Spring is on its way, the days are getting longer, the daffodils are starting to flower and there’s now a warmth in the sun. So it’s nearly time to replace the vitamin D supplements for the real thing – sunshine!
My previous blog (Sunshine on my Shoulders – pt 1) discussed why vitamin D is so important, supplements and Vitamin D3. I also raised the inevitable questions about how to get enough of it from the sun.
As expected, it’s not one simple, easy answer, as the amount of vitamin D you get from exposing your bare skin to the sun depends on all these factors (ref: Vitamin D Council):
- The time of day – your skin produces more vitamin D if you expose it during the middle of the day.
- The amount of skin you expose – the more skin you expose, the more vitamin D you can produce.
- Where you live – the closer to the equator you live, the easier it is for you to produce vitamin D from sunlight all year round. Also you make more vitamin D at higher altitude.
- The colour of your skin – pale skins make vitamin D more quickly than darker skins.
- How old you are – as you get older, your skin has a harder time producing vitamin D.
- Environmental factors – cloud cover and pollution levels will also affect the amount of UVB getting through the atmosphere.
So let’s start with the easier questions:
Can we get our Vitamin D through a window? (ref: NHS – Live well – Vitamin D)
No. You can’t make vitamin D from sitting indoors by a sunny window because ultraviolet B (UVB) rays can’t get through & that’s what you need to make vitamin D. So unfortunately sitting in a lovely conservatory may get you warm, but it won’t help your Vitamin D levels. But you can still burn, so be careful.
Does sunscreen affect our ability to absorb Vitamin D? (ref: Vitamin D Council)
Yes. To get your vitamin D intake go out into the sun without any sunscreen. Then cover up, go under shade or use a sunscreen (UVA & UVB protection) before you burn. The question about the health safety of sunscreens is a whole separate blog that I need to write!
Now for the hardest question:
How long should we spend in the sun? (ref: NHS – Live well – Vitamin D)
Most people can make enough vitamin D from being out in the sun daily for short periods with their forearms, hands or lower legs uncovered and without sunscreen from March to October, especially from 11am to 3pm.
A ‘short period of time’ in the sun is about 10 to 15 minutes for most lighter-skinned people – and is less than the time it takes you to start going red or burn. Exposing yourself for longer is unlikely to provide any additional benefits.
People with darker skin will need to spend longer in the sun to produce the same amount of vitamin D.
How long it takes for your skin to go red or burn varies from person to person. Cancer Research UK has a useful tool where you can find out your skin type, to see when you might be at risk of burning.
In the UK, our skin isn’t able to make vitamin D from October to March, as the sunlight hasn’t got enough UVB radiation. During the winter, we get vitamin D from our body’s stores, which are built up during the summer and food sources plus you can add supplements such as cod liver oil (see my blog: Sunshine on my Shoulders – pt 1).
Here’s the ‘Shadow Rule’ to get the most vitamin D out of the sun (Ref:Save our Bones – shadow trick for vitamin D & Vitamin D Council):
The closer to midday you expose your skin, the better this angle and the more vitamin D is produced. A good rule of thumb is if your shadow is longer than you are tall, you’re not making much vitamin D. In winter, you’ll notice that your shadow is longer than you for most of the day, while in summer, your shadow is much shorter for a good part of the middle of the day
But remember, the key to avoiding skin damage such as premature aging of the skin or the dreaded melanoma, is to keep sun exposure during these times for a short duration and definitely not long enough to burn.
Do tanning beds help with producing vitamin D? (Ref: Vitamin D Council & Mercola):
Your skin can also make vitamin D if you use an indoor tanning bed. As with natural sunlight, making the vitamin D you need from a tanning bed happens within minutes. You don’t need to tan your skin, or use a tanning bed for a long time to get the vitamin D you need.
If you choose to use a tanning bed, the Vitamin D Council recommends using the same common sense you use in getting sunlight. This includes:
- Getting half the amount of exposure that it takes for your skin to turn pink.
- Using low-pressure beds that has good amount of UVB light, rather than high-intensity UVA light.
So now you know why Englishmen go out in the midday sun – to get their vitamin D!