This morning the BBC news reported that everyone in the UK, over the age of one, should take a supplement of 10 micrograms of Vitamin D every day. We go outside everyday, rain or shine, so have never thought about Vitamin D supplements. We get enough sun, don't we? Do we need Vitamin D supplements?
Maybe not, according to the Scientific Advisory Committee on Nutrition (SACN)1 the current guidelines, set in 1991, are not appropriate with current lifestyles and public health advice (eg to wear sunscreen, stay out of the sun).
SACN has identified those who are most at risk. These are;
- anyone who does not spend time outdoors
- those that do but cover most of their body
- those with darker skin
Vitamin D is synthesized in the skin on exposure to sunlight. To do this you obviously need your skin exposed to the sun. Darker skins need longer exposure as they have natural protection, very fair skins may only need a few minutes. In the UK Vitamin D is not synthesised during the winter months, roughly from October to April.
This made me ask myself many questions and I searched the internet for answers. I hope these answer any questions you have too
How much sunlight do I need?
It is not possible to make any recommendations regarding the amount of sunlight exposure that would be required during the summer..... winter because of the number and complexity of factors that affect endogenous vitamin D productionThat didn't help much. Do I need 5 minutes or 5 hours?
What happens if I use sunscreen?
SACN conclude that most of us do not apply sunscreen to all our exposed skin or at the recommended concentration so in controlled situations it did significantly reduce the synthesis of Vitamin D but not so much in normal usage. So if I apply sunscreen properly then I probably need supplements.
Is it better to burn or to be lacking in Vitamin D?
Fairer skin synthesises Vitamin D faster than darker skin, this also fits in with burning so in theory you should be able to get enough Vitamin D without burning. The problem is that sunscreen should be put on 20 minutes or so before being exposed to the sun. I just do not think I would be good enough to sit in the sun for 10 minutes, come in, put sunscreen on, wait 20 minutes and then go out again. What a faff.
Can I get enough in food?
The report thinks not. It states that
S.42 Since it is difficult to achieve the RNI/Safe Intake from natural food sources alone, it is recommended that the Government gives consideration to strategies for the UK population to achieve the RNI of 10 µg/dSo eating lots of oily fish, meat and fortified foods will not be enough on their own.
What are the effects of too much Vitamin D?
Too much Vitamin D can lead to too much calcium in the blood but levels would have to be very high.
SACN report that it is not possible to overdose on Vitamin D in the UK through food and sunlight. NHS choices recommends that 10 micrograms a day will not lead to overdosing and recommends not taking more than 100 micrograms a day.
I already take supplementary Vitamin D in the winter as it helps with my SAD (Seasonal Affective Disorder) and I have had no ill effects only good ones. I probably won't take supplements in the summer as we spend a lot of time outside but I will make sure that some of my skin is uncovered to allow the sun to get to it.
What do you think?