In my opinion we shouldn't take vitamin B12 supplements this is because vitamin B12 is found in animal products including poultry, meat, egg, fish and milk products. There is also fortified breakfast cereals, which are also a vitamin B12 source. Consequently the majority of people will cover the recommended dietary allowances.

On the other hand there are some groups such as older adults, vegetarians, individuals with gastrointestinal disorders, individuals who have had gastrointestinal surgery, individuals with pernicious anemia and pregnant and lactating women who follow strict vegetarian diets and their infants,  that are at risk of vitamin B12 deficiency. In these cases and only if your doctor or healthcare provider tells you that you are low in vitamin B12, you may need to take a supplement.

However the ability of the body to absorb vitamin B12 from dietary supplements is limited by the capacity of intrinsic factor. For instance only about 10 mcg of a 500 mcg oral supplement is actually absorbed in healthy people. Except for oral dietary supplements, vitamin B12 is also available in sublingual preparations as tablets.

 A unique essential nutrient, vitamin B12 isn’t produced by plants, animals, or even fungi, instead being produced only by certain bacteria. Naturally occurring sources of Vitamin B12 are found primarily in foods of animal origin and among fortified foods of vegetarian/vegan origin. In my opinion for vegan, supplementation may be the best option. 

I agree with the above recommendations and wanted to add a little that for the vegetarian/vegan group, fermented products like the pickles is the best and probably the only source of vitamin B12 so they should include it in their diet to avoid its deficiency.

 That is very interesting that fermented products like the pickles is the best and probably the only source of vitamin B12. Thank you Faiz ul Hassan Shah.

Best regards

Beware, unfermented pickles do not contain vitamin B12 and I have never tested sauerkraut etc. The stomachs of ruminants produce B12 via the intestinal microorganisms provided there is cobalt in their grazing so B12 is in milk and other dairy products as well as in meat. Strict vegans may have low vitamin B12 concentrations but somehow often seem to get by. The consequences of lack of B12 can be severe, subacute combined degeneration of the spinal  cord, and other neurological conditions, macrocytic anaemia, skin changes and more. Our bodies are conditioned to collect and store the small amounts of B12 in our (normal) diet. intrinsic factor in the stomach attaches to B12 and delivers it to the ileum where it is absorbed and passed through the portal vein to the liver where it is stored against times of lean supply. In older people, gastric atrophy may result in lack of intrinsic factor and produce pernicious anaemia. Auto-immunity against the parietal cells which produce intrinsic factor can have the same consequence.

Enjoy a good wide diiet

The world of micronutrients still has many gaps, and the specific case of vitamin b12 is particularly complex given the clinical importance of its levels, which are low, but also high. In this sense, in complement to the debate question, I want to share with you the following manuscript detailing the aspects associated with high levels of vitamin b12.

Article Hipervitaminosis B12 una mirada desde la atención primaria