Published by

Rosie on 7th August 2020

Keeping your body in healthy working order can sometimes feel like a bit of a minefield. On the one hand, we’re told that most people in the UK are vitamin D deficient and should go out into direct sunlight daily to absorb what they need. On the other hand, we’re warned to protect our skin from burning and about the risk of skin cancer.  

So… what are the rules?

Vitamin D is an essential nutrient that your body produces in order to support bone health. The best source of vitamin D is sunshine: when the cholesterol in your skin cells comes into contact with the sun’s ultraviolet B (UVB) rays, it is converted into vitamin D. Your body can make much more vitamin D through this process than it can by absorbing it through food. 

However, Cancer Research warns that spending time out in the sunshine without any protection could lead to significant skin damage. According to their website, “Getting sunburn, just once every 2 years, can triple your risk of melanoma skin cancer.”

In this article we will answer the most frequently asked questions about how to safely get enough vitamin D from the sun without harming your skin. 

How Long Should You Spend in the Sun?

In brief: It depends on a number of factors, including the time of the year, the time of the day and the colour of your skin. 

In depth: Precise numbers are often bandied about in answer to this question (just a small amount of online research has pulled up guidelines of 15 minutes, 20 minutes and 30 minutes). However, the NHS makes it clear that there is no official time limit:

Let’s take a closer look at the factors:

1. Time of the year

In the UK there is unlikely to be enough sunshine outside of the summer months (late March to the end of September) for your body to make enough vitamin D. Since 2016 the government has recommended that the majority of the UK population take a vitamin D supplement in winter to make up the shortfall.

2. Time of the day 

When the sun is shining in summer, most people can get the daily dose of vitamin D that they need by being outside “for short periods” between 11am and 3pm with their lower legs, forearms and hands uncovered. However, this period when the sun’s UV rays are strongest also requires sun protection to prevent burning, which means that most people will need to cover up with loose clothes and a hat and apply sunscreen once they have absorbed enough vitamin D.  

3. Proximity to the equator 

Don’t be caught out on holiday. If you travel to a sunny destination close to the equator, be aware that the sun’s rays will be stronger all year round. You will need to protect yourself from sunburn more quickly (and more frequently) than you would at home.

4. Colour of your skin 

People with darker skin, such as those of African, African-Caribbean or South Asian heritage, have a higher amount of melanin in their skin than people with light skin. This provides better protection from harmful UV rays, but also prevents the production of vitamin D. Those with darker skin are more likely to need longer exposure to the sun without protection to get enough vitamin D. Conversely, Caucasians with light or fair skin, freckles or moles are more likely to need sun protection sooner.

Note: There has been a disproportionate amount of research into sun exposure on light-coloured skin rather than dark-coloured skin.  

“Well that all sounds frustratingly wishy-washy”, I hear you cry. 

It’s true: I haven’t really answered your question, because it’s dependent on so many different variables. However, you might be interested in this small 2018 study on the vitamin D/sunburn threshold. The lead researcher, Professor Lesley Rhodes, used the findings to come up with a formula for how much sunlight both light-skinned people and dark-skinned people would need in the UK to get enough vitamin D, working with atmospheric physicist Professor Ann Webb. 

1. Can you get vitamin D through glass?

No, you can’t. Almost all commercial glass blocks the UVB rays needed for the production of vitamin D. In order to make the most of the sun you need to get direct exposure. 

2. Does sunscreen block vitamin D?

Yes – sunscreen is designed to block harmful UV rays, including UVB. However, it’s rare for someone applying sunscreen to cover every expanse of bare skin and keep it covered for the whole of the day. So, in practice, wearing sunscreen – even factor 50 – is unlikely to have a huge effect on your vitamin D production.

3. Can you get vitamin D from sunbeds?

Although sunbeds do emit the UVB rays needed for the body to produce vitamin D, they also emit harmful UVA rays that do not contribute towards vitamin D and are linked to skin cancer. The overwhelming advice from medical experts is to stay away from sunbeds, and certainly not see them as a good source of vitamin D.  

4. Should you take vitamin D in summer?

For all the reasons listed above, this very much depends on your own circumstances. It is possible that you are not getting enough vitamin D even in the summer months – especially if you don’t go outside very often, if your skin is darker or if you are extremely sensitive to sunlight. If this is the case, you may want to take vitamin D supplements all year round.

If you have symptoms of vitamin D deficiency or you’re worried about your levels, make sure you get advice from your doctor. 

Staying Sensible in the Sunshine

If you’re looking for advice about how long to stay in the sun during the summer months, perhaps Professor Rhodes sums it up best: “While a vitamin D deficiency can be rectified by supplements, skin damage from the sun can have disastrous effects, sometimes years down the line.”  Do you have a good routine for enjoying the sun while staying safe? We’d love to hear your tips! Leave a message for our community on Facebook.