Several studies have suggested that it may contribute to a lack of the mineral’s production, but now three separate studies have concluded that its use has no impact on vitamin D levels in most people.
Vitamin D helps regulate helps regulate the amount of calcium and phosphate in the body, theNHSstates.
The body creates it in response to ultraviolet radiation (UVR) from sunlight. However, UVR is a major cause of skin cancer, which is one of the most common cancers in the world.
To research the impact of sunscreen on Vitamin D production, one study conducted by researchers from King’s College London, split participants into four groups.
Three of the groups went on a week-long holiday toTenerife, Spain which has a very high UV index.
During the trip, 20 participants received a broad spectrum sunscreen – which provides a balance of UVA and UVB protection – with a Sun Protection Factor (SPF) of 15, which offered UVB protection and a high UVA protection.
Meanwhile, a further 20 individuals received a non-broad spectrum sunscreen which also had an SPF 15 but with low UVA protection.
The two groups were told how to use their sunscreens correctly in order to achieve the labelled SPF.
In a third group, 22 participants used their own sunscreen with no instructions on how to apply it.
Blood samples were taken from all participants 24 hours before and up to 48 hours after the holiday.
Meanwhile, a control group of 17 people did not go on the trip and remained in Poland.
The study found that SPF 15 sunscreens applied at sufficient thickness to prevent sunburn allowed a “highly significant” improvement of Vitamin D levels.
Moreover, the broad spectrum sunscreen also enabled higher Vitamin D synthesis than a low UVA protective sunscreen. This is believed to have happened because the former may transmit slightly more UVB than the latter.
Lead author of the study Professor Antony Young, of King’s College London, said of the study: “Sunscreens can prevent sunburn and skin cancer, but there has been a lot of uncertainty about the effects of sunscreens on Vitamin D. Our study, during a week of perfect weather in Tenerife, showed that sunscreens, even when used optimally to prevent sunburn, allowed excellent vitamin D synthesis.”
A second study reviewed 75 published experimental studies, field trials, and observational studies published between 1970 and 2017 which researched the effect of sunscreen on Vitamin D production.
The study’s researchers, who come from the QIMR Berghofer Medical Research Institute in Australia and the Australian National University, found that the experimental studies (conducted using artificial light sources in a lab setting) support previous theories that sunscreen use may affect Vitamin D.
However, they said that the evidence from field trials and observational studies – which were conducted using natural sunlight – suggests that the risk is low.
The latter which reported a link between Vitamin D levels and sunscreen application most commonly found a positive relationship.
Holly Barber, of theBritish Association of Dermatologists, added that the studies’ results are “really encouraging”.
“The risk of Vitamin D deficiency from sunscreen has been found to be low, and therefore is unlikely to outweigh the benefits of sunscreen for skin cancer prevention,” she said.
She added: “Further research is required on SPF 30 and higher sunscreen, as this is what we recommend people use for optimal protection in real-life situations. People with dark skin types are at a higher risk of Vitamin D deficiency, and lower risk of skin cancer, so further research is also required to see how these findings translate to people with dark skin types.”
The findings of the studies, which are due to be published in theBritish Journal of Dermatology(BJD), are supported by a systematic review of 75 papers on sunscreen and Vitamin D which were also published recently by the journal.