Much better advice: Get out in the sun, lose the sunscreen!
There is the image of the bronzed aussie which comes from being outside without sun protection - (t) shirt, hat, sunscreen. These days in Australia it would be irresponsible to suggest that people play outside in Summer without adequate protection. Myself, I have been very badly sunburnt on two occasions (volcanic) and since endeavored not to have that happen again.
On the flip side, when it's not Summer or if you sun exposure is going to be minimal, why wear sunscreen? You need that vitamin D.
Local comment: here in Japan, it's the fashion for women to have pale skin. Plenty go around in summer with large parasols and probably lots of sunscreen. I worry about their vitamin D intake.
"Vitamin D deficiency is an unrecognized epidemic among both children and adults in the United States" http://www.ncbi.nlm.nih.gov/pubmed/15585788
For those of us who are healthy and drink plenty of milk, wearing sunscreen when we're out in the sun for a long time is a great way to stay healthy.
From the article:
""" Sensible sun exposure (usually 5-10 min of exposure of the arms and legs or the hands, arms, and face, 2 or 3 times per week) and increased dietary and supplemental vitamin D intakes are reasonable approaches to guarantee vitamin D sufficiency. """
I believe that milk contains Vitamin D2, which is has a low bioavailability. Vitamin D from your skin, created by UVB exposure from sunlight, is Vitamin D3, which has a high bioavailability.
So, it's not true to say that milk is a replacement for sunshine.
Of course, there are Vitamin D3 supplements that you could take.