A lack of vitamin D is now one of the most commonly diagnosed vitamin deficiencies in the developed world, leading some dermatologists to question if a rise in the use of sunscreens may have something to do with this.

Solar UVB is one of the main sources of vitamin D, and deficiency can lead to symptoms such as bone pain and muscle weakness, which in turn has been linked to a heightened risk of cardiovascular death, asthma and even cancer.

One-week field study on the beach in Spain​

The research, which was sponsored by UK retailer and sunscreen manufacturer Boots Group, was led by Anthony R Young, professor of experimental photobiology at the college’s Institute of Dermatology, and took the form of a one-week field study, that exposed volunteers to the sun.

Two groups of volunteers were divided into a non-intervention group and those that applied SPF 15 sunscreen according to SPF test specifications on a beach in the Spanish island of Tenerife.

All the volunteers who joined in the study were said to have had healthy levels of vitamin D blood serum at the start of the experiment, which is recognised as being approximately 50 nmol/l.

Sunscreen helps prevent sunburn, does not inhibit vit D synthesis​

As expected, the results of the experiment showed that the use of sunscreen helped prevent sunburn in the intervention group, whereas burns were recorded in the non-intervention group.

However, the study also assessed vitamin D levels in both groups, both pre- and post-exposure, finding that, although synthesis of vitamin D was greater in the non-intervention group, both groups were deemed to have had significant increases.

The study found that on average vitamin D blood serum levels in individuals that used the sunscreen rose by approximately 16 nmol/l.

Good vitamin D synthesis is possible with sunscreen​

In the study report, Professor Young noted that from the results showed that good vitamin D synthesis is possible with proper use of sunscreens and without any burning.

“This study shows that using sunscreens in an intense UV environment still allows for significant vitamin D production without any burning of the skin,”​ said Professor Young.

“It is the first time that such a comprehensive study has been undertaken and it provides new clinical evidence on the impact sunscreen has on vitamin D synthesis.”​