In reply to iksander:
> (In reply to Ciro)
> [...]
>
> >build up a natural tan for resistance to the sun rather than using sunscreen.
>
> WRONG
>
> I used to think this too, before I went to Oz where they know a thing or two about sun and skin damage.
>
> "A tan is not a sign of good health or wellbeing, despite many Australians referring to a “healthy tan”. Fifty per cent of Australian adults still hold the misguided belief that a tan looks healthy.
>
> Tanning is a sign that you have been exposed to enough UV radiation (from the sun or solarium) to damage your skin. This will eventually cause loss of elasticity (wrinkles), sagging, yellowish discolouration and even brown patches to appear on your skin. Worst of all, it increases your risk of skin cancer.
>
> A tan will offer limited protection from sunburn, but usually no more than SPF4, depending on your skin type. It does not protect from DNA damage, which can lead to skin cancer." - Cancer Council Australia
>
>
http://www.cancer.org.au/cancersmartlifestyle/SunSmart/Whatputsyouatrisk.ht...
Unprotected skin would burn in about 15 minutes in the summer in Perth WA, SP4 four would therefore give you about an hour. When I lived there, with a tan I would be out in the sun all day without burning, so "A tan will offer limited protection from sunburn, but usually no more than SPF4, depending on your skin type." is clearly nonsense, no matter what authority it comes from.
I don't mind developing wrinkles, sagging, yellowish discolouration or brown patches of skin.
I'm not particularly keen on gettin skin cancer, but I'm even less keen on cancer of the colon, which is a lot more deadly (and in my case there is a family history) and which has been linked to vitamin D defficiency.
We seem to need more than our dietary intake of vitamin D for good health, and we evolved to generate vitamin D from sun exposure, so blocking off all the sun doesn't sound like a good idea to me. Again, that's just my opinion - and as such it's valid, whether you want to shout wrong or not.