We've had some fantastically sunny spring weather recently and while summer holiday getaways are no longer on anyone's agenda we have some more sun filled months coming up (hopefully). Therefore minds may be turning toward stocking up on sunscreen.
Sun exposure is vital for vitamin D absorption
Protecting our skin sufficiently against sun damage must be a top priority of course but we are also becoming more and more aware of the importance of skin exposure to the sun in order to keep our body's vitamin D levels at an optimum. It makes sense that some people are worried that the ability of sunscreen to block harmful UVA and UVB rays may also stop absorption of vitamin D.
Does sunscreen stop vitamin D absorption?
You're not alone if you're unsure what to do for the best when it comes to applying sunscreen full stop - you may think you don't need to wear SPF if you're mostly indoors, and that there is enough protection provided by your moisturiser or foundation. Both, in fact, are commonly held misconceptions and adding to the confusion is the question of whether sunscreen stops vitamin D absorption.
The thinking has previously been that high SPF not only prevents UV rays from damaging the skin, but it also prevents the absorption of vitamin D from sunlight. However this research comes, in the main, from experimental studies using artificial light sources. The evidence from field trials and observational studies using natural sunlight suggests otherwise.
A study conducted by King's College London divided participants into four groups. Three of those groups holidayed to sunny Spain. The first group included 20 participants whom received a broad spectrum sunscreen (SF15) providing a balance of UVA and UVB protection. The second group included 20 individuals whom received a non-broad spectrum sunscreen which also had an SPF 15 but with low UVA protection. The third group included 22 participants whom used their own sunscreen with no instructions on how to apply it. The control group did not go on the trip and remained in Poland.
The participants had their blood tested 24hrs before and 48hrs after they returned from holiday. The study found SPF 15 sunscreens applied at sufficient thickness to prevent sunburn allowed a "highly significant" improvement of Vitamin D levels. 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."
Another 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, which were conducted using artificial light sources in a lab setting, support previous theories that sunscreen use may affect Vitamin D. However they stated the evidence from field trials and observational studies, which were conducted using natural sunlight, suggests that the risk is low.
Holly Barber, of the British Association of Dermatologists says:
"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."
So in summary
There is also advice circulating from experts that recommends that we all we need to do to keep out bodies well supplied with vitamin D is to expose our unprotected skin to the sun for around 15 minutes per day. But why even do that if you don't need to?
Keep your skin well protected by applying a sun cream with an SPF of at least 30 (the British Association of Dermatologists recommend always using a minimum of SPF 30, which blocks 97% of UVB), don your sun glasses and get out an enjoy the fresh air and sunshine!
If you're worried you're low in vitamin D it might be an idea to include more oily fish, dairy, eggs and fortified foods in your daily diet as well as considering a good quality supplement to support your nutrition. Government guidelines now recommend everybody take a daily vitamin D supplement of 400IU to support good health.
A healthy balanced diet is the best way to consume all the nutrients we need. Sometimes however this isn't possible and then supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying any supplements or herbal medicines.