
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.
Authors

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.
Subscription offer
Subscribe and try your first 3 issues for just £5. After your introductory period you will pay just £22.99 every 6 issues by Direct Debit. Receive every issue delivered direct to your door with FREE UK delivery.