Vitamin D and sunshine

I am astonished that a physician has recommended ''sitting by a sunny window''
to increase Vitamin D production !!   Most all window glass blocks the UV rays
and since UV rays are needed for normal body production of Vitamin D...
hmmm!




This discussion is related to Vitamin D adverse reaction?.

[gymdandee]

While glass absorbs short wavelength ultraviolet light, it does pass 350 to 400 nanometer
ultraviolet. While this longer wavelength ultraviolet is less harmful
than the shorter wavelength variety, you can still tan or burn if you
get enough exposure. Glass is like sunscreen--it protects you pretty
well but it isn't perfect.
All you need is about 15 minutes in the sun to get your daily allowance of D.

[beatrice44]

Interesting!  But are you referencing the glass used in energy efficient windows as well?
The double-pane ones?
Fifteen minutes outside in the sun...rather than 15 minutes sitting at a sunny window?

[gymdandee]

Double Pane layer of Low-E coating  blocks 95%+ of the sun's UV rays