3. A normal energy metabolism
4. The normal functioning of the immune system
5. Homocysteine ​​metabolism*

In addition, vitamin B12 is also good for:

1. The memory
2. The state of mind
3. Fatigue
4. The nervous system

(*) Homocysteine ​​is converted in the body into methionine and cysteine, two important amino acids your body needs to make proteins. For this conversion, your body needs, among other things, B12.

The natural forms of vitamin B12 found in foods are:

1. Methylcobalamin
2. Hydroxycobalamin
3. S-adenosylcobalamin

Enriched products and B12 supplements use other forms of the vitamin. If you're considering buying vitamin B12 as a supplement, be sure to check the form of the vitamin.

The types of vitamin B12 differ primarily in their chemical structure . But the most important difference is that there are active and inactive forms :

Can be used directly by the body for essential processes. This makes them more efficient and faster-acting compared to inactive forms.

Examples:

1. Methylcobalamin - Highly effective because it's already an active form of vitamin B12 that the body can easily use. It's well absorbed.
2. Adenosylcobalamin – Also an active form of B12, particularly important for energy production and mitochondrial function. It can be helpful for people experiencing specific energy issues.

Must first be converted before they can perform their functions.

Examples:

1. Cyanocobalamin - Although less immediately active than the other forms, it is often used because of its stability and lower cost.
2. Hydroxycobalamin - Often used in injectable forms of B12 supplementation because of its longer duration of action in the body.

For best results, choose the active forms methylcobalamin or adenosylcobalamin.

Adults need 2.8 mcg of vitamin B12 daily , according to the Health Council. This recommended daily amount is the same for men and women.

An adjusted RDA applies to children, pregnant women and women who are breastfeeding:

Vitamin B12 deficiency can be caused by insufficient intake, limited absorption into the body and reduced absorption.

Although B12 is present in many different (animal) foods, not only vegans and the elderly are at risk for a deficiency. How well your body can absorb vitamin B12 plays a crucial role and can vary significantly depending on the food source.

This means that your body cannot always utilize all the B12 from food, even if you regularly consume animal products.

A vitamin B12 deficiency can lead to a form of anemia called macrocytic anemia.

You can notice this by these symptoms:

1. Fatigue
2. Dizziness
3. Palpitations

In addition, neurological complaints may occur such as:

1. Tingling in the fingers
2. Memory loss
3. Coordination disorders

Your body can also store a (limited) amount of B12 . So you can get too little B12 and still rely on your reserves for a while.

If you experience any of the above symptoms, I recommend that you ask your doctor for a blood test.

This is especially true if you:

1. Following a restrictive diet, such as veganism
2. Are older than 60 years
3. Are pregnant or breastfeeding
4. Have a medical condition that can lower B12 levels (such as Crohn's disease, gluten allergy, etc.)
5. Taking medications that deplete B12

If a vitamin B12 deficiency has been confirmed by a blood test, I recommend investigating the cause.

If you don't have any gastrointestinal problems, you may not be getting enough B12:

1. Eat animal products - Such as meat, fish, eggs, dairy and other animal products as natural sources of B12.
2. Choose fermented foods - Fermented products like tempeh, miso, and sauerkraut may contain small amounts of B12. This is certainly an option if you're following a vegan diet. Note, however: This form may be less well absorbed by your body than B12 from animal sources!
3. Consider B12 supplements - If it is difficult to get enough B12 from food, consult with an expert in the field about appropriate B12 supplements.
4. Monitor your B12 levels - Have your vitamin B12 levels checked regularly, especially if you are at risk for a deficiency or suspect you may have a deficiency.

If the cause turns out to be reduced absorption due to problems in your stomach and/or intestines, make an action plan with your doctor.

Stomach acid helps digest and release vitamin B12 from food. In addition, intrinsic factor (IF) is produced in the stomach lining, essential for the absorption of B12 in the small intestine.

Without sufficient stomach acid or intrinsic factor, vitamin B12 cannot be properly absorbed, which can lead to a B12 deficiency despite adequate dietary intake.

B12 sprays and injections can be a way to bypass the intrinsic factor through the normal digestive pathway. This can be helpful for people with digestive problems.

In both humans and animals, vitamin B12 is produced in the gastrointestinal tract by certain bacteria. It is therefore primarily found in animal products such as meat, fish, eggs, and dairy products.

Plant foods are generally low in vitamin B12, except for some fermented foods (more on this later).

Vitamin B12 absorption varies by dietary source, with fish, meat, and dairy generally offering higher bioavailability.(2)

These foods are high in B12:

Natural sources of vitamin B12 are limited in plant foods, as B12 is mainly found in animal products.

It's therefore important for vegetarians, and especially vegans, to be aware of alternative sources. Some fermented foods , such as tofu and tempeh, may contain small amounts of B12.

In addition, there are algae and certain mushrooms that can serve as sources of B12.

I mention these sources with some caution, because the bioavailability and amounts of B12 in these sources have not yet been sufficiently investigated.(3)

With a long history in various cultures, fermented plants continue to evolve and are considered the food of the future. That's why I have high hopes for this area!

Sources used

1. Nutrition Center. (nd-c). Vitamin B12 (cobalamin) . https://www.voedingscentrum.nl/encyclopedie/vitamine-b12
2. Lavriša, Ž., Hristov, H., Hribar, M., Žmitek, K., Kušar, A., Seljak, B.K., Gregorič, M., Blaznik, U., Gregorič, N., Zaletel, K., Oblak, A., Osredkar, J., & Pravst, I. (2022). Dietary Intake and Status of Vitamin B12 in Slovenian Population. Nutrients, 14(2), 334. https://doi.org/10.3390/nu14020334
3. Reissig, G. N., De Carvalho Oliveira, T. F., Bragança, G. C. M., Da Silva Rodrigues, R., & Da Fonseca Barbosa, F. (2023). Fermented vegetables and fruits as vitamin B12 sources: An overview. International Food Research Journal, 30(5), 1093–1104. https://doi.org/10.47836/ifrj.30.5.02