> may be they had better ample sources of those vitamins other than
> caribou
> liver ( fishes liver,  seal liver ?)

I recall reading of early French explorers who had considerable trouble
with scurvy in the winter months, until some local Indians taught them
to use some kind of pine  or spruce (I forget exactly) needle to
prevent it. It wouldn't take much to clear the obvious symptoms of
scurvy, I suppose other nutrients are the same, the locals know, and
develop a tradition of eating this food in that season. Frontier people
in America used to take "spring tonics" to ward off deficiencies, made
of various wild greens.