Vitamin D

Sunscreen can reduce the sun’s adverse effects, but there are concerns that it might inhibit the body’s production of vitamin D. In a newBritish Journal of Dermatology study, however, investigators record an increase of vitamin D in participants during a week of cloudless weather, with very high UV index, even when sunscreens were usedproperly and prevented sunburn.

Incidence of melanoma

Solar UVR is responsible for an increasing incidence of melanoma, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), especially in white skinned populations, for which sunburn is a risk factor. Much public health effort has been spent advising those at risk to minimize solar UVR exposure.
The use of sunscreens is one approach and there is evidence ,from randomize trials,that sunscreens inhibit SCC, actinic keratosis (AK; a surrogate risk marker for SCC) and melanoma. The role of sunscreens in melanoma prevention has also been supported by large population based studies. However, sunscreen use may impact vitamin D status. Reviews report that different studies reach different conclusions.

The sun protection factor (SPF) of a sunscreen is a quantitative measure of its ability to inhibit erythema. Regulatory authorities specify many requirements for SPF determination, one of which is an application thickness of 2mg/cm. However, people typically apply much less, e.g. 0.8mg/cm, with a commensurate reduction in SPF.

Missing facial coverage

Furthermore, application is often patchy with, for example, missing facial coverage. Additionally, people use sunscreens to prolong their intentional solar exposure time. There is a consensus that typical sub optimal sunscreen use is likely to have a limited effect on vitamin D production (Passeron et al under review, Neale et al under review).
Sunlight contains UVA and UVB radiation, and the latter is essential for vitamin D synthesis.Two sunscreens with the same SPF were compare. Sunscreen with a high UVA protection factor enable significantly higher vitamin D synthesis; so than a low UVA protection factor sunscreen; so likely because it allows more UVB transmission.The findings indicate that the benefits of sunscreen; hence use can be obtaine without compromising vitamin D levels.
“Sunlight is the main source of vitamin D. Sunscreens can prevent sunburn and skin cancer; but there has been a lot of uncertainty about the effects of sunscreens on vitamin D,” said lead author Prof. Antony Young, of King’s College London. Our study, during a week of perfect weather in Tenerife, show that sunscreens; so even when use optimally to prevent sunburn, allowed excellent vitamin D synthesis.