Vitamin B12 (C63H88CoN14O14P; cobalamin) is unique in several ways. Only 3 micrograms per day, a tiny amount, is necessary. The body uses cobalamin to produce red blood cells.
B12 is made by many bacteria and yeasts. Eggs contain B12. In contrast, any food of plant origin, not fermented, and free of all bacteria and insects, will not contain B12. Unprocessed organic produce invariably contains trace amounts of B12.
In cultures where food is organically grown and consumed, B12 deficiencies are rare, even if no animal products are consumed. Further, the flora in a healthy gut produce B12.
The typical first symptom of B12 deficiency is chronic low energy. Prolonged deficiency causes anemia and psychological symptoms, including confusion, irritability, and paranoia.
Ingestion is not the only cause of B12 deficiency. Absorption is a problem with some people.
The right level of stomach acid is important for B12 absorption. As chronic anxiety affects digestion, it can play a role in creating a B12 deficiency.