commended daily intake of vitamin D for an adult is 400 or 600 IU depending on the country
This assumes that the RDA that those organization publish are trustworthy. You have other organization like the Encodrine society that recommend an order of magnitude more vitamin D.
If the RDA of 400 or 600 IU would be sensible you also could solve it by being a lot in the sun once every two weeks.
This assumes that the RDA that those organization publish are trustworthy. You have other organization like the Encodrine society that recommend an order of magnitude more vitamin D.
If the RDA of 400 or 600 IU would be sensible you also could solve it by being a lot in the sun once every two weeks.