Many of the great historical cultures had one sacred food which they relied on to ensure strong mind, body, and spirit: Fermented fish/fish liver oil.
The Mighty Roman Soldier was given a daily ration of fermented fish oil. The Stoic Scandinavian Viking had a drum of fermenting cod livers outside the door of his home. Grandma always had a bottle of cod liver oil in the back cupboard.
Nutrient amounts, including vitamins A and D, for our fermented oils vary widely depending on methodology, lab and batch. Current science struggles to answer the questions we have on our sacred fermented foods. There are many naturally occurring metabolites and co-factors that make the issue of measuring natural nutrients difficult in the fermented oils. We do know that historical cultures liberally consumed these sacred foods to great benefit without today’s standardization of knowledge.