As the long, gorgeous summer continues, and the POTENTIAL for vitamin D production is maintained, you might be wondering just how much vitamin D might I have at the end of the summer?
Well, according to some new research, not as much as you might think.
Here is the issue:
In the UK, the sun is only strong enough to make vitamin D from around 11 AM until 4 PM.
A simple rule of thumb for patients is:
- If your shadow is shorter than you are, you have the potential to make vitamin D
- If your shadow is longer than you, you cannot make any vitamin D
However, as well as the sun being strong enough, you must have at least 25% of your skin, if not more, out.
With fully exposed skin in laboratory controlled conditions where the whole body is turned slightly pink (though this isn’t recommended as it indicates burning), you can generate between 10 and 20,000 IU’s (or 125-250 mcg).
See below. 1MED is full-body pinkness.
So, in reality, we must recognize that most patients do not strip down to very little for extended periods of time whenever there is strong sun indicated by a UV index of three or above, which will only occur when your shadow is shorter than you are.
They MIGHT get lower arms out, possibly lower legs too (shorts and t-shirt).
Then we have to address the topic of the new research.
– Using sun lotion with a high SPF, blocks production of vitamin D and may lead to more deficiencies.
Now this is hardly a surprise, given that the entire point of sun lotion is to block UVB. The number on the front of the bottle is how strong/how well the lotion blocks UVB.
We have clear lab data on this:
The newer research followed a group of 639 Australians and followed them over a full year.
Half were told to use SPF 50 when the UV index was over 3. The other half were told to use sunscreen at their discretion.
That, for me, is an issue as many people, especially those in very sunny climates like Australia, will routinely use it, so leaving it to “discretion” is potentially an issue.
Regardless, at the end of the study they found:
“Routinely applying high SPF sunscreen results in lower 25(OH)D concentrations than would be seen with discretionary sun- screen use. Regular sunscreen users may need vitamin D supplementation.”
and conclude:
“Our findings provide evidence that daily use of high SPF sunscreen over 1 year increases the risk of vitamin D deficiency. As a result, while we recommend continued regular sunscreen use, vitamin D testing and/or supplementation may be needed.”
In reality, this is news, but it does confirm the underlying issues with SPF lotions.
So, if in doubt, two things to remember:
- 3 key risk factors for deficiency all year round
And, if needed, don’t guess, TEST.
https://optimaltesting.co.uk/product/vit-d/
And remember the deficiency/insufficiency rates:
Remember, we want to mimic living in a sunny climate year round, where you get UVB all year and would not need vitamin D supplements.
For that we need to aim for the 100’s nmol/L.
The best way to get vitamin D naturally is to expose your skin to UVB >3 (11AM – 4 pm), and with as much skin as you can and then stop at approximately 1/3 to 1/2 the time it would take to go pink.
Some people really struggle with the idea that you should not use SPF50 the whole time, especially with their children, if so just supplement.
Remember we have a plethora of infographics and patient education materials to use.
All available free of charge to be sent to your clinic, and online via this link:
https://drive.google.com/drive/folders/1TnQhM6jRZLDH0ehwEUuE74tNdGtHZJzE
And the patient education video for the vitamin D supplements also talks about all of this.
Just click the SHARE VIDEOS tab once logged in:
And then click the video you want:
At the bottom, it autopopulates your name and address, and you just add the patient’s email, and it is delivered.
Click it:
