Researchers reported in the British Journal of Dermatology that when using sunscreen in concordance with what the World HealthOrganization (WHO) suggests, little to no vitamin D is produced, leading to vitamin D deficiency.
Annesofie Faurschou, M.D., Ph.D., of Bispebjerg Hospital in Copenhagen, Denmark and colleagues measured serum vitamin D levels in 37 healthy, fair skinned participants.
Sunscreen with SPF 8 was applied on 25% of the participants body with varying degree’s of thickness. The participants vitamin D levels were tested before and after exposure to UVB following sunscreen application.
The researchers found vitamin D serum levels increased exponentially with decreasing thickness of sunscreen in response to UVB exposure. Among those who had the greatest thickness of sunscreen applied, vitamin D levels did not rise significantly.
So remember, getting some sun while slathered in sunscreen prevents your body from making the D it needs.
Faurschou A, Beyer DM, Schmedes A, Bogh MK, Philipsen PA, Wulf HC. The relation between sunscreen layer thickness and vitamin D production after UVB exposure – a randomized clinical trial. British Journal of Dermatology. Apr 2012.