Optimal application of broad-spectrum sunscreens with a sun protection factor (SPF) of 15 offers protection against sunburn during a day with a high UV index. These sunscreens may also allow for increases in the synthesis and concentration of serum 25(OH)D3 (vitamin D) while still offering protection against sunburn and the risk for skin cancer. This is according to findings from a study published in the British Journal of Dermatology.
A total of 79 participants from Poland who spent a 1-week sun holiday in Tenerife, Spain, were recruited. Participants spent a week on the island with cloudless weather under a maximum UV index of 9. Group A (n=20) and group B (n=20) received approximately 50-gram tubes of daily sunscreen with an SPF of 15 and high or low UVA protection factor (UVA-PF), respectively. Each participant was asked to apply a sufficient amount of sunscreen in the morning, in the middle of the day, and in the afternoon to achieve the SPF on the label. The investigators compared groups A and B as well as groups with discretionary sunscreen use (n=22) and non-holiday groups (n=17) in terms of vitamin D concentrations at 24 to 48 hours after the holiday.
In terms of vitamin D concentrations, there was no difference between the pre- and post-holiday samples across the control and sunscreen A and B groups (P >.09). The group with discretionary sunscreen use showed the highest increase in post-holiday vitamin D concentrations (28.0±6.5; P =9×10-8) , followed by participants who applied sunscreen with a high UVA-PF (19.0±14.2; P ≤9.8×10-6) and sunscreen with a low UVA-PF (13.0±11.4; P ≤6.7×10-5). Individuals in the non-holiday group had a reduction in vitamin D of 2.5±5.6 nmol/L (P =.08).
Limitations of the study include the small sample size as well as the inclusion of only individuals from Poland who vacationed in a single location in Spain.
“Our data support the use of sunscreens to prevent adverse effects of UV radiation,” the researchers wrote, “without compromising vitamin D synthesis.”
The authors reported no relevant pharmaceutical disclosures or conflicts of interest.
Young AR, Narbutt J, Harrison GI, et al. Optimal sunscreen use, during a sun holiday with a very high ultraviolet index, allows vitamin D synthesis without sunburn [published online May 8, 2019]. Br J Dermatol. doi:10.1111/bjd.17888.