Vitamin B (VEET-ah-meen BAY) is good connections (gute Beziehungen) to influential people, an expression that came out of World War II and food rationing. Vitamin B2 (BAY-tsvye) is even better connections.
I also found some interesting historical information about it as well:
East Germany had a command economy, in which virtually all decisions were made by the governing communist party, the Socialist Unity Party (SED). The system of planning was inflexible and eventually caused ruinous economic conditions. Power, influence, and personal connections (Beziehungen, or “vitamin B”) drove economic decisions, and all groups, including trade unions, were expected to collaborate to achieve the SED's economic objectives.
I need more Vitamin B, for sure.