Can you absorb vitamin D through a window?

It's a sunny day, get outside and soak up some rays!


Asked by: Steven Collins, by E-mail

You don’t absorb vitamin D from the Sun, your skin synthesises it in response to sunlight. It’s the UVB portion of the ultra-violet spectrum that’s needed.

This wavelength range is effectively blocked by glass so you can become deficient in vitamin D if you don’t go out and don’t eat enough oily fish or dairy products to compensate.

Read more:

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.