A new study by UK researchers claims that the use of sunscreen on sunny days doesn't stop the body from producing vitamin D.
Skin exposure to sunlight is the primary source of vitamin D
Vitamin D is made by the body on skin exposure to UV light, it is the primary source of vitamin D as it's nearly impossible to get enough from food sources alone. However, UV rays are also a major cause of skin cancer, which in fact is the UK's most common type of cancer.
This latest finding is thought, by health experts, to help encourage more people to protect themselves from skin cancer by debunking the idea that sunscreen leads to vitamin D deficiency.
Vitamin D deficiency is a global issue
Vitamin D deficiency is a very big problem globally and debates on how to tackle this while limiting the risk of skin cancer have been ongoing however three separate studies published by leading experts from London and Australia in the British Journal of Dermatology have concluded that the use of sunscreen does not impact on the vitamin D status in the majority of people.
Professor Antony Young, of Kings College London and lead author of the first study said:
"Sunlight is the main source of vitamin D. 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."
What the research found
In the first study, participants were allocated to four groups and then all, apart from the control group, went on holiday for a week to an area with a high UV index.
- The first group was given a broad spectrum sunscreen with a Sun Protection Factor (SPF) of 15, offering UVB protection and high UVA protection.
- A second group was given a broad spectrum sunscreen, also SPF15 but with low UVA protection.
Both these groups were told how to apply the sunscreen in order to ensure they were getting the labelled SPF.
- A third group was told to use their own sunscreen and no application instructions were given.
- The fourth group formed a control whom remained in Poland.
Samples of blood were taken from the participants 24 hours before the holiday and then 24-48 hours after they returned.
The results showed that SPF sunscreens applied at sufficient thickness to minimise 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 thought to be because the former transmits more UVB than the latter.
Those that used their own sunscreens also achieved significant vitamin D synthesis but they all got sunburn. And this was almost certainly down to the fact they did not apply the sunscreen correctly.
Holly Barber, of the British Association of Dermatologists, said:
"The ability to achieve adequate protection from the sun to avoid sunburn, a risk factor of skin cancer, whilst not impacting vitamin D production is 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."
"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."
NHS advice on vitamin D supplementation
The advice from Public Health England is that adults and children over the age of one should consider taking a daily supplement containing 10mcg of vitamin D, particularly during autumn and winter. People who have a higher risk of vitamin D deficiency are being advised to take a supplement all year round.
The recommendation from the NHS is that children aged one to four years should have a daily 10mcg vitamin D supplement all year round.
As a precaution, all babies under one year should have a daily 8.5-10mcg vitamin D supplement to make sure they get enough. However, babies who have more than 500ml (about a pint) of infant formula a day don't need a vitamin D supplement as formula is already fortified with it.