I recommend a teaspoon to a table spoon of Norwegian cod liver oil in the winter for folks living up north.
I already take two caplets of cod liver oil daily (because I can't stand the taste of cod liver oil).
I just checked this out, and each caplet contains 135 IU of vitamin D. I also take a daily caplet of vitamin D, 400 IU, along with calcium citrate.
The moral of the story seems to be that I should add one more caplet of vitamin D. That would make a total of 1070 IU daily, which is evidently enough.
I agree with you, though. Cod liver oil is an excellent supplement.