Which Vitamin D are they talking about?
D1?
D2?
D3? (from sunshine)
D4?
Just from general reading....D3 is better absorbed by the body. Just in general, if you sit on the patio in the spring/summer for an hour...you probably get the normal dose you require. It’s the winter months that you need that ‘extra’ boost.
While D2 (ergocalciferol) comes from plants and fortified foods and D3 (cholecalciferol) from animal products and sunlight exposure, Dr. Holick states both forms raise and maintain vitamin D levels equally.