#NEWINSCIENCE: DOES SUNSCREEN USE LEAD TO VITAMIN D3 DEFICIENCY?
Sunscreen use can prevent the development of skin cancer, but does it also lead to vitamin D deficiency?
Increasing evidence suggests that vitamin D deficiency has enormous consequences for human health. Some of which include muscle weakness, many types of cancer (breast, colon, etc), and neurocognitive diseases. In most living conditions, 90% of the human body's need in Vitamin D is synthesized in the skin through the action of solar or artificial UVB radiation, only a small amount of vitamin D is taken in through food. Yes, we get most of our vitamin D by exposing ourselves to the sun. We have always been advised to apply sunscreen to prevent skin cancer and other forms of sun damage, but by doing so, are we actually exposing ourselves to a whole host of other health problems associated with Vitamin D deficiency?
There definitely has been a long lasting concern that sunscreen application can result in vitamin D deficiency. The vitamin D3 precursor is converted by UVB radiation to previtamin D3 in our skin. The previtamin D3 is then isomerized to vitamin D3 before being transported through the blood circulation to reach internal organs.
The good news is sunscreen use is likely to have minimal impact on vitamin D status. Controlled clinical studies have shown that sunscreen application did not affect the level of serum vitamin D3.
One possible explanation for this would be that the participants might not have applied enough sunscreen. However, this does not seem to be the case. A holiday study in Tenerife during a week of very high UV index reported that optimal SPF15 sunscreen use inhibited UVB-induced sunburn, but still enabled considerable vitamin D production. Thus optimal UVA+B protection does NOT compromise vitamin D synthesis! In support of these findings, other studies looking at SPF >15 also reported no association between high SPF sunscreen use and vitamin D deficiency. In fact, some studies reported a positive link between sunscreen use and vitamin D3 levels, probably because sunscreen use may have increased the time spent outdoors and therefore sun exposure.
In conclusion, research to date seems to suggest that the doses of UVB rays required for vitamin D3 biosynthesis are very low. As a result, typical sunscreen use is unlikely to lead to vitamin D deficiency. Other photoprotection behaviours, such as protective clothing and shades, may have more prominent impact on the level of vitamin D3.
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Passeron et al (2019) DOI: 10.1111/bjd.17992
Young et al. (2019). DOI: 10.1111/bjd.17888
Wolf (2019). DOI: 10.1111/bjd.18430