Vitamin B12 is synthesized exclusively by bacteria and archaea, according to nutritionist Alessandra Luglio.
This biological limitation means humans cannot produce the nutrient internally, making dietary intake or supplementation critical for neurological and systemic health.
Speaking on the program "Viva Bem" on Jovem Pan News, Luglio said that cobalamin, the scientific name for vitamin B12, is found in organic soil and the intestines of animals [1]. Because animals do not produce the vitamin themselves, they acquire it through these microorganisms [1].
Luglio said that vegans must supplement their diets because they avoid the animal-based sources where these bacteria concentrate the vitamin [1]. However, the need for supplementation is not limited to those on plant-based diets. The nutritionist said that omnivores can also develop deficiencies, necessitating professional medical guidance to determine if supplements are required [1].
Deficiency in this nutrient can be widespread regardless of diet. One study from Tufts University involving individuals between the ages of 26 and 83 found that 40% [4] of participants had a vitamin B12 deficiency.
The production of the vitamin depends entirely on microorganisms, and the liver typically maintains a safety reserve of the nutrient to protect the body during periods of low intake [3]. Despite this reserve, Luglio said that monitoring levels is essential for maintaining long-term health [1].
“Vitamin B12 is synthesized exclusively by bacteria and archaea.”
The fact that B12 is a bacterial byproduct rather than an animal product challenges the common perception that it is only a concern for vegans. Because deficiency can affect 40% of a broad adult population, it suggests that absorption issues or environmental factors may be as significant as dietary choices in public health.
