The ‘wrong’ kind of sunlight

Frankly after the wind and rain I was battered with at the weekend any kind of sunshine would be welcome, but just like there is the ‘wrong’ kind of snow, there can also apparently be the ‘wrong’ kind of sun.The problem is if you are getting your sun through a window, as this way your vitamin D levels can be reduced. Let the sun shine – but not through your window if you want to get the full benefit. There are two basic forms of ultraviolet radiation from the sun: UVA, and UVB and they work differently when your body is exposed to them.

UVB is the ‘good’ guy as it forms the precursor to vitamin D in the skin, but sadly it is also the ‘bad’ guy that when overexposed leads to sunburn and skin damage but we are generally exposed to it mostly in the summer time. UVA is not so much a ‘bad guy’ as an out and out villain, giving your skin the appearance of an alligator handbag and causing skin cancer and is present throughout the year.

This is the problem; even when the sky seems overcast, UVA rays are beaming down on you, and they can pass through glass. Although UVB radiation is filtered out as it passes through the window, UVB mostly goes right through it.

We know there are many health benefits associated with sensible exposure to sunlight, but it is the vitamin D we get from exposure to UVB that we need. If you are basking in the sun in your conservatory or even sitting by a window when the sky is cloudy you are in danger of destroying vitamin D as you are exposed to UVA radiation.

This is particularly important in the winter when we seek out light and sun to cheer us up, and we are getting very little vitamin D from UVB rays. Maximise your intake of vitamin D by avoiding sitting directly by a window in the winter and getting out at every opportunity for short, safe, exposure to the sun. Why should we care about this? Vitamin D is formed from exposure to UVB rays, whereas UVA radiation actually destroys vitamin D.